Roux-en-Y Gastric Bypass Modulates AMPK, Autophagy and Inflammatory Response in Leukocytes of Obese Patients

Obesity is characterized by low-grade chronic inflammation, metabolic overload, and impaired endothelial and cardiovascular function. Roux-en-Y gastric bypass (RYGB) results in amelioration of the pro-oxidant status of leukocytes and the metabolic profile. Nevertheless, little is known about the precise mechanism that drives systemic and metabolic improvements following bariatric surgery. In this cohort study, we investigated the effect of RYGB on molecular pathways involving energy homeostasis in leukocytes in 43 obese subjects one year after surgery. In addition to clinical and biochemical parameters, we determined protein expression of systemic proinflammatory cytokines by Luminex®, different markers of inflammation, endoplasmic reticulum (ER) stress, autophagy/mitophagy by western blot, and mitochondrial membrane potential by fluorescence imaging. Bariatric surgery induced an improvement in metabolic outcomes that was accompanied by a systemic drop in hsCRP, IL6, and IL1β levels, and a slowing down of intracellular inflammatory pathways in leukocytes (NF-κB and MCP-1), an increase in AMPK content, a reduction of ER stress (ATF6 and CHOP), augmented autophagy/mitophagy markers (Beclin 1, ATG5, LC3-I, LC3-II, NBR1, and PINK1), and a decrease of mitochondrial membrane potential. These findings shed light on the specific molecular mechanisms by which RYGB facilitates metabolic improvements, highlighting the relevance of pathways involving energy homeostasis as key mediators of these outcomes. In addition, since leukocytes are particularly exposed to physiological changes, they could be used in routine clinical practice as a good sensor of the whole body’s responses.

Role of Oxidative Stress and Mitochondrial Dysfunction in Skeletal Muscle in Type 2 Diabetic Patients

Type 2 diabetes can increase the risk of skeletal muscle dysfunction and, consequently, that of cardiovascular diseases, including coronary artery disease and stroke. It is also related to a reduced capacity for exercise, but the underlying mechanism is only partially understood. There are several factors that contribute to the development of skeletal muscle dysfunction, of which oxidative stress and mitochondrial dysfunction are among the most important. This review discusses the role of oxidative stress in the development and progression of skeletal and cardiac dysfunction associated with diabetes. It also provides an overview of the potential actions of antioxidants in general and mitochondria-targeted antioxidants in particular in the treatment of muscle dysfunction in type 2 diabetes.

Effects of metformin on mitochondrial function of leukocytes from polycystic ovary syndrome patients with insulin resistance

OBJECTIVE

Oxidative stress and mitochondrial dysfunction are implicated in polycystic ovary syndrome (PCOS). The present study assesses the effect of metformin treatment on mitochondrial function in polymorphonuclear cells from PCOS subjects. Additionally, we evaluate endocrine parameters and levels of interleukin 6 (IL6) and tumour necrosis factor alpha (TNFα).

DESIGN AND METHODS

Our study population was comprised of 35 women of reproductive age diagnosed with PCOS and treated with metformin for 12 weeks, and their corresponding controls (n=41), adjusted by age and BMI. We evaluated the alteration of endocrinological and anthropometrical parameters and androgen levels. Mitochondrial O2 consumption (using a Clark-type O2 electrode), membrane potential, mitochondrial mass, and levels of reactive oxygen species (ROS) and glutathione (GSH) (by means of fluorescence microscopy) were assessed in poymorphonuclear cells. H2O2 was evaluated with the Amplex Red(R) H2O2/Peroxidase Assay kit. IL6 and TNFα were measured using the Luminex 200 flow analyser system.

RESULTS

Metformin had beneficial effects on patients by increasing mitochondrial O2 consumption, membrane potential, mitochondrial mass and glutathione levels, and by decreasing levels of reactive oxygen species and H2O2. In addition, metformin reduced glucose, follicle-stimulating hormone, IL6 and TNFα levels and increased dehydroepiandrosterone sulfate levels. HOMA-IR and mitochondrial function biomarkers positively correlated with ROS production (r=0.486, P=0.025), GSH content (r=0.710, P=0.049) and H2O2 (r=0.837, P=0.010), and negatively correlated with membrane potential (r=-0.829, P=0.011) at baseline. These differences disappeared after metformin treatment.

CONCLUSIONS

Our results demonstrate the beneficial effects of metformin treatment on mitochondrial function in leukocytes of PCOS patients.

Altered mitochondrial function and oxidative stress in leukocytes of anorexia nervosa patients

Context

Anorexia nervosa is a common illness among adolescents and is characterised by oxidative stress.

Objective

The effects of anorexia on mitochondrial function and redox state in leukocytes from anorexic subjects were evaluated.

Design and setting

A multi-centre, cross-sectional case-control study was performed.

Patients

Our study population consisted of 20 anorexic patients and 20 age-matched controls, all of which were Caucasian women.

Main outcome measures

Anthropometric and metabolic parameters were evaluated in the study population. To assess whether anorexia nervosa affects mitochondrial function and redox state in leukocytes of anorexic patients, we measured mitochondrial oxygen consumption, membrane potential, reactive oxygen species production, glutathione levels, mitochondrial mass, and complex I and III activity in polymorphonuclear cells.

Results

Mitochondrial function was impaired in the leukocytes of the anorexic patients. This was evident in a decrease in mitochondrial O₂ consumption (P<0.05), mitochondrial membrane potential (P<0.01) and GSH levels (P<0.05), and an increase in ROS production (P<0.05) with respect to control subjects. Furthermore, a reduction of mitochondrial mass was detected in leukocytes of the anorexic patients (P<0.05), while the activity of mitochondrial complex I (P<0.001), but not that of complex III, was found to be inhibited in the same population.

Conclusions

Oxidative stress is produced in the leukocytes of anorexic patients and is closely related to mitochondrial dysfunction. Our results lead us to propose that the oxidative stress that occurs in anorexia takes place at mitochondrial complex I. Future research concerning mitochondrial dysfunction and oxidative stress should aim to determine the physiological mechanism involved in this effect and the physiological impact of anorexia.

Intracellular vacuolation induced by culture filtrates of Plesiomonas shigelloides isolated from environmental sources

AIMS

Potential virulence factors produced by culture filtrates of Plesiomonas shigelloides isolated from water were investigated.

METHODS AND RESULTS

Culture filtrates of P. shigelloides strains were assayed for cytotoxic activity in CHO (Chinese hamster ovary), Vero (African green monkey kidney), HeLa (human cervix), HT29 (human epithelial intestinal) and SK6 (swine epithelial kidney) cells. Microscopic analyses revealed intensive cytoplasmic vacuolation including cell rounding and swelling, with gradual destruction of the monolayer in filtrate-treated cells. Neutral red assays showed that CHO, HeLa and Vero cells were the most sensitive to the vacuolating activity, which was evident within 30 min of culture filtrate exposure. This activity was inactived by heating at 56 degrees C for 15 min and partially neutralized by antiserum to the cytotoxin of Aeromonas hydrophila. All P. shigelloides strains had a cell-associated haemolysin in the agar plate assay. Three isolates were found to produce a cell-free haemolytic activity at 37 degrees C. In the suckling mouse test, two P. shigelloides culture supernatants were positive for enterotoxic activity.

CONCLUSIONS

P. shigelloides culture filtrates isolated from aquatic environment cause intracellular vacuolation on mammalian cells, and produce haemolytic and enterotoxic activities.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work revealed the presence of putative virulence factors that could be associated with human infections involving Plesiomonas strains.