Jean-Pierre Montani

Jean-Pierre Montani
Université de Fribourg · Department of Medicine

MD

About

255
Publications
37,277
Reads
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8,171
Citations
Additional affiliations
July 2002 - August 2002
Memorial University of Newfoundland
Position
  • Professor
October 1995 - present
Université de Fribourg
Position
  • Professor (Full) and Head of Physiology
Description
  • Teaching to Medical Students (first 3 years): Bachelor in Medicine Teaching to Biomedical Students (3-year Bachelor program) Research in Cardiovascular and Metabolic Integrative Physiology

Publications

Publications (255)
Article
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Purpose Sales for sugar-sweetened and caffeinated beverages are still rising globally and their consumption has been linked to the development of cardiovascular diseases. However, direct evidence from human interventional studies in response to such beverages is still scarce. Methods Seven young, non-obese men participated in a randomized crossove...
Article
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Societal erosion of daily life low-level physical activity has had a great influence on the obesity epidemic. Given that low fat oxidation is also a risk factor for obesity, we investigated, in a repeated measures design, the dynamics of fat oxidation from a resting state to a light-intensity leg cycling exercise (0–50 watts) in inactive, healthy y...
Article
Several areas of research into the prevention and treatment of obesity today can be traced to one or more of the scientific works pioneered by Ancel Keys between the 1930s to 1970s in fields that cut across the physiology of extremes and public health nutrition. These range from his classical studies into how body and mind respond to chronic exposu...
Article
Ancel Keys, whose life spanned over 100 years (1904–2004), made a wealth of seminal scientific and public health contributions. As a physiologist, nutritionist, and public health scientist, he has left his mark on the 20th century by exploring different areas of physiology and nutrition, as well as by contributing to the understanding of basic publ...
Article
The most appropriate type of diets to maintain or lose body weight over the medium to long term has been a matter of controversy and debates for more than half a century. Both voluntarily and coercive food restriction, resulting in negative energy and macronutrient balance and hence weight loss, have not been designed to be maintained for the long...
Article
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Background The role of mineral components in the hemodynamic response to water drinking is still elusive. Methods We conducted a randomized crossover study in 16 non-obese, healthy subjects (8 women) to investigate cardiovascular responses to water drinks differing in the mineral content. Continuous measurements included beat-to-beat blood pressur...
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The notion that dieting makes some people fatter has in the past decade gained considerable interest from both epidemiological predictions and biological plausibility. Several large-scale prospective studies have suggested that dieting to lose weight is associated with future weight gain and obesity, with such predictions being stronger and more co...
Article
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It is increasingly recognized that the use of body mass index (BMI) cut-off points for diagnosing obesity and proxy measures for body fatness in a given population needs to take into account the potential impact of ethnicity on the BMI-Fat% relationship in order to avoid adiposity status misclassification. This relationship was studied here in 377...
Article
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Aim: Sharing a festive meal associated with alcohol is quite common. While the cardiovascular changes occurring after meal ingestion of different nutrient composition has been well-established, the effects of ingesting a festive versus a standard meal accompanied with alcohol are less clear. Here, we compared the postprandial hemodynamics, cutaneou...
Article
The recovery of body weight after substantial weight loss or growth retardation is often characterized by a disproportionately higher rate of fat mass vs lean mass recovery, with this phenomenon of 'preferential catch-up fat' being contributed by energy conservation (thrifty) metabolism. To test the hypothesis that a low core body temperature (Tc)...
Article
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Implementation of efficacious dietary interventions to regulate energy balance requires understanding of the determinants of individual response. To date, information regarding individual variability in response to elevated meal protein content is lacking. This study investigates whether sex and/or oral contraceptive pill (OCP) use play a role in t...
Article
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Objective: The recovery of body composition after weight loss is characterized by an accelerated rate of fat recovery (preferential catch-up fat) resulting partly from an adaptive suppression of thermogenesis. Although the skeletal muscle has been implicated as an effector site for such thrifty (energy conservation) metabolism driving catch-up fat,...
Article
Increasing lifestyle energy expenditure has long been advocated in the prevention and treatment of obesity, as embodied in the ancient prescription of Hippocrates (the ‘father of modern medicine’) that people with obesity should eat less and exercise more. However, the long‐term outcome of exercise alone or in combination with dieting in obesity ma...
Conference Paper
Background: There is a need to establishthe range of proteinintake that would constitute an acceptable ‘high-protein’ diet for weight management, particularly towards the prevention of obesity and weight relapse. The pilot study described here aimed to (i) define the dose–response relationship between meal protein content and postprandial thermogen...
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Aim: Red wine is usually ingested as an unmixed drink. However, mixtures of wine with juices and/or sucrose (mixed wine) are becoming more and more popular and could be ingested at either cold or hot temperature. Although the temperature effects on the cardiovascular system have been described for water and tea, with greater energy expenditure and...
Conference Paper
Introduction: Obesity is more prevalent in women than men worldwide, with the rising prevalence amongst young women of child-bearing age of particular concern. Whilst the underlying mechanism for this gender disparity is largely unknown, oral contraceptive pill (OCP) use may be a factor that contributes to the alteration in energy balance in young...
Article
Type-II l-arginine:ureahydrolase, arginase-II (Arg-II), is abundantly expressed in the kidney. The physiologic role played by Arg-II in the kidney remains unknown. Herein, we report that in mice that are deficient in Arg-II (Arg-II-/-), total and membrane-associated aquaporin-2 (AQP2) protein levels were significantly higher compared with wild-type...
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Although Switzerland is considered a small country, it has its share in discoveries, inventions and developments for the assessment of energy metabolism. This includes seminal contributions to respiratory and metabolic physiology and to devices for measuring energy expenditure by direct and indirect calorimetry in vivo in humans and small animals (...
Article
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Aim: Tea is usually consumed at two temperatures (as hot tea or as iced tea). However, the importance of drink temperature on the cardiovascular system and on metabolism has not been thoroughly investigated. The purpose of this study was to compare the cardiovascular, metabolic and cutaneous responses to the ingestion of caffeinated herbal tea (Yer...
Article
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Type-II L-arginine:ureahydrolase, arginase-II (Arg-II), is shown to activate mechanistic target of rapamycin complex 1 (mTORC1) pathway and contributes to cell senescence and apoptosis. In an attempt to elucidate the underlying mechanism, we identified myosin-1b (Myo1b) as a mediator. Overexpression of Arg-II induces re-distribution of lysosome and...
Article
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Aim: Acute ingestion of alcohol is often accompanied by cardiovascular dysregulation, malaise and even syncope. The full hemodynamic and cutaneous responses to the combination of alcohol and sugar (i.e., alcopops), a common combination in young people, and the mechanisms for the propensity to orthostatic intolerance are not well established. Thus,...
Article
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Orthostatic challenge produced by upright posture may lead to syncope if the cardiovascular system is unable to maintain adequate brain perfusion. This review outlines orthostatic intolerance related to the aging process, long-term bedrest confinement, drugs, and disease. Aging-associated illness or injury due to falls often leads to hospitalizatio...
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The mitochondrial arginase type II (Arg-II) has been shown to interact with ribosomal protein S6 kinase 1 (S6K1) and mitochondrial p66Shc and to promote cell senescence, apoptosis and inflammation under pathological conditions. However, the impact of Arg-II on organismal lifespan is not known. In this study, we demonstrate a significant lifespan ex...
Article
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Purpose: There is increasing interest into the potentially beneficial effects of galactose for obesity and type 2 diabetes management as it is a low-glycemic sugar reported to increase satiety and fat mobilization. However, fructose is also a low-glycemic sugar but with greater blood pressure elevation effects than after glucose ingestion. Therefo...
Article
Recent body composition studies on the island of Mauritius in young adults belonging to the two main ethnicities—Indians (South Asian descent) and Creoles (African/Malagasy descent)—have shown gender-specific ethnic differences in their body mass index (BMI)-Fat% relationships. We investigated here whether potential gender and ethnic differences in...
Article
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Objective: There is much interest in the role of dietary protein for weight control. However, there remains a need to characterize individual determinants of the thermogenic effects of protein. This study aimed to investigate the influence of menstrual cycle phase and the combined, monophasic oral contraceptive pill on the thermogenic response to...
Article
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Background There is increasing interest in the use of pill-sized ingestible capsule telemetric sensors for assessing core body temperature (Tc) as a potential indicator of variability in metabolic efficiency and thrifty metabolic traits. The aim of this study was to investigate the feasibility and accuracy of measuring Tc using the CorTemp® system....
Conference Paper
Introduction: Successful approaches to weight control should elicit effects on both sides of the energy balance equation, i.e., energy intake and expenditure. For this reason there has been much interest in the role of dietary protein, which has been demonstrated to favourably affect satiety, thermogenesis, body weight and body composition. However...
Article
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Standardized approaches to assess human energy expenditure (EE) are well defined at rest and at moderate to high‐intensity exercise, but not at light intensity physical activities energetically comparable with those of daily life (i.e., 1.5–4 times the resting EE, i.e., 1.5–4 METs). Our aim was to validate a graded exercise test for assessing the e...
Article
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PurposeDue to sedentarity-associated disease risks, there is much interest in methods to increase low-intensity physical activity. In this context, it is widely assumed that altering posture allocation can modify energy expenditure (EE) to impact body-weight regulation and health. However, we have recently shown the existence of two distinct phenot...
Article
Aging is associated with glucose intolerance. Arginase-II (Arg-II), the type-II L-arginine-ureahydrolase, is highly expressed in pancreas. However, its role in regulation of pancreatic ?-cell function is not known. Here we show that female (not male) mice deficient in Arg-II (Arg-II(-/-)) are protected from age-associated glucose intolerance and re...
Article
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Background Augmented arginase-II (Arg-II) is implicated in endothelial senescence and inflammation through a mutual positive regulatory circuit with S6K1. This study was conducted to investigate whether Arg-I, another isoform of arginase that has been also reported to play a role in vascular endothelial dysfunction, promotes endothelial senescence...
Article
Isometric thermogenesis as applied to human energy expenditure refers to heat production resulting from increased muscle tension. While most physical activities consist of both dynamic and static (isometric) muscle actions, the isometric component is very often essential for the optimal performance of dynamic work given its role in coordinating pos...
Article
Among the multitude of dietary and lifestyle behaviours that have been proposed to contribute to the obesity epidemic, those that have generated considerable research scrutiny in the past decade are centred upon sleep behaviours, sedentary behaviours (sitting or lying while awake) and diminished low-level physical activities of everyday life, with...
Article
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Obesity is associated with development and progression of chronic kidney disease (CKD). Recent evidence demonstrates that enhanced levels of the L-arginine:ureahydrolase, including the two isoenzymes arginase-I (Arg-I) and arginase-II (Arg-II) in vascular endothelial cells promote uncoupling of endothelial nitric oxide synthase (eNOS), leading to i...
Article
Background and Aims Global estimates of overweight and obesity prevalence are based on the World Health Organisation (WHO) body mass index (BMI) cut-off values of 25 and 30 kg m⁻², respectively. To validate these BMI cut-offs for adiposity in the island population of Mauritius, we assessed the relationship between BMI and measured body fat mass in...
Article
Globally, the popularity of energy drinks is steadily increasing. Scientific interest in their effects on cardiovascular and cerebrovascular systems in humans is also expanding and with it comes a growing number of case reports of adverse events associated with energy drinks. The vast majority of studies carried out in the general population report...
Article
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Background and Purpose: Energy drinks (EDs) are suspected to induce potential adverse cardiovascular effects and have recently been shown to reduce cerebral blood flow velocity (CBFV) in young, healthy subjects. Gender differences in CBFV in response to EDs have not previously been investigated, despite the fact that women are more prone to cardiov...
Article
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Uninephrectomy (UniNX) in rats on a fixed food intake leads to increased lipolysis and a low-grade inflammation with an increased subset of circulating cytokines. Because UniNX ablates renal nerves on the side of the removed kidney, we tested the contribution of unilateral renal denervation in the phenotype of UniNX. We compared Sham-operated contr...
Article
Low-intensity physical activity is increasingly promoted as an alternative to sedentary behavior. However, much research to date has focused on moderate- to vigorous-intensity physical activity, and in particular dynamic work, with the effect of low-intensity isometric exercise (<4 METs) on substrate utilization yet to be explored. Here we investig...
Article
To the Editor Dr Svatikova and colleagues1 investigated acute cardiovascular responses in healthy adults 30 minutes after ingestion of an energy drink (containing 62 g of sugar, caffeine, and taurine) compared with a placebo drink (containing approximately 62 g of sugar but no caffeine or other stimulants). In addition, the authors investigated the...
Article
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Background and aim: There is increasing recognition about the importance of enhancing energy expenditure (EE) for weight control through increases in low-intensity physical activities comparable with daily life (1.5-4 METS). Whole-body vibration (WBV) increases EE modestly and could present both a useful adjuvant for obesity management and tool fo...
Article
Endothelium-derived nitric oxide (NO) produced from endothelial NO-synthase (eNOS) is one of the most important vasoprotective molecules in cardiovascular physiology. Dysfunctional eNOS such as uncoupling of eNOS leads to decrease in NO bioavailability and increase in superoxide anion (O2(.-)) production, and in turn promotes cardiovascular disease...
Article
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Circumstantial evidence suggests that substitution of glucose or sucrose by the low-glycaemic index sugar galactose in the diet may lead to greater thermogenesis and/or fat oxidation. Using ventilated hood indirect calorimetry, we investigated, in twelve overnight-fasted adults, the resting energy expenditure (REE) and respiratory quotient (RQ) for...
Article
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Nonalcoholic fatty liver disease (NAFLD) associates with obesity and type 2 diabetes. Hypoactive AMP-activated protein kinase (AMPK), hyperactive mammalian target of rapamycin (mTOR) signaling, and macrophage-mediated inflammation are mechanistically linked to NAFLD. Studies investigating roles of arginase particularly the extrahepatic isoform argi...
Article
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Recent human studies have suggested that mild reduction in kidney function can alter immune response and increase susceptibility to infection. The role of mild reduction in kidney function in altering susceptibility to bacterial lipopolysaccharide (LPS) responses was investigated in uninephrectomized rats compared to Sham-operated controls rats 4 w...
Article
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Background/objectives: Drinking large amounts of water is often recommended for weight control. Whether water intake stimulates energy and fat metabolism is, however, controversial with some studies reporting that drinking half a litre or more of water increases resting energy expenditure (REE) by 10-30% and decreases respiratory quotient (RQ), wh...