IFNγ-producing NK cells in adipose tissue are associated with hyperglycemia and insulin resistance in obese women.

BACKGROUND/OBJECTIVES: Innate lymphoid cells (ILCs) play an important role in the maintenance of immune and metabolic homeostasis in adipose tissue (AT). The crosstalk between AT ILCs and adipocytes and other immune cells coordinates adipocyte differentiation, beiging, glucose metabolism and inflammation. Although the metabolic and homeostatic functions of mouse ILCs have been extensively investigated, little is known about human adipose ILCs and their roles in obesity and insulin resistance (IR). SUBJECTS/METHODS: Here we characterized T and NK cell populations in omental AT (OAT) from women (n = 18) with morbid obesity and varying levels of IR and performed an integrated analysis of metabolic parameters and adipose tissue transcriptomics. RESULTS: In OAT, we found a distinct population of CD56-NKp46+EOMES+ NK cells characterized by expression of cytotoxic molecules, pro-inflammatory cytokines, and markers of cell activation. AT IFNγ+ NK cells, but not CD4, CD8 or γδ T cells, were positively associated with glucose levels, glycated hemoglobin (HbA1c) and IR. AT NK cells were linked to a pro-inflammatory gene expression profile in AT and developed an effector phenotype in response to IL-12 and IL-15. Moreover, integrated transcriptomic analysis revealed a potential implication of AT IFNγ+ NK cells in controlling adipose tissue inflammation, remodeling, and lipid metabolism. CONCLUSIONS: Our results suggest that a distinct IFNγ-producing NK cell subset is involved in metabolic homeostasis in visceral AT in humans with obesity and may be a potential target for therapy of IR.

High Prevalence of Obesity in Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) Requiring Invasive Mechanical Ventilation.

OBJECTIVE: The COVID-19 pandemic is rapidly spreading worldwide, notably in Europe and North America where obesity is highly prevalent. The relation between obesity and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has not been fully documented. METHODS: This retrospective cohort study analyzed the relationship between clinical characteristics, including BMI, and the requirement for invasive mechanical ventilation (IMV) in 124 consecutive patients admitted in intensive care for SARS-CoV-2 in a single French center. RESULTS: Obesity (BMI > 30) and severe obesity (BMI > 35) were present in 47.6% and 28.2% of cases, respectively. Overall, 85 patients (68.6%) required IMV. The proportion of patients who required IMV increased with BMI categories (P < 0.01, χ2 test for trend), and it was greatest in patients with BMI > 35 (85.7%). In multivariate logistic regression, the need for IMV was significantly associated with male sex (P < 0.05) and BMI (P < 0.05), independent of age, diabetes, and hypertension. The odds ratio for IMV in patients with BMI > 35 versus patients with BMI < 25 was 7.36 (1.63-33.14; P = 0.02). CONCLUSIONS: The present study showed a high frequency of obesity among patients admitted in intensive care for SARS-CoV-2. Disease severity increased with BMI. Obesity is a risk factor for SARS-CoV-2 severity, requiring increased attention to preventive measures in susceptible individuals.