The Murray-Darling Medical Schools Network Research Collaboration: protocol for a longitudinal, multi-university program of work to explore the effect of rurally based medical school programs in the Murray-Darling region.

INTRODUCTION: There is now strong evidence to support the positive impact of place-based medical education on the recruitment and retention of the rural health workforce in Australia. Much of this work, however, has been undertaken in the context of 'extended rural clinical placement' - students undertaking part of their medical degree in a rural location. Until recently, there were only a few places in Australia in which students could undertake the entirety of their medical degree in a rural area. With the introduction of the Murray-Darling Medical Schools Network (MDMSN) initiative, this dynamic is changing. The MDMSN is part of the Stronger Rural Health Strategy and builds on the Australian Government's existing Rural Health Multidisciplinary Training Program to establish a network of rurally based medical programs in the Murray-Darling region. The MDMSN offers a unique opportunity to explore the effect of complete rural immersion during medical school on subsequent rural practice. This article describes the establishment of a research collaboration intended to ensure the harmonisation of research data collection from the outset of the MDMSN program. METHODS: The MDMSN research collaboration is a longitudinal, multi-university program of work to explore the effect of rurally based medical school programs in the Murray-Darling region. Initially it has been agreed that administrative student data will be collected from existing university datasets to help characterise this novel student cohort. Each university will then distribute an entry survey to all first-year MDMSN students. The survey will collect demographic information as well as information regarding rural background, preferences and future practice intention. Questions have been aligned with and adapted from the Medical Schools Outcomes Database survey, the Australian Bureau of Statistics, and from the literature. This information will be combined with graduate information from the Australian Health Practitioner Regulation Agency. RESULTS: The MDMSN research collaboration will work toward the co-design of research projects, to facilitate and progress multi-site research addressing nationally relevant research questions. Early research efforts are focused on our ability to better understand the new cohort of students embarking on rurally based medical education, their practice intentions and realisation. Subsequent work of the collaboration may lead to deeper understanding of the rural student experience, any effect of 'place', changes in student professional identity over time, and their relationship to subsequent rural practice. CONCLUSION: The MDMSN research collaboration is a proactive initiative that brings together data and experience from five new rurally based medical programs, and answers calls for multi-institution and longitudinal studies. It is uniquely placed to capture the impact of the MDMSN program, including the effect of complete rural immersion on the future practice location of these graduates. Ultimately, the combined research efforts of the MDMSN research collaboration will add knowledge to address the known rural workforce maldistribution, particularly how to attract and retain medical workforce.

Using a Combination of Indirect Calorimetry, Infrared Thermography, and Blood Glucose Levels to Measure Brown Adipose Tissue Thermogenesis in Humans.

In mammals, brown adipose tissue (BAT) is activated rapidly in response to cold in order to maintain body temperature. Although BAT has been studied greatly in small animals, it is difficult to measure the activity of BAT in humans. Therefore, little is known about the heat-generating capacity and physiological significance of BAT in humans, including the degree to which components of the diet can activate BAT. This is due to the limitations in the currently most used method to assess the activation of BAT-radiolabeled glucose (fluorodeoxyglucose or 18FDG) measured by positron emission tomography-computerized tomography (PET-CT). This method is usually performed in fasted subjects, as feeding induces glucose uptake by the muscles, which can mask the glucose uptake into the BAT. This paper describes a detailed protocol for quantifying total-body human energy expenditure and substrate utilization from BAT thermogenesis by combining indirect calorimetry, infrared thermography, and blood glucose monitoring in carbohydrate-loaded adult males. To characterize the physiological significance of BAT, measures of the impact of BAT activity on human health are critical. We demonstrate a protocol to achieve this by combining carbohydrate loading and indirect calorimetry with measurements of supraclavicular changes in temperature. This novel approach will help to understand the physiology and pharmacology of BAT thermogenesis in humans.

Both caffeine and Capsicum annuum fruit powder lower blood glucose levels and increase brown adipose tissue temperature in healthy adult males.

Using a combination of respiratory gas exchange, infrared thermography, and blood glucose (BGL) analysis, we have investigated the impact of Capsicum annuum (C. annuum) fruit powder (475 mg) or caffeine (100 mg) on metabolic activity in a placebo controlled (lactose, 100 mg) double-blinded three-way cross-over-design experiment. Metabolic measurements were made on day 1 and day 7 of supplementation in eight adult male participants (22.2 ± 2 years of age, BMI 23 ± 2 kg/m2, x̅ ± SD). Participants arrived fasted overnight and were fed a high carbohydrate meal (90 g glucose), raising BGL from fasting baseline (4.4 ± 0.3 mmol/L) to peak BGL (8.5 ± 0.3 mmol/L) 45 min after the meal. Participants consumed the supplement 45 min after the meal, and both caffeine and C. annuum fruit powder restored BGL (F (8,178) = 2.2, p = 0.02) to near fasting levels within 15 min of supplementation compared to placebo (120 min). In parallel both supplements increased energy expenditure (F (2, 21) = 175.6, p < 0.001) over the 120-min test period (caffeine = 50.74 ± 2 kcal/kg/min, C. annuum fruit = 50.95 ± 1 kcal/kg/min, placebo = 29.34 ± 1 kcal/kg/min). Both caffeine and C. annuum fruit powder increased supraclavicular fossa temperature (F (2,42) = 32, p < 0.001) on both day 1 and day 7 of testing over the 120-min test period. No statistical difference in core temperature or reference point temperature, mean arterial pressure or heart rate was observed due to supplementation nor was any statistical difference seen between day 1 and day 7 of intervention. This is important for implementing dietary ingredients as potential metabolism increasing supplements. Together the results imply that through dietary supplements such as caffeine and C. annuum, mechanisms for increasing metabolism can be potentially targeted to improve metabolic homeostasis in people.

Corrigendum: Both caffeine and Capsicum annuum fruit powder lower blood glucose levels and increase brown adipose tissue temperature in healthy adult males.

[This corrects the article DOI: 10.3389/fphys.2022.870154.].

Effects of Caffeine on Brown Adipose Tissue Thermogenesis and Metabolic Homeostasis: A Review.

The impact of brown adipose tissue (BAT) metabolism on understanding energy balance in humans is a relatively new and exciting field of research. The pathogenesis of obesity can be largely explained by an imbalance between caloric intake and energy expenditure, but the underlying mechanisms are far more complex. Traditional non-selective sympathetic activators have been used to artificially elevate energy utilization, or suppress appetite, however undesirable side effects are apparent with the use of these pharmacological interventions. Understanding the role of BAT, in relation to human energy homeostasis has the potential to dramatically offset the energy imbalance associated with obesity. This review discusses paradoxical effects of caffeine on peripheral adenosine receptors and the possible role of adenosine in increasing metabolism is highlighted, with consideration to the potential of central rather than peripheral mechanisms for caffeine mediated BAT thermogenesis and energy expenditure. Research on the complex physiology of adipose tissue, the embryonic lineage and function of the different types of adipocytes is summarized. In addition, the effect of BAT on overall human metabolism and the extent of the associated increase in energy expenditure are discussed. The controversy surrounding the primary ß-adrenoceptor involved in human BAT activation is examined, and suggestions as to the lack of translational findings from animal to human physiology and human in vitro to in vivo models are provided. This review compares and distinguishes human and rodent BAT effects, thus developing an understanding of human BAT thermogenesis to aid lifestyle interventions targeting obesity and metabolic syndrome. The focus of this review is on the effect of BAT thermogenesis on overall metabolism, and the potential therapeutic effects of caffeine in increasing metabolism via its effects on BAT.