Gut Microbiota and Acylcarnitine Metabolites Connect the Beneficial Association between Estrogen and Lipid Metabolism Disorders in Ovariectomized Mice

High-Coverage Metabolomics Reveals Gut Microbiota-Related Metabolic Traits of Type-2 Diabetes in Serum

Metabolic perturbations of the gut microbiome have been implicated in the pathogenesis of multiple human diseases, including type-2 diabetes (T2D). However, our understanding of the global metabolic alterations of the gut microbiota in T2D and their functional roles remains limited. To address this, we conducted a high-coverage metabolomics profiling analysis of serum samples from 1282 Chinese individuals with and without T2D. Among the 220 detected microbiota-associated compounds detected, 111 were significantly altered, forming a highly interactive regulatory network associated with T2D development. Pathway enrichment and correlation analyses revealed aberrant metabolic pathways, primarily including the activation of pyrimidine metabolism, unsaturated fatty acid biosynthesis, and diverse amino acid metabolisms such as Tryptophan metabolism, Lysine metabolism, and Branched-chain amino acid biosynthesis. A microbiota-dependent biomarker panel, comprising pipecolinic acid, methoxysalicylic acid, N-acetylhistamine, and 3-hydroxybutyrylcarnitine, was defined and validated with satisfactory sensitivity (>78%) for large-scale, population-based T2D screening. The functional role of a gut microbial product, N-acetylhistamine, was further elucidated in T2D progression through its inhibition of adenosine monophosphate-activated protein kinase phosphorylation. Overall, this study expands our understanding of gut microbiota-driven metabolic dysregulation in T2D and suggests that monitoring these metabolic changes could facilitate the diagnosis and treatment of T2D.

The associations between prenatal plastic phthalate exposure and lipid acylcarnitine levels in humans and mice

Phthalates are ubiquitous environmental pollutants known for their endocrine-disrupting properties, particularly during critical periods such as pregnancy and early childhood. Phthalates alter lipid metabolism, but the role of prenatal exposure on the offspring lipidome is less understood. In particular, we focused on long chain acylcarnitines - intermediates of fatty acid oxidation that serve as potential biomarkers of mitochondrial function and energy metabolism. This study aimed (i) to investigate the association between prenatal phthalate exposure and the child's blood acylcarnitine concentrations and, (ii) to evaluate the impact of prenatal administration of di-(2-ethylhexyl) phthalate (DEHP) on acylcarnitine levels in mouse offspring blood, brain and liver. We conducted analyses of both a prospective birth cohort study and an experimental study in mice. From the Barwon Infant Study cohort (1074 mother-child pairs), prenatal phthalate exposure was assessed at 36 weeks' gestation and its association with acylcarnitine levels was examined in cord blood, and child's blood at 6 months, 12 months and 4 years. In mice, pregnant C57BL/6 J mouse dams were exposed to 20 μg/kg DEHP for 5 days mid-gestation, and offspring tissues were analyzed at 1 month of age postnatally for acylcarnitine profiles. Our findings demonstrate that prenatal phthalate levels (specifically butyl benzyl phthalate (BBzP) and diisobutyl phthalate (DiBP)) are inversely associated with total long chain acylcarnitine levels in human cord blood at birth. In contrast, BBzP was positively associated with the long chain acylcarnitines at 12 months of age. In mice, prenatal DEHP exposure for only 5 days led to decreased palmitoylcarnitine (AC16:0) levels in the brain and liver, but not in blood. Taken together, our findings highlight that prenatal phthalate exposure can alter acylcarnitine profiles, indicating disruptions in fatty acid metabolism that may have long-term effects on metabolic health.

Menopause and Alzheimer's disease susceptibility: Exploring the potential mechanisms

Alzheimer's Disease (AD), responsible for 62% of all dementia cases, is a progressive neurodegenerative condition that leads to cognitive dysfunction. The prevalence of AD is consistently higher in women suggesting they are disproportionately affected by this disease. Despite this, our understanding of this female AD vulnerability remains limited. Menopause has been identified as a potential contributing factor to AD in women, with earlier menopause onset associated with greater AD risk. However, the underlying mechanisms responsible for this increased risk are not fully understood. This review examines the potential role of menopause in the development of Alzheimer's Disease providing a mechanistic overview of the available literature from hormones to pathology. While literature is now emerging that indicates a role of hormonal shifts, gut dysbiosis, lipid dysregulation and inflammation, more research is needed to fully elucidate the mechanisms involved.

New Modifiable Risk Factors Influencing Coronary Artery Disease Severity

Cardiovascular diseases (CVDs) remain the leading cause of death worldwide with coronary artery disease (CAD) being the first culprit in this group. In terms of CAD, not only its presence but also its severity plays a role in the patient's treatment and prognosis. CAD complexity can be assessed with the indicator named the SYNTAX score (SS). A higher SS is associated with major adverse cardiovascular event (MACE) occurrence in short- and long-term observations. Hence, the risk factors affecting CAD severity based on SS results may help lower the risk among patients with already developed CAD to reduce their impact on coronary atherosclerosis progression. The well-established risk factors of CAD are consistent with those associated with the coronary plaque burden. However, recently, it was shown that new indicators exist, which we present in this paper, that significantly contribute to CAD complexity such as inflammatory parameters, C-reactive protein (CRP), ratios based on blood smear results, and uric acid. Moreover, microbiota alteration, vitamin D deficiency, and obstructive sleep apnea (OSA) also predicted CAD severity. However, sometimes, certain indicators were revealed as significant only in terms of chronic coronary syndromes (CCSs) or specific acute coronary syndromes (ACSs). Importantly, there is a need to apply the interdisciplinary and translational approach to the novel CAD severity risk assessment to maximize the impact of secondary prevention among patients at risk of coronary atherosclerosis progression.

17β-Estradiol protects female rats from bilateral oophorectomy-induced nonalcoholic fatty liver disease induced by improving linoleic acid metabolism alteration and gut microbiota disturbance

After surgical or natural menopause, women face a high risk of nonalcoholic fatty liver disease (NAFLD), which can be diminished by hormone replacement therapy (HRT). The gut microbiota is subject to modulation by various physiological changes and the progression of diseases. This microbial ecosystem coexists symbiotically with the host, playing pivotal roles in immune maturation, microbial defense mechanisms, and metabolic functions essential for nutritional and hormone homeostasis. E2 supplementation effectively prevented the development of NAFLD after bilateral oophorectomy (OVX) in female rats. The changes in the gut microbiota such as abnormal biosynthetic metabolism of fatty acids caused by OVX were partially restored by E2 supplementation. The combination of liver transcriptomics and metabolomics analysis revealed that linoleic acid (LA) metabolism, a pivotal pathway in fatty acids metabolism was mainly manipulated during the induction and treatment of NAFLD. Further correlation analysis indicated that the gut microbes were associated with abnormal serum indicators and different LA metabolites. These metabolites are also closely related to serum indicators of NAFLD. An in vitro study verified that LA is an inducer of hepatic steatosis. The changes in transcription in the LA metabolism pathway could be normalized by E2 treatment. The metabolic perturbations of LA may directly and secondhand impact the development of NAFLD in postmenopausal individuals. This research focused on the sex-specific pathophysiology and treatment of NAFLD, providing more evidence for HRT and calling for the multitiered management of NAFLD.

Unravelling the Crosstalk between Estrogen Deficiency and Gut-biotaDysbiosis in the Development of Diabetes Mellitus

Estrogens are classically considered essential hormonal signals, but they exert profound effects in a number of physiological and pathological states, including glucose homeostasis and insulin resistance. Estrogen deficiency after menopause in most women leads to increased androgenicity and changes in body composition, and it is recommended to manipulate the β-cell function of the pancreas, insulin-induced glucose transport, and hepatic glucose output, hence, the increasing incidence of type 2 diabetes mellitus. Recently, studies have reported that gut biota alteration due to estrogen deficiency contributes to altered energy metabolism and, hence, accentuates the pathology of diabetes mellitus. Emerging research suggests estrogen deficiency via genetic disposition or failure of ovaries to function in old age modulates the insulin resistance and glucose secretion workload on pancreatic beta cells by decreasing the levels of good bacteria such as Akkermansia muciniphila, Bifidobacterium spp., Lactobacillus spp., Faecalibacterium prausnitzii, Roseburia spp., and Prevotella spp., and increasing the levels of bad bacteria's such as Bacteroides spp., Clostridium difficile, Escherichia coli, and Enterococcus spp. Alteration in these bacteria's concentrations in the gut further leads to the development of impaired glucose uptake by the muscles, increased gluconeogenesis in the liver, and increased lipolysis and inflammation in the adipose tissues. Thus, the present review paper aims to clarify the intricate interactions between estrogen deficiency, gut microbiota regulation, and the development of diabetes mellitus.