Impact of statins on cognitive deficits in adult male rodents after traumatic brain injury: a systematic review

Weijun Peng, Jingjing Yang, Bo Yang, Lexing Wang, Xin-gui Xiong, Qinghua Liang, Weijun Peng, Jingjing Yang, Bo Yang, Lexing Wang, Xin-gui Xiong, Qinghua Liang

Abstract

The efficacy of statin treatment on cognitive decline is controversial, and the effect of statins on cognitive deficits in individuals with traumatic brain injury (TBI) has yet to be investigated. Therefore, we systematically reviewed the effect of statins on cognitive deficits in adult male rodents after TBI. After identifying eligible studies by searching four electronic databases on February 28, 2014, we assessed study quality, evaluated the efficacy of statin treatment, and performed stratified metaregression and metaregression to assess the influence of study design on statin efficacy. Eleven studies fulfilled our inclusion criteria from a total of 183 publications. The overall methodological quality of these studies was poor. Meta-analysis showed that statins exert statistically significant positive effects on cognitive performance after TBI. Stratified analysis showed that atorvastatin has the greatest effect on acquisition memory, simvastatin has the greatest effect on retention memory, and statin effects on acquisition memory are higher in closed head injury models. Metaregression analysis further showed that that animal species, study quality, and anesthetic agent impact statin effects on retention memory. We conclude that statins might reduce cognitive deficits after TBI. However, additional well-designed and well-reported animal studies are needed to inform further clinical study.

Figures

Figure 1
Figure 1
Flow diagram of study search process.
Figure 2
Figure 2
Effects of statins on acquisition memory (a) and retention memory (b). Horizontal lines represent the mean estimated effect size and 95% CI for each comparison. Vertical gray bars represent the 95% CI of the pooled estimated effect size.
Figure 3
Figure 3
Effect size for acquisition memory stratified by (a) type of statin, (b) dose, (c) quality of study, and (d) animal species. Grey bands represent the 95% CI for the global estimated effect size.
Figure 4
Figure 4
Effect size for retention memory stratified by (a) type of statin, (b) dose, (c) quality of study, and (d) animal species. Grey bands represent the 95% CI for the global estimated effect size.
Figure 5
Figure 5
Effect size for acquisition memory stratified by (a) method of TBI induction, (b) anesthetic agent, and (c) route of drug delivery. Grey bands represent the 95% CI for the global estimated effect size.
Figure 6
Figure 6
Effect size for retention memory stratified by (a) method of TBI induction and (b) anesthetic agent. Grey bands represent the 95% CI for the global estimated effect size.
Figure 7
Figure 7
Funnel plot for acquisition memory (a) and retention memory (b).

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Source: PubMed

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