Obesity drives adipose-derived stem cells into a senescent and dysfunctional phenotype associated with P38MAPK/NF-KB axis

BACKGROUND

Adipose-derived stem cells (ADSC) are multipotent cells implicated in tissue homeostasis. Obesity represents a chronic inflammatory disease associated with metabolic dysfunction and age-related mechanisms, with progressive accumulation of senescent cells and compromised ADSC function. In this study, we aimed to explore mechanisms associated with the inflammatory environment present in obesity in modulating ADSC to a senescent phenotype. We evaluated phenotypic and functional alterations through 18 days of treatment. ADSC were cultivated with a conditioned medium supplemented with a pool of plasma from eutrophic individuals (PE, n = 15) or with obesity (PO, n = 14), and compared to the control.

RESULTS

Our results showed that PO-treated ADSC exhibited decreased proliferative capacity with G2/M cycle arrest and CDKN1A (p21WAF1/Cip1) up-regulation. We also observed increased senescence-associated β-galactosidase (SA-β-gal) activity, which was positively correlated with TRF1 protein expression. After 18 days, ADSC treated with PO showed augmented CDKN2A (p16INK4A) expression, which was accompanied by a cumulative nuclear enlargement. After 10 days, ADSC treated with PO showed an increase in NF-κB phosphorylation, while PE and PO showed an increase in p38MAPK activation. PE and PO treatment also induced an increase in senescence-associated secretory phenotype (SASP) cytokines IL-6 and IL-8. PO-treated cells exhibited decreased metabolic activity, reduced oxygen consumption related to basal respiration, increased mitochondrial depolarization and biomass, and mitochondrial network remodeling, with no superoxide overproduction. Finally, we observed an accumulation of lipid droplets in PO-treated ADSC, implying an adaptive cellular mechanism induced by the obesogenic stimuli.

CONCLUSIONS

Taken together, our data suggest that the inflammatory environment observed in obesity induces a senescent phenotype associated with p38MAPK/NF-κB axis, which stimulates and amplifies the SASP and is associated with impaired mitochondrial homeostasis.

Cost-Utility of Gastric Bypass Surgery Compared to Clinical Treatment for Severely Obese With and Without Diabetes in the Perspective of the Brazilian Public Health System

PURPOSE

Obesity is associated with increased morbidity and mortality. Weight loss due to gastric bypass (GBP) surgery improves clinical outcomes and may be a cost-effective intervention. To estimate the cost-effectiveness of GBP compared to clinical treatment in severely obese individuals with and without diabetes in the perspective of the Brazilian public health system.

MATERIALS AND METHODS

A Markov model was developed to compare costs and outcomes of gastric bypass in an open approach to clinical treatment. Health states were living with diabetes, remission of diabetes, non-fatal and fatal myocardial infarction, and death. We also included the occurrence of complications related to surgery and plastic surgery after the gastric bypass surgery. The direct costs were obtained from primary data collection performed in three public reference centers for obesity treatment. Utility values also derived from this cohort, while transition probabilities came from the international literature. A sensitivity analysis was performed to evaluate uncertainties. The model considered a 10-year time horizon and a 5% discount rate.

RESULTS

Over 10 years, GBP increased quality-adjusted life years (QALY) and costs compared to clinical treatment, resulting in an incremental cost-effectiveness ratio (ICER) of Int$1820.17/QALY and Int$1937.73/QALY in individuals with and without diabetes, respectively. Sensitivity analysis showed that utility values and direct costs of treatments were the parameters that affected the most the ICERs.

CONCLUSION

The study demonstrated that GBP is a cost-effective intervention for severely obese individuals in the Brazilian public health system perspective, with a better result in individuals with diabetes.

Endothelial Function of Patients with Morbid Obesity Submitted to Roux-en-Y Gastric Bypass With and Without Obstructive Sleep Apnea-Hypopnea Syndrome

BACKGROUND

Obesity is associated with obstructive sleep apnea-hypopnea syndrome (OSA) and both induce endothelial dysfunction. However, the effect of OSA on endothelial function after bariatric surgery has not been investigated yet.

OBJECTIVES

This study aims to evaluate the impact of weight loss on endothelial function in patients with and without obstructive sleep apnea (OSA) in the first 6 months after bariatric surgery.

SETTING

This study was conducted at a university hospital, in Brazil.

METHODS

The sample consisted of 56 patients homogeneously divided into groups with and without OSA. All patients underwent Roux-en-Y gastric bypass (RYGB), and the diagnosis of OSA was performed by polysomnography. The patients were evaluated preoperatively and 6 months after surgery. The evaluations included anthropometric measures, electrical bioimpedance, clinical symptoms of OSA, and endothelial function (flow-mediated dilation). RYGB improved the anthropometric, bioimpedance, and endothelial function results in both groups.

RESULTS

Patients presented a significant clinical improvement in OSA symptoms throughout the study. However, patients with OSA had an improvement in the endothelial function 2.5% lower (p < 0.001) than patients without APNEA syndrome.

CONCLUSION

This study demonstrates that the existence of OSA prior to bariatric surgery interferes in the improvement of endothelial function.

Weight-loss interventions and gut microbiota changes in overweight and obese patients: a systematic review

Imbalances in the gut microbiota, the bacteria that inhabit the intestines, are central to the pathogenesis of obesity. This systematic review assesses the association between the gut microbiota and weight loss in overweight/obese adults and its potential manipulation as a target for treating obesity. This review identified 43 studies using the keywords 'overweight' or 'obesity' and 'microbiota' and related terms; among these studies, 17 used dietary interventions, 11 used bariatric surgery and 15 used microbiota manipulation. The studies differed in their methodologies as well as their intervention lengths. Restrictive diets decreased the microbiota abundance, correlated with nutrient deficiency rather than weight loss and generally reduced the butyrate producers Firmicutes, Lactobacillus sp. and Bifidobacterium sp. The impact of surgical intervention depended on the given technique and showed a similar effect on butyrate producers, in addition to increasing the presence of the Proteobacteria phylum, which is related to changes in the intestinal absorptive surface, pH and digestion time. Probiotics differed in strain and duration with diverse effects on the microbiota, and they tended to reduce body fat. Prebiotics had a bifidogenic effect and increased butyrate producers, likely due to cross-feeding interactions, contributing to the gut barrier and improving metabolic outcomes. All of the interventions under consideration had impacts on the gut microbiota, although they did not always correlate with weight loss. These results show that restrictive diets and bariatric surgery reduce microbial abundance and promote changes in microbial composition that could have long-term detrimental effects on the colon. In contrast, prebiotics might restore a healthy microbiome and reduce body fat.

Obesity depresses the anti-inflammatory HSP70 pathway, contributing to NAFLD progression

OBJECTIVES

To evaluate whether reduced activity of the anti-inflammatory HSP70 pathway correlates with nonalcoholic fatty liver disease (NAFLD) progression and with markers of oxidative stress because obesity activates inflammatory JNKs, whereas HSP70 exerts the opposite effect.

METHODS

Adult obese patients (N = 95) undergoing bariatric surgery were divided into steatosis (ST), steatohepatitis (SH), and fibrosis (SH+F) groups. The levels of HSP70, its major transcription factor, HSF1, and JNKs were assessed by immunoblotting hepatic and visceral adipose tissue; data were confirmed by immunohistochemistry. Plasma biochemistry (lipids, HbA1c , HOMA, hepatic enzymes, and redox markers) was also evaluated.

RESULTS

In both liver and adipose tissue, decreased HSP70 levels, paralleled by similar reductions in HSF1 and reduced plasma antioxidant enzyme activities, correlated with insulin resistance and with NAFLD progression (expression levels were as follows: ST > SH > SH + F). The immunohistochemistry results suggested Kupffer cells as a site of HSP70 inhibition. Conversely, JNK1 content and phosphorylation increased.

CONCLUSIONS

Decreased HSF1 levels in the liver and fat of obese patients correlated with impairment of HSP70 in an NAFLD stage-dependent manner. This impairment may affect HSP70-dependent anti-inflammation, with consequent oxidative stress and insulin resistance in advanced stages of NAFLD. Possible causal effects of fat cell senescence are discussed.

Changes in bone mineral density in women following 1-year gastric bypass surgery

BACKGROUND

Roux-en-Y gastric bypass (RYGB) surgery is the gold standard surgical treatment for obesity. However, unintended nutritional deficiencies following this surgery are common, including changes in bone metabolism. We assessed changes in bone mineral density (BMD), nutritional compounds, and bone resorption markers before and 1 year following RYGB surgery.

METHODS

Our study included 22 female patients with class II/III obesity. A clinical questionnaire, a 24-h recall, blood and urine samples, and dual-energy X-ray absorptiometry were provided.

RESULTS

Mean age was 37.2 ± 9.6 years; 86 % were Caucasian and 77.2 % were premenopausal. Mean preoperative body mass index was 44.4 ± 5.0 and 27.5 ± 4.5 kg/m(2) at 1-year follow-up (p < 0.001). 25-OH-vitamin D-levels were similar in both periods [11.7 (9.7-18.0) vs. 15.7 (10.2-2.7) pg/dL, p = 0.327]. Serum N-telopeptide (16.3 ± 3.4 vs. 38.2 ± 7.0 nM BCE, p < 0.001) and parathyroid hormone (45.4 ± 16.7 vs. 62.7 ± 28.9 pg/mL, p = 0.026) increased after RYGB surgery, reflecting bone resorption. BMD decreased after RYGB surgery in the lumbar spine (1.13 ± 0.11 vs. 1.04 ± 0.09 g/cm(2), p = 0.001), femoral neck (1.03 ± 0.15 vs. 0.94 ± 0.16 g/cm(2), p = 0.001), and total femur (1.07 ± 0.11 vs. 0.97 ± 0.15 g/cm(2), p = 0.003).

CONCLUSIONS

Decreased BMD in the lumbar spine, femoral neck, and total femur is detectable in women 1 year after RYGB surgery. Calcium malabsorption, caused by vitamin D deficiency and increased bone resorption, is partially responsible for these outcomes and should be targeted in future clinical trials.

Pregnancy after bariatric surgery: 39 pregnancies follow-up in a multidisciplinary team

BACKGROUND

We investigate the outcomes of pregnancy in women who undergone restrictive-malabsorptive procedure at Centro da Obesidade Mórbida-Hospital São Lucas (COM HSL-PUCRS), Porto Alegre, Brazil.

METHODS

All pregnancies started after the bariatric surgery and with estimated due date until June 2008 were eligible for the study. Only the first pregnancy of each patient was included in the data analysis. Data was collected from medical records.

RESULTS

Forty seven pregnancies were identified in 41 women. Eight of them were ineligible. There were 30 complete pregnancies and nine miscarriages (23%). Cesarean delivery was performed in 69% of the complete pregnancies. Mature infants occurred in 93.1%. Twelve pregnancies (30.8%) occurred in the first year after surgery. Vitamin B12 was low in 53.4% patients; folic acid in 16.1%, iron in 6.7%, ferritin in 41.7%, calcium in 16.7%, and albumin in 10.3% of the patients. Nineteen women (79.2%) had no complication during the pregnancy and two (8.3%) presented with internal hernia. The average of newborns weight and length on delivery were 3,037 g and 48.07 cm, respectively. Children from pregnancies started in the first year of post operatory had similar outcomes of children from pregnancies started after 1 year of surgery.

CONCLUSIONS

Pregnancy after bariatric surgery is safe and has fewer complications than pregnancy in morbidly obese women. However, the recommendation to delay the pregnancy for at least 12-18 months post-operatively should be kept.