Leucine suppresses α-cell cAMP and glucagon secretion via a combination of cell-intrinsic and islet paracrine signaling.

Glucagon is critical for the maintenance of blood glucose, however nutrient regulation of pancreatic α-cells remains poorly understood. Here, we identified a role for leucine, a well-known ß-cell fuel, in the α-cell intrinsic regulation of glucagon release. In islet perifusion assays, physiological concentrations of leucine strongly inhibited alanine and arginine-stimulated glucagon secretion from human and mouse islets under hypoglycemic conditions. Mechanistically, leucine dose-dependently reduced α-cell cAMP, independently of Ca2+, ATP/ADP, or fatty acid oxidation. Leucine also reduced α-cell cAMP in islets treated with Sstr2 antagonists or diazoxide, compounds that limit paracrine signaling from ß/δ-cells. Studies in dispersed mouse islets confirmed an α-cell intrinsic effect. The inhibitory effect of leucine on cAMP was mimicked by glucose, α-ketoisocaproate, succinate, and the glutamate dehydrogenase activator BCH, and blocked by cyanide, indicating a mechanism dependent on mitochondrial metabolism. Glucose dose-dependently reduced the impact of leucine on α-cell cAMP, indicating an overlap in function, however leucine was still effective at suppressing glucagon secretion in the presence of elevated glucose, amino acids, and the incretin GIP. Taken together, these findings show that leucine plays an intrinsic role in limiting α-cell secretory tone across the physiological range of glucose levels, complementing the inhibitory paracrine actions of ß/δ-cells.

Care seeking for childhood illnesses in rural Mtwara, south-east Tanzania: a mixed methods study.

BACKGROUND: Care seeking was assessed in preparation for a study of the health impact of novel design houses in rural Mtwara, Tanzania. METHODS: A total of 578 residents of 60 villages participated in this mixed-methods study from April to August 2020. Among them, 550 participated in a healthcare-seeking survey, 17 in in-depth interviews and 28 in key informant interviews. RESULTS: The decision to seek care was based on symptom severity (95.4% [370]). Caregivers first visited non-allopathic healthcare providers or were treated at home, which led to delays in seeking care at healthcare facilities. More than one-third (36.0% [140]) of respondents took >12 h seeking care at healthcare facilities. The majority (73.0% [282]) visited healthcare facilities, whereas around one-fifth (21.0% [80]) sought care at drug stores. Treatment costs deterred respondents from visiting healthcare facilities (61.4% [338]). Only 10 (3.6%) of the households surveyed reported that they were covered by health insurance. CONCLUSIONS: Quality of care, related to institutional factors, impacts timely care seeking for childhood illnesses in Mtwara, Tanzania. Ensuring accessibility of facilities is therefore not sufficient.

Identification of high-performing antibodies for the reliable detection of Tau proteoforms by Western blotting and immunohistochemistry.

Antibodies are essential research tools whose performance directly impacts research conclusions and reproducibility. Owing to its central role in Alzheimer's disease and other dementias, hundreds of distinct antibody clones have been developed against the microtubule-associated protein Tau and its multiple proteoforms. Despite this breadth of offer, limited understanding of their performance and poor antibody selectivity have hindered research progress. Here, we validate a large panel of Tau antibodies by Western blot (79 reagents) and immunohistochemistry (35 reagents). We address the reagents' ability to detect the target proteoform, selectivity, the impact of protein phosphorylation on antibody binding and performance in human brain samples. While most antibodies detected Tau at high levels, many failed to detect it at lower, endogenous levels. By WB, non-selective binding to other proteins affected over half of the antibodies tested, with several cross-reacting with the related MAP2 protein, whereas the "oligomeric Tau" T22 antibody reacted with monomeric Tau by WB, thus calling into question its specificity to Tau oligomers. Despite the presumption that "total" Tau antibodies are agnostic to post-translational modifications, we found that phosphorylation partially inhibits binding for many such antibodies, including the popular Tau-5 clone. We further combine high-sensitivity reagents, mass-spectrometry proteomics and cDNA sequencing to demonstrate that presumptive Tau "knockout" human cells continue to express residual protein arising through exon skipping, providing evidence of previously unappreciated gene plasticity. Finally, probing of human brain samples with a large panel of antibodies revealed the presence of C-term-truncated versions of all main Tau brain isoforms in both control and tauopathy donors. Ultimately, we identify a validated panel of Tau antibodies that can be employed in Western blotting and/or immunohistochemistry to reliably detect even low levels of Tau expression with high selectivity. This work represents an extensive resource that will enable the re-interpretation of published data, improve reproducibility in Tau research, and overall accelerate scientific progress.

The effect of physical barriers under a raised house on mosquito entry: an experimental study in rural Gambia.

BACKGROUND: Anopheles gambiae, the major malaria mosquito in sub-Saharan Africa, feed largely indoors at night. Raising a house off the ground with no barriers underneath reduces mosquito-house entry. This experiment tested whether walling off the space under an elevated hut affects mosquito-hut entry. METHODS: Four inhabited experimental huts, each of which could be moved up and down, were used in rural Gambia. Nightly collections of mosquitoes were made using light traps and temperature and carbon dioxide levels monitored indoors and outdoors using loggers. Each night, a reference hut was kept at ground level and three huts raised 2 m above the ground; with the space under the hut left open, walled with air-permeable walls or solid walls. Treatments were rotated every four nights using a randomized block design. The experiment was conducted for 32 nights. Primary measurements were mosquito numbers and indoor temperature in each hut. RESULTS: A total of 1,259 female Anopheles gambiae sensu lato were collected in the hut at ground level, 655 in the hut with an open ground floor, 981 in the hut with air-permeable walls underneath and 873 in the hut with solid walls underneath. Multivariate analysis, adjusting for confounders, showed that a raised hut open underneath had 53% fewer mosquitoes (95% CI 47-58%), those with air-permeable walls underneath 24% fewer (95% CI 9-36%) and huts with solid walls underneath 31% fewer (95% CI 24-37%) compared with a hut on the ground. Similar results were found for Mansonia spp. and total number of female mosquitoes, but not for Culex mosquitoes where hut entry was unaffected by height or barriers. Indoor temperature and carbon dioxide levels were similar in all huts. CONCLUSION: Raising a house 2 m from the ground reduces the entry of An. gambiae and Mansonia mosquitoes, but not Culex species. The protective effect of height is reduced if the space underneath the hut is walled off.

GLP-1 metabolite GLP-1(9-36) is a systemic inhibitor of mouse and human pancreatic islet glucagon secretion.

AIMS/HYPOTHESIS: Diabetes mellitus is associated with impaired insulin secretion, often aggravated by oversecretion of glucagon. Therapeutic interventions should ideally correct both defects. Glucagon-like peptide 1 (GLP-1) has this capability but exactly how it exerts its glucagonostatic effect remains obscure. Following its release GLP-1 is rapidly degraded from GLP-1(7-36) to GLP-1(9-36). We hypothesised that the metabolite GLP-1(9-36) (previously believed to be biologically inactive) exerts a direct inhibitory effect on glucagon secretion and that this mechanism becomes impaired in diabetes. METHODS: We used a combination of glucagon secretion measurements in mouse and human islets (including islets from donors with type 2 diabetes), total internal reflection fluorescence microscopy imaging of secretory granule dynamics, recordings of cytoplasmic Ca2+ and measurements of protein kinase A activity, immunocytochemistry, in vivo physiology and GTP-binding protein dissociation studies to explore how GLP-1 exerts its inhibitory effect on glucagon secretion and the role of the metabolite GLP-1(9-36). RESULTS: GLP-1(7-36) inhibited glucagon secretion in isolated islets with an IC50 of 2.5 pmol/l. The effect was particularly strong at low glucose concentrations. The degradation product GLP-1(9-36) shared this capacity. GLP-1(9-36) retained its glucagonostatic effects after genetic/pharmacological inactivation of the GLP-1 receptor. GLP-1(9-36) also potently inhibited glucagon secretion evoked by ß-adrenergic stimulation, amino acids and membrane depolarisation. In islet alpha cells, GLP-1(9-36) led to inhibition of Ca2+ entry via voltage-gated Ca2+ channels sensitive to ω-agatoxin, with consequential pertussis-toxin-sensitive depletion of the docked pool of secretory granules, effects that were prevented by the glucagon receptor antagonists REMD2.59 and L-168049. The capacity of GLP-1(9-36) to inhibit glucagon secretion and reduce the number of docked granules was lost in alpha cells from human donors with type 2 diabetes. In vivo, high exogenous concentrations of GLP-1(9-36) (>100 pmol/l) resulted in a small (30%) lowering of circulating glucagon during insulin-induced hypoglycaemia. This effect was abolished by REMD2.59, which promptly increased circulating glucagon by >225% (adjusted for the change in plasma glucose) without affecting pancreatic glucagon content. CONCLUSIONS/INTERPRETATION: We conclude that the GLP-1 metabolite GLP-1(9-36) is a systemic inhibitor of glucagon secretion. We propose that the increase in circulating glucagon observed following genetic/pharmacological inactivation of glucagon signalling in mice and in people with type 2 diabetes reflects the removal of GLP-1(9-36)'s glucagonostatic action.

Understanding reticence to occupy free, novel-design homes: A qualitative study in Mtwara, Southeast Tanzania.

INTRODUCTION: The population of Africa set to reach 2 billion by 2050. There is therefore great demand for housing across the continent. Research on modified novel designs for housing is a priority to ensure that these homes are not sites of infection for diseases transmission such as malaria. One trial to assess the protection afforded by novel design houses is underway in Mtwara Region, southeastern Tanzania. After constructing 110 of such homes across 60 villages, project staff encountered a certain reticence of the target population to occupy the homes and were faced with accusations of having nefarious intentions. This article explores these accusations, their impacts on home occupancy and lessons for future housing studies. METHODS: This qualitative study drew on in-depth interviews and focus group discussions with ten occupants of the intervention homes, six community leaders and a further 24 community members. Interviews were recorded, transcribed verbatim and translated to English for qualitative content analysis. RESULTS: In communities around the Star Homes, during construction and handover, project staff were widely associated with 'Freemasons', a term used to practices, secrecy, and other conspiracy theories in rural Tanzania. These connections were attributed to other community members and explained in terms of knowledge deficit or envy, with others hoping to be allocated the home. The stories were embedded in assumptions of reciprocity and suspicions about study motives, linked to limited experience of research. The relationship between the accusations of freemasonry and reticence to occupy the houses was not straightforward, with project staff or relatives playing a role in decisions. The stakes were high, because the recipients of Star Homes were the poorest families in targeted communities. CONCLUSION: The results indicate the need for long-term and proactive community engagement, which focuses on building relationships and providing information through recognizable voices and formats. Given the stakes at play in housing interventions, research teams should be prepared for the social upheaval the provision of free new housing can cause.

GDF15 increases insulin action in the liver and adipose tissue via a ß-adrenergic receptor-mediated mechanism.

Growth differentiation factor 15 (GDF15) induces weight loss and increases insulin action in obese rodents. Whether and how GDF15 improves insulin action without weight loss is unknown. Obese rats were treated with GDF15 and displayed increased insulin tolerance 5 h later. Lean and obese female and male mice were treated with GDF15 on days 1, 3, and 5 without weight loss and displayed increased insulin sensitivity during a euglycemic hyperinsulinemic clamp on day 6 due to enhanced suppression of endogenous glucose production and increased glucose uptake in WAT and BAT. GDF15 also reduced glucagon levels during clamp independently of the GFRAL receptor. The insulin-sensitizing effect of GDF15 was completely abrogated in GFRAL KO mice and also by treatment with the ß-adrenergic antagonist propranolol and in ß1,ß2-adrenergic receptor KO mice. GDF15 activation of the GFRAL receptor increases ß-adrenergic signaling, in turn, improving insulin action in the liver and white and brown adipose tissue.

Metabolic regulation of glucagon secretion.

Since the discovery of glucagon 100 years ago, the hormone and the pancreatic islet alpha cells that produce it have remained enigmatic relative to insulin-producing beta cells. Canonically, alpha cells have been described in the context of glucagon's role in glucose metabolism in liver, with glucose as the primary nutrient signal regulating alpha cell function. However, current data reveal a more holistic model of metabolic signalling, involving glucagon-regulated metabolism of multiple nutrients by the liver and other tissues, including amino acids and lipids, providing reciprocal feedback to regulate glucagon secretion and even alpha cell mass. Here we describe how various nutrients are sensed, transported and metabolised in alpha cells, providing an integrative model for the metabolic regulation of glucagon secretion and action. Importantly, we discuss where these nutrient-sensing pathways intersect to regulate alpha cell function and highlight key areas for future research.

Glucose Controls Glucagon Secretion by Regulating Fatty Acid Oxidation in Pancreatic α-Cells.

Whole-body glucose homeostasis is coordinated through secretion of glucagon and insulin from pancreatic islets. When glucose is low, glucagon is released from α-cells to stimulate hepatic glucose production. However, the mechanisms that regulate glucagon secretion from pancreatic α-cells remain unclear. Here we show that in α-cells, the interaction between fatty acid oxidation and glucose metabolism controls glucagon secretion. The glucose-dependent inhibition of glucagon secretion relies on pyruvate dehydrogenase and carnitine palmitoyl transferase 1a activity and lowering of mitochondrial fatty acid oxidation by increases in glucose. This results in reduced intracellular ATP and leads to membrane repolarization and inhibition of glucagon secretion. These findings provide a new framework for the metabolic regulation of the α-cell, where regulation of fatty acid oxidation by glucose accounts for the stimulation and inhibition of glucagon secretion. ARTICLE HIGHLIGHTS: It has become clear that dysregulation of glucagon secretion and α-cell function plays an important role in the development of diabetes, but we do not know how glucagon secretion is regulated. Here we asked whether glucose inhibits fatty acid oxidation in α-cells to regulate glucagon secretion. We found that fatty acid oxidation is required for the inhibitory effects of glucose on glucagon secretion through reductions in ATP. These findings provide a new framework for the regulation of glucagon secretion by glucose.

Amino acids and the changing face of the α-cell.

Glucagon has long been defined by its glucogenic action and as a result α-cells have been characterised based largely on their interaction with glucose. Recent findings have challenged this preconception, bringing to the fore the significant role glucagon plays in amino acid breakdown and underlining the importance of amino acids in glucagon secretion. The challenge that remains is defining the mechanism that underlie these effects - understanding which amino acids are most important, how they act on the α-cell and how their actions integrate with other fuels such as glucose and fatty acids. This review will describe the current relationship between amino acids and glucagon and how we can use this knowledge to redefine the α-cell.

Studying the health benefits of improved housing in rural Tanzania: challenges and progress.

Millions of affordable healthy homes are needed for the rapidly expanding population of sub-Saharan Africa. This enormous challenge is an opportunity to address pervasive health issues linked to housing, where diseases that most impact children-malaria, diarrhoea and respiratory tract infections-are often acquired. A pilot project in northern Tanzania demonstrated the potential of novel house designs to reduce infectious disease transmission in homes. To conduct a randomized controlled trial of one novel-design house, the research team moved to the southeast of the country. This article describes the challenges experienced during the construction and initial evaluation of the novel house.

Effect of passive and active ventilation on malaria mosquito house entry and human comfort: an experimental study in rural Gambia.

Rural houses in sub-Saharan Africa are typically hot and allow malaria mosquitoes inside. We assessed whether passive or active ventilation can reduce house entry of malaria mosquitoes and cool a bedroom at night in rural Gambia. Two identical experimental houses were used: one ventilated and one unventilated (control). We evaluated the impact of (i) passive ventilation (solar chimney) and (ii) active ventilation (ceiling fan) on the number of mosquitoes collected indoors and environmental parameters (temperature, humidity, CO2, evaporation). Although the solar chimney did not reduce entry of Anopheles gambiae sensu lato, the ceiling fan reduced house entry by 91% compared with the control house. There were no differences in indoor nightly temperature, humidity or CO2 between intervention and control houses in either experiment. The solar chimney did not improve human comfort assessed using psychrometric analysis. While the ceiling fan improved human comfort pre-midnight, in the morning it was too cool compared with the control house, although this could be remedied through provision of blankets. Further improvements to the design of the solar chimney are needed. High air velocity in the ceiling fan house probably reduced mosquito house entry by preventing mosquito flight. Improved ventilation in houses may reduce malaria transmission.

Acute urinary retention in men: 21-year trends in incidence, subsequent benign prostatic hyperplasia-related treatment and mortality: A Danish population-based cohort study.

OBJECTIVE: To examine trends in incidence of acute urinary retention, subsequent benign prostatic hyperplasia-related treatment and mortality in the era of medical therapy for benign prostatic hyperplasia. Additionally, to compare mortality with the general population. MATERIALS AND METHODS: We conducted a Danish nationwide registry-based study including 70,775 men aged 45 years or older with a first hospitalization for acute urinary retention during 1997-2017. We computed annual standardized incidence rates, subsequent 1-year cumulative incidence of benign prostatic hyperplasia-related surgical and medical treatment, and standardized 3-month and 1-year mortality rates. Finally, we compared standardized all-cause and cause-specific mortality ratios with the general population. RESULTS: The standardized incidence rate of acute urinary retention per 1000 person-years increased transiently from 2.34 to 3.42 during 1997-2004, but gradually declined to 2.95 in 2017. The 1-year cumulative incidence of benign prostatic hyperplasia-related surgery declined from 31.2% to 19.8% and 20.5% to 7.7% after spontaneous and precipitated acute urinary retention, respectively. During 1997-2017, the standardized 1-year mortality declined from 22.2% to 17.2%. Compared with the general population, mortality was 4-5 times higher after 3 months and 2-3 times higher after 1 year of acute urinary retention. The cause-specific standardized mortality ratios were particularly high for deaths attributable to malignancies, urogenital disease, certain infections, chronic pulmonary disease, and diabetes. CONCLUSION: During 1997-2017, we observed a transient increase in the incidence of acute urinary retention. The subsequent use of benign prostatic hyperplasia-related surgery declined considerably and mortality continued to be high, mainly because of deaths from malignancies, urogenital disease, infections, and preexisting comorbidity.

Loss of tetraspanin-7 expression reduces pancreatic ß-cell exocytosis Ca2+ sensitivity but has limited effect on systemic metabolism.

BACKGROUND: Tetraspanin-7 (Tspan7) is an islet autoantigen involved in autoimmune type 1 diabetes and known to regulate ß-cell L-type Ca2+ channel activity. However, the role of Tspan7 in pancreatic ß-cell function is not yet fully understood. METHODS: Histological analyses were conducted using immunostaining. Whole-body metabolism was tested using glucose tolerance test. Islet hormone secretion was quantified using static batch incubation or dynamic perifusion. ß-cell transmembrane currents, electrical activity and exocytosis were measured using whole-cell patch-clamping and capacitance measurements. Gene expression was studied using mRNA-sequencing and quantitative PCR. RESULTS: Tspan7 is expressed in insulin-containing granules of pancreatic ß-cells and glucagon-producing α-cells. Tspan7 knockout mice (Tspan7y/- mouse) exhibit reduced body weight and ad libitum plasma glucose but normal glucose tolerance. Tspan7y/- islets have normal insulin content and glucose- or tolbutamide-stimulated insulin secretion. Depolarisation-triggered Ca2+ current was enhanced in Tspan7y/- ß-cells, but ß-cell electrical activity and depolarisation-evoked exocytosis were unchanged suggesting that exocytosis was less sensitive to Ca2+ . TSPAN7 knockdown (KD) in human pseudo-islets led to a significant reduction in insulin secretion stimulated by 20 mM K+ . Transcriptomic analyses show that TSPAN7 KD in human pseudo-islets correlated with changes in genes involved in hormone secretion, apoptosis and ER stress. Consistent with rodent ß-cells, exocytotic Ca2+ sensitivity was reduced in a human ß-cell line (EndoC-ßH1) following Tspan7 KD. CONCLUSION: Tspan7 is involved in the regulation of Ca2+ -dependent exocytosis in ß-cells. Its function is more significant in human ß-cells than their rodent counterparts.

House screening for malaria control: views and experiences of participants in the RooPfs trial.

BACKGROUND: The housing stock of rural sub-Saharan Africa is changing rapidly. With millions of new homes required over the coming decades, there is an opportunity to protect residents by screening homes from malaria mosquitoes. This study, undertaken in the Upper River Region of The Gambia, explores local perceptions of what a good house should provide for its inhabitants and responses to living in a house that has been modified as part of a randomized control trial designed to assess whether improved housing provided additional protection against clinical malaria in children (the RooPfs trial). METHODS: This descriptive, exploratory study was undertaken over 22 months using mixed-methods (informal conversations, observations, focus group discussions, photovoice, and a questionnaire survey) in a parallel convergent design. Analysis was conducted across the data sets using a framework approach. Following coding, the textual data were charted by a priori and emerging themes. These themes were compared with the quantitative survey results. The nature and range of views about housing and the RooPfs study modifications and the relationships among them were identified and described. RESULTS: The data were derived from a total of 35 sets of observations and informal conversations in 10 villages, 12 discussions with the photovoice photographers, 26 focus group discussions (across 13 villages) and 391 completed questionnaires. The study participants described a 'good house' as one with a corrugate-metal roof, cement walls (preferably cement block, but mud block covered with cement plaster was also an acceptable and cheaper substitute) and well-fitting doors. These features align with local perceptions of a modern house that provides social status and protection from physical harms. The RooPfs modifications were largely appreciated, although poor workmanship caused concerns that houses had become insecure. However, the long-term trusting relationship with the implementing institution and the actions taken to rectify problems provided reassurance and enhanced acceptability. CONCLUSION: In developing housing to address population needs in Africa, attention should be paid to local perceptions of what is required to make a house secure for its inhabitants, as well as providing a healthy environment.

Healthcare Resource Utilization and Costs for Empagliflozin Versus Glucagon-Like Peptide-1 Receptor Agonists in Routine Clinical Care in Denmark.

INTRODUCTION: The sodium-glucose cotransporter 2 inhibitor (SGLT2i) empagliflozin has shown reductions in major adverse cardiac events similar to glucagon-like peptide-1 receptor agonists (GLP-1RAs). However, evidence is limited about how these therapies compare regarding overall healthcare resource utilization and costs in routine clinical care. METHODS: We conducted a comparative cohort study based on linked prospective healthcare databases for the entire population of Denmark during 2015-2018. We included 13,747 new users of empagliflozin and 13,249 new users of GLP-1RAs. Propensity scores were applied to balance potential confounders across the two treatment groups through inverse probability treatment weighting (IPTW). We assessed directly referable costs per person-year associated with healthcare resource utilization (inpatient, emergency room, and outpatient clinic hospital care, primary care health services, and prescription medication costs at pharmacies) among drug initiators while on-treatment. RESULTS: The two IPTW cohorts were well balanced at baseline (median age 61 years, 60% men, diabetes duration 6.7 years, 19% with pre-existing ischemic heart disease, 8% with pre-existing cerebrovascular disease), with similar healthcare costs in the previous year. During follow-up, average on-treatment costs per person-year were very similar among empagliflozin and GLP-1 RA initiators for the following services: inpatient hospitalizations (13,565 DKK versus 13,275 DKK), hospital outpatient clinic visits (12,007 DKK versus 12,152 DKK), emergency room visits (370 DKK versus 399 DKK), and primary care services (4108 DKK versus 4302 DKK). Total costs for any prescription drugs were clearly lower for empagliflozin initiators than for GLP-1 RA initiators (8946 DKK versus 14,029 DKK). In sum, overall healthcare costs on-treatment were lower for empagliflozin initiators (38,995 DKK per person-year) than for GLP-1RA initiators (44,157 DKK per person-year). CONCLUSIONS: In this nationwide population-based cohort study, average healthcare costs after drug initiation and while on treatment were lower for empagliflozin initiators than for GLP-1RAs initiators, driven by lower drug costs. REGISTRATION: The study protocol and analysis plan have been registered on the website of the European Network of Centres for Pharmacoepidemiology and Pharmacovigilance (ENCEPP) ( http://www.encepp.eu/encepp/viewResource.htm?id=37726 , first protocol registration 4 June 2019), and on clinicaltrials.gov ( https://clinicaltrials.gov/ct2/show/NCT03993132 , first posted 20 June 2019).

Risk factors associated with mortality among individuals with type 2 diabetes and depression across two cohorts.

Objective: Depression has been linked to excess mortality in individuals with type 2 diabetes, but it remains unclear what drives this association. We examined if the association depends on unhealthy lifestyle and medical comorbidity. Methods: We followed a clinically recruited cohort of Danish people with type 2 diabetes (n = 8175) with fine-grained clinical information and a population-wide register-based cohort of Danish individuals with HbA1c-defined type 2 diabetes (n = 87 500) representing everyday clinical practice. Antidepressant drug use prior to the onset of type 2 diabetes was used as a proxy for preexisting depression. In both cohorts, we first estimated the association between depression and 5-year mortality following type 2 diabetes, using a Cox proportional hazards model, yielding sex- and age-adjusted mortality rate ratios (MRRs). We subsequently examined how further adjustment for markers of unhealthy lifestyle (smoking, physical inactivity, obesity, alcohol abuse, and marital status) and medical comorbidity affected the association. Results: Preexisting depression was associated with an approximately 50% increased age- and sex-adjusted all-cause mortality rate in both the clinically recruited- (5-year MRR: 1.46; 95% CI: 1.12-1.90) and the register-based type 2 diabetes cohort (5-year MRR: 1.51; 95% CI: 1.45-1.57). The excess mortality associated with depression almost disappeared when the analyses were adjusted for unhealthy lifestyle and medical comorbidity in both the clinically recruited- (MRR: 1.05; 95% CI: 0.72-1.52) and the register-based type 2 diabetes cohort (MRR: 1.14, 95% CI: 1.09-1.19). Conclusions: A large fraction of the excess mortality associated with preexisting depression in type 2 diabetes is attributable to the unhealthy lifestyle and medical comorbidity accompanying depression.

Assessing the impact of a novel house design on the incidence of malaria in children in rural Africa: study protocol for a household-cluster randomized controlled superiority trial.

BACKGROUND: Traditional rural housing in hot, humid regions of sub-Saharan Africa usually consists of single-level, poorly ventilated dwellings. Houses are mostly poorly screened against malaria mosquitoes and limited airflow discourages the use of bednets resulting in high indoor transmission. This study aims to determine whether living in a novel design house with elevated bedrooms and permeable screened walls reduces malaria, respiratory tract infections, and diarrhoea among children in rural Tanzania. METHODS/STUDY DESIGN: This is a household-randomized, controlled study in 60 villages in Mtwara, Tanzania. A total of 550 households are randomly selected, 110 of which are allocated a novel design house and 440 households continue to reside in traditional houses. A dynamic cohort of about 1650 children under 13 years will be enrolled and followed for 3 years, approximately 330 living in novel design houses and 1320 in traditional rural houses. The primary endpoint is the incidence of malaria; secondary endpoints are incidences of acute respiratory tract infections and diarrhoea diseases detected by passive and active surveillance. Exposure to malaria vectors will be assessed using light traps in all study houses. Structural, economic, and social science studies will assess the durability, cost-effectiveness, and acceptability of the new houses compared with traditional housing. Environmental data will be collected indoors and outdoors in study homes to assess the differences between house typologies. DISCUSSION: This is the first randomized controlled trial to assess the protective efficacy of a new house design targeting malaria in sub-Saharan Africa. The findings of this study could influence the future construction of homes in hot and humid zones of Africa. TRIAL REGISTRATION: ClinicalTrials.gov NCT04529434 . Registered on August 27, 2020.

Beta2 -agonist increases skeletal muscle interleukin 6 production and release in response to resistance exercise in men.

OBJECTIVE: Several tissues produce and release interleukin-6 (IL-6) in response to beta2 -adrenergic stimulation with selective agonists (beta2 -agonists). Moreover, exercise stimulates muscle IL-6 production, but whether beta2 -agonists regulate skeletal muscle production and release of IL-6 in humans in association with exercise remains to be clarified. Thus, we investigated leg IL-6 release in response to beta2 -agonist salbutamol in lean young men at rest and in recovery from resistance exercise. DESIGN: The study employed a randomized controlled crossover design, where 12 men ingested either salbutamol (16 mg) or placebo for 4 days, followed by the last dose (24 mg) administered 1½ h before exercise. Arterial and femoral venous plasma IL-6 as well as femoral artery blood flow was measured before and ½-5 h in recovery from quadriceps muscle resistance exercise. Furthermore, vastus lateralis muscle biopsies were collected ½ and 5 h after exercise for determination of mRNA levels of IL-6 and Tumor Necrosis Factor (TNF)-α. RESULTS: Average leg IL-6 release was 1.7-fold higher (p = 0.01) for salbutamol than placebo, being 138 ± 76 and 79 ± 66 pg min-1 (mean ± SD) for salbutamol and placebo, respectively, but IL-6 release was not significantly different between treatments within specific sampling points at rest and after exercise. Muscle IL-6 mRNA was 1.5- and 1.7-fold higher (p = 0.001) for salbutamol than placebo ½ and 5 h after exercise, respectively, whereas no significant treatment differences were observed for TNF-α mRNA. CONCLUSIONS: Beta2 -adrenergic stimulation with high doses of the selective beta2 -agonist salbutamol, preceeded by 4 consecutive daily doses, induces transcription of IL-6 in skeletal muscle in response to resistance exercise, and increases muscle IL-6 release in lean individuals.