Cutaneous Application of Capsaicin Cream Reduces Clinical Signs of Experimental Colitis and Repairs Intestinal Barrier Integrity by Modulating the Gut Microbiota and Tight Junction Proteins.

Capsaicin, a pungent compound in chili peppers, is described as having potent anti-inflammatory, antioxidant, and antimicrobial properties. It is also described as a potential modulator of the immune system and intestinal microbiota. Oral or rectal administration of capsaicin has been studied to treat or prevent colitis. However, those vias are often not well accepted due to the burning sensation that capsaicin can cause. Our objective was to evaluate whether the application of capsaicin skin creams (0.075%) would be effective in improving inflammation and epithelial barrier function as well as the composition of the gut microbiota in a model of mild colitis induced by dextran sulfate sodium (1.5%). The results showed that the cutaneous application of capsaicin reversed weight loss and decreased colon shortening and diarrhea, all typical signs of colitis. There was also an improvement in the intestinal epithelial barrier, preserving proteins from tight junctions. We also evaluated the biodistribution of 99mtechnetium-radiolabeled capsaicin (99mTc-CAPS) applied to the back skin of the animals. We found significant concentrations of 99 mTc-Cap in the colon and small intestine after 2 and 4 h of administration. In addition, there was an increased expression of capsaicin receptor TRPV1 in the colon. Moreover, animals with colitis receiving cutaneous capsaicin presented a better short-chain fatty acid profile and increased levels of SIgA, suggesting increased microbiota diversity. In conclusion, our work opens avenues for further studies to better understand capsaicin's potential benefits and mechanisms in addressing colitis through cutaneous application.

Evaluation of the Treatment with Akkermansia muciniphila BAA-835 of Chemotherapy-induced Mucositis in Mice.

Mucositis is a high-incidence side effect in cancer patients undergoing chemotherapy. Next-generation probiotics are emerging as new therapeutic tools for managing various disorders. Studies have demonstrated the potential of Akkermansia muciniphila to increase the efficiency of anticancer treatment and to mitigate mucositis. Due to the beneficial effect of A. muciniphila on the host, we evaluated the dose-response, the microorganism viability, and the treatment protocol of A. muciniphila BAA-835 in a murine model of chemotherapy-induced mucositis. Female Balb/c mice were divided into groups that received either sterile 0.9% saline or A. muciniphila by gavage. Mucositis was induced using a single intraperitoneal injection of 5-fluorouracil. The animals were euthanized three days after the induction of mucositis, and tissue and blood were collected for analysis. Prevention of weight loss and small intestine shortening and reduction of neutrophil and eosinophil influx were observed when animals were pretreated with viable A. muciniphila at 1010 colony-forming units per mL (CFU/mL). The A. muciniphila improved mucosal damage by preserving tissue architecture and increasing villus height and goblet cell number. It also improved the integrity of the epithelial barrier, decreasing intestinal permeability and bacterial translocation. In addition, the treatment prevented the expansion of Enterobacteriaceae. The immunological parameters were also improved by decreasing the expression of pro-inflammatory cytokines (IL6, IL1ß, and TNF) and increasing IL10. In conclusion, pretreatment with 1010 CFU/mL of viable A. muciniphila effectively controlled inflammation, protected the intestinal mucosa and the epithelial barrier, and prevented Enterobacteriaceae expansion in treated mice.

Are We Ready to Recommend Capsaicin for Disorders Other Than Neuropathic Pain?

Capsaicin, a lipophilic, volatile compound, is responsible for the pungent properties of chili peppers. In recent years, a significant increase in investigations into its properties has allowed the production of new formulations and the development of tools with biotechnological, diagnostic, and potential therapeutic applications. Most of these studies show beneficial effects, improving antioxidant and anti-inflammatory status, inducing thermogenesis, and reducing white adipose tissue. Other mechanisms, including reducing food intake and improving intestinal dysbiosis, are also described. In this way, the possible clinical application of such compound is expanding every year. This opinion article aims to provide a synthesis of recent findings regarding the mechanisms by which capsaicin participates in the control of non-communicable diseases such as obesity, diabetes, and dyslipidemia.

Oral methylmercury intoxication aggravates cardiovascular risk factors and accelerates atherosclerosis lesion development in ApoE knockout and C57BL/6 mice.

Methylmercury (MeHg) intoxication is associated with hypertension, hypercholesterolemia, and atherosclerosis by mechanisms that are not yet fully understood. We investigated the effects of MeHg intoxication in atherosclerosis-prone (ApoE-KO) and resistant C57BL/6 mice. Mice were submitted to carotid stenosis surgery (to induce atherosclerosis faster) and received water or MeHg solution (20 mg/L) for 15 days. Tail plethysmography was performed before and after MeHg exposure. Food and MeHg solution intakes were monitored weekly. On the 15th day, mice were submitted to intravital fluorescence microscopy of mesenteric vasculature to observe in vivo leukocyte rolling and adhesion. Results showed that despite the high hair and liver Hg concentrations in the MeHg group, food and water (or MeHg solution) consumption and liver function marker levels were similar to those in controls. MeHg exposure increased total cholesterol, the atherogenic (non-HDL) fraction and systolic and diastolic blood pressure. MeHg exposure also induced inflammation, as seen by the increased rolling and adhered leukocytes in the mesenteric vasculature. Atherosclerosis lesions were more extensive in the aorta and carotid sites of MeHg-ApoE knockout mice. Surprisingly, MeHg exposure also induced atherosclerosis lesions in C57BL/6 mice, which are resistant to atherosclerosis formation. We concluded that MeHg intoxication might represent a risk for cardiovascular diseases since it accelerates atherogenesis by exacerbating several independent risk factors.