Risk of COVID-19 hospital admission and COVID-19 mortality during the first COVID-19 wave with a special emphasis on ethnic minorities: an observational study of a single, deprived, multiethnic UK health economy.

OBJECTIVES: The objective of this study was to describe variations in COVID-19 outcomes in relation to local risks within a well-defined but diverse single-city area. DESIGN: Observational study of COVID-19 outcomes using quality-assured integrated data from a single UK hospital contextualised to its feeder population and associated factors (comorbidities, ethnicity, age, deprivation). SETTING/PARTICIPANTS: Single-city hospital with a feeder population of 228 632 adults in Wolverhampton. MAIN OUTCOME MEASURES: Hospital admissions (defined as COVID-19 admissions (CA) or non-COVID-19 admissions (NCA)) and mortality (defined as COVID-19 deaths or non-COVID-19 deaths). RESULTS: Of the 5558 patients admitted, 686 died (556 in hospital); 930 were CA, of which 270 were hospital COVID-19 deaths, 47 non-COVID-19 deaths and 36 deaths after discharge; of the 4628 NCA, there were 239 in-hospital deaths (2 COVID-19) and 94 deaths after discharge. Of the 223 074 adults not admitted, 407 died. Age, gender, multimorbidity and black ethnicity (OR 2.1 (95% CI 1.5 to 3.2), p<0.001, compared with white ethnicity, absolute excess risk of <1/1000) were associated with CA and mortality. The South Asian cohort had lower CA and NCA, lower mortality compared with the white group (CA, 0.5 (0.3 to 0.8), p<0.01; NCA, 0.4 (0.3 to 0.6), p<0.001) and community deaths (0.5 (0.3 to 0.7), p<0.001). Despite many common risk factors for CA and NCA, ethnic groups had different admission rates and within-group differing association of risk factors. Deprivation impacted only the white ethnicity, in the oldest age bracket and in a lesser (not most) deprived quintile. CONCLUSIONS: Wolverhampton's results, reflecting high ethnic diversity and deprivation, are similar to other studies of black ethnicity, age and comorbidity risk in COVID-19 but strikingly different in South Asians and for deprivation. Sequentially considering population and then hospital-based NCA and CA outcomes, we present a complete single health economy picture. Risk factors may differ within ethnic groups; our data may be more representative of communities with high Black, Asian and minority ethnic populations, highlighting the need for locally focused public health strategies. We emphasise the need for a more comprehensible and nuanced conveyance of risk.

Potential Clinical Error Arising From Use of HbA1c in Diabetes: Effects of the Glycation Gap.

The glycation gap (GGap) and the similar hemoglobin glycation index (HGI) define consistent differences between glycated hemoglobin and actual glycemia derived from fructosamine or mean blood glucose, respectively. Such a disparity may be found in a substantial proportion of people with diabetes, being >1 U of glycated HbA1c% or 7.2 mmol/mol in almost 40% of estimations. In this review we define these indices and explain how they can be calculated and that they are not spurious, being consistent in individuals over time. We evaluate the evidence that GGap and HGI are associated with variation in risk of complications and mortality and demonstrate the potential for clinical error in the unquestioning use of HbA1c. We explore the underlying etiology of the variation of HbA1c from mean glucose in blood plasma, including the potential role of enzymatic deglycation of hemoglobin by fructosamine-3-kinase. We conclude that measurement of GGap and HGI are important to diabetes clinicians and their patients in individualization of therapy and the avoidance of harm arising from consequent inappropriate assessment of glycemia and use of therapies.

Downregulation of aquaporin 3 inhibits cellular proliferation, migration and invasion in the MDA-MB-231 breast cancer cell line.

Aquaporins are membrane proteins that regulate cellular water flow. Recently, aquaporins have been proposed as mediators of cancer cell biology. A subset of aquaporins, referred to as aquaglyceroporins are known to facilitate the transport of glycerol. The present study describes the effect of gene knockdown of the aquaglyceroporin AQP3 on MDA-MB-231 breast cancer cell proliferation, migration, invasion, adherence and response to the chemotherapeutic agent 5-fluorouracil. shRNA mediated AQP3 gene knockdown induced a 28% reduction in cellular proliferation (P<0.01), a 39% decrease in migration (P<0.0001), a 24% reduction in invasion (P<0.05) and a 25% increase in cell death at 100 µM 5-FU (P<0.01). Analysis of cell permeability to water and glycerol revealed that MDA-MB-231 cells with knocked down AQP3 demonstrated a modest decrease in water permeability (17%; P<0.05) but a more marked decrease in glycerol permeability (77%; P<0.001). These results suggest that AQP3 has a role in multiple aspects of breast cancer cell pathophysiology and therefore represents a novel target for therapeutic intervention.

Evidence That Differences in Fructosamine-3-Kinase Activity May Be Associated With the Glycation Gap in Human Diabetes.

The phenomenon of a discrepancy between glycated hemoglobin levels and other indicators of average glycemia may be due to many factors but can be measured as the glycation gap (GGap). This GGap is associated with differences in complications in patients with diabetes and may possibly be explained by dissimilarities in deglycation in turn leading to altered production of advanced glycation end products (AGEs). We hypothesized that variations in the level of the deglycating enzyme fructosamine-3-kinase (FN3K) might be associated with the GGap. We measured erythrocyte FN3K concentrations and enzyme activity in a population dichotomized for a large positive or negative GGap. FN3K protein was higher and we found a striking threefold greater activity (323%) at any given FN3K protein level in the erythrocytes of the negative-GGap group compared with the positive-GGap group. This was associated with lower AGE levels in the negative-GGap group (79%), lower proinflammatory adipokines (leptin-to-adiponectin ratio) (73%), and much lower prothrombotic PAI-1 levels (19%). We conclude that FN3K may play a key role in the GGap and thus diabetes complications such that FN3K may be a potential predictor of the risk of diabetes complications. Pharmacological modifications of its activity may provide a novel approach to their prevention.

The role of adipokines in ß-cell failure of type 2 diabetes.

ß-Cell failure coupled with insulin resistance is a key factor in the development of type 2 diabetes. Changes in circulating levels of adipokines, factors released from adipose tissue, form a significant link between excessive adiposity in obesity and both aforementioned factors. In this review, we consider the published evidence for the role of individual adipokines on the function, proliferation, death and failure of ß-cells, focusing on those reported to have the most significant effects (leptin, adiponectin, tumour necrosis factor α, resistin, visfatin, dipeptidyl peptidase IV and apelin). It is apparent that some adipokines have beneficial effects whereas others have detrimental properties; the overall contribution to ß-cell failure of changed concentrations of adipokines in the blood of obese pre-diabetic subjects will be highly dependent on the balance between these effects and the interactions between the adipokines, which act on the ß-cell via a number of intersecting intracellular signalling pathways. We emphasise the importance, and comparative dearth, of studies into the combined effects of adipokines on ß-cells.

Regulation of beta-cell viability and gene expression by distinct agonist fragments of adiponectin.

Obesity is an established risk factor for type 2 diabetes. Activation of the adiponectin receptors has a clear role in improving insulin resistance although conflicting evidence exists for its effects on pancreatic beta-cells. Previous reports have identified both adiponectin receptors (ADR-1 and ADR-2) in the beta-cell. Recent evidence has suggested that two distinct regions of the adiponectin molecule, the globular domain and a small N-terminal region, have agonist properties. This study investigates the effects of two agonist regions of adiponectin on insulin secretion, gene expression, cell viability and cell signalling in the rat beta-cell line BRIN-BD11, as well as investigating the expression levels of adiponectin receptors (ADRs) in these cells. Cells were treated with globular adiponectin and adiponectin (15-36) +/-leptin to investigate cell viability, expression of key beta-cell genes and ERK1/2 activation. Both globular adiponectin and adiponectin (15-36) caused significant ERK1/2 dependent increases in cell viability. Leptin co-incubation attenuated adiponectin (15-36) but not globular adiponectin induced cell viability. Globular adiponectin, but not adiponectin (15-36), caused a significant 450% increase in PDX-1 expression and a 45% decrease in LPL expression. ADR-1 was expressed at a higher level than ADR-2, and ADR mRNA levels were differentially regulated by non-esterified fatty acids and peroxisome-proliferator-activated receptor agonists. These data provide evidence of roles for two distinct adiponectin agonist domains in the beta-cell and confirm the potentially important role of adiponectin receptor agonism in maintaining beta-cell mass.

Visfatin regulates insulin secretion, insulin receptor signalling and mRNA expression of diabetes-related genes in mouse pancreatic beta-cells.

The role of the adipocyte-derived factor visfatin in metabolism remains controversial, although some pancreatic beta-cell-specific effects have been reported. This study investigated the effects of visfatin upon insulin secretion, insulin receptor activation and mRNA expression of key diabetes-related genes in clonal mouse pancreatic beta-cells. beta-TC6 cells were cultured in RPMI 1640 and were subsequently treated with recombinant visfatin. One-hour static insulin secretion was measured by ELISA. Phospho-specific ELISA and western blotting were used to detect insulin receptor activation. Real-time SYBR Green PCR array technology was used to measure the expression of 84 diabetes-related genes in both treatment and control cells. Incubation with visfatin caused significant changes in the mRNA expression of several key diabetes-related genes, including marked up-regulation of insulin (9-fold increase), hepatocyte nuclear factor (HNF)1beta (32-fold increase), HNF4alpha (16-fold increase) and nuclear factor kappaB (40-fold increase). Significant down-regulation was seen in angiotensin-converting enzyme (-3.73-fold) and UCP2 (-1.3-fold). Visfatin also caused a significant 46% increase in insulin secretion compared to control (P<0.003) at low glucose, and this increase was blocked by co-incubation with the specific nicotinamide phosphoribosyltransferase inhibitor FK866. Both visfatin and nicotinamide mononucleotide induced activation of both insulin receptor and extracellular signal-regulated kinase (ERK)1/2, with visfatin-induced insulin receptor/ERK1/2 activation being inhibited by FK866. We conclude that visfatin can significantly regulate insulin secretion, insulin receptor phosphorylation and intracellular signalling and the expression of a number of beta-cell function-associated genes in mouse beta-cells.

Resistin down-regulates insulin receptor expression, and modulates cell viability in rodent pancreatic beta-cells.

The adipokine resistin is known to induce insulin resistance in rodent tissues. Increases in adipose tissue mass are known to have a negative effect on pancreatic beta-cell function, although the mechanisms are poorly understood. This study investigated the effects of resistin on insulin secretion, insulin receptor expression and cell viability in pancreatic beta-cells. BTC-6 or BRIN-BD11 cells were treated for 24h with resistin, and insulin receptor expression, insulin secretion and cell viability were measured. Incubation with 40ng/ml resistin caused significant decreases in insulin receptor mRNA and protein expression, but did not affect insulin secretion. At low concentrations, resistin caused significant increases in cell viability. These data implicate resistin as a factor that may regulate beta-cell function/viability, and suggests a potential mechanism by which increased adiposity causes beta-cell dysfunction.

Leptin decreases apoptosis and alters BCL-2 : Bax ratio in clonal rodent pancreatic beta-cells.

AIMS/HYPOTHESIS: The adipocyte derived peptide hormone leptin is known to regulate apoptosis and cell viability in several cells and tissues, as well as having several pancreatic islet beta-cell specific effects such as inhibition of glucose-stimulated insulin secretion. This study investigated the effects of leptin upon apoptosis induced by serum depletion and on expression of the apoptotic regulators B-cell leukaemia 2 gene product (BCL-2) and BCL2-associated X protein (Bax) in the glucose-responsive BRIN-BD11 beta-cell line. METHODS: BRIN-BD11 cells were cultured in RPMI 1640 and subsequently serum depleted +/- leptin (10 and 50 ng/mL) for 24 h. Cell viability and apoptosis were measured using a modified MTS assay and TUNEL/YO-PRO-1 assays, respectively. BCL-2 and Bax expression were measured by real-time PCR and Western blotting. RESULTS: Leptin caused a reduction in serum-depleted apoptosis, although it failed to have any effect on the overall cell viability, causing a 68% shift from apoptosis to necrosis. Leptin significantly increased the level of BCL-2 mRNA expression (150% compared to serum depletion alone), without altering Bax mRNA expression. At the protein level, leptin increased BCL-2 and decreased Bax, altering the BCL-2 : Bax ratio. CONCLUSIONS: We conclude that leptin reduces apoptosis in beta-cells at physiological concentrations, possibly via its ability to up-regulate BCL-2 and Bax expression.

Lipopolysaccharide induces nitric oxide synthase expression and platelet-activating factor increases nitric oxide production in human fetal membranes in culture.

BACKGROUND: Platelet-activating factor and nitric oxide may be involved in the initiation of human labour as inflammatory mediators. The aim of this study was to test whether platelet-activating factor and lipopolysaccharide were able to induce nitric oxide synthase expression and stimulate the production of nitric oxide in human fetal membrane explants in culture. METHODS: Fetal membranes were collected from Caesarean sections at term. RNA was extracted from membranes and subjected to a qualitative RT-PCR to assess the baseline expression of iNOS. Discs of fetal membranes were cultured for 24 hours in the presence of platelet-activating factor at a dose range of 0.1 nanomolar--1 micomolar or 1 microgram/ml lipopolysaccharide. Nitric oxide production was measured via nitrite ions in the culture medium and mRNA for iNOS was detected by RT-PCR. RESULTS: Culturing the membrane discs in medium containing serum induced nitric oxide synthase expression and platelet-activating factor significantly stimulated the production of nitric oxide under these conditions. When cultured without serum inducible nitric oxide synthase expression was induced by lipopolysaccharide, but not by platelet-activating factor. CONCLUSION: Platelet-activating factor may have a role in the initiation of labour, at term or preterm, via the increased local production of nitric oxide as an inflammatory mediator. In this model of intrauterine infection, lipopolysaccharide was found to induce iNOS expression by fetal membranes, and this mechanism could be involved in preterm labour.

Glucose induces and leptin decreases expression of uncoupling protein-2 mRNA in human islets.

Elevated islet uncoupling protein-2 (UCP-2) impairs beta-cell function and UCP-2 may be increased in clinical obesity and diabetes. We investigated the effects of glucose and leptin on UCP-2 expression in isolated human islets. Human islets were incubated for 24 h with glucose (5.5-22 mmol/l)+/-leptin (0-10 nmol/l). Some islet batches were incubated at high (22 mmol/l), and subsequently lower (5.5 mmol/l), glucose to assess reversibility of effects. Leptin effects on insulin release were also measured. Glucose dose-dependently increased UCP-2 expression in all islet batches, maximally by three-fold. This was not fully reversed by subsequently reduced glucose levels. Leptin decreased UCP-2 expression by up to 75%, and maximally inhibited insulin release by 47%, at 22 mmol/l glucose. This is the first report of UCP-2 expression in human islets and provides novel evidence of its role in the loss of beta-cell function in diabetes.