The Effects of Statins on Infections after Stroke or Transient Ischemic Attack: A Meta-Analysis

New Directions in Infection-Associated Ischemic Stroke

The relationship between infections and stroke has not been fully characterized, probably delaying the development of specific treatments. This narrative review addresses mechanisms of stroke linked to infections, including hypercoagulability, endothelial dysfunction, vasculitis, and impaired thrombolysis. SARS-CoV-2, the virus that causes COVID-19, may promote the development of stroke, which may represent its most severe neurological complication. The development of specific therapies for infection-associated stroke remains a profound challenge. Perhaps the most important remaining issue is the distinction between infections that trigger a stroke versus infections that are truly incidental. This distinction likely requires the establishment of appropriate biomarkers, candidates of which are elevated levels of fibrin D-dimer and anticardiolipin/antiphospholipid antibodies. These candidate biomarkers might have potential use in identifying pathogenic infections preceding stroke, which is a precursor to establishing specific therapies for this syndrome.

The Association between Statins Intake and Risk of Post Stroke Pneumonia: A Systematic Review and Meta-Analysis

AIM

This research aimed to examine the relationship between the intake of statins and the risk of post-stroke pneumonia in a systematic review and meta-analysis study.

METHODS

An extensive search of published articles on March 21st, 2023, was done in several databases, like Web of Science (ISI), PubMed, Cochrane Library, Embase, Scopus, and Google Scholar. The Newcastle Ottawa Scale (NOS) checklist was employed to evaluate the quality of observational studies. Statistical tests (Chi-square test and I2) and graphical techniques (Forest plot) were used to determine whether heterogeneity existed in the meta-analysis studies. Funnel plots and Begg and Egger's tests were used to assess the publication bias.

RESULTS

Seven studies (5 cohort and 2 case-control studies) were retrieved to examine the association between statins and post-stroke pneumonia. The sample size of the studies compiled in the meta- analysis was obtained to be 68,966 participants. Meta-analysis demonstrated that the overall odds of post-stroke pneumonia in the statin group was equal to 0.87 (95% CI: 0.67 - 1.13; p-value 0.458). Subgroup analysis indicated that the odds of post-stroke pneumonia in the statin group was equal to 0.93 (95% CI: 0.73-1.18; p-value = 0.558) in the cohort studies, and equal to 0.92 (95% CI: 0.37-2.26; p-value = 0.857) in the case-control studies. The examination of the association between the intake of statins and post-stroke pneumonia showed no evidence of publication bias (Begg's test, p-value = 0.368; Eggers test, p-value = 0.282).

CONCLUSION

In this study, no relationship has been observed between receiving statins and the risk of post-stroke pneumonia.

Herb Formula (GCis) Prevents Pulmonary Infection Secondary to Intracerebral Hemorrhage by Enhancing Peripheral Immunity and Intestinal Mucosal Immune Barrier

Lung infection is a common complication induced by stroke and seriously affects the prognosis and life quality of patients. However, effective therapeutic strategies are still lacking. In the present study, the herb formula GCis was confirmed to prevent pulmonary infection induced by intracerebral hemorrhage (ICH). The animal model of lung infection induced by ICH, GCis (Ginseng Radix et Rhizoma, Aconiti Lateralis Radix Praeparata, and Cistanches Herba) was orally administrated every day for 7 days. Lung microbial biomass and pathological results showed that the GCis formula pretreatment significantly reduced lung bacterial biomass and alleviated pathological abnormalities. These results indicated that the GCis formula has a clear pharmacological effect on preventing lung infection induced by ICH. Immunosuppression induced by ICH seemed to be the main mechanism of lung infection. Our results showed that the spleen and thymus indexes, WBC, and LY% contents were significantly increased in the GCis formula group. Moreover, bone marrow cells were further analyzed by transcriptome sequencing, and GO and KEGG enrichment analysis results showed that immune function was the main pathway enriched by differential genes after GCis formula intervention. More importantly, our results showed that GCis pretreatment had no significant effect on the mRNA expression of IL-1β, IL-6, and TNF-α in the brain. These results indicated that the GCis formula could enhance immunity after ICH. The intestinal barrier function was further investigated in the present study, considering the origin of the source of infection. Our results showed that the mRNA expressions of intestinal ZO-1, SIgA, and MUC2 were significantly increased, villi structure was intact, inflammatory cell infiltration was reduced, and goblet cell number was increased after GCis formula treatment. These results suggest that the GCis formula can enhance the intestinal mucosal immune barrier. This study provides a herb formula (GCis) that could enhance peripheral immunity and intestinal mucosal immune barrier to prevent pulmonary infection induced by ICH. It would be beneficial in the prevention of severe clinical infections.

Effect of Statins on the Risk of Poststroke Pneumonia: National Population-Based Cohort Study

Purpose

Statins are widely prescribed medications for treatment of dyslipidemia and prevention of cardiovascular disease. Beyond their lipid-lowering property, statins exhibit multiple pleiotropic and antimicrobial effects. We aimed to investigate the effect of statins on the long-term risk of pneumonia after acute ischemic stroke.

Methods

This retrospective observational research was performed using South Korean National Health Insurance Service claim data, which consist of population-based random sampling. We included patients discharged with acute ischemic stroke (I63 in the ICD10) and no prior history of pneumonia. The primary outcome measure was the occurrence of pneumonia determined based on ICD10 code J09–J18. Treatment with statins during follow-up was collected as a time-dependent variable based on prescription records.

Results

A total of 7,001 subjects with acute ischemic stroke and no prior history of pneumonia were included. During the mean 3.96-year follow-up, pneumonia occurred in 1,715 subjects (24.5%). On multivariate time-dependent Cox proportional hazard–regression analyses, significant preventive benefit of treatment with statins against pneumonia was noted (adjusted HR 0.86, 95% CI 0.77–0.97). Compared to no use of statin, adjusted HRs (95% CIs) for current use of low–intermediate high-intensity statins were 0.88 (0.78–0.99) and 0.49 (0.27–0.87), respectively.

Conclusion

Our retrospective national cohort study found reduced risk of poststroke pneumonia with statin therapy after acute ischemic stroke. Our study suggests that treatment with statins may have a preventive effect against the common complication of poststroke pneumonia.

Old Dog New Tricks; Revisiting How Stroke Modulates the Systemic Immune Landscape

Infections in the post-acute phase of cerebral ischaemia impede optimal recovery by exacerbating morbidity and mortality. Our review aims to reconcile the increased infection susceptibility of patients post-stroke by consolidating our understanding of compartmentalised alterations to systemic immunity. Mounting evidence has catalogued alterations to numerous immune cell populations but an understanding of the mechanisms of long-range communication between the immune system, nervous system and other organs beyond the involvement of autonomic signalling is lacking. By taking our cues from established and emerging concepts of neuro-immune interactions, immune-mediated inter-organ cross-talk, innate immune training and the role of microbiota-derived signals in central nervous system (CNS) function we will explore mechanisms of how cerebral ischaemia could shape systemic immune function. In this context, we will also discuss a key question: how are immune requirements critical for mediating repair of the ischaemic insult balanced by the need for anti-microbial immunity post-stroke, given that they are mediated by mutually exclusive immune networks? Our reformed understanding of the immune landscape post-stroke and novel mechanisms at play could guide targeted therapeutic interventions and initiate a step-change in the clinical management of these infectious complications post-stroke.

Statin use in cirrhotic patients with infectious diseases: A population-based study

Background

Recent studies have shown benefits of statins in patients with liver cirrhosis. However, it is still unknown if statins have a beneficial effect on the mortality of cirrhotic patients with bacterial infections.

Methods

The Taiwan National Health Insurance Database was searched, and 816 cirrhotic patients receiving statins with bacterial infections hospitalized between January 1, 2010 and December 31, 2013 were included in the study. A one-to-four propensity score matching was performed to select a comparison group based on age, sex, and comorbid disorders.

Results

The overall 30-day mortalities in statin and non-statin group were 5.3% and 9.8%, respectively (P = 0.001). After Cox regression modeling adjusting for age, sex, and comorbid disorders, the hazard ratio (HR) of statin use on 30-day mortality was 0.52 (95% confidence interval [CI]: 0.38–0.72, P<0.001). In subgroup analysis, the 30-day mortality effect of statin use was more pronounced in patients with pneumonia (HR = 0.34; 95% CI: 0.19–0.59; P<0.001) and bacteremia (HR = 0.55; 95% CI: 0.35–0.85; P = 0.008). Atovastatin (HR = 0.59; 95% CI: 0.37–0.93) and rosuvastatin (HR = 0.59; 95% CI: 0.36–0.98) were associated with a decreased 30-day mortality risk compared to patients not taking statins.

Conclusions

Statin use decreases the 30-day mortality of cirrhotic patients with bacteremia and pneumonia.

Serum prealbumin is a predictive biomarker for stroke-associated infection after an ischemic stroke

BACKGROUND

Several prior studies have linked serum prealbumin (PA) as a predictor for perioperative infection. However, whether peripheral blood PA levels can be used as an indicator of stroke-associated infection (SAI) is still unclear. In this study, we attempt to find whether serum PA is a meaningful predictor in SAI after an ischemic stroke, so as to provide theoretical basis for clinical treatment.

METHODS

Consecutive patients with acute ischemic stroke who were admitted to our hospital were enrolled and serum PA was collected. A prospective study was conducted to observe the predictive value of PA in the SAI incident in ischemic stroke patients.

RESULTS

Of 104 patients, 29 (27.9%) developed an SAI after 7 d of follow-up. The stroke with SAI group had significantly lower PA levels than the stroke without SAI group (  p < 0.05). The optimal cutoff value for predicting SAI was PA ≤ 191 mg/L, with sensitivity and specificity of 58.62% and 81.33%, respectively. Kaplan-Meier survival analysis showed that stroke patients with low serum PA level (PA ≤ 191 mg/L) had a higher SAI rates (log-rank test, χ² = 16.870, p < 0.001). Cox regression analysis showed that PA ≤ 191 mg/L (hazard ratio = 3.207; 95% CI, 1.430-7.190, p = 0.005) was an independent risk factor for SAI.

CONCLUSIONS

Early detection of serum PA during the acute phase of ischemic stroke may help us to identify at-risk SAI patients, and hence rapidly guide the intervention to prevent SAI.