Farmacoterapia en TVM.pdf

J Neurosurg: Spine / Volume 17 / September 2012

J Neurosurg Spine (Suppl) 17:157229, 2012

157

Despite advances in the medical, surgical, and re-habilitation management of human SCI, there is no widely accepted treatment that attenuates the complex biological processes that constitute the second-ary injury. One major category of treatment is neuropro-tection by pharmacotherapy offered in the acute and sub-

acute phases of injury and designed to protect spinal cord tissue from the severely damaging pathophysiological events that occur in the CNS after physical trauma. There have been remarkable advances in our understanding of the secondary injury events after CNS trauma in both the brain and spinal cord, and there are more than 25 second-ary injury processes that have been identified, offering multiple potential therapeutic opportunities to counteract them.6,40,58,73 In the past 30 years a huge effort has been expended by clinicians, basic scientists, and industry to discover effective neuroprotective agents for SCI, which thus far have largely failed to improve recovery. There

Translational potential of preclinical trials of neuroprotection through pharmacotherapy for spinal cord injuryCharles h. TaTor, M.D., Ph.D.,1 robin hashiMoTo, Ph.D.,2 annie raiCh, M.P.h.,2 Daniel norvell, Ph.D.,2 MiChael G. FehlinGs, M.D., Ph.D.,1 JaMes s. harroP, M.D.,3 JaMes GuesT, M.D., Ph.D.,4 bizhan aarabi, M.D., F.r.C.s.C.,5 anD roberT G. GrossMan, M.D.61Division of Neurosurgery and Spinal Program, Toronto Western Hospital and University of Toronto, Ontario, Canada; 2Spectrum Research, Inc., Tacoma, Washington; 3Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania; 4Department of Neurological Surgery and the Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, Florida; 5Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland; and 6Department of Neurosurgery, The Methodist Hospital, Houston, Texas

There is a need to enhance the pipeline of discovery and evaluation of neuroprotective pharmacological agents for patients with spinal cord injury (SCI). Although much effort and money has been expended on discovering effec-tive agents for acute and subacute SCI, no agents that produce major benefit have been proven to date. The deficien-cies of all aspects of the pipeline, including the basic science input and the clinical testing output, require examination to determine remedial strategies. Where has the neuroprotective/pharmacotherapy preclinical process failed and what needs to be done to achieve success? These are the questions raised in the present review, which has 2 objectives: 1) identification of articles that address issues related to the translational readiness of preclinical SCI pharmacologi-cal therapies; and 2) examination of the preclinical studies of 5 selected agents evaluated in animal models of SCI (including blunt force trauma, penetrating trauma, or ischemia). The 5 agents were riluzole, glyburide, magnesium sulfate, nimodipine, and minocycline, and these were selected because of their promise of translational readiness as determined by the North American Clinical Trials Network Consortium.

The authors found that there are major deficiencies in the effort that has been extended to coordinate and conduct preclinical neuroprotection/pharmacotherapy trials in the SCI field. Apart from a few notable exceptions such as the NIH effort to replicate promising strategies, this field has been poorly coordinated. Only a small number of articles have even attempted an overall evaluation of the neuroprotective/pharmacotherapy agents used in preclinical SCI trials. There is no consensus about how to select the agents for translation to humans on the basis of their preclinical performance and according to agreed-upon preclinical performance criteria.

In the absence of such a system and to select the next agent for translation, the Consortium has developed a Treatment Strategy Selection Committee, and this committee selected the most promising 5 agents for potential trans-lation. The results show that the preclinical work on these 5 agents has left numerous gaps in knowledge about their preclinical performance and confirm the need for significant changes in preclinical neuroprotection/pharmacotherapy trials in SCI. A recommendation is made for the development and validation of a preclinical scoring system involving worldwide experts in preclinical and clinical SCI.(http://thejns.org/doi/abs/10.3171/2012.5.AOSPINE12116)

Key WorDs spinalcordinjury neuroprotection pharmacotherapy

157

Abbreviations used in this paper: BBB = Basso-Beattie-Bres-nahan; MABP = mean arterial blood pressure; MDA = malondial-dehyde; MgSO4 = magnesium sulfate; NACTN = North American Clinical Trials Network; PEG = polyethylene glycol; SCI = spinal cord injury; SSEP = somatosensory evoked potential.

C. H. Tator et al.

158 J Neurosurg: Spine / Volume 17 / September 2012

have already been many comprehensive reviews of neu-roprotective/pharmacological agents for SCI,6,71,72 and the present report will not duplicate these reviews, but rather is aimed at providing a focused analysis of the field of neuroprotection/pharmacotherapy for SCI for the pur-pose of ascertaining the translational readiness of a se-lection of key promising agents.

The present review is focused on neuroprotection afforded by pharmacotherapy, and so omits other neu-roprotective strategies such as hypothermia. The review has 2 objectives: 1) to identify, describe, and discuss the strengths and weaknesses of the existing preclinical grad-ing systems or recommended criteria (that is, translational criteria) for determining whether a given pharmacologi-cal therapy should be translated from the laboratory into clinical trials; and 2) using the information gained in the first objective as a guide to identify, describe, and sum-marize the characteristics of preclinical trials that evalu-ate 5 neuroprotective agents that the NACTN has deemed to be of current interest and that we have selected because of their actual or potential for translation as neuroprotec-tion for SCI. These include riluzole, glyburide, MgSO4 (with and without PEG), nimodipine, and minocycline. The preclinical studies of these agents will be discussed and the results put into the context of the translational cri-teria summarized from the first objective. It is of interest that a recent publication that scored translational readi-ness of 12 agents for SCI trials included 3 selected by the current authors.40

Methods

Electronic Literature DatabaseA systematic search was conducted in PubMed for

literature published from 1966 through November 2011. Details of the search may be found in Tables 1 and 2. Re-sults were limited to articles with abstracts published in the English language. Reference lists of key articles were also systematically checked.

For our first objective (Table 3), articles were identi-fied that addressed issues related to the translational read-iness of SCI pharmacological therapies for clinical trials. The primary focus was to identify articles that proposed specific grading criteria for studies on pharmacological treatment of SCI. Unfortunately, there was a lack of litera-ture on this topic; therefore, the search was expanded to include those articles with a primary focus on evaluating criteria used to translate a pharmacological therapy from preclinical to clinical trials (that is, translational crite-ria). These criteria include experimental injury models, the timing of therapy, evidence of beneficial effects of therapy, safety and toxicity of therapy, reproducibility/replication and publication of study results, and miscel-laneous issues. Articles were excluded by title or abstract if it was clear that the primary focus was not relevant to SCI translation. Other exclusions included abstracts, let-ters, white papers, and studies not written in English.

For the second objective (Table 4), preclinical stud-

TABLE 1: Search strategy for Key Question 1: grading systems/criteria for translating pharmacological or cell-based SCI therapy from laboratory to clinical studies*

Search No. Search Term No. of Articles

1 Spinal Cord Injuries [Majr] OR spinal cord injury OR Spinal Cord Injuries/therapy* [MeSH] 231252 Biomedical Research* OR Biomedical Research/methods [MeSH] OR Biomedical Research/

trends [MeSH] OR Clinical Trials as Topic* [MeSH] OR Diffusion of Innovation* [MeSH] OR Drug Evaluation, Preclinical/methods [MeSH] OR Drug Evaluation, Preclinical/standards [MeSH] OR Drug Evaluation, Preclinical/trends [MeSH] OR grading system [ti/abs] OR Guidelines as Topic [MeSH] OR Translational research [MeSH] OR Translational research/ methods [MeSH] OR Translational research/standards [MeSH] OR Translational research/ trends [MeSH]

240732

3 1 AND 2 5634 3 NOT (neoplasm OR cancer OR coronary OR comparative study OR comparative studies OR

cross-sectional studies OR cross-sectional study OR prospective studies OR prospective study OR multicenter studies OR multicenter study OR liver OR renal OR urinary OR disasters OR malnutrition OR wound* OR retrospective studies OR retrospective study OR multiple sclerosis OR pilot projects OR pilot study OR adaptation, psychological OR grief OR dogs OR canine* OR social behavior OR pressure ulcer OR muscle contraction OR controlled study OR controlled studies OR randomized controlled trial OR randomized controlled trials OR spinal fusion OR follow-up study OR follow-up studies OR cats)

234

246 articles reviewed at ti/abs level (234 from PubMed search + 12 articles identified in hand-searching relevant bibliographies) Include at ti/abs review: 26 Include at full-text review: 4

* PubMed search date: 11/16/2011; search limits: English, only items with abstracts. Abbreviation: ti/abs = title/abstract.


Translational potential of pharmacotherapy for SCI

159

ies were identified in which the neuroprotective effects of riluzole, glyburide, MgSO4, nimodipine, or minocycline were evaluated in animal models of SCI (including blunt force trauma, penetrating trauma, or ischemia). Studies were excluded by title or abstract if they evaluated fewer than 5 animals, if the pharmacological agent was deliv-ered prior to SCI, or if they were not explicitly testing some aspect of the neuroprotective effect of the agent. Studies that clearly indicated that the pharmacological agent was being tested in non-SCI models, in models of infection- or tumor-based SCI, ex vivo studies, or in vi-tro studies were also excluded. Full-text articles of the remaining studies were obtained and reviewed for inclu-sion. Furthermore, articles that did not contain a control group (that is, SCI plus saline, vehicle, or no treatment) were excluded. Other exclusions included preclinical tri-als without outcome data, studies of human subjects, un-

published data, technique papers, reviews, editorials, and studies not written in English.Data Extraction

Each retrieved citation was assessed by 2 reviewers working independently (R.H. and A.R.). Most articles were excluded on the basis of information provided by the title or abstract. Full-text versions of all citations that appeared to be appropriate, including those that could not be excluded unequivocally on the basis of the title and abstract, were then assessed by the 2 reviewers. Any disagreement between them was resolved by consensus. The following information was extracted for Objective 1: the type of therapy addressed, the basis of the crite-ria, scoring, components of criteria or preclinical study characteristics, or issues discussed. For Objective 2 the following data were extracted from the preclinical stud-

TABLE 2: Search strategy for Key Question 2: preclinical studies*

AgentSearch

No. Search Term No. of Articles

riluzole1 Spinal Cord Injuries[Majr] OR spinal cord injury OR Spinal Cord Injuries/therapy*[MeSH] 231542 Riluzole OR riluzole[MeSH] 7723 1 AND 2 27

Include at ti/abs review: 18Include at full-text review: 12

glyburide1 Spinal Cord Injuries[Majr] OR spinal cord injury OR Spinal Cord Injuries/therapy*[MeSH] 231542 Glyburide OR glibenclamide OR Glyburide[MeSH] 72053 1 AND 2 5


MgSO41 Spinal Cord Injuries[Majr] OR spinal cord injury OR Spinal Cord Injuries/therapy*[MeSH] 231542 magnesium OR magnesium sulfate OR magnesium sulfate[MeSH] 546513 1 AND 2 71


nimodipine1 Spinal Cord Injuries[Majr] OR spinal cord injury OR Spinal Cord Injuries/therapy*[MeSH] 231932 nimodipine OR nimodipine[MeSH] 29913 1 AND 2 30


minocycline1 Spinal Cord Injuries[Majr] OR spinal cord injury OR Spinal Cord Injuries/therapy*[MeSH] 231932 minocycline OR minocycline[MeSH] 35573 1 AND 2 42


* Riluzole: search date, 11/28/2011; search database, PubMed; limits, Englishonly items with abstracts. Glyburide: search date, 11/28/2011; search database, PubMed; limits, Englishonly items with abstracts. MgSO4: search date, 11/28/2011; search database, PubMed; limits, Englishonly items with abstracts. Nimodipine: search date, 12/5/2011; search database, PubMed; limits, Englishonly items with abstracts. Minocycline: search date, 12/5/2011; search database, PubMed; limits, Englishonly items with abstracts.

C. H. Tator et al.


ies: animal model, injury model, experimental groups, timing of therapy, dosage(s) used, route of intervention, randomization of animals to treatment groups, blinded or independent assessment of outcomes, and reporting of results for all animals. Data on the effectiveness of the therapy (including pathology of the lesion, biochemical studies, electrophysiological studies, motor function, sen-sory function, other neurological function, neuropathic pain, and spasticity) and the safety of the therapy, includ-ing toxicology and adverse events, were also extracted.Data Analysis

Data for each key question were abstracted in tables. For the first objective, grading criteria and issues related to translational research in SCI, such as animal/injury model and efficacy of a therapy were summarized, and strengths and weaknesses of the group of articles were discussed. This information was then used to propose components that should be considered when evaluating whether a given pharmacological therapy is ready for clinical translation. For the second objective, the preclini-cal studies were summarized and discussed in terms of the readiness of the specific agent for clinical transla-tion. It was hypothesized that this analysis will serve as a prototype methodology to evaluate which characteris-tics best determine whether a therapy is ready for clinical translation and to suggest additional criteria that may be included in such an evaluation process.

Results

Objective 1: Review of Criteria for Determining the Translational Readiness of a Pharmacological Therapy From the Laboratory Into Clinical Trials

We identified 246 articles from the literature search

that addressed readiness of SCI pharmacological thera-pies for clinical translation. However, only 26 articles were judged suitable for full-text review, 22 of which were excluded after full-text review for the following rea-sons: 19 articles did not specifically address translation research of SCI pharmacological therapies, 1 article was an update of one of the included articles, and 2 articles addressed only cell-based therapies. Therefore, only 4 ar-ticles met the inclusion criteria, and only 1 of the 4 (Kwon et al.41) proposed a scoring system. Although the other 3 discussed issues related to the translation of pharmaco-logical therapies in patients with SCI or stroke,3,13,15 they did not include a scoring system or discuss the relative importance of the issues. The grading system proposed by Kwon et al.41 assigns a total score based on the transla-tional potential of a specific therapy, where a higher score indicates a potentially more promising experimental treatment for a clinical trial. A summary of the findings is presented in Table 5.

Animal/Injury Model(s). All 4 articles addressed the issue of the animal species and injury models used in studies of pharmacological therapies. The grading scale in Kwon et al.41 (Table 6) assigned the highest number of points to treatments in studies using primate and large-animal models (for example: dog, cat, sheep) and fewer points for small rodents. Other authors also placed im-portance on the use of research in larger animals,13,15 with Anderson et al.3 proposing that more invasive or higher-risk treatments be tested in the large-animal models. Sev-eral authors stressed that treatments should be deemed effective in several animal models13,15 before moving to clinical trials, with a lesion in which the volume, location, and origin were representative of the type of SCIs that occur in humans.15 Kwon et al.s grading scale assigned the highest points to treatments in studies using cervical

TABLE 3: Inclusion and exclusion criteria for Objective 1: translational readiness for SCI

Study Component Inclusion Exclusion

Study design Articles that provide grading criteria to evaluate quality of preclinical trials for clinical translationArticles in which primary focus is on translational research grading criteria, components, or issues

Articles in which primary focus is not on translational research grading criteria, components, or issuesArticles that dont specifically address SCI translational research issuesArticles in which primary focus is on addressing issues in clinical research

Intervention Pharmacological agents being evaluated for improving outcomes following SCI

Pharmacological agents being evaluated for improving outcomes in other disease modelsHypothermia & other physical modalitiesBioengineered scaffolds

Preclinical study characteristics of interest

Type of therapy addressedBasis of criteria ScoringComponents of criteria or preclinical study characteristics including animal/injury models, timing of therapy, evidence of beneficial effects of therapy, safety & toxicity of therapy, reproducibility/replication & publication of study results, & miscellaneous issues

Publication Articles written in English in peer-reviewed literature w/ abs available

Abs, lettersWhite papers



161

contusion and clip compression SCI models, fewer points to thoracic contusion and clip compression, and the low-est number of points to cervical or thoracic partial sharp transection SCI models.

Timing of Therapy. All 4 articles discussed the tim-ing of the proposed therapy and its therapeutic efficacy. Kwon et al.41 assigned a higher number of points to treat-ments that demonstrate efficacy after a longer treatment delay postinjury. Dobkin15 and Dietrich13 proposed that the timing and dose of the treatment replicate that which a human patient would receive.

Evidence of Beneficial Effects of Therapy. All 4 ar-ticles addressed the issue of judging the beneficial effects of a therapy. Kwon et al.41 assigned points to various be-havioral and nonbehavioral outcome measures, including locomotor tests, and considered the use of dose-response analysis for behavioral and nonbehavioral outcomes in the grading scale. Dietrich13 asserted that the quantitative methods of assessing outcomes after treatment should be clinically relevant. Anderson et al.3 suggested that any therapeutic benefits of a treatment should persist for at least 3 months after injury to ensure that true differences

exist between treated and untreated animals. Dobkin15 advised caution in the interpretation of behavioral out-comes found in rodent SCI models because many behav-iors tested in rodents cannot be extrapolated to a similar response in humans.

Reproducibility/Replication and Publication. All arti-cles stressed the need for study results to be peer-reviewed by independent experts,3,13 published in peer-reviewed journals,3,13,41 and independently replicated3,13,15,41 before translation to clinical trials. The grading system proposed by Kwon et al.41 assigns a higher number of points to treat-ments having a greater number of studies that report ben-eficial effects of the therapy, with negative points assigned to treatments having studies that report negative results of the therapy.

Safety/Toxicity. Surprisingly, only 2 articles addressed the need for safety or toxicity monitoring in preclinical studies. Anderson et al.3 proposed that highly invasive or risky interventions should meet a higher standard of pre-clinical safety and efficacy. They also stressed that animals should be monitored for effects such as pain, worsened au-tonomic dysfunction, and spasticity for a time period de-

TABLE 4: Inclusion and exclusion criteria for Objective 2: preclinical studies of the 5 selected agents*

Study Component Inclusion Exclusion

Intervention Selected neuroprotective agents (riluzole, glyburide, MgSO4, nimodipine, & minocycline) evaluated for improving outcomes post-SCI

Neuroprotective agents evaluated for improving outcomes w/ Tx prior to SCINeuroprotective agents not explicitly tested for some aspect of their neuroprotective effect

Population Animal models of SCI, including (but not limited to) blunt force trauma SCI, penetrating trauma SCI, ischemic SCI

Animal models of ALS, MS, etc.In vitro models of SCIEx vivo models of SCI

Characteristics of interest

Study characteristics, including: animal model injury model experimental groups timing of therapy dosage(s) used route of intervention randomization of animals to Tx groups blinded or independent assessment of outcomes whether all animals were accounted forEffectiveness of therapy, including: pathology of lesion & surrounding area biochemical studies electrophysiology studies motor & neurological function neuropathic pain spasticitySafety of therapy, including toxicology & adverse events

Study design Comparative preclinical trials published in peer-reviewed journals

Studies w/ no control groupStudies evaluating

C. H. Tator et al.


TABL

E 5:

Sum

mar

y of c

riter

ia ad

dres

sed

in th

e 4 se

lect

ed ar

ticle

s rel

ated

to th

e tra

nsla

tiona

l rea

dine

ss o

f neu

ropr

otec

tion/

phar

mac

othe

rapy

for S

CI fr

om la

bora

tory

to cl

inic

al tri

al*

Key C

riter

iaKw

on et

al., 2

011 (

gra

ding

)Do

bkin,

2007

Ande

rson

et al

., 200

5Di

etrich

, 200

3

Anim

al/inj

ury m

odel(

s)An

imal

spec

ies (m

ore p

oints

for la

rger

anim

als)

Injur

y par

adigm

s (mo

re po

ints f

or ce

rvi-

ca

l con

tusio

n & cl

ip co

mpre

ssion

vs

th

orac

ic co

ntusio

n & cl

ip co

mpre

s-

sio

n)

Use o

f larg

er an

imals

Txs s

hown

to be

effec

tive i

n sev

eral

anim

al mo

dels

Injur

y mod

el re

pres

enta

tive o

f SCI

in

hu

mans

Larg

er an

imals

for in

vasiv

e/hig

h-ris

k Txs

Use o

f larg

er an

imals

Txs s

hown

to be

effec

tive i

n sev

eral

anim

al mo

dels

Timi

ng of

ther

apy

Tim

e wi

ndow

of e

ffica

cy (m

ore

poin

ts

fo

r effi

cacy

dem

onst

rate

d at

long

er

de

lay of

Tx)

Timi

ng/do

se si

milar

to th

at wh

ich hu

man

wo

uld re

ceive

Cons

idera

tion o

f chr

onic/

acute

injur

iesTi

ming

/dose

simi

lar to

that

which

huma

n

would

rece

iveCo

nside

ratio

n of c

hron

ic/ac

ute in

juries

Evid

ence

of b

enefi

cial

ef

fects

of th

erap

yTy

pes o

f beh

avior

al/no

nbeh

avior

al ou

t-

come

mea

sure

sCa

ution

in in

terpr

etati

on of

beha

viora

l

outco

mes i

n rod

ent S

CI m

odels

Ther

apeu

tic b

enefi

ts s

houl

d pe

rsist

3 m

osQu

antita

tive m

ethod

s ass

essin

g out-

come

s sho

uld be

clini

cally

relev

ant

Safet

y/tox

icity

NRNR

Invas

ive/ri

sky t

hera

pies m

eet h

igh st

anda

rd

of

saf

ety/

effic

acy

Anim

als sh

ould

be m

onito

red f

or ap

prop

riate

tim

e per

iod fo

r pain

, wor

sene

d auto

nomi

c

dysfu

nctio

n, &

spas

ticity

Safet

y/tox

icity

to be

cons

idere

d at e

very

study

phas

e

Repr

oduc

ibility

/repli

ca-

tio

n & pu

blica

tion

Publi

catio

n of s

tudy

resu

lts in

peer

-

revie

wed j

ourn

alSt

udy r

esult

s ind

epen

dentl

y rep

licate

d

(mor

e po

ints

for s

tudi

es w

/ ben

eficia

l

resu

lts vs

stud

ies w

/ neg

ative

re-

su

lts)

Stud

y res

ults i

ndep

ende

ntly r

eplic

ated

Stud

y res

ults p

eer-r

eview

ed by

inde

pend

ent

ex

perts

Publi

catio

n of s

tudy

resu

lts in

peer

-revie

wed

jou

rnal

Stud

y res

ults i

ndep

ende

ntly r

eplic

ated

Stud

y res

ults p

eer-r

eview

ed by

inde

pen-

dent

expe

rtsPu

blica

tion o

f stu

dy re

sults

in pe

er-

re

viewe

d jou

rnal

Stud

y res

ults i

ndep

ende

ntly r

eplic

ated

Othe

rNA

Cons

iders

that

lab en

viron

ment

can c

on-

fo

und i

nterp

reta

tion o

f stu

dy re

sults

Cons

iders

effec

t of m

ultipl

e inte

rven

tions

/

rout

inely

take

n med

icatio

ns by

huma

n

patie

nts

NASe

eks k

nowl

edge

of ba

sic m

echa

nisms

by w

hich a

ther

apy w

orks

* Kw

on et

al.41

is th

e only

artic

le wi

th a p

oint s

ystem

assig

ned t

o the

vario

us cr

iteria

. Abb

revia

tions

: NA

= no

t app

licab

le; N

R =

not r

epor

ted or

addr

esse

d in t

he ar

ticle.

Repli

catio

n of th

e stu

dy re

sults

in in

depe

nden

t labo

rator

ies in

the s

ame a

nimal

and i

njury

mod

els.



163

signed to detect significant adverse events. Dietrich13 noted that safety issues, including toxicity, should be considered at every phase of the study.

Other. Other issues were noted by authors as needing further research or discussion. Dobkin15 suggested that the laboratory environment experienced by rodents might confound the interpretation of experiments and thus the translation of a treatment from animal models to human studies. This environment includes deprivation of social interaction, exercise, and environmental enrichment. Di-etrich13 suggested that knowledge of the basic mecha-nisms by which a therapy works would assist researchers in revising treatment protocols and investigating cause-

and-effect relationships between treatments and observed outcomes.

Strengths and Weaknesses of Existing Grading Cri-teria. There are various strengths and weaknesses identi-fied in each of the 4 articles that proposed grading criteria or issues in the translational research of pharmacological therapies for SCI, which are summarized in Table 7; more detailed information is available in Table 8. Although most of the articles discussed important issues such as animal and injury models, reproducibility and publica-tion of study results, and evidence of beneficial effects of the therapy, there are some weaknesses. Most of the articles did not discuss the relative importance of the is-

TABLE 6: Preclinical grading scale, neuroprotective therapies for acute SCI*

Component Items PointsMax

Score

Animal species in which efficacy has been demonstrated

Models of traumatic SCI primate large animal rat mouse

8642

20

Injury paradigms in which efficacy has been demonstrated

SCI models cervical contusion thoracic contusion cervical clip compression thoracic clip compression cervical partial transection, sharp thoracic partial transection, sharp

636311

20

Time window of efficacy Efficacy demonstrated w/ Tx delay of 12 hrs delay of 4 hrs &

C. H. Tator et al.


sues raised.3,13,15 Several articles made little or no mention of safety or toxicity,15,41 and none of the articles discussed the importance of randomizing the treatment or having the investigators work in a blinded fashion. The grading system of Kwon et al.41 has several additional weaknesses: there was no consideration of the commercial potential of a given therapy, only scientists or spine surgeonsci-entists were invited to the focus group meeting that de-cided the weighting factors for each subscale in the grad-ing criteria, and the focus group was composed mainly of American and Canadian researchers.Objective 2: Preclinical Characteristics and Outcomes for the 5 Selected Neuroprotective Agents

The following is a detailed account of the 5 agents selected for analysis on the basis of their promise of use-fulness for translation to human SCI.

GlyburideBackground. The management of parenchymal hem-

orrhage has been reported to be critical for promoting neurological recovery after SCI.22 Glyburide works pri-marily by blocking sulfonylurea receptor 1 (SUR1)regu-lated, Ca2+-activated, [ATP]i-sensitive nonspecific cation (NCCa-ATP) channels, which helps mitigate the effects of secondary hemorrhage and progressive hemorrhagic ne-crosis following SCI.57,64,65 Glyburide has been approved by the FDA for the treatment of Type 2 diabetes at a dose of 1.2520 mg (standard) or 0.7512 mg (micronized) orally in 1 or 2 divided doses.

Systematic Search for Preclinical Studies. Of the 5 studies identified in our literature search, 3 that evaluated glyburide (glibenclamide) in preclinical studies were se-lected to undergo full-text review, and all 3 met the inclu-sion criteria.57,64,65

Study Characteristics. Study characteristics are sum-marized in Table 9; detailed information can be found in Table 10. All 3 studies used rats, and no other species were used to test the effects of glyburide. The total num-ber of animals per study ranged from 10 to 54 (1 study did not report the number), with 38 animals per treatment group. A blunt force weight-drop injury model was used in all 3 studies to injure the cervical spine. All 3 studies compared glyburide to vehicle/saline following SCI, and Simard et al.64 additionally included a no SCI/no treat-

ment group. Simard et al.65 gave a loading dose of 10 mg/kg glyburide within 15 minutes of SCI, and Popovich et al.57 did the same in 1 of 3 experiments; otherwise, infu-sion began within minutes of the injury. Glyburide was administered continuously at a rate of 200 ng/hour via a subcutaneous osmotic pump in all studies; vehicle/sa-line was given similarly. No studies evaluated the dose-response effects of glyburide. In all 3 studies, blinded in-vestigators evaluated outcomes. Popovich et al.57 random-ized animals to treatment groups, whereas no mention of randomization was made by the other 2 studies. Popovich et al. accounted for all 54 animals included in the study, but the other 2 studies did not report whether all animals were accounted for.

Effectiveness of Therapy. The effect of glyburide on intraspinal hemorrhaging was evaluated by 2 studies. Si-mard et al.64 concluded that glyburide treatment resulted in less hemorrhaging compared with the control groups at 24 hours, as measured by spectrophotometric analysis of blood in the cord homogenates (p < 0.05 at 6, 12, 18, and 24 hours), as well as by other assays. Popovich et al.57 reported that glyburide given continuously at a dose of 200 ng/hour resulted in no differences in the amounts of visible hemorrhaging between treatment groups at up to 24 hours postinjury in one experiment. However, in a sec-ond similar experiment, and in a third in which a loading dose was given after injury and followed with continuous infusion of lower doses, less hemorrhaging was visible in the glyburide group compared with the SCI/vehicle group at 24 hours. There were slight differences between these experiments, including details of the weight drop injury, which may have contributed to differences in these results. The studies performed by Simard et al. in 2007 and 2010 both suggested that glyburide treatment resulted in less visible hemorrhaging compared with the control groups at 24 hours. Lesion size was also shown to be sig-nificantly reduced at 1 week64 and 6 weeks65 postinjury in animals treated with glyburide compared with vehicle in the 2 studies in which this outcome was evaluated (p < 0.001).

Functional improvements in glyburide-treated rats were observed in all 3 studies. Two studies reported improvements in spontaneous rearing (vertical explora-tion), which was statistically higher in animals treated with glyburide compared with vehicle at each time point

TABLE 7: Summary of strengths and weaknesses of studies that address translational readiness of a pharmacotherapy for SCI trials

Strengths Weaknesses

Large range of animals & use of relevant injury models, including randomization & blinding, & adequate numbers of animals

No consideration of randomization or blinding

Appropriate timing of therapy No discussion of relative importance of grading issuesEvidence of beneficial effects on the basis of a range of outcome measures No consideration of commercial potential of therapySafety/toxicity included in evaluation Only scientists/spine surgeons & mostly Americans &/or Canadians

in focus groupsReproducibility/replication & detailed publication of study results Little mention of lab environments effects on interpretation of study

resultsLittle mention of knowledge of basic mechanisms by which a therapy works



165

TABL

E 8:

Gra

ding

crite

ria an

d is

sues

rela

ted

to tr

ansla

tion

rese

arch

of p

harm

acol

ogic

al th

erap

ies f

or S

CI*

Auth

ors &

Yea

rTy

pe of

The

rapy

Basis

of C

riter

iaSc

oring

Comp

onen

ts or

Issu

esSt

reng

ths/

Wea

knes

ses

Kwon

et al

.,

2011

(gra

ding

sy

stem

)

Neur

opro

tectiv

e

ther

apies

for

ac

ute S

CI

Pers

pecti

ves/o

pinion

s of 2

00+

cli

nician

s & sc

ientis

ts in

SCI fi

eld

via q

uest

ionn

aire

Final

crite

ria by

cons

ensu

s of

25

invit

ed s

cient

ific e

xper

ts

&

spine

surg

eon

scien

tists

in m

odifi

ed D

elph

i exe

rcise

010

0; ex

tent to

whic

h a

pa

rticu

lar Tx

has b

een

stu

died,

w/ hi

gher

scor

e ind

icatin

g a

gr

eater

body

of pe

er-

re

viewe

d lite

ratur

e

Prov

ides

an ob

jectiv

e mea

sure

of th

e tra

nsla-

tiona

l pot

entia

l of a

spe

cific

ther

apy

base

d on

a sys

temati

cally

colle

cted s

et of

litera

ture

su

ppor

ting i

ts ap

plica

tion i

n acu

te SC

IAn

imal

mod

els

in w

hich

effi

cacy

has

bee

n de

m-

on

strate

dIn

jury

mod

els

in w

hich

effi

cacy

has

bee

n de

mon

-

strate

dTi

me

wind

ow o

f effi

cacy

Dem

onst

ratio

n of

clin

ical

ly m

eani

ngfu

l ef

ficac

yIn

depe

nden

t rep

rodu

cibilit

y/rep

licati

on

No co

nside

ratio

n of c

omme

rcial

poten

tial o

f

ther

apy

Full s

pectr

um of

inter

natio

nal in

put s

omew

hat

lac

king

Prop

osed

Tx ca

n pos

sibly

achie

ve a

highe

r sco

re

in

abse

nce o

f som

e elem

ents

Exclu

ded s

afety

(dee

med t

o be a

regu

lator

y

issue

for a

ll neu

ropr

otecti

ve ag

ents)

Only

scien

tists

or sp

ine su

rgeo

nsc

ientis

ts (P

Is)

inv

ited t

o foc

us gr

oup m

eetin

g tha

t dec

ided

we

ightin

g fac

tors f

or ea

ch su

bsca

leQ

ualit

y of

scie

ntific

pre

clini

cal S

CI s

tudi

es n

ot

as

sess

edNe

eds

to b

e m

odifie

d fo

r oth

er th

erap

ies

(cel

l

trans

plant

ation

or bi

ologic

al th

erap

ies)

Dobk

in, 20

07Ne

ural

repa

ir afte

r

strok

e or S

CINA

None

Anim

al mo

dels

desig

ned t

o be r

eleva

nt to

huma

n

disea

seDi

ffere

nces

btwn

rode

nt br

ain/sp

inal c

ord &

hu-

ma

n CNS

Diffe

renc

es bt

wn va

rious

rode

nt mo

dels

(repli

ca-

tio

n of s

ame i

njury

& re

pair m

odel

in dif

feren

t

labs o

ften n

ot pe

rform

ed)

Repr

oduc

e key

resu

lts in

>1 la

bDi

ffere

nces

in in

jury i

nduc

tion

Dose

& tim

ing of

inter

venti

ons

Anato

mica

l site

& go

al of

inter

venti

ons

Comb

inatio

nal th

erap

ies &

mult

iple i

nterv

entio

nsLa

b env

ironm

ent (

for e

xamp

le, an

imals

isola

tion

or

depr

ivatio

n), re

habil

itatio

n, po

stles

ion re

-

orga

nizati

onPh

ysiol

ogica

l, hist

ologic

al, &

mole

cular

mar

kers

can s

erve

as su

rroga

tes fo

r beh

avior

al ou

t-

come

s, &

limite

d rod

ent b

ehav

iors a

re te

sted

No in

dicati

on of

relat

ive im

porta

nce o

f issu

esLit

tle m

entio

n of s

afety,

adve

rse e

vents

, or

tox

icolog

y

(cont

inued

)

C. H. Tator et al.


TABL

E 8:

Gra

ding

crite

ria an

d is

sues

rela

ted

to tr

ansla

tion

rese

arch

of p

harm

acol

ogic

al th

erap

ies f

or S

CI* (

cont

inue

d)

Auth

ors &

Yea

rTy

pe of

The

rapy

Basis

of C

riter

iaSc

oring

Comp

onen

ts or

Issu

esSt

reng

ths/

Wea

knes

ses

Ande

rson

et

al.

, 200

5Ph

arma

colog

ical,

ce

ll-bas

ed, &

other

ther

apies

for S

CI

Base

d on g

uideli

nes i

ssue

d

by th

e ASN

TR (s

ee R

amer

et al.

)

None

Appr

opria

te da

ta sh

ould

be ac

quire

d in a

nimals

prior

to hu

man s

tudie

s, inc

luding

:

Inj

ury m

odel

in hu

mans

shou

ld be

valid

ated

by

prec

linica

l mod

el in

anim

als (f

or

ex

ample

, con

tusion

or is

chem

ia)

Ti

me fr

ame o

f Tx i

n anim

als sh

ould

repli

-

cate

that

of ac

ute or

chro

nic th

erap

ies in

huma

ns

Ri

skier

inter

venti

ons s

hould

mee

t high

er

st

anda

rd o

f saf

ety/

effic

acy

Tx sh

ould

have

demo

nstra

ble &

stati

stica

lly

sig

nific

ant b

enefi

t in

anim

al m

odel

s

St

udy r

esult

s sho

uld be

peer

-revie

wed b

y

indep

ende

nt ex

perts

Outco

mes s

hould

be as

sess

ed at

cellu

lar,

ph

ysiol

ogica

l, & be

havio

ral le

vels

in an

appr

opria

te mo

del o

f SCI

Pers

isten

ce o

f the

rape

utic

bene

fit s

houl

d

be

show

n for

at le

ast 3

mos

posti

njury

Evide

nce o

f inde

pend

ent r

eplic

ation

shou

ld

be

pres

ent b

efore

tran

slatio

n

An

imal

mode

ls sh

ould

be m

onito

red f

or

sa

fety/a

dver

se ef

fects

(pain

, wor

sene

d

auton

omic

dysfu

nctio

n, sp

astic

ity) in

sys-

tems a

bove

the l

esion

for a

time p

eriod

desig

ned

to d

etec

t sig

nific

ant a

dver

se

ev

ents

No in

dicati

on of

relat

ive im

porta

nce o

f issu

es

(cont

inued

)



167

measured, ranging from 1 day to 1 week57 or 6 weeks (p < 0.01).65 Two studies found improvements in inclined-plane test scores in animals treated with glyburide com-pared with vehicle as measured between 1 and 7 days (p < 0.05),57,64 and 1 study each reported improvements in ip-silateral paw placement64 and in BBB scores (p < 0.001)57 at 1 day following injury.

Safety of Therapy. None of the studies assessed the safety of glyburide.

Summary of Preclinical Trials of Glyburide. Thus, according to the criteria shown in Tables 5 and 7, there are numerous deficiencies in the translational readiness of this agent.

Magnesium SulfateBackground. For the treatment of SCI, the primary

mechanism of action for MgSO4 appears to be limiting levels of intracellular calcium by blockage of N-methyl-D-aspartate receptors and of voltage-gated calcium chan-nels, subsequently reducing free radical generation, gluta-mate release, expression of p53-related proteins, lipid per-oxidation, lactate accumulation, and cell death.24,44,46,78,79,86 Magnesium sulfate is currently indicated in humans for the immediate control of life-threatening convulsions in the treatment of severe toxemias (preeclampsia and ec-lampsia) of pregnancy, for the treatment of acute nephri-tis in children, and as a replacement therapy in MgSO4 deficiency, especially in acute hypomagnesemia accom-panied by signs of tetany. It is also used to prevent prema-ture contractions in pregnancy and to treat patients with heart attack and asthma. The drug can be administered intramuscularly or intravenously, and the dose is very variable, ranging from 1 to 3 g daily for a maintenance dose for adults, to 1014 g for severe preeclampsia or ec-lampsia.

Systematic Search for Preclinical Studies. We identi-fied 71 articles that evaluated MgSO4, of which 14 were eligible for full-text review. Five studies were excluded after full-text review for the following reasons: 4 studies administered MgSO4 prior to injury, and 1 study did not evaluate MgSO4. Therefore, 9 articles met our inclusion criteria.14,26,35,36,42,53,66,69,81

Study Characteristics. Study characteristics are sum-marized in Table 11; detailed information can be found in Table 12. Administration of MgSO4 following SCI was tested in rats in 8 of the studies14,26,35,36,42,66,69,81 and in rabbits in 1 study (Ozdemir et al.).53 The total number of animals per study ranged from 30 to 122, with 620 animals per treatment group. Most studies evaluated tho-racic SCI: blunt force trauma by weight drop was used in 6 studies26,35,36,42,66,81 and clip compression in 2 (Ditor et al.14 and Szer et al.69); 1 study provided no details on the injury model.53 In all studies, MgSO4 was administered systemically, 5 intraperitoneally26,35,66,69,81 and 4 intrave-nously.14,36,42,53 The dosages of MgSO4 used were 60 mg/kg (2 doses nearly 6 hours apart),42 100 mg/kg,35,53 300 mg/kg,14,69 and 600 mg/kg.26,35,36,66,69,81 Only Kaptanoglu et al.35 and Szer et al.69 evaluated more than one dose of MgSO4. All but 1 study gave the first injection of MgSO4 within 015 minutes postinjury; Szer et al. administered the TA

BLE

8: G

radi

ng cr

iteria

and

issu

es re

late

d to

tran

slatio

n re

sear

ch o

f pha

rmac

olog

ical

ther

apie

s for

SCI

* (co

ntin

ued)

Auth

ors &

Ye

arTy

pe of

The

rapy

Basis

of C

riter

iaSc

oring

Comp

onen

ts or

Issu

esSt

reng

ths/

Wea

knes

ses

Dietr

ich, 2

003

Neur

opro

tectiv

e or

re

gene

rativ

e

ther

apies

for

SC

I

NRNo

neTh

erap

y mus

t wor

k in s

ever

al an

imal

mode

ls, in

-

cludin

g con

sider

ation

of an

imal

spec

ies, s

ex,

&

large

anim

al mo

dels

(non

huma

n prim

ates)

Com

pellin

g ev

iden

ce o

f ben

efit,

inclu

ding

the

de-

gr

ee o

f ben

efit,

a wi

de th

erap

eutic

win

dow,

dosin

g, cli

nicall

y rele

vant

meth

ods o

f ass

ess-

ing ou

tcome

, & id

eally

an un

ders

tand

ing of

basic

mec

hanis

ms by

whic

h the

ther

apy w

orks

Stud

y is c

linica

lly re

levan

t & re

plica

ted in

an in

-

depe

nden

t lab

Maj

or fi

ndin

gs a

re p

ublis

hed

in p

eer-r

evie

wed

journ

alsSa

fety i

ssue

s, inc

luding

toxic

ity, a

re ad

dres

sed a

t

ever

y tes

ting p

hase

Cons

idera

tion o

f acu

te, su

bacu

te, &

chro

nic in

-

jury s

ettin

gs

No in

dicati

on of

relat

ive im

porta

nce o

f com

po-

ne

nts

* AS

NTR

= Am

erica

n Soc

iety f

or N

eura

l Tra

nspla

ntati

on an

d Rep

air; P

I = pr

incipa

l inve

stiga

tor.

Th

e meth

od or

sour

ce us

ed to

prop

ose c

riter

ia or

issu

es in

tran

slatin

g pha

rmac

ologic

al th

erap

ies fr

om pr

eclin

ical to

clini

cal s

tudie

s.

C. H. Tator et al.


drug at 1 hour. Wiseman et al.81 conducted 2 experiments, one in which MgSO4 was given at 10 minutes, and another in which animals received an injection at either 8, 12, or 24 hours. In 2 studies injections were given at 15 minutes and again at 6 hours: in Ditor et al.14 at 300 mg/kg/injection and Kwon et al.42 at 60 mg/kg/injection. All but 1 study53 clearly stated that animals were randomized to treatment groups, and that assessment was done in a blinded manner; all but 2 studies53,66 used blinded assessment of treatment outcomes. Five studies accounted for 100% of the ani-mals;14,26,35,42,69 1 study accounted for 100% of the animals in the first experiment, but did not account for the animals in the second experiment;81 3 studies did not account for all included animals.36,53,66

Effectiveness of Therapy. Lesion size was assessed by 2 studies. Kwon et al.42 found that 6 weeks after SCI, intravenous administration of MgSO4 (2 doses of 60 mg/kg, one at 15 minutes, and the other at 6 hours) reduced lesion volumes by 33% compared with rats that received saline alone (p = 0.03). When MgSO4 was given in PEG,

lesion volumes were reduced even more, by 51% com-pared with saline controls (p = 0.0012) (PEG alone re-duced lesion volumes by 20% compared with saline controls). The delivery of MgSO4 in PEG significantly reduced lesion size compared with administration of MgSO4 alone (p = 0.0386). In contrast, Wiseman et al.81 reported no differences in lesion lengths between treat-ment groups measured 24 hours postinjury, but noted that the small number of specimens and the large variability in the control group samples may have affected the re-sults. The authors reported significantly improved white matter sparing following MgSO4 (and methylpredniso-lone + MgSO4) treatment compared with saline alone: the percentage of myelin preservation was 20.2% in the sa-line group compared with 32.3% (p = 0.002) for MgSO4, 30.3% (p = 0.006) for methylprednisolone, and 42.3% (p = 0.0007) for the 2 drugs combined. In this study, rats were treated with 600 mg/kg MgSO4 (and/or 30 mg/kg methylprednisolone) 10 minutes after injury.

The effects of MgSO4 on neuronal apoptosis follow-

TABLE 9: Summary of glyburide preclinical study characteristics*

Characteristic Popovich et al., 2012 Simard et al., 2007 Simard et al., 2010

animal model: rats no. of animals 54 NR 10 no./group 68 35 5injury model: blunt force (wt drop) cervical X X Xtiming of intervention postinjury 23 min w/ cont infusion X X 15 min w/ cont infusion for 7 days Xroute of intervention: osmotic pumps placed caudal to injury in subcutaneous pocket X X X IPdosage 200 ng/hr cont infusion until planned death X X initial dose of 10 g/kg; cont infusion of 200 ng/hr for 7 days X>1 dose evaluated? yes no X X Xcontrol groups SCI (saline, DMSO) X X X no SCI Xindependent or blind assessment yes X X X no NRanimals randomized to Tx groups yes X no NR X X% animals accounted for 100% (54 of 54) NR NR

* Cont = continuous; DMSO = dimethyl sulfoxide; IP = intraperitoneal.



169

TABL

E 10

: Cha

ract

erist

ics o

f SCI

anim

al st

udie

s usin

g gl

ybur

ide (

glib

encl

amid

e)*

Auth

ors &

Ye

arAn

imal

& Inj

ury M

odels

Expe

rimen

tal

Grou

psInt

erve

ntion

Det

ails

Repo

rted O

utcom

esCo

mmen

ts

Popo

vich e

t al.,

20

12An

imal

mode

l:Lo

ng-E

vans

rats

N =

54Se

x: 10

0% F

Age:

10 w

ksW

t: 247

8

gSC

I mod

el:Bl

unt fo

rce i

mpac

tor; in

jury

at

C-5 l

evel

(1.3-

mm im

-

pacto

r hea

d driv

en by

10-g

wt d

ropp

ed ve

rti-

ca

lly fr

om a

25-m

m

he

ight)

SCI +

vehic

le (sa

line

+

DMSO

; con

trols)

SCI +

glibe

nclam

ide6

8 rats

/grou

p

Route

: osm

otic p

umps

plac

ed ca

udal

to inj

ury

sit

e in a

subc

utan

eous

pock

et Ti

ming

: 23

min

after

SCI

Dosa

ge:

Contr

ol: eq

uivale

nt vo

l of D

MSO

dilut

ed in

0.9%

NaC

lGl

ibenc

lamide

: 800

l o

f sto

ck so

lution

(5.0

mg/m

l glib

encla

mide

diss

olved

in D

MSO

)

dilute

d w/ 4

.2 m

l ster

ile 0.

9% N

aCl

Infus

ion ra

te: 0.

5 l/h

r, yiel

ding 2

00 ng

/hr o

f

glibe

nclam

ideEx

pt 1

: at O

SU (i

njur

y m

odel

: Infi

nite

Hor

izons

blunt

impa

ct)Ex

pt 2:

at UM

(injur

y mod

el: w

t dro

p tec

h-

niq

ue),

+ us

ed an

imme

diate

posti

njury

(w/

in

5 min)

load

ing do

se of

glibe

nclam

ide

(10

g/

kg)

Expt

3: at

OSU

w/ U

M inj

ury d

evice

Anim

als ki

lled:

NR

Gros

s Visu

al Ins

pecti

on of

the W

hole

Spina

l Cor

d:Ex

pt 1:

at 6,

12, o

r 24 h

rs po

stinju

ry re

veale

d sim

ilar

am

ounts

of he

morrh

age a

t the s

ite of

impa

ct, w

/ som

e

visibl

e bloo

d exte

nding

into

rostr

al &

caud

al sp

inal s

eg-

me

nts in

both

vehic

le &

glibe

nclam

ide-tr

eated

anim

alsEx

pt 2:

acute

deliv

ery o

f glib

encla

mide

was

foun

d to l

imit

int

rasp

inal h

emor

rhag

e (vs

vehic

le)Ex

pt 3:

6 rats

wer

e tre

ated w

/ glib

encla

mide

or ve

hicle

(3/

gr

oup),

then

intra

spina

l hem

orrh

age w

as as

sess

ed 24

hrs l

ater;

a red

uctio

n in i

ntras

pinal

hemo

rrhag

e was

foun

d sim

ilar t

o Exp

t 2M

otor T

ests:

Sign

ifican

t pre

serv

atio

n of

hin

dlim

b fu

nctio

n wa

s ev

iden

t

in gli

benc

lamide

-trea

ted ra

ts 1 d

ay po

stinju

ry ac

cord

ing

to

the B

BB lo

como

tor ra

ting s

cale

Simi

lar im

prov

emen

ts we

re de

tected

on th

e inc

lined

-plan

e

& cy

linde

r tas

ksRe

aring

& pa

w pla

ceme

nt bt

wn 3

& 7 d

ays:

22 re

aring

even

ts fo

r glib

encla

mide

comp

ared

w/ 3

even

ts fo

r

vehic

le-tre

ated r

atsAv

erag

e dur

ation

of re

aring

was

~15 s

ec fo

r glib

encla

mide

& ~1

sec f

or ve

hicle

Safet

y/Adv

erse

Eve

nts/T

oxico

logy:

NR

Main

goal

of ar

ticle

was t

o rep

licate

Sima

rd et

al.

(2

007)

resu

lts

Sima

rd et

al.,

2007

Anim

al mo

del:

Long

-Eva

ns ra

tsN

= NR

Sex:

100%

FAg

e: ad

ults

Wt: 2

753

50 g

SCI m

odel:

Blun

t forc

e imp

actor

; injur

y

at C4

5 le

vel (1

.3-m

m

im

pacto

r hea

d driv

en

by

10-g

wt d

ropp

ed

ve

rtica

lly fr

om a

25-m

m

heigh

t)

No S

CI (c

ontro

ls)SC

I + ve

hicle

(salin

e

+ DM

SO)

SCI +

glibe

nclam

ide

35 r

ats/gr

oup

Route

: osm

otic p

umps

plac

ed ca

udal

to inj

ury

sit

e in a

subc

utan

eous

pock

etTi

ming

: 23

min

after

SCI

Dosa

ge:

50 m

g (or

25 m

g) of

drug

into

10 m

l DM

SOInf

usion

solut

ions m

ade b

y plac

ing 4

00

l (or

80

0 l) s

tock

into

4.6 m

l (or 4

.2 m

l)

unbu

ffere

d sali

ne (0

.9%

NaC

l)Inf

usion

solut

ions o

f glib

encla

mide

& re

pa-

gli

nide w

ere d

elive

red a

t 0.5

l/h

r, yiel

ding

inf

usion

dose

s of 2

00 ng

/hr

Anim

als ki

lled:

at va

rious

times

after

SCI

(51

1/gro

up)

Upre

gulat

ion of

SUR

1 in S

CI:

In co

ntrols

, SCI

caus

ed a

prog

ress

ively

expa

nsive

lesio

n

w/ fr

agme

ntati

on of

capil

laries

, hem

orrh

age t

hat

do

ubled

in vo

l ove

r 12 h

rs, ti

ssue

necr

osis,

& se

vere

neur

ologic

al dy

sfunc

tion

SUR1

expr

essio

n was

upre

gulat

ed in

capil

laries

& ne

u-

ro

ns su

rroun

ding n

ecro

tic le

sions

Patch

clam

p of c

ultur

ed en

doth

elial

cells

expo

sed t

o hy-

po

xia sh

owed

that

upre

gulat

ion of

SUR

1 was

asso

ci-

ate

d w/ e

xpre

ssion

of fu

nctio

nal S

UR1-

regu

lated

NCCa

-ATP

chan

nels

Follo

wing

SCI

, bloc

k of S

UR1 b

y glib

encla

mide

or re

pag-

linide

or su

ppre

ssion

of A

bcc8

was

asso

ciated

w/

sig

nific

ant s

parin

g of

whi

te m

atte

r tra

cts

& a

3-fo

ld re

-

ducti

on in

lesio

n vol,

& re

sulte

d in m

arke

d neu

robe

hav-

ior

al fu

nctio

nal (i

nclin

ed-p

lane t

est &

ipsil

at pa

w pla

ce-

me

nt) im

prov

emen

t com

pare

d w/ c

ontro

lsSa

fety/A

dver

se E

vents

/Tox

icolog

y: NR

(cont

inued

)

C. H. Tator et al.


ing SCI were examined by Solaroglu et al.66 by measuring caspase-3 activity. A single dose of MgSO4 (600 mg/kg) was given immediately following weight drop injury, and animals were killed at 24 hours. Compared with no treat-ment or vehicle alone, MgSO4 reduced caspase-3 activity levels (p < 0.05) in experimental animals, as did meth-ylprednisolone. Of note, methylprednisolone treatment resulted in a greater reduction in caspase-3 activation compared with MgSO4 (p < 0.05). Caspase-3 activity was measured in 1-cm samples of spinal cord tissue homog-enates taken around the injury site. The results suggest that MgSO4 may have antiapoptotic effects in the first 24 hours following SCI.

Kaptanoglu et al.35 reported the ultrastructural find-ings in a 1-mm cross-section of the spinal cord obtained at the trauma site after 2 different doses of MgSO4 (100 and 600 mg/kg) given immediately after weight drop SCI in rats killed at 24 hours. The higher dose of MgSO4 sig-nificantly improved the general neural score, which as-sessed whole subcellular changes, compared with the no treatment or saline controls (p < 0.001); in fact, the scores from the animals that received this dose were statistically similar to those in the no injury control group. This ef-fect was not seen with the lower dose of MgSO4 (100 mg/kg). Similar results were seen for the higher but not lower dose of MgSO4 for measurements of intracytoplasmic edema, nuclear protection, and axon myelin. Both doses of MgSO4 improved the axonal score (a measure of axo-nal injury) compared with the no treatment control (p < 0.05), and the improvements were statistically similar to the no injury control group.

Spinal cord lactate and/or MDA levels were assessed in 2 studies. Lactate accumulation and MDA formation occur following neural injury. Ozdemir et al.53 found that rabbits treated with 100 mg/kg MgSO4 5 minutes after SCI had significantly lower lactate and MDA levels than animals treated with saline. Furthermore, these levels were statistically similar to those seen in the no injury control animals. Szer et al.69 reported similarly decreased MDA levels 24 hours postinjury in rats treated with a higher dose (600 mg/kg) but not a lower dose (300 mg/kg) of MgSO4 1 hour after SCI.

Gok et al.26 reported that infiltration of neutrophils into the spinal cord region, as evaluated by myeloperoxi-dase activity of spinal cord homogenates, was significant-ly reduced in animals treated with MgSO4 (or methyl-prednisolone) compared with saline (p < 0.05). Treatment was given immediately after trauma; the time at which the tissue samples were collected was not reported.

Vascular permeability was assessed at 2 and 24 hours following SCI in rats treated with 600 mg/kg MgSO4 im-mediately after trauma by Kaptanoglu and colleagues.36 The authors evaluated the extent of bloodspinal cord barrier damage and the increase in microvascular per-meability by using a 10-minute perfusion of Evans blue dye. Animals treated with MgSO4 had lower Evans blue content and thus lower vascular permeability than the trauma group at both 2 and 24 hours, although the Evans blue content was still higher than in the no trauma control animals. Furthermore, Evans blue content increased with time in the trauma group who received no MgSO4. These T

ABLE

10: C

hara

cter

istic

s of S

CI an

imal

stud

ies u

sing

glyb

urid

e (gl

iben

clam

ide)

* (co

ntin

ued)

Auth

ors &

Ye

arAn

imal

& Inj

ury M

odels

Expe

rimen

tal

Grou

psInt

erve

ntion

Det

ails

Repo

rted O

utcom

esCo

mmen

ts

Sima

rd et

al.,

20

10An

imal

mode

l:Ra

tsN

= 10

SCI m

odel:

Rats

had a

unila

t cer

vical

injur

y

SCI +

glibe

nclam

ide

(n

= 5)

SCI +

salin

e/DM

SO

(n

= 5)

Route

: sub

cuta

neou

s inj

Dosa

ge &

timing

:W

/in 15

min

of SC

I, a lo

ading

dose

of gl

iben-

clami

de (1

0 g/

kg) w

as gi

ven I

PCo

nt inf

usion

of gl

ibenc

lamide

(200

ng/h

r

subc

utan

eous

ly fo

r 7 da

ys)

Anim

als ki

lled:

NR

Glib

encla

mid

e Tx

in ra

ts re

sulte

d in

sig

nific

antly

(p

Farmacoterapia en TVM.pdf

Documents

Transcript of Farmacoterapia en TVM.pdf