Weight loss reduces anti-ADAMTS13 autoantibodies and improves inflammatory and coagulative parameters in obese patients

Circulating ADAMTS13 Levels Are Associated with an Increased Occurrence of Obstructive Sleep Apnea

Background and Aims. Obstructive sleep apnea (OSA) is strongly associated with obesity, metabolic diseases, coronary artery disease (CAD), stroke, hypertension, and other disorders. This study assessed the relationship between circulating a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13 (ADAMTS13) levels and the presence of OSA. Materials and Methods. This cross-sectional study included a total of 223 patients. We used a powerful high-throughput multiplexed immunobead-based assay to detect circulating levels of ADAMTS13. The associations between circulating ADAMTS13 levels and OSA were evaluated by multivariate logistic regression analysis. Results. Circulating ADAMTS13 levels were significantly elevated in patients with OSA compared with controls (0.8 vs. 2.7 μg/mL, respectively, $P<0.001$ ). After adjusting for confounding factors, circulating ADAMTS13 levels were significantly independently associated with the presence of OSA ( $\text{odds}\text{ratio}=9.96$ , 95% confidence interval (CI) =4.11–24.13, $P<0.001$ ). Furthermore, circulating ADAMTS13 levels showed discriminatory accuracy in assessing the presence of OSA (area under the curve: 0.87, 95% CI 0.81–0.93, $P<0.001$ ). Conclusion. Circulating ADAMTS13 levels were significantly correlated with the presence of OSA. ADAMTS13 may therefore function as a novel biomarker for monitoring the development and progression of OSA.

The association of von willebrand factor and its cleaving protease (ADAMTS13) with health behaviours in young black and white adults: the African-PREDICT study

To reduce cardiovascular risks imposed by Von Willebrand factor (vWF) and ADAMTS13 from young ages, knowledge on health behaviours that may affect their concentrations is essential. We therefore determined whether circulating vWF antigen and ADAMTS13 associate with health behaviours. We included 1196 black and white healthy adults aged 20-30 years and used questionnaires for socio-economic, tobacco and alcohol use data. vWF:Ag was measured from citrated samples and ADAMTS13, cotinine and gamma-glutamyl transferase (GGT) from serum. Salt intake was estimated from 24-hour urine and body mass index (BMI) was calculated. Black adults had higher vWF:Ag and lower ADAMTS13 levels compared to whites (all p < 0.001). In multiple regression analyses in the total group, vWF:Ag associated positively with BMI (p = 0.037), while ADAMTS13 associated negatively with BMI (p = 0.016) and cotinine (p = 0.029); and positively with GGT (p = 0.002). When exploring within each ethnic group, vWF:Ag associated positively with estimated salt intake (p = 0.043) only in blacks. In whites, vWF:Ag associated positively with BMI (p = 0.023) while ADAMTS13 associated positively with GGT (p = 0.003) and negatively with cotinine (p = 0.041). Young black adults may have an increased thrombotic risk due to higher vWF and lower ADAMTS13. The ethnic-specific associations observed may have implications for public health initiatives to improve cardiovascular outcomes.

When Two Pandemics Meet: Why Is Obesity Associated with Increased COVID-19 Mortality?

A growing body of evidence indicates that obesity is strongly and independently associated with adverse outcomes of COVID-19, including death. By combining emerging knowledge of the pathological processes involved in COVID-19 with insights into the mechanisms underlying the adverse health consequences of obesity, we present some hypotheses regarding the deleterious impact of obesity on the course of COVID-19. These hypotheses are testable and could guide therapeutic and preventive interventions. As obesity is now almost ubiquitous and no vaccine for COVID-19 is currently available, even a modest reduction in the impact of obesity on mortality and morbidity from this viral infection could have profound consequences for public health.

Metabolic Syndrome Features: Is There a Modulation Role by Mineral Water Consumption? A Review

Metabolic syndrome (MetSyn) promotes, among others, the development of atherosclerotic cardiovascular disease and diabetes. Its prevalence increases with age, highlighting the relevance of promoting precocious MetSyn primary prevention and treatment with easy-to-implement lifestyle interventions. MetSyn features modulation through mineral water consumption was reviewed on Pubmed, Scopus and Google Scholar databases, using the following keywords: metabolic syndrome, hypertension, blood pressure (BP), cholesterol, triglycerides, apolipoprotein, chylomicron, very low-density lipoprotein, low-density lipoprotein, high-density lipoprotein (HDL), glucose, insulin, body weight, body mass index, waist circumference (WC), obesity and mineral(-rich) water. Twenty studies were selected: 12 evaluated BP, 13 assessed total-triglycerides and/or HDL-cholesterol, 10 analysed glucose and/or 3 measured WC. Mineral waters were tested in diverse protocols regarding type and composition of water, amount consumed, diet and type and duration of the study. Human and animal studies were performed in populations with different sizes and characteristics. Distinct sets of five studies showed beneficial effects upon BP, total-triglycerides, HDL-cholesterol and glucose. WC modulation was not reported. Minerals/elements and active ions/molecules present in mineral waters (and their pH) are crucial to counterbalance their inadequate intake and body status as well as metabolic dysfunction and increased diet-induced acid-load observed in MetSyn. Study characteristics and molecular/physiologic mechanisms that could explain the different effects observed are discussed. Further studies are warranted for determining the mechanisms involved in the putative protective action of mineral water consumption against MetSyn features.

Serum proteome changes and accelerated reduction of fat mass after laparoscopic gastric plication in morbidly obese patients

Laparoscopic Gastric Plication (LGP) is a relatively new bariatric surgical procedure which no part of the stomach is removed. It is not clearly understood how LGP leads to fatty tissue reduction. We aimed to investigate the impact of LGP on serum proteome and understand molecular mechanisms of LGP-induced weight loss post-surgery. A Prospective observational study of 16 obese individuals who underwent LGP was performed. A Label-free quantitative shotgun proteomics approach was used to compare serum proteome of subjects before surgery with serum of the same individuals 1 to 2 months post-surgery (T1) and 4 to 5 months post-surgery (T2). The proteome analysis revealed that 48 proteins were differentially regulated between pre-surgery and T1, and seven proteins between pre-surgery and T2 of which six proteins were shared between the two timepoints. Among differentially regulated proteins, four proteins (SRGN, FETUB, LCP1 and CFP) have not previously been described in the context of BMI/weight loss. Despite few differences following LGP, most regulated serum proteins are in accordance with alternative weight loss procedures. Pathway analysis revealed changes to lipid- and inflammatory pathways, including PPARα/RXRα, LXR/RXR and FXR/RXR activation, especially at T1. At T2, the pathways related to inflammation and immune system are most affected. SIGNIFICANCE: Among the available clinical therapies for morbid obesity, bariatric surgery is considered as the most effective approach to achieve long-term weight loss, alongside a significant improvement in metabolic syndrome. However, very little is known about the underlying mechanism associated with significant weight loss post-surgery. Understanding such mechanisms could lead to development of safer non-surgical weight loss approaches. We here present the first analysis of the impact of LGP on the serum proteome, to bring new insights into the underlying molecular mechanism. Our findings indicate that LGP has a comprehensive systemic effect based on the blood serum proteome profile which might account for accelerated reduction of fat mass after surgery, thus, food restriction is not the only reason for weight loss following this unique surgical approach. As secretory regions of the stomach are preserved in LGP and it is associated with minimal physiological and anatomical changes, the findings are of high importance in the field of bariatric surgery and weight loss.

ADAMTS13: origins, applications, and prospects

ADAMTS13 is an enzyme that acts by cleaving prothrombotic von Willebrand factor (VWF) multimers from the vasculature in a highly regulated manner. In pathologic states such as thrombotic thrombocytopenic purpura (TTP) and other thrombotic microangiopathies (TMAs), VWF can bind to the endothelium and form large multimers. As the anchored VWF chains grow, they provide a greater surface area to bind circulating platelets (PLTs), generating unique thrombi that characterize TTP. This results in microvasculature thrombosis, obstruction of blood flow, and ultimately end-organ damage. Initial presentations of TTP usually occur in an acute manner, typically developing due to an autoimmune response toward, or less commonly a congenital deficiency of, ADAMTS13. Triggers for TMAs that can be associated with ADAMTS13 deficiency, including TTP, have been linked to events that place a burden on hemostatic regulation, such as major trauma and pregnancy. The treatment plan for cases of suspected TTP consists of emergent therapeutic plasma exchange that is continued on a daily basis until normalization of PLT counts. However, a subset of these patients does not respond favorably to standard therapies. These patients necessitate a better understanding of their diseases for the advancement of future therapeutic options. Given ADAMTS13's key role in the cleavage of VWF and the prevention of PLT-rich thrombi within the microvasculature, future treatments may include anti-VWF therapeutics, recombinant ADAMTS13 infusions, and ADAMTS13 expression via gene therapy.

Effects of gastric bypass surgery followed by supervised physical training on inflammation and endothelial function: A randomized controlled trial

BACKGROUND AND AIMS

Obesity and physical inactivity are both associated with low-grade inflammation and endothelial dysfunction. Bariatric surgery improves markers of inflammation and endothelial function, but it is unknown if physical training after bariatric surgery can improve these markers even further. Therefore, we aimed to investigate the effects of Roux-en-Y gastric bypass (RYGB) followed by physical training on markers of low-grade inflammation and endothelial function.

METHODS

Sixty patients approved for RYGB underwent examinations pre-surgery, 6, 12, and 24 months post-surgery. Six months post-surgery, they were randomized 1:1 to an intervention group or a control group. The interventions consisted of two weekly sessions of supervised moderate intensity physical training for a period of 26 weeks. Fasting blood samples were analyzed for concentrations of interleukin 6 (IL-6), C-reactive protein (CRP), intercellular adhesion molecule 1 (ICAM-1), tissue-type plasminogen activator antigen (t-PA:Ag) and von Willebrand factor (vWF).

RESULTS

RYGB markedly improved markers of inflammation (IL-6, CRP) (p < 0.001) and endothelial function (ICAM-1, t-PA:Ag, vWF) (p < 0.05), and the improvements were sustained 24 months post-surgery (p < 0.01), except for the effects on vWF. We found no correlations between the changes in weight or BMI and the changes in markers of inflammation and endothelial function, except that the change in vWF was found to be inversely correlated with the changes in weight and BMI. We observed no effects of supervised physical training on markers on inflammation or endothelial function (p>0.1 for all).

CONCLUSIONS

RYGB causes substantial and sustained favorable effects on markers of inflammation and endothelial function. Supervised physical training after RYGB did not cause additional improvements.

Platelet rescue by macrophage depletion in obese ADAMTS-13-deficient mice at risk of thrombotic thrombocytopenic purpura

Essentials Obesity is a potential risk factor for development of thrombotic thrombocytopenic purpura (TTP). Obese ADAMTS-13-deficient mice were triggered with von Willebrand factor (VWF). Depletion of hepatic and splenic macrophages protects against thrombocytopenia in this model. VWF enhances phagocytosis of platelets by macrophages, dose-dependently.

SUMMARY

Background Thrombotic thrombocytopenic purpura (TTP) is caused by the absence of ADAMTS-13 activity. Thrombocytopenia is presumably related to the formation of microthrombi rich in von Willebrand factor (VWF) and platelets. Obesity may be a risk factor for TTP; it is associated with abundance of macrophages that may phagocytose platelets. Objectives To evaluate the role of obesity and ADAMTS-13 deficiency in TTP, and to establish whether macrophages contribute to thrombocytopenia. Methods Lean or obese ADAMTS-13-deficient (Adamts-13-/- ) and wild-type (WT) mice were injected with 250 U kg-1 of recombinant human VWF (rVWF), and TTP characteristics were evaluated 24 h later. In separate experiments, macrophages were depleted in the liver and spleen of lean and obese WT or Adamts-13-/- mice by injection of clodronate-liposomes, 48 h before injection of rVWF. Results Obese Adamts-13-/- mice had a lower platelet count than their lean counterparts, suggesting that they might be more susceptible to TTP development. Lean Adamts-13-/- mice triggered with a threshold dose of rVWF did not develop TTP, whereas typical TTP symptoms developed in obese Adamts-13-/- mice, including severe thrombocytopenia and higher lactate dehydrogenase (LDH) levels. Removal of hepatic and splenic macrophages by clodronate injection in obese Adamts-13-/- mice before treatment with rVWF preserved the platelet counts measured 24 h after the trigger. In vitro experiments with cultured macrophages confirmed a VWF dose-dependent increase of platelet phagocytosis. Conclusions Obese Adamts-13-/- mice are more susceptible to the induction of TTP-related thrombocytopenia than lean mice. Phagocytosis of platelets by macrophages contributes to thrombocytopenia after rVWF injection in this model.