Curcumin limits weight gain, adipose tissue growth, and glucose intolerance following the cessation of exercise and caloric restriction in rats

ER stress in obesity pathogenesis and management

Given the unprecedented global pandemic of obesity, a better understanding of the etiology of adiposity will be necessary to ensure effective management of obesity and related complications. Among the various potential factors contributing to obesity, endoplasmic reticulum (ER) stress refers to a state of excessive protein unfolding or misfolding that is commonly found in metabolic diseases including diabetes mellitus, insulin resistance (IR), and non-alcoholic fatty liver disease, although its role in obesogenesis remains controversial. ER stress is thought to drive adiposity by dampening energy expenditure, making ER stress a likely therapeutic target for the management of obesity. We summarize the role of ER stress and the ER stress response in the onset and development of obesity, and discuss the underlying mechanisms involved with a view to identifying novel therapeutic strategies for obesity prevention and management.

Turmeric extract alleviates endocrine-metabolic disturbances in letrozole-induced PCOS by increasing adiponectin circulation: A comparison with Metformin

One of the most common causes of female infertility is polycystic ovarian syndrome, which affects 6–21% of the population. Regrettably, the currently available treatments are mostly symptomatic and ineffective. As a result, safer options are needed now more than ever. In a letrozole PCOS albino mouse model, the current study compares the therapeutic advantages of Turmeric extract (Curcuma longa) to metformin. Adiponectin is a circulating protein generated by adipocytes that has been linked to metabolic diseases (MDs) in an inverse relationship. The effects of Turmeric Extract (Curcuma Longa) in contrast to Metformin, as well as the involvement of adiponectin in endocrine-metabolic abnormalities in experimentally induced PCOS mice model, were studied in this study. Letrozole (6 mg/kg) was administered orally (p.o) for 21 days to induce PCOS, followed by a dose of Turmeric Extract (Curcuma longa) (175 mg/kg and p.o) and Metformin (150 mg/kg) for 30 days, both with normal saline water (0.9%) as the carrier. The findings revealed that LET-treated mice displayed PCOS-like characteristics, such as higher LH levels, increased body weight growth, and ovarian morphology with numerous cysts, increase in fasting blood glucose, lipid profile, plasma lipid peroxidation (MDA) and IL-6, as well as a decrease in serum Progesterone, Estrogen, FSH, SOD and GSH levels in the ovary. These changes were linked to lower levels of circulating adiponectin and were reversed when treated Turmeric extract. By altering circulating androgen-adiponectin balance, the data implies that Turmeric extract alleviates endocrine-metabolic abnormalities and inflammation-related comorbidities associated with LET-induced PCOS.

Alterations in mitochondrial biogenesis and respiratory activity, inflammation of the senescence-associated secretory phenotype, and lipolysis in the perirenal fat and liver of rats following lifelong exercise and detraining

The primary aims of this study were to determine the effects of lifelong exercise and detraining on age-related alterations in mitochondrial function, inflammation associated with senescence-associated secretory phenotype (SASP), and lipolysis in the perirenal fat and liver of rats. Female Sprague-Dawley rats were randomly assigned to four groups: young control (n = 12), old control (n = 12), detraining (n = 12), and lifelong exercise (n = 12). We then investigated mitochondrial function, SASP-associated inflammation, and lipolysis in the perirenal fat and liver using qRT-PCR and western blotting to assess the expression of AKT, hypoxia-inducible factor 1α (HIF-1α), nuclear factor-kappa B (NF-κB), c-jun kinase (JNK), and p38 mitogen-activated protein kinase (p38MAPK). In the tissues of both the perirenal fat and liver, lifelong exercise significantly improved mitochondrial function, SASP-associated inflammation, and lipolysis. Meanwhile, pathways associated with inflammatory regulation were inhibited, predominantly via the activation of phosphorylated-AKT (p-AKT) and suppression of HIF-1α in both tissues, and via JNK in the perirenal fat and p38MAPK in the liver. Furthermore, detraining activated NF-κB expression in both tissues and induced the upregulation of serum high-sensitivity C-reactive protein (hsCRP) levels. Collectively, lifelong exercise was found to exert beneficial effects by ameliorating age-related alterations in mitochondrial function, SASP-associated inflammation, and lipolysis in perirenal fat and liver tissues, potentially inhibiting inflammation via the JNK and p38 MAPK pathways, respectively, as well as the HIF-1α and AKT pathways in both tissues. In contrast, detraining induced high levels of circulating hsCRP by activating the NF-κB signaling pathway in both tissues.

Phytochemicals as Potential Epidrugs in Type 2 Diabetes Mellitus

Type 2 diabetes Mellitus (T2DM) prevalence has significantly increased worldwide in recent years due to population age, obesity, and modern sedentary lifestyles. The projections estimate that 439 million people will be diabetic in 2030. T2DM is characterized by an impaired β-pancreatic cell function and insulin secretion, hyperglycemia and insulin resistance, and recently the epigenetic regulation of β-pancreatic cells differentiation has been underlined as being involved. It is currently known that several bioactive molecules, widely abundant in plants used as food or infusions, have a key role in histone modification and DNA methylation, and constituted potential epidrugs candidates against T2DM. In this sense, in this review the epigenetic mechanisms involved in T2DM and protein targets are reviewed, with special focus in studies addressing the potential use of phytochemicals as epidrugs that prevent and/or control T2DM in vivo and in vitro. As main findings, and although some controversial results have been found, bioactive molecules with epigenetic regulatory function, appear to be a potential replacement/complementary therapy of pharmacological hypoglycemic drugs, with minimal side effects. Indeed, natural epidrugs have shown to prevent or delay the T2DM development and the morbidity associated to dysfunction of blood vessels, eyes and kidneys due to sustained hyperglycemia in T2DM patients.

Skeletal muscle ceramides do not contribute to physical-inactivity-induced insulin resistance

Physical inactivity increases the risk to develop type 2 diabetes, a disease characterized by a state of insulin resistance. By promoting inflammatory state, ceramides are especially recognized to alter insulin sensitivity in skeletal muscle. The present study was designed to analyze, in mice, whether muscle ceramides contribute to physical-inactivity-induced insulin resistance. For this purpose, we used the wheel lock model to induce a sudden reduction of physical activity, in combination with myriocin treatment, an inhibitor of de novo ceramide synthesis. Mice were assigned to 3 experimental groups: voluntary wheel access group (Active), a wheel lock group (Inactive), and wheel lock group treated with myriocin (Inactive-Myr). We observed that 10 days of physical inactivity induces hyperinsulinemia and increases basal insulin resistance (HOMA-IR). The muscle ceramide content was not modified by physical inactivity and myriocin. Thus, muscle ceramides do not play a role in physical-inactivity-induced insulin resistance. In skeletal muscle, insulin-stimulated protein kinase B phosphorylation and inflammatory pathway were not affected by physical inactivity, whereas a reduction of glucose transporter type 4 content was observed. Based on these results, physical-inactivity-induced insulin resistance seems related to a reduction in glucose transporter type 4 content rather than defects in insulin signaling. We observed in inactive mice that myriocin treatment improves glucose tolerance, insulin-stimulated protein kinase B, adenosine-monophosphate-activated protein kinase activation, and glucose transporter type 4 content in skeletal muscle. Such effects occur regardless of changes in muscle ceramide content. These findings open promising research perspectives to identify new mechanisms of action for myriocin on insulin sensitivity and glucose metabolism.

Curcumin reduces inflammation in knee osteoarthritis rats through blocking TLR4 /MyD88/NF-κB signal pathway

Preclinical Research & Development Curcumin has been shown to possess a series of beneficial effects, such as antiinflammatory, antioxidant, analgesic, and promoting healing. However, the effect and relative mechanism of curcumin on knee osteoarthritis (OA) have not been elucidated. The aim of this study is to explore the protective effect of curcumin on monosodium iodoacetate (MIA)-induced OA. Forty-eight rats were randomized into four experimental groups: control group, OA group, OA + PBS group, and OA + curcumin group, respectively. A single intraarticular injection of MIA was applied to establish the rat model of knee OA. Hematoxylin-eosin staining was used to evaluate histological changes of knee joint. The paw withdrawal threshold was collected and the expression of synovial fluid cytokine levels was measured by ELISA. The protein expression of TRL-4, MyD88, p-IκBα, NF-κB, TNF-α, IL-1β, and IL6 was measured by western blot. Treating with curcumin can significantly reduce joint diameter and Mankin's score, and increase the paw withdrawal threshold. The expression of synovial fluid inflammatory biomarkers, IL-6, IL-1β, and TNF-α in the OA + curcumin group were lower than that in OA and OA + PBS group. The protein expression of the TLR4 receptor was increased in the OA, OA + PBS, and OA + curcumin group compared to the control group. However, curcumin treatment can significantly decrease the expression of MyD88, p-IκBα, NF-κB, TNF-α, IL-1β, and IL6 in OA + curcumin group. These findings may indicate that curcumin could block TLR4/NF-κB signal pathway, and reduce inflammation level to prevent knee wound in OA rats. Curcumin may be a feasible kind of medicament in the treatment of knee OA.