Overnutrition in the early postnatal period influences lifetime metabolic risk: Evidence for impact on pancreatic ß-cell mass and function.

Overconsumption of energy-rich foods that disrupt caloric balance is a fundamental cause of overweight, obesity and diabetes. Dysglycemia and the resulting cardiovascular disease cause substantial morbidity and mortality worldwide, as well as high societal cost. The prevalence of obesity in childhood and adolescence is increasing, leading to younger diabetes diagnosis, and higher severity of microvascular and macrovascular complications. An important goal is to identify early life conditions that increase future metabolic risk, toward the goal of preventing diabetes and cardiovascular disease. An ample body of evidence implicates prenatal and postnatal childhood growth trajectories in the programming of adult metabolic disease. Human epidemiological data show that accelerated childhood growth increases risk of type 2 diabetes in adulthood. Type 2 diabetes results from the combination of insulin resistance and pancreatic ß-cell failure, but specific mechanisms by which accelerated postnatal growth impact one or both of these processes remain uncertain. This review explores the metabolic impact of overnutrition during postnatal life in humans and in rodent models, with specific attention to the connection between accelerated childhood growth and future adiposity, insulin resistance, ß-cell mass and ß-cell dysfunction. With improved knowledge in this area, we might one day be able to modulate nutrition and growth in the critical postnatal window to maximize lifelong metabolic health.

Noncanonical CDK4 signaling rescues diabetes in a mouse model by promoting ß cell differentiation.

Expanding ß cell mass is a critical goal in the fight against diabetes. CDK4, an extensively characterized cell cycle activator, is required to establish and maintain ß cell number. ß cell failure in the IRS2-deletion mouse type 2 diabetes model is, in part, due to loss of CDK4 regulator cyclin D2. We set out to determine whether replacement of endogenous CDK4 with the inhibitor-resistant mutant CDK4-R24C rescued the loss of ß cell mass in IRS2-deficient mice. Surprisingly, not only ß cell mass but also ß cell dedifferentiation was effectively rescued, despite no improvement in whole body insulin sensitivity. Ex vivo studies in primary islet cells revealed a mechanism in which CDK4 intervened downstream in the insulin signaling pathway to prevent FOXO1-mediated transcriptional repression of critical ß cell transcription factor Pdx1. FOXO1 inhibition was not related to E2F1 activity, to FOXO1 phosphorylation, or even to FOXO1 subcellular localization, but rather was related to deacetylation and reduced FOXO1 abundance. Taken together, these results demonstrate a differentiation-promoting activity of the classical cell cycle activator CDK4 and support the concept that ß cell mass can be expanded without compromising function.

The feasibility, acceptability, and usability of telehealth visits.

Background: Telemedicine is now common practice for many fields of medicine, but questions remain as to whether telemedicine will continue as an important patient care modality once COVID-19 becomes endemic. We explored provider and patients' perspectives on telemedicine implementation. Methods: Physicians from three specialties within the Department of Medicine of a single institution were electronically surveyed regarding their perceptions of satisfaction, benefits, and challenges of video visits, as well as the quality of interactions with patients. Patients were surveyed via telephone by the Survey Research Group at Cornell about participation in video visits, challenges encountered, perceived benefits, preferences for care, and overall satisfaction. Results: Providers reported an overwhelmingly positive experience with video visits, with the vast majority agreeing that they were comfortable with the modality (98%) and that it was easy to interact with patients (92%). Most providers (72%) wanted to have more telemedicine encounters in the future. Key factors interfering with successful telemedicine encounters were technical challenges and insufficient technical support. Overall, patients also perceived video visits very positively regarding ease of communication and care received and had few privacy concerns. Some (10%-15%) patients expressed interest in receiving more technical support and training. There was a gradient of satisfaction with telemedicine across specialties with patients receiving weight management reporting more favorable responses while patients with lymphoma expressed more mixed responses. Conclusion: Both providers and patients found telemedicine to be an acceptable and useful modality to provide or receive medical care. The principal barrier to successful encounters was technical challenges.

High-throughput analysis of ANRIL circRNA isoforms in human pancreatic islets.

The antisense non-coding RNA in the INK locus (ANRIL) is a hotspot for genetic variants associated with cardiometabolic disease. We recently found increased ANRIL abundance in human pancreatic islets from donors with certain Type II Diabetes (T2D) risk-SNPs, including a T2D risk-SNP located within ANRIL exon 2 associated with beta cell proliferation. Recent studies have found that expression of circular species of ANRIL is linked to the regulation of cardiovascular phenotypes. Less is known about how the abundance of circular ANRIL may influence T2D phenotypes. Herein, we sequence circular RNA in pancreatic islets to characterize circular isoforms of ANRIL. We identify several consistently expressed circular ANRIL isoforms whose expression is correlated across dozens of individuals and characterize ANRIL splice sites that are commonly involved in back-splicing. We find that samples with the T2D risk allele in ANRIL exon 2 had higher ratios of circular to linear ANRIL compared to protective-allele carriers, and that higher circular:linear ANRIL was associated with decreased beta cell proliferation. Our study points to a combined involvement of both linear and circular ANRIL species in T2D phenotypes and opens the door for future studies of the molecular mechanisms by which ANRIL impacts cellular function in pancreatic islets.

Weight Loss Outcomes With Telemedicine During COVID-19.

Background: Amidst the COVID-19 pandemic, telemedicine was rapidly implemented to maintain patient care during quarantine. However, there is little data on how this transition may have impacted weight loss outcomes and interventions among patients with overweight or obesity. Methods: This was a retrospective observational study of adults who established care for medically managed obesity at the Weill Cornell Comprehensive Weight Control Center during September-November 2019 and May-July 2020 and who completed 6 months of follow-up. Weight loss outcomes and weight management interventions were explored and stratified by patient-provider interaction: in-person visits only, in-person and video visits, and video visits only. Results: Of 499 charts eligible for review, 245 (49%) returned for their 6-month follow-up visit and were included for analysis. Of 245 patients, 69 had in-person visits only ("in-person"), 85 started in-person and later switched to video visits ("hybrid"), and 91 had video visits only ("video"). All cohorts were predominantly white and female. Median ages were 56, 49, and 49 years; baseline median weights were 98.9, 96.8, and 93.0 kg; and baseline median BMIs were 35.3, 34.4, and 34.0 kg/m2 for in-person, hybrid, and video cohorts, respectively. The median percent weight changes over 6 months were not significantly different among cohorts: -4.3% [-8.5, -1.5] in the in-person cohort, -5.6% [-8.7, -2.2] in the hybrid group, and -5.8% [-9.7, -2.4] in the video cohort. The percent of patients who achieved ≥5% weight loss were also similar: 46.4%, 55.3%, and 59.3%, respectively. The median number of visits in the video cohort was more than in the in-person or hybrid groups (5 vs. 4). Median number of anti-obesity medications (AOMs) prescribed was similar among groups. The most common AOMs were metformin (all cohorts) followed by semaglutide 1.0 mg (in-person and video) or topiramate (hybrid). Conclusion: Patients on anti-obesity medications who were followed for 6 months via video or video plus in-person visits (hybrid) experienced clinically significant weight loss. Median number of AOMs were similar among groups, and the most common AOMs were metformin, semaglutide 1.0 mg, and topiramate. More investigation is required to compare telemedicine models with in-person care.

Beta-cell specific Insr deletion promotes insulin hypersecretion and improves glucose tolerance prior to global insulin resistance.

Insulin receptor (Insr) protein is present at higher levels in pancreatic ß-cells than in most other tissues, but the consequences of ß-cell insulin resistance remain enigmatic. Here, we use an Ins1cre knock-in allele to delete Insr specifically in ß-cells of both female and male mice. We compare experimental mice to Ins1cre-containing littermate controls at multiple ages and on multiple diets. RNA-seq of purified recombined ß-cells reveals transcriptomic consequences of Insr loss, which differ between female and male mice. Action potential and calcium oscillation frequencies are increased in Insr knockout ß-cells from female, but not male mice, whereas only male ßInsrKO islets have reduced ATP-coupled oxygen consumption rate and reduced expression of genes involved in ATP synthesis. Female ßInsrKO and ßInsrHET mice exhibit elevated insulin release in ex vivo perifusion experiments, during hyperglycemic clamps, and following i.p. glucose challenge. Deletion of Insr does not alter ß-cell area up to 9 months of age, nor does it impair hyperglycemia-induced proliferation. Based on our data, we adapt a mathematical model to include ß-cell insulin resistance, which predicts that ß-cell Insr knockout improves glucose tolerance depending on the degree of whole-body insulin resistance. Indeed, glucose tolerance is significantly improved in female ßInsrKO and ßInsrHET mice compared to controls at 9, 21 and 39 weeks, and also in insulin-sensitive 4-week old males. We observe no improved glucose tolerance in older male mice or in high fat diet-fed mice, corroborating the prediction that global insulin resistance obscures the effects of ß-cell specific insulin resistance. The propensity for hyperinsulinemia is associated with mildly reduced fasting glucose and increased body weight. We further validate our main in vivo findings using an Ins1-CreERT transgenic line and find that male mice have improved glucose tolerance 4 weeks after tamoxifen-mediated Insr deletion. Collectively, our data show that ß-cell insulin resistance in the form of reduced ß-cell Insr contributes to hyperinsulinemia in the context of glucose stimulation, thereby improving glucose homeostasis in otherwise insulin sensitive sex, dietary and age contexts.

Ergocalciferol in New-onset Type 1 Diabetes: A Randomized Controlled Trial.

CONTEXT: The effect of the anti-inflammatory and immunomodulatory actions of vitamin D on the duration of partial clinical remission (PR) in youth with type 1 diabetes (T1D) is unclear. OBJECTIVE: This work aimed to determine the effect of adjunctive ergocalciferol on residual ß-cell function (RBCF) and PR in youth with newly diagnosed T1D who were maintained on a standardized insulin treatment protocol. The hypothesis was that ergocalciferol supplementation increases RBCF and prolongs PR. METHODS: A 12-month, randomized, double-blind, placebo-controlled trial was conducted of 50 000 IU of ergocalciferol per week for 2 months, and then once every 2 weeks for 10 months, vs placebo in 36 individuals aged 10 to 21 years, with T1D of less than 3 months and a stimulated C-peptide (SCP) level greater than or equal to 0.2 nmol/L (≥ 0.6 ng/mL). The ergocalciferol group had 18 randomly assigned participants (10 male/8 female), mean age 13.3 ±â€…2.8 years, while the control group had 18 participants (14 male/4 female), aged 14.3 ±â€…2.9 years. RESULTS: The ergocalciferol treatment group had statistically significantly higher serum 25-hydroxyvitamin D at 6 months (P = .01) and 9 months (P = .02) than the placebo group. At 12 months, the ergocalciferol group had a statistically significantly lower serum tumor necrosis factor α (TNF-α) concentration (P = .03). There were no statistically significant differences between the groups at each time point from baseline to 12 months for SCP concentration (P = .08), glycated hemoglobin A1c (HbA1c) (P = .09), insulin dose-adjusted A1c (IDAA1c), or total daily dose of insulin. Temporal trends for rising HbA1c (P = .04) and IDAA1c (P = .02) were statistically significantly blunted in the ergocalciferol group. CONCLUSION: Ergocalciferol statistically significantly reduced serum TNF-α concentration and the rates of increase both in A1c and IDAA1c, suggesting a protection of RBCF and PR in youth with newly diagnosed T1D.

Hyperglycemia in acute COVID-19 is characterized by insulin resistance and adipose tissue infectivity by SARS-CoV-2.

Individuals infected with SARS-CoV-2 who also display hyperglycemia suffer from longer hospital stays, higher risk of developing acute respiratory distress syndrome (ARDS), and increased mortality. Nevertheless, the pathophysiological mechanism of hyperglycemia in COVID-19 remains poorly characterized. Here, we show that hyperglycemia is similarly prevalent among patients with ARDS independent of COVID-19 status. Yet among patients with ARDS and COVID-19, insulin resistance is the prevalent cause of hyperglycemia, independent of glucocorticoid treatment, which is unlike patients with ARDS but without COVID-19, where pancreatic beta cell failure predominates. A screen of glucoregulatory hormones revealed lower levels of adiponectin in patients with COVID-19. Hamsters infected with SARS-CoV-2 demonstrated a strong antiviral gene expression program in the adipose tissue and diminished expression of adiponectin. Moreover, we show that SARS-CoV-2 can infect adipocytes. Together these data suggest that SARS-CoV-2 may trigger adipose tissue dysfunction to drive insulin resistance and adverse outcomes in acute COVID-19.

Living Dangerously: Protective and Harmful ER Stress Responses in Pancreatic ß-Cells.

Type 2 diabetes (T2D) is a growing cause of poor health, psychosocial burden, and economic costs worldwide. The pancreatic ß-cell is a cornerstone of metabolic physiology. Insulin deficiency leads to hyperglycemia, which was fatal before the availability of therapeutic insulins; even partial deficiency of insulin leads to diabetes in the context of insulin resistance. Comprising only an estimated 1 g or <1/500th of a percent of the human body mass, pancreatic ß-cells of the islets of Langerhans are a vulnerable link in metabolism. Proinsulin production constitutes a major load on ß-cell endoplasmic reticulum (ER), and decompensated ER stress is a cause of ß-cell failure and loss in both type 1 diabetes (T1D) and T2D. The unfolded protein response (UPR), the principal ER stress response system, is critical for maintenance of ß-cell health. Successful UPR guides expansion of ER protein folding capacity and increased ß-cell number through survival pathways and cell replication. However, in some cases the ER stress response can cause collateral ß-cell damage and may even contribute to diabetes pathogenesis. Here we review the known beneficial and harmful effects of UPR pathways in pancreatic ß-cells. Improved understanding of this stress response tipping point may lead to approaches to maintain ß-cell health and function.

Endoplasmic Reticulum Stress Induced Proliferation Remains Intact in Aging Mouse ß-Cells.

Aging is associated with loss of proliferation of the insulin-secreting ß-cell, a possible contributing factor to the increased prevalence of type 2 diabetes in the elderly. Our group previously discovered that moderate endoplasmic reticulum (ER) stress occurring during glucose exposure increases the adaptive ß-cell proliferation response. Specifically, the ATF6α arm of the tripartite Unfolded Protein Response (UPR) promotes ß-cell replication in glucose excess conditions. We hypothesized that ß-cells from older mice have reduced proliferation due to aberrant UPR signaling or an impaired proliferative response to ER stress or ATF6α activation. To investigate, young and old mouse islet cells were exposed to high glucose with low-dose thapsigargin or activation of overexpressed ATF6α, and ß-cell proliferation was quantified by BrdU incorporation. UPR pathway activation was compared by qPCR of target genes and semi-quantitative Xbp1 splicing assay. Intriguingly, although old ß-cells had reduced proliferation in high glucose compared to young ß-cells, UPR activation and induction of proliferation in response to low-dose thapsigargin or ATF6α activation in high glucose were largely similar between young and old. These results suggest that loss of UPR-led adaptive proliferation does not explain the reduced cell cycle entry in old ß-cells, and raise the exciting possibility that future therapies that engage adaptive UPR could increase ß-cell number through proliferation even in older individuals.

Preadmission predictors of severe COVID-19 in patients with diabetes mellitus.

OBJECTIVE: To explore predictors of severe COVID-19 disease in patients with diabetes hospitalized for COVID-19. METHODS: This is a retrospective observational study of adults with diabetes admitted for COVID-19. Bivariate tests and multivariable Cox regression were used to identify risk factors for severe COVID-19, defined as a composite endpoint of intensive care unit admission/intubation or in-hospital death. RESULTS: In 1134 patients with diabetes admitted for COVID-19, more severe disease was associated with older age (HR 1.02, p<0.001), male sex (HR 1.28, p=0.017), Asian race (HR 1.34, p=0.029 [reference: white]), and greater obesity (moderate obesity HR 1.59, p=0.015; severe obesity HR 2.07, p=0.002 [reference: normal body mass index]). Outpatient diabetes medications were not associated with outcomes. CONCLUSIONS: Age, male sex, Asian race, and obesity were associated with increased risk of severe COVID-19 disease in adults with type 2 diabetes hospitalized for COVID-19. SUMMARY: In patients with type 2 diabetes hospitalized for COVID-19 disease, we observed that age, male sex, Asian race, and obesity predicted severe COVID-19 outcomes of intensive care unit admission, intubation, or in-hospital death. The risk conferred by obesity increased with worsening obesity. Outpatient diabetes medications were not observed to be significant predictors of study outcomes.

In vivo screen identifies a SIK inhibitor that induces ß cell proliferation through a transient UPR.

It is known that ß cell proliferation expands the ß cell mass during development and under certain hyperglycemic conditions in the adult, a process that may be used for ß cell regeneration in diabetes. Here, through a new high-throughput screen using a luminescence ubiquitination-based cell cycle indicator (LUCCI) in zebrafish, we identify HG-9-91-01 as a driver of proliferation and confirm this effect in mouse and human ß cells. HG-9-91-01 is an inhibitor of salt-inducible kinases (SIKs), and overexpression of Sik1 specifically in ß cells blocks the effect of HG-9-91-01 on ß cell proliferation. Single-cell transcriptomic analyses of mouse ß cells demonstrate that HG-9-91-01 induces a wave of activating transcription factor (ATF)6-dependent unfolded protein response (UPR) before cell cycle entry. Importantly, the UPR wave is not associated with an increase in insulin expression. Additional mechanistic studies indicate that HG-9-91-01 induces multiple signalling effectors downstream of SIK inhibition, including CRTC1, CRTC2, ATF6, IRE1 and mTOR, which integrate to collectively drive ß cell proliferation.

Hyperglycemia in Acute COVID-19 is Characterized by Adipose Tissue Dysfunction and Insulin Resistance.

COVID-19 has proven to be a metabolic disease resulting in adverse outcomes in individuals with diabetes or obesity. Patients infected with SARS-CoV-2 and hyperglycemia suffer from longer hospital stays, higher risk of developing acute respiratory distress syndrome (ARDS), and increased mortality compared to those who do not develop hyperglycemia. Nevertheless, the pathophysiological mechanism(s) of hyperglycemia in COVID-19 remains poorly characterized. Here we show that insulin resistance rather than pancreatic beta cell failure is the prevalent cause of hyperglycemia in COVID-19 patients with ARDS, independent of glucocorticoid treatment. A screen of protein hormones that regulate glucose homeostasis reveals that the insulin sensitizing adipokine adiponectin is reduced in hyperglycemic COVID-19 patients. Hamsters infected with SARS-CoV-2 also have diminished expression of adiponectin. Together these data suggest that adipose tissue dysfunction may be a driver of insulin resistance and adverse outcomes in acute COVID-19.

The Independent Risk of Obesity and Diabetes and Their Interaction in COVID-19: A Retrospective Cohort Study.

OBJECTIVE: This study aimed to assess whether diabetes mellitus (DM) or obesity is an independent risk factor for severe coronavirus disease 2019 (COVID-19) outcomes and to explore whether the risk conferred by one condition is modified by the other. METHODS: This retrospective cohort study of inpatient adults with COVID-19 used multivariable Cox regression to determine the independent effects of DM and obesity on the composite outcome of intubation, intensive care unit admission, or in-hospital mortality. Effect modification between DM and obesity was assessed with a statistical interaction term and an exploration of stratum-specific effects. RESULTS: Out of 3,533 patients, a total of 1,134 (32%) had DM, 1,256 (36%) had obesity, and 430 (12%) had both. DM and obesity were independently associated with the composite outcome (hazard ratio [HR] 1.14 [95% CI: 1.01-1.30] and HR 1.22 [95% CI: 1.05-1.43], respectively). A statistical trend for potential interaction between DM and obesity was observed (P = 0.20). Stratified analyses showed potential increased risk with obesity compared with normal weight among patients with DM (HR 1.34 [95% CI: 1.04-1.74]) and patients without DM (HR 1.18 [95% CI: 0.96-1.43]). CONCLUSIONS: DM and obesity are independent risk factors associated with COVID-19 severity. Stratified analyses suggest that obesity may confer greater risk to patients with DM compared with patients without DM, and this relationship requires further exploration.

Intersection of the ATF6 and XBP1 ER stress pathways in mouse islet cells.

Success or failure of pancreatic beta cell adaptation to ER stress is a determinant of diabetes susceptibility. The ATF6 and IRE1/XBP1 pathways are separate ER stress-response effectors important to beta cell health and function. ATF6α. and XBP1 direct overlapping transcriptional responses in some cell types. However, the signaling dynamics and interdependence of ATF6α and XBP1 in pancreatic beta cells have not been explored. To assess pathway-specific signal onset, we performed timed exposures of primary mouse islet cells to ER stressors and measured the early transcriptional response. Comparing the time course of induction of ATF6 and XBP1 targets suggested that the two pathways have similar response dynamics. The role of ATF6α in target induction was assessed by acute knockdown using islet cells from Atf6α flox/flox mice transduced with adenovirus expressing Cre recombinase. Surprisingly, given the mild impact of chronic deletion in mice, acute ATF6α knockdown markedly reduced ATF6-pathway target gene expression under both basal and stressed conditions. Intriguingly, although ATF6α knockdown did not alter Xbp1 splicing dynamics or intensity, it did reduce induction of XBP1 targets. Inhibition of Xbp1 splicing did not decrease induction of ATF6α targets. Taken together, these data suggest that the XBP1 and ATF6 pathways are simultaneously activated in islet cells in response to acute stress and that ATF6α is required for full activation of XBP1 targets, but XBP1 is not required for activation of ATF6α targets. These observations improve understanding of the ER stress transcriptional response in pancreatic islets.

Continuous glucose monitoring reduces pubertal hyperglycemia of type 1 diabetes.

Background Physiologic hyperglycemia of puberty is a major contributor to poor glycemic control in youth with type 1 diabetes (T1D). This study's aim was to determine the effectiveness of continuous glucose monitoring (CGM) to improve glycemic control in pubertal youth with T1D compared to a non-CGM cohort after controlling for age, sex, BMI, duration, and insulin delivery methodology. The hypothesis is that consistent CGM use in puberty improves compliance with diabetes management, leading to increased percentage (%) time in range (TIR70-180 mg/dL) of glycemia, and lowering of HbA1c. Methods A longitudinal, retrospective, case-controlled study of 105 subjects consisting of 51 T1D controls (60.8% male) age 11.5 ± 3.8 y; and 54 T1D subjects (48.1% male) age 11.1 ± 5.0 y with confirmed CGM use for 12 months. Pubertal status was determined by Tanner staging. Results were adjusted for baseline HbA1c and diabetes duration. Results HbA1c was similar between the controls and the CGM group at baseline: 8.2 ± 1.1% vs 8.3 ± 1.2%, p=0.48 respectively; but was significantly lower in the CGM group 12 months later, 8.2 ± 1.1% vs. 8.7 ± 1.4%, p=0.035. Longitudinal change in HbA1c was similar in the prepubertal cohort between the control- and CGM groups: -0.17 ± 0.98% vs. 0.38 ± 1.5%, p=0.17. In contrast, HbA1c increased with advancing age and pubertal status in the pubertal controls but not in the pubertal CGM group: 0.55 ± 1.4 vs -0.22 ± 1.1%, p=0.020. Percent TIR was inversely related to HbA1c in the CGM group, r=-0.6, p=0.0004, for both prepubertal and pubertal subjects. Conclusions CGM use significantly improved glycemic control in pubertal youth with T1D compared to non-CGM users.

Hypusine biosynthesis in ß cells links polyamine metabolism to facultative cellular proliferation to maintain glucose homeostasis.

Deoxyhypusine synthase (DHPS) uses the polyamine spermidine to catalyze the hypusine modification of the mRNA translation factor eIF5A and promotes oncogenesis through poorly defined mechanisms. Because germline deletion of Dhps is embryonically lethal, its role in normal postnatal cellular function in vivo remains unknown. We generated a mouse model that enabled the inducible, postnatal deletion of Dhps specifically in postnatal islet ß cells, which function to maintain glucose homeostasis. Removal of Dhps did not have an effect under normal physiologic conditions. However, upon development of insulin resistance, which induces ß cell proliferation, Dhps deletion caused alterations in proteins required for mRNA translation and protein secretion, reduced production of the cell cycle molecule cyclin D2, impaired ß cell proliferation, and induced overt diabetes. We found that hypusine biosynthesis was downstream of protein kinase C-ζ and was required for c-Myc-induced proliferation. Our studies reveal a requirement for DHPS in ß cells to link polyamines to mRNA translation to effect facultative cellular proliferation and glucose homeostasis.