Association between human herpesviruses and multiple sclerosis: A systematic review and meta-analysis.

AIM: The aim of this study was to investigate the prevalence and potential association between infection with different herpes viruses and multiple sclerosis (MS). METHODS: A systematic literature search was performed by finding relevant cross-sectional and case-control studies from a large online database. Heterogeneity, Odds ratio (OR), and corresponding 95% Confidence interval (CI) were applied to all studies by meta-analysis and forest plots. The analysis was performed using Stata Software v.14. RESULTS: One hundred and thirty-four articles (289 datasets) were included in the meta-analysis, 128 (245 datasets) of which were case/control and the rest were cross-sectional. The pooled prevalence of all human herpes viruses among MS patients was 50% (95% CI: 45-55%; I2 = 96.91%). In subgroup analysis, the pooled prevalence of Herpes simplex virus (HSV), Varicella-zoster virus (VZV), Epstein-Barr virus (EBV), Cytomegalovirus (CMV), Human herpes virus 6 (HHV-6), Human herpes virus 7 (HHV-7), and Human herpes virus 8 (HHV-8) was 32%, 52%, 74%, 41%, 39% 28%, and 28%, respectively. An association was found between infection with human herpes viruses and MS [summary OR 2.07 (95% CI (1.80-2.37); I2 = 80%)]. CONCLUSION: The results of the present study showed that EBV, VZV, and HHV-6 infection are associated with multiple sclerosis and can be considered as potential risk factors for MS. Although the exact molecular mechanism of the role of herpes viruses in the development of MS is still unknown, it seems that molecular mimicry, the release of autoreactive antibodies, and inflammation in the CNS following viral infection can be important factors in the induction of MS.

Recent advancements to engineer mesenchymal stem cells and their extracellular vesicles for targeting and destroying tumors.

Mesenchymal stem cells (MSCs) have the ability to migrate into tumor sites and release growth factors to modulate the tumor microenvironment. MSC therapy have shown a dual role in cancers, promoting or inhibiting. However, MSCs could be used as a carrier of anticancer agents for targeted tumor therapy. Recent technical improvements also allow engineering MSCs to improve tumor-targeting properties, protect anticancer agents, and decrease the cytotoxicity of drugs. While some of MSC functions are mediated through their secretome, MSCs-derived extracellular vesicles (EVs) are also proposed as a possible viechle for cancer therapy. EVs allow efficient loading of anticancer agents and have an intrinsic ability to target tumor cells, making them suitable for targeted therapy of tumors. In addition, the specificity and selectivity of EVs to the tumor sites could be enhanced by surface modification. In this review, we addressed the current approaches used for engineering MSCs and EVs to effectively target tumor sites and deliver anticancer agents.