Background/Aims: MicroRNA (miRNA) isoforms (isomiRs) broaden the regulatory landscape of canonical miRNAs, but their role in metabolic dysfunction-associated steatotic liver disease (MASLD) remains unknown. We aimed to characterize the hepatic isomiR landscape in MASLD and define their association with disease activity and fibrosis. Methods: Small RNA (sRNA) sequencing was performed on liver biopsies from 79 patients across the histological spectrum of MASLD. IsomiRs were annotated and quantified. Their association to disease activity and fibrosis score was assessed by differential expression, ordinal regression, and machine learning. Parallel mRNA sequencing and pathway enrichment were used to map isomiR–mRNA interactions and regulatory networks, which were validated against an independent dataset. Results: MiRNAs accounted for 75% of sRNAs in liver tissue, of which 67% were isomiRs. Across MASLD severity, 173 isomiRs correlated with disease activity and 58 with fibrosis stage. Key findings included a miR-122 isomiR uniquely targeting INSIG1 (cholesterol metabolism) and a miR-21 isomiR targeting PPARA and HMGCS2 (lipid and fibrosis pathways). Integration with mRNA data revealed 33 dysregulated pathways, including PPAR signaling, insulin resistance, and TGF-β response. Several novel isomiRs from miR-26b, let-7c, and miR-32 families were also linked to lipid metabolism and fibrosis progression. Conclusions IsomiRs represent the majority of hepatic miRNAs and uncover novel regulatory networks masked by canonical miRNA analysis. These findings provide new insights into the molecular heterogeneity of MASLD, highlight candidate pathways driving disease progression, and identify potential biomarkers and therapeutic targets for precision hepatology.

Testosterone deficiency (TD) is an increasingly common problem with significant health implications, but its diagnosis and management can be challenging. A multi-disciplinary panel from BSSM reviewed the available literature on TD and provide evidence-based statements for clinical practice. Evidence was derived from Medline, EMBASE and Cochrane searches on hypogonadism, testosterone therapy (T Therapy) and cardiovascular safety from May 2017 to September 2022. This revealed 1,714 articles, including 52 clinical trials and 32 placebo-controlled randomised controlled trials. A total of twenty-five statements are provided, relating to five key areas: screening, diagnosis, initiating T Therapy, benefits and risks of T Therapy, and follow-up. Seven statements are supported by level 1 evidence, eight by level 2, five by level 3, and five by level 4. Recent studies have demonstrated that low levels of testosterone in men are associated with increased risk of incident type 2 diabetes mellitus, worse outcomes in chronic kidney disease and COVID 19 infection with increased all-cause mortality, along with significant quality of life implications. These guidelines should help practitioners to effectively diagnose and manage primary and age-related TD.

The aim of the present study was to investigate the modulatory role of activated 5-HT(3) receptors in the central amygdala (CeA) on mitogen concanavalin A (ConA)-stimulated proliferative response of thymocytes in rats and the underlying neuroendocrine regulation circuits. 1-phenylbiguanide (PBG), a putative selective 5-HT(3) receptor agonist, was administered by intraperitoneal (i.p.), bilateral intracerebroventriclular (i.c.v.), and bilateral intracentral amygdala (i.c.a.) injection. In addition, thymocytes isolated from untreated rats were incubated with PBG (at a range of concentrations of 1x10(-8)-1x10(-5) mol/L) in vitro in the presence and absence of ConA, in order to investigate any direct effect of PBG on the proliferation in vitro. MTT method was applied to demonstrate the effect of PBG on the proliferative response of thymocytes. An immunohistochemical SABC assay was used to describe the expression profiles of c-Fos-positive cells in different brain regions including the CeA, hippocampus, cortex, hypothalamus and periaqueductal gray (PAG) at 1, 2, 4 and 8 h after bilateral single-administration of PBG by i.c.a. (1.0 microg/side). Results showed that PBG (1x10(-8)-1x10(-5) mol/L) had no significant influence on the proliferative responses of the isolated thymocytes in vitro, no matter ConA was present or not. The proliferation of thymocytes stimulated by ConA was not significantly changed when PBG was administered by i.p. (0.5 mg/kg per day, for consecutive 5 d), whereas it was remarkably enhanced after bilateral i.c.v. injection of PBG (10 microg/side per day, for consecutive 5 d). Similarly, when PBG was injected bilaterally by i.c.a. (1.0 microg/side per day, for 1 d or consecutive 3, 5 and 7 d), a significantly enhanced proliferation occurred on the 1st day and continued until reaching its peak on the 5th day before decreasing on the 7th day. All of the promoting effects of PBG on the ConA-stimulated proliferation of thymocytes were reversed by pretreatment with the 5-HT(3) receptor antagonist tropisetron (TRP) 5 min prior to the administration of PBG. Interestingly, compared to the treatment with normal saline or TRP + PBG, after a bilateral single-administration of PBG (1.0 microg/side) by i.c.a., the number of c-Fos-positive cells in different brain regions significantly increased at 1 h in the CeA, 1-2 h in the hippocampus, 1-2 h in the cortex, 4 h in the hypothalamus and 8 h in the PAG, respectively, with each maximum response at 1 h in the CeA, 2 h in the hippocampus and cortex, and 4 h in the hypothalamus. Subsequently, the number of cells expressing c-Fos gradually reduced to the minimum at 4 h in the CeA, and at 8 h in the hippocampus, cortex and hypothalamus. In conclusion, the 5-HT(3) receptors in the CeA of rats mediate the modulation of thymus function, at least partly, through the neuroendocrine circuit of the limbic system-cortex-hypothalamus-PAG.
Amygdala ; metabolism ; physiology ; Animals ; Male ; Neuroimmunomodulation ; physiology ; Rats ; Rats, Sprague-Dawley ; Receptors, Serotonin, 5-HT3 ; metabolism ; physiology ; Thymus Gland ; cytology ; physiology