Que devient le tissu adipeux dans l’obésité ?

Adipose tissue exerts multiples functions related to glucose and lipid homeostasis. The adipose tissue is a site of low-grade inflammation in obese subjects, evidenced by immune cells accumulation, mainly macrophages. Pro-inflammatory factors produced by macrophages alter adipocytes biology and may contribute to the severity of metabolic complications, including insulin resistance and hepatic diseases. However, macrophages might also be beneficial to tissue homeostasis through the elimination of deficient adipocytes or pro-angiogenic effects. The cellular and molecular mechanisms of macrophage infiltration are related, at least in part, to a dialogue among hypertrophied adipocytes, macrophages and other cell-types, including lymphocytes, pre-adipocytes and endothelial cells within adipose tissue. A newly discovered consequence of adipose tissue inflammation is fibrosis that is organized both in bundles and around adipocytes. These cellular and structural alterations are only partly reversible after weight loss and reflect the pathology of adipose tissue that may contribute to the chronicity of obesity. In this context, identification of pharmacological means to maintain adipose tissue integrity remains a major challenge in the field.     

Immunosénescence et infections,mythe ou réalité ?

The susceptibility of elderly people to infectious diseases is usually associated to increasing risk factors found in young adults. However, the role of immune function ageing is associated with the decline of immune function but this decline is not homogenous. Some functions such as the cellular immune system are altered but others are enhanced such as innate immunity. The important events of immune ageing are modifications of lymphocyte subsets with accumulation of memory cells, decrease in proliferative response, and a chronic inflammatory state. The chronic antigenic load throughout life is responsible for gaps in the antigenic system with a greater sensitivity to new antigens. These immune system changes are all the more important that diseases are severe and that denutrition is associated. These diseases will speed up the ageing process. The interaction between immunosenescence and pathology is an important phenomenon to consider. This review outlines the immune system changes due to ageing, their relationship with diseases of the aged patient, and the consequences of these modifications on vaccination effectiveness.     

Obésité : que nous dit l’épidémiologie ?

In most developed and developing countries, a regular increase of the prevalence of obesity has been documented during the last decade(s) of the xxth century. The last figure from the USA is for the first time discordant with this general trend by showing a clear slowing down since year 2000. In children likewise, a rapid increase in the prevalence of obesity took place in the second half of the xxth century but recent publications from France, Switzerland, UK, USA also report a stabilization of childhood overweight and obesity prevalences. The experience of developing countries clearly shows the impact of socioeconomic status improvement and urbanization on the prevalence of obesity. In developed countries like France, a striking element was the diffuse nature of the adult obesity epidemic observed from the 1990s. The general improvement of living conditions after the Second World War probably explains the diffuse nature of the epidemics. Specifically, the changes in the nutritional status of children that happened at that time have long lasting consequences for adult obesity epidemics. Indeed, a new current in epidemiology, lifecourse epidemiology, has prompted over the past decade a new approach of the pathophysiology of chronic diseases, including obesity. Lifecourse epidemiology considers factors affecting the susceptibility to diseases over the whole life with critical periods during developmental phases. Critical periods for the susceptibility to obesity have been documented in prenatal life, during the first 6 months of postnatal life and from 3 years on starting at the time of the adiposity rebound. Parental obesity is involved at each of the critical periods. The transgenerational transmission of obesity is explained by genetic factors, shared lifestyle but also epigenetics especially during the early developmental periods. The slowing down of the childhood obesity epidemics observed in several developed countries may signal that factors affecting the early susceptibility to obesity have recently changed.     

Prise en charge de l’obésité : quel est le niveau de formation des médecins généralistes du département de la Haute-Vienne et comment perçoivent-ils leur pratique ?

Introduction

Obesity is a public health problem affecting in France at least one person in seven over 15 years. General practitioners (GPs) play a major role in the management of this chronic disease, but little is known about their level of education and their modalities of care in front of obese patients. The main objectives of the study were to assess knowledge and practices on obesity of the GPs in a French department.

Methods

An anonymous declarative questionnaire was sent to a sample of 200 GPs of the Haute-Vienne department. The questionnaire noted epidemiological data on GPs, asked their level of education and knowledge on obesity, assessed their modalities of care, their difficulties facing this disease and their proposals for improvement.

Results

Exactly 40.5% of GPs gave answers. 19.5% of their patients were obese. 23.5% of GPs have been educated on nutrition. A percentage of 76.6 of GPs detected obesity with BMI at a threshold ≥ 30 kg/m². A percentage of 96.3% were involved in the care of their obese patients, and 70.0% in partnership with a specialist. Only 12.8% of GPs proposed an association between the three modalities of treatment: dietary intervention, higher physical activity and psychobehavioral care. Precisely, 27.7% of practitioners used medicaments and 21.0% protein diets. Bariatric surgery had already been used by 60.8% of GPs. Several difficulties noted were already known, but they particularly pointed out the lack of reimbursement for dietetic visit. The main suggestions were to improve networking, to promote a better education of patients and their families, to obtain a special coding for obesity visits and better psychobehavioral care.

Conclusions

The management of obese patients is an important part of GPs’ activity. Their care habits are broadly consistent with recommendations for the diagnosis of obesity and weight loss goals. However, few practitioners are trained in nutrition, resulting in a high use of specialists and a low proportion of GPs managing their patients in a full-recommended manner. One of the main suggestions of GPs is to work on obesity with a better-structured environment.     

Des réseaux « de nutrition » : pourquoi et comment ?

We hereby intend to clarify the notion of healthcare network in nutrition. Following a brief statement on the background of health and healthcare networks in France, we give a definition of healthcare networks in nutrition. Then we provide some information to answer to the following question: Why do such networks in the nutrition field exist and how to constitute and evaluate them? Although the theory and practice concerning healthcare networks can be surely applied in the nutrition field, the experiences are actually too sparse to provide a strong knowledge in this area. Healthcare networks are certainly a future strategy to take up the great challenges in Public Health (on the one hand, the malnutrition, and on the other hand, obesity and overweight disorders). The development of healthcare networks in nutrition should allow a successful improvement in the nutritional status of the population, as well as a major reorganisation in the clinical practice for nutritional and other disorders. Many efforts must be accomplished, and numerous obstacles must be overcome: definition of operational objectives, creation of adapted tools, development of reference frames, poor motivation of health and social professionals, evolution of medical practices, definition of methodologies for nutrition-specific evaluations (e.g. indicators), creation of flexible sources of income, adapted and enabling the perpetuation of healthcare networks. Healthcare networks in nutrition could help toward the development of real politic in nutrition in France, which was lacking until now. Besides the willing of politics and professionals in nutrition, it will be of primary importance to create a concerning healthcare networks in nutrition newly constituted in order to draw up a new assessment and realise adaptations.     

La privation de sommeil fait grossir : mythe ou réalité ?

Our current lifestyle leads to a gradual reduction in the time allocated to sleep. In France, one in three people is sleeping less than 7 hours a night. In parallel, the number of patients suffering from obesity increases. Numerous epidemiological studies emphasize the link between short sleep duration and weight gain. They highlight a number of factors that can influence this relationship including age, female gender or genetic factors. Experimental studies have also found that sleep deprivation altered feeding behaviour by increasing the feeling of hunger, food intake and plasma levels of ghrelin. The circadian cycle due to the alternation of light/darkness has a major influence on sleep but also on eating behaviour. Light acts on suprachiasmatic nuclei and then on preoptical as well as on lateral nuclei of the hypothalamus by increasing the secretion of orexins. Several theories have been advanced in order to explain the increase in food intake: the first, phylogenetic, would be linked to changes in sleep duration over the seasons; the second concerns anticipatory adaptation face to the awakening; the last to be related to the hedonic regulation of food intake. Many pathologies act by changing the sleep–eating behaviour relationship. Therefore, it is necessary to better understanding this relationship to prevent nutritional consequences by an optimal dietary management and by learning healthy lifestyle in children.     

Excès de cas humains et animaux de tularémie en France au cours de l’hiver 2007–2008 : émergence ou phénomène isolé ?

Context

Tularemia is a zoonosis affecting humans and hares in France. We describe the results of surveillance in both species, in 2007 and 2008.

Methods

Human tularemia cases are mandatorily notifiable in France since 2003. In hares, surveillance relies on volunteer hunter associations in all districts of the country. Data from mandatory reports and volunteer surveillance in 2007/2008 were analyzed and compared with previous results.

Results

In 2007/2008, 144 cases were reported in humans and 117 cases in hares. This was a 100% increase compared to previous years. Human cases differed from those of previous years only by the frequency of contact with breeding animals. Human cases without any documented risk exposure were also more frequent.

Conclusion

An increase of tularemia cases occurred in 2007/2008 in both species. Complementary studies are needed to identify the species reservoir in France to understand the causes of this peak of cases.