Circadian alignment of food intake and glycaemic control by time-restricted eating: A systematic review and meta-analysis

Daily rhythms of metabolic function are supported by molecular circadian clock systems that are strongly regulated by feeding and fasting. Intermittent fasting diets have been associated with weight loss and improved metabolism. However, the effects of time-restricted eating (TRE) on glycemic parameters are still under debate. In this review, we aim to systematically analyze the effects of TRE on glycemic parameters. We searched on PubMed, EMBASE, and the Cochrane Library for controlled studies in which subjects followed TRE for at least 4 weeks. 20 studies were included in the qualitative systematic review, and 18 studies (n = 1169 subjects) were included in the meta-analysis. Overall, TRE had no significant effect on fasting glucose (Hedges's g = -0.08; 95% CI:-0.31,0.16; p = 0.52), but it did reduce HbA1c levels (Hedges's g = -0.27; 95% CI: -0.47, -0.06; p = 0.01). TRE significantly reduced fasting insulin (Hedges's g = -0.40; 95% CI: -0.73,-0.08; p = 0.01) and showed a tendency to decrease HOMA-IR (Hedges's g = -0.32; 95% CI:-0.66,0.02; p = 0.06). Interestingly, a cumulative analysis showed that the beneficial effects of TRE regarding glucose levels were less apparent as studies with later TRE windows (lTRE) were being included. Indeed, a subgroup analysis of the early TRE (eTRE) studies revealed that fasting glucose was significantly reduced by eTRE (Hedges's g = -0.38; 95% CI:-0.62, -0.14; p < 0.01). Our meta-analysis suggests that TRE can reduce HbA1c and insulin levels, and that timing of food intake is a crucial factor in the metabolic benefit of TRE, as only eTRE is capable of reducing fasting glucose levels in subjects with overweight or obesity.PROSPERO registration number CRD42023405946.

Cardiovascular benefits of SGLT2 inhibitors and GLP-1 receptor agonists through effects on mitochondrial function and oxidative stress

Overloaded glucose levels in several metabolic diseases such as type 2 diabetes (T2D) can lead to mitochondrial dysfunction and enhanced production of reactive oxygen species (ROS). Oxidative stress and altered mitochondrial homeostasis, particularly in the cardiovascular system, contribute to the development of chronic comorbidities of diabetes. Diabetes-associated hyperglycemia and dyslipidemia can directly damage vascular vessels and lead to coronary artery disease or stroke, and indirectly damage other organs and lead to kidney dysfunction, known as diabetic nephropathy. The new diabetes treatments include Na+-glucose cotransporter 2 inhibitors (iSGLT2) and glucagon-like 1 peptide receptor agonists (GLP-1RA), among others. The iSGLT2 are oral anti-diabetic drugs, whereas GLP-1RA are preferably administered through subcutaneous injection, even though GLP-1RA oral formulations have recently become available. Both therapies are known to improve both carbohydrate and lipid metabolism, as well as to improve cardiovascular and cardiorenal outcomes in diabetic patients. In this review, we present an overview of current knowledge on the relationship between oxidative stress, mitochondrial dysfunction, and cardiovascular therapeutic benefits of iSGLT2 and GLP-1RA. We explore the benefits, limits and common features of the treatments and remark how both are an interesting target in the prevention of obesity, T2D and cardiovascular diseases, and emphasize the lack of a complete understanding of the underlying mechanism of action.

Inhibiting the endoplasmic reticulum stress response enhances the effect of doxorubicin by altering the lipid metabolism of liver cancer cells

Hepatocellular carcinoma (HCC) is characterized by a low and variable response to chemotherapeutic treatments. One contributing factor to the overall pharmacodynamics is the activation of endoplasmic reticulum (ER) stress pathways. This is a cellular stress mechanism that becomes activated when the cell's need for protein synthesis surpasses the ER's capacity to maintain accurate protein folding, and has been implicated in creating drug-resistance in several solid tumors.

OBJECTIVE

To identify the role of ER-stress and lipid metabolism in mediating drug response in HCC.

METHODS

By using a chemically-induced mouse model for HCC, we administered the ER-stress inhibitor 4μ8C and/or doxorubicin (DOX) twice weekly for three weeks post-tumor initiation. Histological analyses were performed alongside comprehensive molecular biology and lipidomics assessments of isolated liver samples. In vitro models, including HCC cells, spheroids, and patient-derived liver organoids were subjected to 4μ8C and/or DOX, enabling us to assess their synergistic effects on cellular viability, lipid metabolism, and oxygen consumption rate.

RESULTS

We reveal a pivotal synergy between ER-stress modulation and drug response in HCC. The inhibition of ER-stress using 4μ8C not only enhances the cytotoxic effect of DOX, but also significantly reduces cellular lipid metabolism. This intricate interplay culminates in the deprivation of energy reserves essential for the sustenance of tumor cells.

CONCLUSIONS

This study elucidates the interplay between lipid metabolism and ER-stress modulation in enhancing doxorubicin efficacy in HCC. This novel approach not only deepens our understanding of the disease, but also uncovers a promising avenue for therapeutic innovation. The long-term impact of our study could open the possibility of ER-stress inhibitors and/or lipase inhibitors as adjuvant treatments for HCC-patients.

Endoplasmic Reticulum Stress and Metabolism in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer, accounting for 85% to 90% of all liver cancer cases. It is a hepatocyte-derived primary tumor, causing 550,000 deaths per year, ranking it as one of the most common cancers worldwide. The liver is a highly metabolic organ with multiple functions, including digestion, detoxification, breakdown of fats, and production of bile and cholesterol, in addition to storage of vitamins, glycogen, and minerals, and synthesizing plasma proteins and clotting factors. Due to these fundamental and diverse functions, the malignant transformation of hepatic cells can have a severe impact on the liver's metabolism. Furthermore, tumorigenesis is often accompanied by activation of the endoplasmic reticulum (ER) stress pathways, which are known to be highly intertwined with several metabolic pathways. Because HCC is characterized by changes in the metabolome and by an aberrant activation of the ER stress pathways, the aim of this review was to summarize the current knowledge that links ER stress and metabolism in HCC, thereby focusing on potential therapeutic targets.

Effects of GLP-1 receptor agonists on mitochondrial function, inflammatory markers and leukocyte-endothelium interactions in type 2 diabetes

OBJECTIVE

Type 2 diabetes (T2D) is linked to metabolic, mitochondrial and inflammatory alterations, atherosclerosis development and cardiovascular diseases (CVDs). The aim was to investigate the potential therapeutic benefits of GLP-1 receptor agonists (GLP-1 RA) on oxidative stress, mitochondrial respiration, leukocyte-endothelial interactions, inflammation and carotid intima-media thickness (CIMT) in T2D patients.

RESEARCH DESIGN AND METHODS

Type 2 diabetic patients (255) and control subjects (175) were recruited, paired by age and sex, and separated into two groups: without GLP-1 RA treatment (196) and treated with GLP-1 RA (59). Peripheral blood polymorphonuclear leukocytes (PMNs) were isolated to measure reactive oxygen species (ROS) production by flow cytometry and oxygen consumption with a Clark electrode. PMNs were also used to assess leukocyte-endothelial interactions. Circulating levels of adhesion molecules and inflammatory markers were quantified by Luminex's technology, and CIMT was measured as surrogate marker of atherosclerosis.

RESULTS

Treatment with GLP-1 RA reduced ROS production and recovered mitochondrial membrane potential, oxygen consumption and MPO levels. The velocity of leukocytes rolling over endothelial cells increased in PMNs from GLP-1 RA-treated patients, whereas rolling and adhesion were diminished. ICAM-1, VCAM-1, IL-6, TNFα and IL-12 protein levels also decreased in the GLP-1 RA-treated group, while IL-10 increased. CIMT was lower in GLP-1 RA-treated T2D patients than in T2D patients without GLP-1 RA treatment.

CONCLUSIONS

GLP-1 RA treatment improves the redox state and mitochondrial respiration, and reduces leukocyte-endothelial interactions, inflammation and CIMT in T2D patients, thereby potentially diminishing the risk of atherosclerosis and CVDs.

The progression of doxorubicin-induced intestinal mucositis in rats

Chemotherapy-induced intestinal mucositis is a severe side effect contributing to reduced quality of life and premature death in cancer patients. Despite a high incidence, a thorough mechanistic understanding of its pathophysiology and effective supportive therapies are lacking. The main objective of this rat study was to determine how 10 mg/kg doxorubicin, a common chemotherapeutic, affected jejunal function and morphology over time (6, 24, 72, or 168 h). The secondary objective was to determine if the type of dosing administration (intraperitoneal or intravenous) affected the severity of mucositis or plasma exposure of the doxorubicin. Morphology, proliferation and apoptosis, and jejunal permeability of mannitol were examined using histology, immunohistochemistry, and single-pass intestinal perfusion, respectively. Villus height was reduced by 40% after 72 h, preceded at 24 h by a 75% decrease in proliferation and a sixfold increase in apoptosis. Villus height recovered completely after 168 h. Mucosal permeability of mannitol decreased after 6, 24, and 168 h. There were no differences in intestinal injury or plasma exposure after intraperitoneal or intravenous doxorubicin dosing. This study provides an insight into the progression of chemotherapy-induced intestinal mucositis and associated cellular mucosal processes. Knowledge from this in vivo rat model can facilitate development of preventive and supportive therapies for cancer patients.

Mitochondrial redox impairment and enhanced autophagy in peripheral blood mononuclear cells from type 1 diabetic patients

Type 1 diabetes (T1D) involves critical metabolic disturbances that contribute to an increased cardiovascular risk. Leukocytes are key players in the onset of atherosclerosis due to their interaction with the endothelium. However, whether mitochondrial redox impairment, altered bioenergetics and abnormal autophagy in leukocytes contribute to T1D physiopathology is unclear. In this study we aimed to evaluate the bioenergetic and redox state of peripheral blood mononuclear cells (PBMCs) from T1D patients in comparison to those from healthy subjects, and to assess autophagy induction and leukocyte-endothelial interactions. T1D patients presented lower levels of fast-acting and total antioxidants in their blood, and their leukocytes produced higher amounts of total reactive oxygen species (ROS) and superoxide radical with respect to controls. Basal and ATP-linked respiration were similar in PBMCs from T1D and controls, but T1D PBMCs exhibited reduced spare respiratory capacity and a tendency toward decreased maximal respiration and reduced non-mitochondrial respiration, compared to controls. The autophagy markers P-AMPK, Beclin-1 and LC3-II/LC3-I were increased, while P62 and NBR1 were decreased in T1D PBMCs versus those from controls. Leukocytes from T1D patients displayed lower rolling velocity, higher rolling flux and more adhesion to the endothelium versus controls. Our findings show that T1D impairs mitochondrial function and promotes oxidative stress and autophagy in leukocytes, and suggest that these mechanisms contribute to an increased risk of atherosclerosis by augmenting leukocyte-endothelial interactions.