Diet-induced obese mouse hearts tolerate an acute high-fatty acid exposure that also increases ischemic tolerance

The isolated, perfused working heart preparation of the mouse-Advantages and pitfalls

Isolated, perfused hearts are viable for hours outside the body, and important research findings have been made using mouse hearts ex vivo. In the Langendorff perfusion mode, the coronary tree is perfused via retrograde flow of a perfusate down the ascending aorta. Although the Langendorff setup is generally simpler and quicker to establish, the working heart mode allows the heart to function in a more physiologically relevant manner, where the perfusate is directed into the left ventricle via the left atrium. The contracting, fluid-filled ventricle will eject the perfusate into the aorta in a more physiologically relevant manner, lifting the physiological relevance of the contractile and energetic data. The workload on the heart (preload, afterload and heart rate) can be precisely adjusted in the working, isolated heart, and the ventricular performance, for example, end-diastolic and end-systolic pressures, stroke volume, cardiac output, and oxygen consumption can be determined. Moreover, using pressure-volume catheters, ventricular performance can be assessed in great detail. With the present review, we highlight the benefits and drawbacks of the technique and indicate where particular attention must be put when building the working heart setup, designing experiments, executing the studies, and analyzing the obtained data.

White Tea Consumption Alleviates Anthropometric and Metabolic Parameters in Obese Patients

Background and Objectives: Obesity and related disorders are an increasing global health problem. Achieving and maintaining long-term weight loss through lifestyle changes and/or pharmacological interventions have not met expectations. Dietary supplements and alternative treatments have also shown limited effectiveness in this regard. The consumption of green tea in general has been shown to benefit obese patients, with effects attributed to caffeine, catechins, polyphenols and other components. However, the potential of white tea to prevent and treat the negative effects of obesity has not been addressed so far. In this study, the effect of white tea (WT) consumption in obese individuals was anthropometrically and biochemically investigated. Materials and Methods: Based on anthropometric and biochemical assessments, the patients were assigned to the control, orlistat, metformin and WT groups. Patients were given a diet and exercise program and one of either orlistat, metformin or WT for 12 weeks. At the end of the 12th week, the anthropometric and biochemical measurements were reassessed. Results: Body weight, waist circumference and BMI parameters decreased significantly in all groups. TNF-α, IL-6, IL-1β and MMP-9 levels decreased significantly in the WT group. In addition, contrary to a significant elevation in HDL-C, the serum cholesterol, LDL-C and TG levels decreased significantly. Furthermore, leptin, ghrelin and asprosin levels decreased significantly. Serum glucose levels decreased significantly in all groups except for the control. In the WT group, while there was a significant decrease in the levels of serum PL MDA and 8-OHdG, the opposite was true for GSH. Conclusions: The oral consumption of WT, its availability and its potency in obesity treatment and prevention pave the way for further delineation of the mechanisms of actions of its bioactive compounds at the cellular and endocrinological levels.

The link between obesity and aging - insights into cardiac energy metabolism

Obesity and aging are well-established risk factors for a range of diseases, including cardiovascular diseases and type 2 diabetes. Given the escalating prevalence of obesity, the aging population, and the subsequent increase in cardiovascular diseases, it is crucial to investigate the underlying mechanisms involved. Both aging and obesity have profound effects on the energy metabolism through various mechanisms, including metabolic inflexibility, altered substrate utilization for energy production, deregulated nutrient sensing, and mitochondrial dysfunction. In this review, we aim to present and discuss the hypothesis that obesity, due to its similarity in changes observed in the aging heart, may accelerate the process of cardiac aging and exacerbate the clinical outcomes of elderly individuals with obesity.

Impairment of Mitochondrial Respiration in Metabolic Diseases: An Overview

Mitochondrial dysfunction has emerged as a central pathomechanism in the setting of obesity and diabetes mellitus, linking these intertwined pathologies that share insulin resistance as a common denominator. High-resolution respirometry (HRR) is a state-of-the-art research method currently used to study mitochondrial respiration and its impairment in health and disease. Tissue samples, cells or isolated mitochondria are exposed to various substrate-uncoupler-inhibitor-titration protocols, which allows the measurement and calculation of several parameters of mitochondrial respiration. In this review, we discuss the alterations of mitochondrial bioenergetics in the main dysfunctional organs that contribute to the development of the obese and diabetic phenotypes in both animal models and human subjects. Herein we review data regarding the impairment of oxidative phosphorylation as integrated mitochondrial function assessed by means of HRR. We acknowledge the critical role of this method in determining the alterations in oxidative phosphorylation occurring in the early stages of metabolic pathologies. We conclude that there is a mutual two-way relationship between mitochondrial dysfunction and insulin insensitivity that characterizes these diseases.

Guidelines on Models of Diabetic Heart Disease

Diabetes is a major risk factor for cardiovascular diseases, including diabetic cardiomyopathy, atherosclerosis, myocardial infarction, and heart failure. As cardiovascular disease represents the number one cause of death in people with diabetes, there has been a major emphasis on understanding the mechanisms by which diabetes promotes cardiovascular disease, and how antidiabetic therapies impact diabetic heart disease. With a wide array of models to study diabetes (both type 1 and type 2), the field has made major progress in answering these questions. However, each model has its own inherent limitations. Therefore, the purpose of this guidelines document is to provide the field with information on which aspects of cardiovascular disease in the human diabetic population are most accurately reproduced by the available models. This review aims to emphasize the advantages and disadvantages of each model, and to highlight the practical challenges and technical considerations involved. We will review the preclinical animal models of diabetes (based on their method of induction), appraise models of diabetes-related atherosclerosis and heart failure, and discuss in vitro models of diabetic heart disease. These guidelines will allow researchers to select the appropriate model of diabetic heart disease, depending on the specific research question being addressed.

Bacterial diversity in intestinal mucosa of mice fed with Dendrobium officinale and high-fat diet

This study aimed to explore the effect of Dendrobium officinale (DO) on the diversity of intestinal mucosal flora in high-fat diet mice and provided an experimental basis for the development and research of DO and its series products. Twenty-four mice were randomly assigned to four equal groups of six mice, namely the control (bcm) group, model (bmm) group, Dendrobium officinale (bdm) group, and positive control (bjm) group. Mice in the bdm group were administrated at the dose of 2.37 g·kg-1·days-1, and those in bjm group were given the Lipid-lowering decoction at the concentration of 1.19 g·kg-1·days-1, and sterile water was used as a placebo control twice a day for 40 consecutive days. We measured the dynamic weight changes and intestinal mucosal flora changes in mice. The analysis showed that DO had a regulatory effect on weight change induced by a high-fat diet in mice. DO could also regulate the changes in the diversity of the intestinal mucosa of mice, which was specifically reflected in the changes of Chao 1, ACE, Shannon and Simpson index. The sample information of the bdm group was relatively concentrated, but the distance from the bmm group was relatively scattered. The relative abundance results showed dominant bacteria phylum (such as Bacteroidetes, Actinobacteria, Verrucomicrobia) and bacterial genus (such as Bifidobacterium, Ruminococcus, Ochrobactrum) in the intestinal mucosa of the four groups. And significant differences in the major microbiota between the bdm and bjm groups. In addition, DO changed the carbohydrate, energy, and amino acid metabolism of intestinal mucosal flora. To sum up, DO has a regulatory effect on weight change induced by high-fat diet in mice and can improve the diversity of intestinal mucosal flora, promote the abundance of Ochrobactrum, inhibit the abundance of Bifidobacterium and Ruminococcus, and influence the intestinal flora to positively affect high-fat diet-induced negative effects in mice.