DPP9 as a Potential Novel Mediator in Gastrointestinal Virus Infection.

Dipeptidyl peptidase 9 (DPP9) is a member of the dipeptidyl peptidase IV family. Inhibition of DPP9 has recently been shown to activate the nucleotide-binding domain leucine-rich repeat 1 (NLRP1) inflammasome. NLRP1 is known to bind nucleic acids with high affinity and directly interact with double stranded RNA, which plays a key role in viral replication. DPP9 has also recently emerged as a key gene related to lung-inflammation in critical SARS-CoV-2 infection. Importantly, DPP9 activity is strongly dependent on the oxidative status. Here, we explored the potential role of DPP9 in the gastrointestinal tract. We performed transcriptomics analyses of colon (microarray, n = 37) and jejunal (RNA sequencing, n = 31) biopsies from two independent cohorts as well as plasma metabolomics analyses in two independent cohorts (n = 37 and n = 795). The expression of DPP9 in the jejunum, colon, and blood was significantly associated with circulating biomarkers of oxidative stress (uric acid, bilirubin). It was also associated positively with the expression of transcription factors (NRF-2) and genes (SOD, CAT, GPX) encoding for antioxidant enzymes, but negatively with that of genes (XDH, NOX) and transcription factors (NF-KB) involved in ROS-generating enzymes. Gene co-expression patterns associated with DPP9 identified several genes participating in antiviral pathways in both tissues. Notably, DPP9 expression in the colon and plasma was strongly positively associated with several circulating nucleotide catabolites (hypoxanthine, uric acid, 3-ureidopropionic acid) with important roles in the generation of ROS and viral infection, as well as other metabolites related to oxidative stress (Resolvin D1, glutamate-containing dipeptides). Gene-drug enrichment analyses identified artenimol, puromycin, anisomycin, 3-phenyllactic acid, and linezolid as the most promising drugs targeting these DPP9-associated genes. We have identified a novel potential pathogenic mechanism of viral infection in the digestive tract and promising existing drugs that can be repositioned against viral infection.

Sexual dimorphism in COVID-19: potential clinical and public health implications.

Current evidence suggests that severity and mortality of COVID-19 is higher in men than in women, whereas women might be at increased risk of COVID-19 reinfection and development of long COVID. Differences between sexes have been observed in other infectious diseases and in the response to vaccines. Sex-specific expression patterns of proteins mediating virus binding and entry, and divergent reactions of the immune and endocrine system, in particular the hypothalamic-pituitary-adrenal axis, in response to acute stress might explain the higher severity of COVID-19 in men. In this Personal View, we discuss how sex hormones, comorbidities, and the sex chromosome complement influence these mechanisms in the context of COVID-19. Due to its role in the severity and progression of SARS-CoV-2 infections, we argue that sexual dimorphism has potential implications for disease treatment, public health measures, and follow-up of patients predisposed to the development of long COVID. We suggest that sex differences could be considered in future pandemic surveillance and treatment of patients with COVID-19 to help to achieve better disease stratification and improved outcomes.

Lipidomics and metabolomics signatures of SARS-CoV-2 mediators/receptors in peripheral leukocytes, jejunum and colon.

Cell surface receptor-mediated viral entry plays a critical role in this infection. Well-established SARS-CoV-2 receptors such as ACE2 and TMPRSS2 are highly expressed in the gastrointestinal tract. In fact, there are evidences that SARS-CoV-2 infects epithelial cells from the digestive system. However, emerging research has identified novel mediators such as DPP9, TYK2, and CCR2, all playing a critical role in inflammation. We evaluated the expression of SARS-CoV-2 receptors in peripheral leukocytes (n = 469), jejunum (n = 30), and colon (n = 37) of three independent cohorts by real-time PCR, RNA-sequencing, and microarray transcriptomics. We also performed HPCL-MS/MS lipidomics and metabolomics analyses to identify signatures linked to SARS-CoV-2 receptors. We found markedly higher peripheral leukocytes ACE2 expression levels in women compared to men, whereas the intestinal expression of TMPRSS2 was positively associated with BMI. Consistent lipidomics signatures associated with the expression of these mediators were found in both tissues and peripheral leukocytes involving n-3 long-chain PUFAs and arachidonic acid-derived eicosanoids, which play a key role in the regulation of inflammation and may interfere with viral entry and replication. Medium- and long-chain hydroxy acids, which have shown to interfere in viral replication, were also liked to SARS-CoV2 receptors. Gonadal steroids were also associated with the expression of some of these receptors, even after controlling for sex. The expression of SARS-CoV2 receptors was associated with several metabolic and nutritional traits in different cell types. This information may be useful in the design of potential therapies targeted at coronavirus entry.

COVID-19 and metabolic disease: mechanisms and clinical management.

Up to 50% of the people who have died from COVID-19 had metabolic and vascular disorders. Notably, there are many direct links between COVID-19 and the metabolic and endocrine systems. Thus, not only are patients with metabolic dysfunction (eg, obesity, hypertension, non-alcoholic fatty liver disease, and diabetes) at an increased risk of developing severe COVID-19 but also infection with SARS-CoV-2 might lead to new-onset diabetes or aggravation of pre-existing metabolic disorders. In this Review, we provide an update on the mechanisms of how metabolic and endocrine disorders might predispose patients to develop severe COVID-19. Additionally, we update the practical recommendations and management of patients with COVID-19 and post-pandemic. Furthermore, we summarise new treatment options for patients with both COVID-19 and diabetes, and highlight current challenges in clinical management.

Blood Hemoglobin Substantially Modulates the Impact of Gender, Morbid Obesity, and Hyperglycemia on COVID-19 Death Risk: A Multicenter Study in Italy and Spain.

Background: Hyperglycemia and obesity are associated with a worse prognosis in subjects with COVID-19 independently. Their interaction as well as the potential modulating effects of additional confounding factors is poorly known. Therefore, we aimed to identify and evaluate confounding factors affecting the prognostic value of obesity and hyperglycemia in relation to mortality and admission to the intensive care unit (ICU) due to COVID-19. Methods: Consecutive patients admitted in two Hospitals from Italy (Bologna and Rome) and three from Spain (Barcelona and Girona) as well as subjects from Primary Health Care centers. Mortality from COVID-19 and risk for ICU admission were evaluated using logistic regression analyses and machine learning (ML) algorithms. Results: As expected, among 3,065 consecutive patients, both obesity and hyperglycemia were independent predictors of ICU admission. A ML variable selection strategy confirmed these results and identified hyperglycemia, blood hemoglobin and serum bilirubin associated with increased mortality risk. In subjects with blood hemoglobin levels above the median, hyperglycemic and morbidly obese subjects had increased mortality risk than normoglycemic individuals or non-obese subjects. However, no differences were observed among individuals with hemoglobin levels below the median. This was particularly evident in men: those with severe hyperglycemia and hemoglobin concentrations above the median had 30 times increased mortality risk compared with men without hyperglycemia. Importantly, the protective effect of female sex was lost in subjects with increased hemoglobin levels. Conclusions: Blood hemoglobin substantially modulates the influence of hyperglycemia on increased mortality risk in patients with COVID-19. Monitoring hemoglobin concentrations seem of utmost importance in the clinical settings to help clinicians in the identification of patients at increased death risk.

Lipidomics and metabolomics signatures of SARS-CoV-2 mediators/receptors in peripheral leukocytes, jejunum and colon

Graphical abstract Cell surface receptor-mediated viral entry plays a critical role in this infection. Well-established SARS-CoV-2 receptors such as ACE2 and TMPRSS2 are highly expressed in the gastrointestinal tract. In fact, there are evidences that SARS-CoV-2 infects epithelial cells from the digestive system. However, emerging research has identified novel mediators such as DPP9, TYK2, and CCR2, all playing a critical role in inflammation. We evaluated the expression of SARS-CoV-2 receptors in peripheral leukocytes (n=469), jejunum (n=30), and colon (n=37) of three independent cohorts by real-time PCR, RNA-sequencing, and microarray transcriptomics. We also performed HPCL-MS/MS lipidomics and metabolomics analyses to identify signatures linked to SARS-CoV-2 receptors. We found markedly higher peripheral leukocytes ACE2 expression levels in women compared to men, whereas the intestinal expression of TMPRSS2 was positively associated with BMI. Consistent lipidomics signatures associated with the expression of these mediators were found in both tissues and peripheral leukocytes involving n-3 long-chain PUFAs and arachidonic acid-derived eicosanoids, which play a key role in the regulation of inflammation and may interfere with viral entry and replication. Medium- and long-chain hydroxy acids, which have shown to interfere in viral replication, were also liked to SARS-CoV2 receptors. Gonadal steroids were also associated with the expression of some of these receptors, even after controlling for sex. The expression of SARS-CoV2 receptors was associated with several metabolic and nutritional traits in different cell types. This information may be useful in the design of potential therapies targeted at coronavirus entry.

Bariatric and metabolic surgery during and after the COVID-19 pandemic: DSS recommendations for management of surgical candidates and postoperative patients and prioritisation of access to surgery.

The coronavirus disease 2019 pandemic is wreaking havoc on society, especially health-care systems, including disrupting bariatric and metabolic surgery. The current limitations on accessibility to non-urgent care undermine postoperative monitoring of patients who have undergone such operations. Furthermore, like most elective surgery, new bariatric and metabolic procedures are being postponed worldwide during the pandemic. When the outbreak abates, a backlog of people seeking these operations will exist. Hence, surgical candidates face prolonged delays of beneficial treatment. Because of the progressive nature of obesity and diabetes, delaying surgery increases risks for morbidity and mortality, thus requiring strategies to mitigate harm. The risk of harm, however, varies among patients, depending on the type and severity of their comorbidities. A triaging strategy is therefore needed. The traditional weight-centric patient-selection criteria do not favour cases based on actual clinical needs. In this Personal View, experts from the Diabetes Surgery Summit consensus conference series provide guidance for the management of patients while surgery is delayed and for postoperative surveillance. We also offer a strategy to prioritise bariatric and metabolic surgery candidates on the basis of the diseases that are most likely to be ameliorated postoperatively. Although our system will be particularly germane in the immediate future, it also provides a framework for long-term clinically meaningful prioritisation.

Practical recommendations for the management of diabetes in patients with COVID-19.

Diabetes is one of the most important comorbidities linked to the severity of all three known human pathogenic coronavirus infections, including severe acute respiratory syndrome coronavirus 2. Patients with diabetes have an increased risk of severe complications including Adult Respiratory Distress Syndrome and multi-organ failure. Depending on the global region, 20-50% of patients in the coronavirus disease 2019 (COVID-19) pandemic had diabetes. Given the importance of the link between COVID-19 and diabetes, we have formed an international panel of experts in the field of diabetes and endocrinology to provide some guidance and practical recommendations for the management of diabetes during the pandemic. We aim to briefly provide insight into potential mechanistic links between the novel coronavirus infection and diabetes, present practical management recommendations, and elaborate on the differential needs of several patient groups.