Hypoxia-driven metabolic reprogramming of adipocytes fuels cancer cell proliferation.

Objective: Obesity increases the risk of certain cancers, especially tumours that reside close to adipose tissue (breast and ovarian metastasis in the omentum). The obesogenic and tumour micro-environment share a common pathogenic feature, oxygen deprivation (hypoxia). Here we test how hypoxia changes the metabolome of adipocytes to assist cancer cell growth. Methods: Human and mouse breast and ovarian cancer cell lines were co-cultured with human and mouse adipocytes respectively under normoxia or hypoxia. Proliferation and lipid uptake in cancer cells were measured by commercial assays. Metabolite changes under normoxia or hypoxia were measured in the media of human adipocytes by targeted LC/MS. Results: Hypoxic cancer-conditioned media increased lipolysis in both human and mouse adipocytes. This led to increased transfer of lipids to cancer cells and consequent increased proliferation under hypoxia. These effects were dependent on HIF1α expression in adipocytes, as mouse adipocytes lacking HIF1α showed blunted responses under hypoxic conditions. Targeted metabolomics of the human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes media revealed that culture with hypoxic-conditioned media from non-malignant mammary epithelial cells (MCF10A) can alter the adipocyte metabolome and drive proliferation of the non-malignant cells. Conclusion: Here, we show that hypoxia in the adipose-tumour microenvironment is the driving force of the lipid uptake in both mammary and ovarian cancer cells. Hypoxia can modify the adipocyte metabolome towards accelerated lipolysis, glucose deprivation and reduced ketosis. These metabolic shifts in adipocytes could assist both mammary epithelial and cancer cells to bypass the inhibitory effects of hypoxia on proliferation and thrive.

Role of Tim4 in the regulation of ABCA1+ adipose tissue macrophages and post-prandial cholesterol levels.

Dyslipidemia is a main driver of cardiovascular diseases. The ability of macrophages to scavenge excess lipids implicate them as mediators in this process and understanding the mechanisms underlying macrophage lipid metabolism is key to the development of new treatments. Here, we investigated how adipose tissue macrophages regulate post-prandial cholesterol transport. Single-cell RNA sequencing and protected bone marrow chimeras demonstrated that ingestion of lipids led to specific transcriptional activation of a population of resident macrophages expressing Lyve1, Tim4, and ABCA1. Blocking the phosphatidylserine receptor Tim4 inhibited lysosomal activation and the release of post-prandial high density lipoprotein cholesterol following a high fat meal. Both effects were recapitulated by chloroquine, an inhibitor of lysosomal function. Moreover, clodronate-mediated cell-depletion implicated Tim4+ resident adipose tissue macrophages in this process. Thus, these data indicate that Tim4 is a key regulator of post-prandial cholesterol transport and adipose tissue macrophage function and may represent a novel pathway to treat dyslipidemia.

Assessment of the effect of the COVID-19 lockdown on glycaemic control in people with type 1 diabetes using flash glucose monitoring.

AIM: To describe the effect of the stringent lockdown measures, introduced in the UK on 23 March 2020 to curtail the transmission of COVID-19, on glycaemic control in people with type 1 diabetes using flash glucose monitoring. METHODS: We undertook an observational study of 572 individuals with type 1 diabetes for whom paired flash glucose monitoring data were available between early March and May 2020. The primary outcome was change in flash glucose monitoring variables. We also assessed clinical variables associated with change in glycaemic control. RESULTS: Percentage of time in range increased between March and May 2020 [median (interquartile range) 53 (41-64)% vs 56 (45-68)%; P < 0.001], with associated improvements in standard deviation of glucose (P <0.001) and estimated HbA1c (P <0.001). There was a small reduction in the number of individuals meeting the hypoglycaemia target of <5% per day (64% vs 58%; P = 0.004). Comparing changes in flash glucose monitoring data from March to May in 2019 with the same period in 2020 confirmed that these differences were confined to 2020. Socio-economic deprivation was an independent predictor of a ≥5% reduction in time in range during lockdown (odds ratio 0.45 for people in the two most affluent Scottish Index of Multiple Deprivation quintiles; P <0.001). CONCLUSIONS: Lockdown was not associated with a significant deterioration in glycaemic control in people with type 1 diabetes using flash glucose monitoring. However, socio-economic deprivation appeared to increase the risk of decline in glycaemic control, which has implications for how support is focused in challenging times.

Hypoxia determines survival outcomes of bacterial infection through HIF-1alpha dependent re-programming of leukocyte metabolism.

Hypoxia and bacterial infection frequently co-exist, in both acute and chronic clinical settings, and typically result in adverse clinical outcomes. To ameliorate this morbidity, we investigated the interaction between hypoxia and the host response. In the context of acute hypoxia, both S. aureus and S. pneumoniae infections rapidly induced progressive neutrophil mediated morbidity and mortality, with associated hypothermia and cardiovascular compromise. Preconditioning animals through longer exposures to hypoxia, prior to infection, prevented these pathophysiological responses and profoundly dampened the transcriptome of circulating leukocytes. Specifically, perturbation of HIF pathway and glycolysis genes by hypoxic preconditioning was associated with reduced leukocyte glucose utilisation, resulting in systemic rescue from a global negative energy state and myocardial protection. Thus we demonstrate that hypoxia preconditions the innate immune response and determines survival outcomes following bacterial infection through suppression of HIF-1α and neutrophil metabolism. The therapeutic implications of this work are that in the context of systemic or tissue hypoxia therapies that target the host response could improve infection associated morbidity and mortality.

Diet-induced weight loss has chronic tissue-specific effects on glucocorticoid metabolism in overweight postmenopausal women.

BACKGROUND/OBJECTIVES: Tissue-specific glucocorticoid metabolism is altered in obesity, and may increase cardiovascular risk. This dysregulation is normalized by short-term calorie restriction and weight loss, an effect that varies with dietary macronutrient composition. However, tissue-specific glucocorticoid metabolism has not been studied during long-term (>6 months) dietary interventions. Therefore our aim was to test whether long-term dietary interventions, either a paleolithic-type diet (PD) or a diet according to Nordic nutrition recommendations (NNR) could normalize tissue-specific glucocorticoid metabolism in overweight and obese women. SUBJECTS/METHODS: Forty-nine overweight/obese postmenopausal women were randomized to a paleolithic diet or a diet according to NNR for 24 months. At baseline, 6 and 24 months anthropometric measurements, insulin sensitivity, excretion of urinary glucocorticoid metabolites in 24-hour collections, conversion of orally administered cortisone to plasma cortisol and transcript levels of 11ß hydroxysteroid dehydrogenase type 1 (11ßHSD1) in subcutaneous adipose tissue were studied. RESULTS: Both diet groups achieved significant and sustained weight loss. Weight loss with the PD was greater than on NNR diet after 6 months (P<0.001) but similar at 24 months. Urinary measurement of 5α-reductase activity was increased after 24 months in both groups compared with baseline (P<0.001). Subcutaneous adipose tissue 11ßHSD1 gene expression decreased at 6 and 24 months in both diet groups (P=0.036). Consistent with increased liver 11ßHSD1, conversion of oral cortisone to cortisol increased at 6 months (P=0.023) but was unchanged compared with baseline by 24 months. CONCLUSIONS: Long-term weight loss in postmenopausal women has tissue-specific and time-dependent effects on glucocorticoid metabolism. This may alter local-tissue cortisol exposure contributing to improved metabolic function during weight loss.

Glucocorticoid receptor gene expression in adipose tissue and associated metabolic risk in black and white South African women.

BACKGROUND: Black women have lower visceral adipose tissue (VAT) but are less insulin sensitive than white women; the mechanisms responsible are unknown. OBJECTIVE: The study aimed to test the hypothesis that variation in subcutaneous adipose tissue (SAT) sensitivity to glucocorticoids might underlie these differences. METHODS: Body fatness (dual energy X-ray absorptiometry) and distribution (computerized tomography), insulin sensitivity (SI, intravenous and oral glucose tolerance tests), and expression of 11ß-hydroxysteroid dehydrogenase-1 (11HSD1), hexose-6-phosphate dehydrogenase and glucocorticoid receptor-α (GRα), as well as genes involved in adipogenesis and inflammation were measured in abdominal deep SAT, superficial SAT and gluteal SAT (GLUT) depots of 56 normal-weight or obese black and white premenopausal South African (SA) women. We used a combination of univariate and multivariate statistics to evaluate ethnic-specific patterns in adipose gene expression and related body composition and insulin sensitivity measures. RESULTS: Although 11HSD1 activity and mRNA did not differ by ethnicity, GRα mRNA levels were significantly lower in SAT of black compared with white women, particularly in the GLUT depot (0.52±0.21 vs 0.91±0.26 AU, respectively, P<0.01). In black women, lower SAT GRα mRNA levels were associated with increased inflammatory gene transcript levels and abdominal SAT area, and reduced adipogenic gene transcript levels, VAT/SAT ratio and SI. Abdominal SAT 11HSD1 activity associated with increased VAT area and decreased SI in white, but not in black women. CONCLUSIONS: In black SA women, downregulation of GRα mRNA levels with obesity and reduced insulin sensitivity, possibly via increased SAT inflammation, is associated with reduced VAT accumulation.

Relationship between final height and health outcomes in adults with congenital adrenal hyperplasia: United Kingdom congenital adrenal hyperplasia adult study executive (CaHASE).

CONTEXT: Treatment of congenital adrenal hyperplasia (CAH) in childhood focuses on growth and development and adult final height (FH) is a measure of effective treatment. We hypothesized that shorter adults will have more severe underlying disease and worse health outcomes. METHODS: This was a cross-sectional analysis of 199 adults with CAH. FH and quality of life were expressed as z-scores adjusted for midparental target height or UK population height. RESULTS: FH correlated inversely with age (men, r = -0.38; women, r = -0.26, P < .01). Men and women had z-scores adjusted for midparental target height of -2 and -1, respectively, and both groups had UK population height z-scores of -1 below the UK population (P < .01). In women, FH was shorter in non-salt-wasting than salt-wasting classic CAH (P < .05) and in moderately affected genotype group B women than either more severely affected groups null and A (P < .01) or the mildest group C (P < .001). Short stature and a higher prevalence of hypertension were observed in classic CAH patients diagnosed late (after 1 y) compared with those diagnosed early and in women treated with glucocorticoid only compared with those treated with both glucocorticoids and mineralocorticoids (P < .05). FH did not associate with insulin sensitivity, lipid profile, adiposity, or quality of life. CONCLUSIONS: Adult CAH patients remain short, although height prognosis has improved over time. The shortest adults are those diagnosed late with moderate severity CAH and are at increased risk of adult hypertension; we hypothesize that these patients are exposed in childhood to high androgens and/or excessive glucocorticoids with potential programming of hypertension. Another possibility is inadequate mineralocorticoid treatment early in life in the late-diagnosed patient group. Prospective studies are now required to examine these hypotheses.

Glucocorticoid treatment regimen and health outcomes in adults with congenital adrenal hyperplasia.

BACKGROUND: Adults with congenital adrenal hyperplasia (CAH) are treated with a wide variety of glucocorticoid treatment regimens. OBJECTIVE, DESIGN AND METHODS: To test whether drug dose and timing of glucocorticoid treatment regimen impacts on health outcomes. This was a cross-sectional study of 196 adult CAH patients in whom treatment and health outcomes were measured. Glucocorticoid dose was converted to prednisolone dose equivalent (PreDEq) using three published formulae. Associations between the type of glucocorticoid regimen and PreDEq with specific health outcome variables were tested using partial correlation and principal components analysis (PCA). RESULTS: Patients on dexamethasone had lower androgens and ACTH but greater insulin resistance compared with those receiving hydrocortisone or prednisolone. Dexamethasone dose and once daily administration were associated with insulin resistance. Partial correlation analysis adjusted for age and sex showed PreDEq weakly correlated (r < 0·2) with blood pressure and androstenedione. Mutation severity was associated with increased PreDEq (F(3,141)  = 4·4, P < 0·01). In PCA, 3 PCs were identified that explained 62% of the total variance (r(2) ) in observed variables. Regression analysis (age and sex adjusted) confirmed that PC2, reflecting disease control (androstenedione, 17-hydroxypregesterone and testosterone), and PC3, reflecting blood pressure and mutations (systolic and diastolic blood pressure and mutation severity), related directly to PreDEq (r(2)  = 23%, P < 0·001). CONCLUSIONS: In adults with congenital adrenal hyperplasia, dexamethasone use was associated with lower androgens but greater insulin resistance, and increasing glucocorticoid dose associated with increased blood pressure, poor disease control and mutation severity.

Glucocorticoids and 11beta-hydroxysteroid dehydrogenase type 1 in obesity and the metabolic syndrome.

Central obesity is associated with type 2 diabetes mellitus, hypertension and dyslipidaemia. This cluster of risk factors is known as the metabolic syndrome, and also occurs in people with primary glucocorticoid excess (Cushing's syndrome). Exogenous glucocorticoid use also increases the risk of cardiovascular disease. Circulating glucocorticoid concentrations are tightly controlled by the hypothalamic-pituitary-adrenal axis, however tissue glucocorticoid levels are also enhanced by the enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1). Transgenic overexpression of 11beta-HSD1 in either adipose tissue or the liver in mice causes components of the metabolic syndrome, while transgenic deletion of 11beta-HSD1 prevents adverse metabolic complications of obesity. Although plasma glucocorticoid levels are not elevated in obesity, dysregulation of 11beta-HSD1 is observed with decreased activity in the liver and increased activity in adipose tissue. 11beta-HSD1 is highly regulated, and dietary composition may be a powerful determinant of activity. Polymorphisms in the 11beta-HSD1 gene are also associated with components of the metabolic syndrome. Inhibition of this enzyme appears to be an attractive option to treat metabolic disease. Selective 11beta-HSD1 inhibitors in rodents cause weight loss, improve insulin sensitivity and delay progression of cardiovascular disease. Trials in humans though will be the ultimate test to determine if inhibition of 11beta-HSD1 offers a new tool in the treatment of metabolic disease.

The diagnostic value of anti-neutrophil cytoplasmic antibody testing in a routine clinical setting.

Anti-neutrophil cytoplasmic antibody (ANCA) tests are a routine clinical assay in most UK hospitals. We examined the role of routine ANCA testing in achieving a diagnosis of systemic vasculitis in a routine clinical setting. From April 1996 to March 2000, 2734 samples from five hospital departments were tested for ANCA by indirect immunofluorescence (IIF) at a single laboratory. After April 1999, enzyme-linked immunosorbent assays (ELISAs) were performed on all IIF-positive samples. Clinical diagnosis was determined for all patients with a positive IIF ANCA, and a sample of the ANCA-negative patients. Some 2-18% of patients with suspected ANCA-associated systemic vasculitis (AASV) had positive IIF ANCA. The AASV diagnosis was confirmed in 0-56% of these cases. Analysis by department suggested that 88-100% of patients with a positive IIF ANCA did not have AASV, except in the Rheumatology department. The positive predictive value (PPV) of IIF ANCA for AASV was 59% and the negative predictive value (NPV) was 84%. Of the patients with proven AASV, 41% did not have ANCA on IIF. Combined ANCA testing by IIF/ELISA had a higher sensitivity and PPV but lower specificity than IIF alone for AASV. For the combined IIF/ELISA test, only the Rheumatology department had a sensitivity or PPV >0% for AASV. The PPV of ANCA by IIF/ELISA for AASV was 79% and the NPV was 63%. The ANCA test is being widely applied with very poor return. Guidelines for more effective usage are proposed.

The use of negative indexes of health to evaluate quality of care in a primary-care group practice.

A quality assessment method using negative indexes of health as a measure of the quality of medical care was applied in a hospital-based primary-care group practice. During a 5-year period, records of 1,147 patients were analyzed. The study led to several observations regarding the use of this method in this setting: 1) The negative indexes of health method encourages physicians to include both primary and secondary preventive measures in their practice of medicine and to see their role as a broad one, from providing good care to individual patients to influencing public policy. 2) Most medical records do not now contain all the data required for use of this method. 3) In cases where this method identifies only a few instances of possibly preventable disease or untimely death, it is impossible to know whether the care is good and the method of evaluation is sensitive, or whether the care is poor and the method is insensitive to deficiencies in care.