Metabolic impact of weight loss induced reduction of adipose ACE-2 - Potential implication in COVID-19 infections?

New Insights into the Effects of SARS-CoV-2 on Metabolic Organs: A Narrative Review of COVID-19 Induced Diabetes

Coronavirus disease 2019 (COVID-19)-induced new-onset diabetes has raised widespread concerns. Increased glucose concentration and insulin resistance levels were observed in the COVID-19 patients. COVID-19 patients with newly diagnosed diabetes may have worse clinical outcomes and can have serious consequences. The types and exact mechanisms of COVID-19-caused diabetes are not well understood. Understanding the direct effects of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on pancreatic beta cells and insulin target metabolism organs, such as the liver, muscle, and adipose tissues, will provide new ideas for preventing and treating the new-onset diabetes induced by COVID-19.

5-Aminovaleric acid betaine predicts impaired glucose metabolism and diabetes

BACKGROUND

5-Aminovaleric acid betaine (5-AVAB) has recently been identified as a diet and microbial-dependent factor inducing obesity and hepatic steatosis in mice fed a Western diet. Accumulating evidence suggests a role in metabolic dysfunction associated with obesity, diabetes, and fatty liver disease. However, whether 5-AVAB plays a role in human disease is unclear, and human data are sparse.

METHODS

We measured circulating 5-AVAB serum levels in 143 individuals with overweight or obesity participating in a randomized intervention study (NCT00850629) investigating the long-term effect of a weight maintenance strategy after diet-induced weight reduction.

RESULTS

Higher 5-AVAB serum levels correlate with worse estimates of obesity, glucose metabolism, and hepatic steatosis after weight loss. Furthermore, higher 5-AVAB levels after weight loss independently predict detrimental changes in glucose metabolism 18 months after the successful weight reduction.

CONCLUSION

Our human data supports previous findings in rodents indicating a relevant, potentially disadvantageous function of 5-AVAB in the context of metabolic dysbalance.

Adipokines in obesity and metabolic-related-diseases

The discovery of leptin in the 1990s led to a reconsideration of adipose tissue (AT) as not only a fatty acid storage organ, but also a proper endocrine tissue. AT is indeed capable of secreting bioactive molecules called adipokines for white AT or batokines for brown/beige AT, which allow communication with numerous organs, especially brain, heart, liver, pancreas, and/or the vascular system. Adipokines exert pro or anti-inflammatory activities. An equilibrated balance between these two sets ensures homeostasis of numerous tissues and organs. During the development of obesity, AT remodelling leads to an alteration of its endocrine activity, with increased secretion of pro-inflammatory adipokines relative to the anti-inflammatory ones, as shown in the graphical abstract. Pro-inflammatory adipokines take part in the initiation of local and systemic inflammation during obesity and contribute to comorbidities associated to obesity, as detailed in the present review.

Biomarkers of glucose homeostasis as mediators of the relationship of body mass index and waist circumference with COVID-19 outcomes among postmenopausal women: The Women's Health Initiative

BACKGROUND & AIMS

Systematic reviews, meta-analyses and Mendelian randomization studies suggest that cardiometabolic diseases may be associated with COVID-19 risk and prognosis, with evidence implicating insulin resistance (IR) as a common biological mechanism. As driving factors for IR, we examined body mass index (BMI) and waist circumference (WC) among postmenopausal women in association with COVID-19 outcomes (positivity and hospitalization), and the role of glucose homeostasis as a mediator of this relationship.

METHODS

Associations of BMI and WC at baseline (1993-1998) with COVID-19 outcomes collected at Survey 1 (June-December, 2020) and/or Survey 2 (September-December, 2021) were evaluated among 42,770 Women's Health Initiative (WHI) participants (baseline age: 59.36 years) of whom 16,526 self-reported having taken ≥1 COVID-19 test, with 1242 reporting ≥1 positive COVID-19 test and 362 reporting ≥1 COVID-19 hospitalization. We applied logistic regression and causal mediation analyses to sub-samples with available fasting biomarkers of glucose homeostasis (glucose, insulin, Homeostatic Model Assessment for Insulin Resistance, Homeostasis Model Assessment for β-cell function, Quantitative Insulin-sensitivity Check Index, Triglyceride-Glucose index (TyG)) at baseline, whereby 57 of 759 reported COVID-19 test positivity and 23 of 1896 reported COVID-19 hospitalization.

RESULTS

In fully adjusted models, higher BMI, WC and TyG were associated with COVID-19 test positivity and hospitalization. Glucose concentrations mediated associations of BMI and WC with COVID-19 positivity, whereas TyG mediated BMI and WC's associations with COVID-19 hospitalization.

CONCLUSIONS

Obesity and central obesity markers collected an average of 24 years prior were associated with COVID-19 outcomes among postmenopausal women. Glucose concentration and TyG partly mediated these associations.

Is prior bariatric surgery associated with poor COVID-19 outcomes? A systematic review and meta-analysis of case-control studies

Background

Obesity is an independent risk factor for severe coronavirus disease 2019 (COVID-19), but there is little evidence on whether prior bariatric surgery benefits the outcomes of patients with COVID-19. We aimed to summarize this relationship by conducting a systematic review and meta-analysis of current case-control studies.

Methods

We searched several electronic databases for case-control studies conducted between January 2020 and March 2022. We compared the rates of mortality, mechanical ventilation, intensive care unit (ICU) admission, dialysis, hospitalization, and length of hospital stay between COVID-19 patients with and without a history of bariatric surgery.

Results

We included six studies with 137 903 patients; 5270 (3.8%) had prior bariatric surgery, while 132 633 (96.2%) did not. COVID-19 patients with a history of bariatric surgery had significantly lower mortality (odds ratio (OR) = 0.42; 95% confidence interval (CI) = 0.23-0.74), ICU admission (OR = 0.48; 95% CI = 0.36-0.65), and mechanical ventilation rates than those with a history of non-bariatric surgery (OR = 0.51; 95% CI = 0.35-0.75).

Conclusions

Prior bariatric surgery was associated with a reduced risk of mortality and reduced severity of COVID-19 in patients with obesity compared to those with no prior bariatric surgery. Further large-sample prospective studies are needed to support these results.

Registration

CRD42022323745.

Post-COVID-19 Syndrome Comprehensive Assessment: From Clinical Diagnosis to Imaging and Biochemical-Guided Diagnosis and Management

The COVID-19 outbreak was first reported in 2019, causing massive morbidity and mortality. The majority of the COVID-19 patients survived and developed Post-COVID-19 Syndrome (PC19S) of varying severity. Currently, the diagnosis of PC19S is achieved through history and symptomatology that cannot be explained by an alternative diagnosis. However, the heavy reliance on subjective reporting is prone to reporting errors. Besides, there is no unified diagnostic assessment tool to classify the clinical severity of patients. This leads to significant difficulties when managing patients in terms of public resource utilization, clinical progression monitorization and rehabilitation plan formulation. This narrative review aims to review current evidence of diagnosis based on triple assessment: clinical symptomatology, biochemical analysis and imaging evidence. Further assessment tools can be developed based on triple assessment to monitor patient's clinical progression, prognosis and intervals of monitoring. It also highlights the high-risk features of patients for closer and earlier monitoring. Rehabilitation programs and related clinical trials are evaluated; however, most of them focus on cardiorespiratory fitness and psychiatric presentations such as anxiety and depression. Further research is required to establish an objective and comprehensive assessment tool to facilitate clinical management and rehabilitation plans.

Understanding metabolic alterations after SARS-CoV-2 infection: insights from the patients' oral microenvironmental metabolites

BACKGROUND

Coronavirus disease 2019 is a type of acute infectious pneumonia and frequently confused with influenza since the initial symptoms. When the virus colonized the patient's mouth, it will cause changes of the oral microenvironment. However, few studies on the alterations of metabolism of the oral microenvironment affected by SARS-CoV-2 infection have been reported. In this study, we explored metabolic alterations of oral microenvironment after SARS-CoV-2 infection.

METHODS

Untargeted metabolomics (UPLC-MS) was used to investigate the metabolic changes between oral secretion samples of 25 COVID-19 and 30 control participants. To obtain the specific metabolic changes of COVID-19, we selected 25 influenza patients to exclude the metabolic changes caused by the stress response of the immune system to the virus. Multivariate analysis (PCA and PLS-DA plots) and univariate analysis (students' t-test) were used to compare the differences between COVID-19 patients and the controls. Online hiplot tool was used to perform heatmap analysis. Metabolic pathway analysis was conducted by using the MetaboAnalyst 5.0 web application.

RESULTS

PLS-DA plots showed significant separation of COVID-19 patients and the controls. A total of 45 differential metabolites between COVID-19 and control group were identified. Among them, 35 metabolites were defined as SARS-CoV-2 specific differential metabolites. Especially, the levels of cis-5,8,11,14,17-eicosapentaenoic acid and hexanoic acid changed dramatically based on the FC values. Pathway enrichment found the most significant pathways were tyrosine-related metabolism. Further, we found 10 differential metabolites caused by the virus indicating the body's metabolism changes after viral stimulation. Moreover, adenine and adenosine were defined as influenza virus-specific differential metabolites.

CONCLUSIONS

This study revealed that 35 metabolites and tyrosine-related metabolism pathways were significantly changed after SARS-CoV-2 infection. The metabolic alterations of oral microenvironment in COVID-19 provided new insights into its molecular mechanisms for research and prognostic treatment.

Antibody responses to COVID-19 vaccination in people with obesity: A systematic review and meta-analysis

COVID-19 vaccine is critical in preventing SARS-CoV-2 infection and transmission. However, obesity's effect on immune responses to COVID-19 vaccines is still unknown. We performed a meta-analysis of the literature and compared antibody responses with COVID-19 vaccines among persons with and without obesity. We used Pubmed, Embase, Web of Science, and Cochrane Library to identify all related studies up to April 2022. The Stata.14 software was used to analyze the selected data. Eleven studies were included in the present meta-analysis. Five of them provided absolute values of antibody titers in the obese group and non-obese group. Overall, we found that the obese population was significantly associated with lower antibody titers (standardized mean difference [SMD] = -0.228, 95% CI [-0.437, -0.019], P < 0.001) after COVID-19 vaccination. Significant heterogeneity was present in most pooled analyses but was reduced after subgroup analyses. No publication bias was observed in the present analysis. The Trim and Fill method did not change the results in the primary analysis. The present meta-analysis suggested that obesity was significantly associated with decreased antibody responses to SARS-CoV-2 vaccines. Future studies should be performed to unravel the mechanism of response to the COVID-19 vaccine in obese individuals.

ASSOCIATION BETWEEN UNDERWEIGHT AND EXCESS BODY WEIGHT BEFORE SARS-COV-2 INFECTION AND CLINICAL OUTCOMES OF COVID-19: MULTICENTER STUDY

Objectives

The present study aimed to identify associations between extremes in body weight status (underweight and excess body weight) before a COVID-19 diagnosis and clinical outcomes in patients infected with SARS coronavirus type 2.

Methods

A multicenter cohort study was conducted in eight different states in northeastern Brazil. Demographic, clinical (previous diagnosis of comorbidities), and anthropometric (self-reported weight and height) data about individuals who tested positive for COVID-19 were collected. Outcomes included hospitalization, mechanical ventilation, and death. Multivariable logistic regression models, adjusted based on age, sex and previous comorbidities, were used to assess the effects of extremes in body weight status on clinical outcomes.

Results

A total of 1308 individuals were assessed (33.6% were elderly individuals). The univariable analyses showed that only hospitalization was more often observed among underweight (3.2% versus 1.2%) and overweight (68.1% versus 63.3%) individuals. In turn, cardiovascular diseases were more often observed in all clinical outcomes (hospitalization: 19.7% versus 4.8%; mechanical ventilation: 19.9% versus 13.5%; death: 21.8% versus 14.1%). Based on the multivariable analysis, body weight status was not associated with risk of hospitalization (underweight: odds ratio [OR]: 1.10; 95% confidence interval [CI] 95%, 0.50–2.41 and excess body weight: OR: 0.81; 95 CI, 0.57–1.14), mechanical ventilation (underweight: OR: 0.92; 95% CI, 0.52–1.62 and excess weight: OR: 0.90; 95% CI, 0.67–1.19), and death (underweight: OR: 0.61; 95% CI, 0.31–1.20 and excess body weight: OR 0.88; 95% CI, 0.63–1.23).

Conclusions

Being underweight and excess body weight were not independently associated with clinical outcomes in patients with COVID-19 in the herein analyzed cohort. This finding indicates that the association between these variables may be confounded by both age and comorbidities.

Long-term impact of the metabolic status on weight loss-induced health benefits

BACKGROUND

While short-term effects of weight loss on quality of life and metabolic aspects appear to be different in metabolically healthy (MHO) and metabolically unhealthy obese (MUO), respective long-term data is still missing. Given the high relevance of long-term changes, we aimed to address these in this post-hoc analysis of the MAINTAIN trial.

METHODS

We analyzed 143 overweight/obese subjects (BMI ≥ 27 kg/m2, age ≥ 18 years) before and after a 3-month weight loss program (≥ 8% weight loss), after a 12-month period of a randomized weight maintenance intervention (n = 121), and after another 6 months without intervention (n = 112). Subjects were retrospectively grouped into MHO and MUO by the presence of metabolic syndrome and secondarily by estimates of insulin sensitivity (HOMA-IR and ISIClamp). Quality of life (QoL), blood pressure, lipids, HOMA-IR, and ISIClamp were assessed and evaluated using mixed model analyses.

RESULTS

Despite similar short- and long-term weight loss, weight loss-induced improvement of HOMA-IR was more pronounced in MUO than MHO after 3 months (MHO: 2.4[95%-CI: 1.9-2.9] vs. 1.6[1.1-2.1], p = 0.004; MUO: 3.6[3.2-4.0] vs. 2.0[1.6-2.4], p < 0.001; p = 0.03 for inter-group comparison). After 21 months, the beneficial effect was no longer seen in MHO (2.0[1.5-2.6], p = 1.0), while it remained partially preserved in MUO (2.9[2.4-3.3], p = 0.002). QueryShort-term improvements of lipid parameters were similar in both groups. However, long-term improvements of HDL-cholesterol and triglycerides were only seen in MUO (44.4[41.5-47.4] vs. 49.3[46.2, 52.3] mg/dl, p < 0.001; 176.8[158.9-194.8] vs. 138.8[119.4-158.3] mg/dl, p < 0.001, respectively) but not in MHO. Weight loss-induced improvements in the QoL and particularly the physical health status were maintained in MUO until the end of the trial, while benefits disappeared over time in MHO. Group allocation by HOMA-IR and ISIClamp revealed higher benefits for MUO mainly in parameters of the glucose metabolism and QoL.

CONCLUSIONS

Our data demonstrates stronger and longer-lasting improvements of metabolism and QoL in MUO after weight loss. Trial registration (ClinicalTrials.gov): NCT00850629. Registered 25 February 2009, https://clinicaltrials.gov/ct2/show/NCT00850629 .

Mechanisms contributing to adverse outcomes of COVID-19 in obesity

A growing amount of epidemiological data from multiple countries indicate an increased prevalence of obesity, more importantly central obesity, among hospitalized subjects with COVID-19. This suggests that obesity is a major factor contributing to adverse outcome of the disease. As it is a metabolic disorder with dysregulated immune and endocrine function, it is logical that dysfunctional metabolism contributes to the mechanisms behind obesity being a risk factor for adverse outcome in COVID-19. Emerging data suggest that in obese subjects, (a) the molecular mechanisms of viral entry and spread mediated through ACE2 receptor, a multifunctional host cell protein which links to cellular homeostasis mechanisms, are affected. This includes perturbation of the physiological renin-angiotensin system pathway causing pro-inflammatory and pro-thrombotic challenges (b) existent metabolic overload and ER stress-induced UPR pathway make obese subjects vulnerable to severe COVID-19, (c) host cell response is altered involving reprogramming of metabolism and epigenetic mechanisms involving microRNAs in line with changes in obesity, and (d) adiposopathy with altered endocrine, adipokine, and cytokine profile contributes to altered immune cell metabolism, systemic inflammation, and vascular endothelial dysfunction, exacerbating COVID-19 pathology. In this review, we have examined the available literature on the underlying mechanisms contributing to obesity being a risk for adverse outcome in COVID-19.

Interplay between endocrinology, metabolism and COVID-19 infection

There are more than 170 million confirmed cases of COVID-19 worldwide, yet its effects on the endocrine system remain under-reported due to lack of awareness by the public, primary care givers and specialists. This is a narrative review using up-to-date literature discussing the consequences that infection with SARS-CoV-2 can have on diabetes and the endocrine glands including the adrenals, thyroid and pituitary, as well as hyponatremia and hypogonadism. Endocrinologists, internists and primary care physicians need to be aware of the involvement of the endocrine organs when dealing with people recovering from COVID-19 and actively manage any complications to reduce mortality and improve the quality of life of those affected.

Novel biomarkers of childhood and adolescent obesity

Regulation of the Renin-Angiotensin System (RAS) and the kallikrein-kinin system (KKS) by obesity in adolescents.

An Overview of Adipose Tissue ACE2 Modulation by Diet and Obesity. Potential Implications in COVID-19 Infection and Severity

The present review is aimed at analysing the current evidence concerning the potential modulation of obesity and/or diet in adipose tissue ACE2. Additionally, the potential implications of these effects on COVID-19 are also addressed. The results published show that diet and obesity are two factors that effectively influence the expression of Ace2 gene in adipose tissue. However, the shifts in this gene do not always occur in the same direction, nor with the same intensity. Additionally, there is no consensus regarding the implications of increased adipose tissue ACE2 expression in health. Thus, while in some studies a protective role is attributed to ACE2 overexpression, other studies suggest otherwise. Similarly, there is much debate regarding the role played by ACE2 in COVID-19 in terms of degree of infection and disease outcomes. The greater risk of infection that may hypothetically derive from enhanced ACE2 expression is not clear since the functionality of the enzyme seems to be as important as the abundance. Thus, the greater abundance of ACE2 in adipose tissue of obese subjects may be counterbalanced by its lower activation. In addition, a protective role of ACE2 overexpression has also been suggested, associated with the increase in anti-inflammatory factors that it may produce.

The serum metabolome of COVID-19 patients is distinctive and predictive

BACKGROUND

Metabolism is critical for sustaining life, immunity and infection, but its role in COVID-19 is not fully understood.

METHODS

Seventy-nine COVID-19 patients, 78 healthy controls (HCs) and 30 COVID-19-like patients were recruited in a prospective cohort study. Samples were collected from COVID-19 patients with mild or severe symptoms on admission, patients who progressed from mild to severe symptoms, and patients who were followed from hospital admission to discharge. The metabolome was assayed using gas chromatography-mass spectrometry.

RESULTS

Serum butyric acid, 2-hydroxybutyric acid, l-glutamic acid, l-phenylalanine, l-serine, l-lactic acid, and cholesterol were enriched in COVID-19 and COVID-19-like patients versus HCs. Notably, d-fructose and succinic acid were enriched, and citric acid and 2-palmitoyl-glycerol were depleted in COVID-19 patients compared to COVID-19-like patients and HCs, and these four metabolites were not differentially distributed in non-COVID-19 groups. COVID-19 patients had enriched 4-deoxythreonic acid and depleted 1,5-anhydroglucitol compared to HCs and enriched oxalic acid and depleted phosphoric acid compared to COVID-19-like patients. A combination of d-fructose, citric acid and 2-palmitoyl-glycerol distinguished COVID-19 patients from HCs and COVID-19-like patients, with an area under the curve (AUC) > 0.92 after validation. The combination of 2-hydroxy-3-methylbutyric acid, 3-hydroxybutyric acid, cholesterol, succinic acid, L-ornithine, oleic acid and palmitelaidic acid predicted patients who progressed from mild to severe COVID-19, with an AUC of 0.969. After discharge, nearly one-third of metabolites were recovered in COVID-19 patients.

CONCLUSIONS

The serum metabolome of COVID-19 patients is distinctive and has important value in investigating pathogenesis, determining a diagnosis, predicting severe cases, and improving treatment.

Factors Associated with the Expression of ACE2 in Human Lung Tissue: Pathological Evidence from Patients with Normal FEV1 and FEV1/FVC

Background

Whether COVID-19 comorbidities and risk factors such as old age, male gender, smoking, obesity, eosinophils and blood types have direct contact with expression of ACE2 and pro-inflammation cytokines in human lung tissues were still unclear.

Patients and Methods

Sixty-four patients with normal FEV₁ and FEV₁/FVC underwent thoracotomy for pulmonary nodules were included. Blinded histological assessments were performed by two pathologists. Clinical features and results of the immunohistochemical staining of ACE2 were collected and analyzed.

Results

ACE2 expressed in alveolar macrophages (most obvious), alveolar epithelia and vascular endothelia, but not in small-airway epithelia. ACE2 expressions are positively related to age (r =0.26, P =0.040), weight (r =0.43, P<0.001), as well as BMI (r = 0.38, P =0.002), and male patients show higher expressions of ACE2 in lungs (P <0.05). ACE2 expressions are negatively related to peripheral eosinophils (r = -0.30, P =0.017). There was no correlation between ABO blood types and ACE2 expression in normal lung tissues (P > 0.05). IL-13 and IL-6R expression in lung tissue increased with age (r =0.26, P <0.05, for both).

Conclusion

Our pathological evidences showed that the alveolar epithelia, vascular endothelia, and alveolar macrophages are susceptible in human lungs for SARS-CoV-2 infection. The risk factors such as high body weight/BMI, old age, male gender, and eosinopenia may be related to ACE2 expression in human lungs, and associated with more chance to develop the severe cases. IL-6R expression in lung tissue also increased with age. Therefore, weight control and smoking cessation are essential to reduce the susceptibility of SARS-CoV-2 infection, especially in obesity, old or male patients. Peripheral eosinophils monitor is also quite necessary to detect severe tendency in COVID-19 patients.

Pathways to Severe COVID-19 for People with Obesity

Increased morbidity and mortality from coronavirus disease 2019 (COVID-19) in people with obesity have illuminated the intersection of obesity with impaired responses to infections. Although data on mechanisms by which COVID-19 impacts health are being rapidly generated, there is a critical need to better understand the pulmonary, vascular, metabolic, and immunologic aspects that drive the increased risk for complications from COVID-19 in people with obesity. This review provides a broad overview of the intersection between COVID-19 and the physiology of obesity in order to highlight potential mechanisms by which COVID-19 disease severity is increased by obesity and identify areas for future investigation toward developing tailored therapy for people with obesity who develop COVID-19.

Mediterranean Diet for the Prevention of Gestational Diabetes in the Covid-19 Era: Implications of Il-6 In Diabesity

The aim of this review is to highlight the influence of the Mediterranean Diet (MedDiet) on Gestational Diabetes Mellitus (GDM) and Gestational Weight Gain (GWG) during the COVID-19 pandemic era and the specific role of interleukin (IL)-6 in diabesity. It is known that diabetes, high body mass index, high glycated hemoglobin and raised serum IL-6 levels are predictive of poor outcomes in coronavirus disease 2019 (COVID-19). The immunopathological mechanisms of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection include rising levels of several cytokines and in particular IL-6. The latter is associated with hyperglycemia and insulin resistance and could be useful for predicting the development of GDM. Rich in omega-3 polyunsaturated fatty acids, vitamins, and minerals, MedDiet improves the immune system and could modulate IL-6, C reactive protein and Nuclear Factor (NF)-κB. Moreover, polyphenols could modulate microbiota composition, inhibit the NF-κB pathway, lower IL-6, and upregulate antioxidant enzymes. Finally, adhering to the MedDiet prior to and during pregnancy could have a protective effect, reducing GWG and the risk of GDM, as well as improving the immune response to viral infections such as COVID-19.

Commentary: COVID-19 and obesity pandemics converge into a syndemic requiring urgent and multidisciplinary action

While substantial evidence points towards obesity and associated cardiometabolic disorders being a major factor for poor outcomes in SARS-CoV2 infections (COVID-19), the complexity of the interplay between these two pandemics is becoming apparent. Indeed, as previously defined, this interaction between obesity and COVID-19 represents a 'syndemic' that requires both current and ongoing attention. At a mechanistic level the chronic inflammatory environment of obesity predisposes to life threatening events such as cytokine storm and enhanced coagulopathy. Obesity and its management are affected by diverse factors manifested at societal, educational, racial, and nutritional levels. A multidisciplinary approach is required to manage obese and type 2 diabetic patients, not only during the current COVID-19 crisis, but to decrease the growing burden of cardiometabolic disease and associated cardiovascular complications impacting future viral pandemics. Further, this syndemic has highlighted disparities in healthcare which need to be addressed to achieve equality in health outcomes in patients infected with COVID-19.