Association between COVID-19 and the incidence of type 1 diabetes in Portugal - a registry study.

BACKGROUND: Viral respiratory infections may precipitate type 1 diabetes (T1D). A possible association between the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for COVID-19, and the incidence of T1D is being determined. This study was carried out using Portuguese registries, aiming at examining temporal trends between COVID-19 and T1D. METHODS: Hospital data, comparing the incidence before and during the COVID-19 pandemic, from children and young adults diagnosed with new-onset T1D, was acquired beginning in 2017 and until the end of 2022. Data was obtained from nine different Portuguese hospital units. The impact of the COVID-19 pandemic, beginning in March 2020, was assessed comparing the annual numbers of new-onset T1D cases. The annual median levels of glucose, glycated hemoglobin (HbA1c) and fasting C-peptide at T1D diagnosis were compared. The annual number of diabetic ketoacidosis (DKA) episodes among new T1D cases was also assessed at two centers. RESULTS: In total, data from 574 newly diagnosed T1D patients was analyzed, including 530 (92.3%) children. The mean ages for child and adult patients were 9.1 (SD 4.4) and 32.8 (SD 13.6) years, respectively. 57.8% (331/573) were male, one patient had unknown sex. The overall median (25-75 percentiles) levels of glucose, HbA1c and fasting C-peptide at diagnosis were 454 mg/dL (356-568), 11.8% (10.1-13.4) and 0.50 µg/L (0.30-0.79), respectively. DKA at T1D diagnosis was present in 48.4% (76/157). For eight centers with complete 2018 to 2021 data (all calendar months), no overall significant increase in T1D cases was observed during the COVID-19 pandemic, i.e. 90 cases in 2018, 90 cases in 2019, 112 in 2020 and 100 in 2021 (P for trend = 0.36). Two of the centers, Faro (CHUA) and Dona Estefânia (CHULC) hospitals, did however see an increase in T1D from 2019 to 2020. No significant changes in glucose (P = 0.32), HbA1c (P = 0.68), fasting C-peptide (P = 0.20) or DKA frequency (P = 0.68) at the time of T1D diagnosis were observed over the entire study period. CONCLUSION: The T1D incidence did not increase significantly, when comparing the years before and during the COVID-19 pandemic, nor did key metabolic parameters or number of DKA episodes change.

Role of CD20+ T cells in cancer, autoimmunity and obesity.

Despite the known link between obesity and insulin resistance (IR) to chronic low-grade inflammation, new markers capable of early IR detection are needed. Immune cells are components of adipose tissue's (AT) stromal vascular fraction (SVF) that regulate AT homeostasis. The altered phenotype and function of AT-infiltrating immune cells may contribute to the development and maintenance of local AT inflammation observed under obesity-induced IR conditions. Impaired AT-specific immunometabolic function may influence the whole organism. Therefore, AT-infiltrating immune cells may be important players in the development of obesity-related metabolic complications, such as type 2 diabetes mellitus (T2DM). B and T cells, particularly CD20+ T cells, play important roles in human pathology, such as autoimmune disease and cancer. However, the question remains as to whether CD20+ T cells have an important contribution to the development of obesity-related IR. While circulating CD20+ T cells are mostly of the central memory phenotype (i.e. antigen-experienced T cells with the ability to home to secondary lymphoid organs), tissues-infiltrated CD20+ T cells are predominantly of the effector memory phenotype (i.e. antigen-experienced T cells that preferentially infiltrate peripheral tissues). The latter produce pro-inflammatory cytokines, such as IFN-γ and IL-17, which play a role in obesity-related IR development. This review describes the CD20 molecule and its presence in both B and T cells, shedding light on its ontogeny and function, in health and disease, with emphasis on AT. The link between CD20+ T cell dysregulation, obesity, and IR development supports the role of CD20+ T cells as markers of adipose tissue dysmetabolism.

The role of CD20+ T cells: Insights in human peripheral blood.

CD20+ T cells constitute a small subset of T cells. These are found among CD4+, CD8+, CD4+CD8+, CD4-CD8- T, and TCRγδ+ T cells, and have been poorly characterized. The aim of this study was to characterize peripheral blood (PB) CD20+ T cells and compare them to their PB CD20- T cell counterparts. PB from 17 healthy individuals was collected. The distribution of CD20+ T cells among maturation-associated T cells compartments (naïve, central memory, transitional memory, effector memory, and effector T cells), their polarization, activation status, and expression of immune-regulatory proteins were evaluated by flow cytometry. Their function was also assessed, by measuring IFN-γ, TNF-α, and IL-17 production. Compared with CD20- T cells, CD20+ T cells represent a higher proportion of transitional memory cells. Furthermore, CD20+ T cells display a proinflammatory phenotype, characterized by the expansion of Th1, Th1/17, and Tc1 cell subsets , associated to a high expression of activation (CD25) and exhaustion (PD-1) markers. In addition, the simultaneous production of the proinflammatory cytokines IFN-γ, TNF-α, and IL-17 was also detected in CD4+CD20+ T cells. Our results show that CD20+ T cells are phenotypically and functionally different from CD20- T cells, suggesting that these cells are a distinct subset of T cells.

Bariatric Surgery Induces Alterations in the Immune Profile of Peripheral Blood T Cells.

Low-grade inflammation is closely linked to obesity and obesity-related comorbidities; therefore, immune cells have become an important topic in obesity research. Here, we performed a deep phenotypic characterization of circulating T cells in people with obesity, using flow cytometry. Forty-one individuals with obesity (OB) and clinical criteria for bariatric surgery were enrolled in this study. We identified and quantified 44 different circulating T cell subsets and assessed their activation status and the expression of immune-checkpoint molecules, immediately before (T1) and 7-18 months after (T2) the bariatric surgery. Twelve age- and sex-matched healthy individuals (nOB) were also recruited. The OB participants showed higher leukocyte counts and a higher percentage of neutrophils. The percentage of circulating Th1 cells were negatively correlated to HbA1c and insulin levels. OB Th1 cells displayed a higher activation status and lower PD-1 expression. The percentage of Th17 and Th1/17 cells were increased in OB, whereas the CD4+ Tregs' percentage was decreased. Interestingly, a higher proportion of OB CD4+ Tregs were polarized toward Th1- and Th1/17-like cells and expressed higher levels of CCR5. Bariatric surgery induced the recovery of CD4+ Treg cell levels and the expansion and activation of Tfh and B cells. Our results show alterations in the distribution and phenotype of circulating T cells from OB people, including activation markers and immune-checkpoint proteins, demonstrating that different metabolic profiles are associated to distinct immune profiles, and both are modulated by bariatric surgery.

Changes in Metabolic and Inflammatory Markers after a Combined Exercise Program in Workers: A Randomized Controlled Trial.

PURPOSE: We investigated the effects of a 16-week combined exercise training on body composition, metabolic and inflammatory markers in sedentary middle-aged workers. We also assessed whether significant alterations in metabolic markers were associated with changes in health-related outcomes. METHODS: This randomized controlled trial involved 46 participants randomly allocated into control and exercise groups. The exercise group performed 16-week combined aerobic and resistance training for 75 min/session, 3 times/week. Fasting blood samples were collected at baseline and after 16-week intervention to determine lipid profile, metabolic and inflammatory markers as primary outcomes. RESULTS: A total of 36 participants completed the intervention (53.70 ± 6.92 years old) (n = 18 in each group). Waist circumference (interaction effect: F = 7.423, p = 0.002), fat mass (interaction effect: F = 5.070, p = 0.011), and muscle mass (interaction effect: F = 5.420, p = 0.007) were improved in the exercise group compared to the control group. Fasting glucose increased after the 16-week follow-up (time effect: F = 73.253, p < 0.001), without an intergroup difference. Insulin levels were greater in the control compared to exercise group (group effect: F = 6.509, p = 0.015). The control group tended to increase the HOMA-IR index (interaction effect: F = 3.493, p = 0.070) and to decrease the QUICKI index (interaction effect: F = 3.364, p = 0.075) to a greater extent compared to the exercise group. Exercise group reduced leptin (interaction effect: F = 11.175, p = 0.002) and adiponectin (interaction effect: F = 4.437, p = 0.043) concentrations in a greater magnitude than control group. IL-6 (time effect: F = 17.767, p < 0.001) and TNF-α (time effect: F = 9.781, p = 0.004) concentrations decreased after the intervention, without an intergroup difference. IL-17A levels increased in the control compared to exercise group (interaction effect: F = 5.010, p = 0.033). Effects on adiponectin, IL-6 and IL-17A levels seem to depend on baseline BMI, age, and sex. Percentage changes in leptin correlated positively with changes in HOMA-IR index in the exercise (r = 0.565, p = 0.015) and control (r = 0.670, p = 0.002) groups. CONCLUSIONS: A combined training program can be an effective strategy to improve body composition and inflammatory markers and prevent marked reductions in insulin sensitivity among middle-aged workers.

Identification and characterization of circulating and adipose tissue infiltrated CD20+ T cells from subjects with obesity that undergo bariatric surgery.

T cells play critical roles in adipose tissue (AT) inflammation. The role of CD20+ T cell in AT dysfunction and their contributing to insulin resistance (IR) and type 2 diabetes progression, is not known. The aim was to characterize CD20+ T cells in omental (OAT), subcutaneous (SAT) and peripheral blood (PB) from subjects with obesity (OB, n=42), by flow cytometry. Eight subjects were evaluated before (T1) and 12 months post (T2) bariatric/metabolic surgery (BMS). PB from subjects without obesity (nOB, n=12) was also collected. Higher percentage of CD20+ T cells was observed in OAT, compared to PB or SAT, in OB-T1. CD20 expression by PB CD4+ T cells was inversely correlated with adiposity markers, while follicular-like CD20+ T cells were positively correlated with impaired glucose tolerance (increased HbA1c). Notably, among OB-T1, IR establishment was marked by a lower percentage and absolute number of PB CD20+ T cells, compared nOB. Obesity was associated with higher percentage of activated CD20+ T cells; however, OAT-infiltrated CD20+ T cells from OB-T1 with diabetes displayed the lowest activation. CD20+ T cells infiltrating OAT from OB-T1 displayed a phenotype towards IFN-γ-producing Th1 and Tc1 cells. After BMS, the percentage of PB CD4+CD20+ T cells increased, with reduced Th1 and increased Th17 phenotype. Whereas in OAT the percentage of CD20+ T cells with Th1/17 and Tc1/17 phenotypes increased. Interestingly, OAT from OB pre/post BMS maintained higher frequency of effector memory CD20+ T cells. In conclusion, CD20+ T cells may play a prominent role in obesity-related AT inflammation.