Lack of an association between the presence of tumor necrosis factor or interleukin-1 alpha in the blood and weight loss among elderly patients

Tumor necrosis factor-alpha and involuntary weight loss in elderly, community-dwelling adults

STUDY OBJECTIVE

To evaluate the association between involuntary weight loss and serum concentrations of tumor necrosis factor (TNF)-alpha in elderly, community-dwelling adults.

DESIGN

Cross-sectional, single-time point investigation.

SETTING

Two primary care ambulatory clinics.

SUBJECTS

Ambulatory adults aged 70 years or older with involuntary weight loss of 2.27 kg (5 lbs) or more, or with stable weight (+/-0.91 kg [2 lbs]) for the 3 months before enrollment.

MEASUREMENTS AND MAIN RESULTS

Ten subjects with weight loss (mean+/-SD-4.9+/-2.6 kg) and 25 subjects with stable weight (+0.06+/-0.55 kg) were enrolled. The latter group was recruited to serve as a comparison group to the weight-loss group. Subjects donated a venous blood sample and were administered the Mini Nutritional Assessment at a single clinic visit. Serum concentrations of TNF-alpha were measured by using enzyme-linked immunosorbent assay. The TNF-alpha concentrations were significantly higher in subjects with weight loss (mean+/-SD 19.3+/-24.9 pg/ml) than in subjects with stable weight (mean+/-SD 1.1+/-2.0 pg/ml, p<0.01). No relationship was found between the TNF-alpha concentration and the degree of weight loss expressed as a percentage of total body weight.

CONCLUSION

Older adults with involuntary weight loss had increased circulating concentrations of TNF-alpha. Whether TNF-alpha plays a causal role in involuntary weight loss among older adults is unclear; however, this finding is consistent with those in other disease states associated with cachexia. Further research is necessary to clarify this relationship and to determine if pharmacotherapeutic interventions targeted at TNF-alpha can prevent or reverse involuntary weight loss and its associated morbidity and mortality.

Serum IL-1beta levels in health and disease: a population-based study. 'The InCHIANTI study'

Interleukin-1 plays a role in normal homeostasis and in the inflammatory response which is deemed to be responsible for the development of major chronic diseases that are highly prevalent in the elderly. Aim of this study is to evaluate the factors influencing the serum levels of Interleukin-1 beta, in a large and representative population. Data were from the InCHIANTI project, a study of factors contributing to the decline of mobility in late life, which sampled people living in two sites in the surroundings of Florence. Blood samples were obtained from 1,292 participants and frozen aliquots were stored at -80 degrees C. The serum levels of several cytokines were measured by enzyme linked immunosorbent assay using an ultrasensitive commercial kit. Interleukin-1 beta serum levels were associated with congestive heart failure (p > 0.001) and angina (p = 0.02), with Ca2+ serum levels (p = 0.02), and with a history of dyslipidemia (p = 0.05). We found no association between serum IL-1beta level and age, sex, consumption of cardioactive drugs and serum levels of IL-1Ra, IL-6, sIL-6R, IL-10 and TNF-alpha. Our data could lend support to the hypothesis that IL-1beta is mainly involved in the functional alterations of cardiomyocytes under conditions marked by mononuclear cell infiltration and by downregulation of calcium.

Ageing, tumour necrosis factor-alpha (TNF-alpha) and atherosclerosis

Ageing is associated with increased inflammatory activity in the blood. The purpose of this study was to investigate if age-related increased plasma levels of TNF-alpha were associated with atherosclerosis in a cohort of 130 humans aged 81 years. The elderly cohort had increased circulating levels of TNF-alpha, C-reactive protein (CRP), total cholesterol (TC), low-density lipoproteins (LDL) and a low high-density lipoprotein (HDL)/TC ratio compared with a young control group (n = 44). The elderly cohort was divided by tertiles into three subgroups with low, intermediate, and high levels of TNF-alpha, respectively. In the group with high TNF-alpha concentrations a significantly larger proportion had clinical diagnoses of atherosclerosis. Furthermore, weak correlations were found between TNF-alpha on one hand and blood concentrations of triglycerides, leucocytes, CRP and a low HDL/TC ratio on the other which are known as risk factors of atherogenesis and thromboembolic complications. No correlations were found between TNF-alpha, TC, LDL, or the body mass index. In conclusion, the present study shows that in a cohort of 81-year-old humans, high levels of TNF-alpha in the blood were associated with a high prevalence of atherosclerosis.

Exercise and the immune system--influence of nutrition and ageing

In essence, the immune system is enhanced during moderate and severe exercise, and only intense long-duration exercise is followed by impairment of the immune system. The latter includes suppressed concentration of lymphocytes, suppressed natural killer cell activity, lymphocyte proliferation and secretory IgA in saliva. During the time of immune impairment, referred to as "the open window", microbial agents, especially viruses may invade the host and infections may be established. One reason for the "overtraining effect" seen in elite athletes could be that this window of opportunism for pathogens is longer and the degree of immunosuppression more pronounced. Alterations in metabolism and metabolic factors may contribute to exercise-associated changes in immune function. Reductions in plasma-glutamine concentrations, altered plasma-glucose level, free oxygen radicals and prostaglandins (PG) released by the elevated number of neutrophils and monocytes may influence the function of lymphocytes and contribute to the impaired function of the later cells. Thus, nutritional supplementation with glutamine, carbohydrate, anti-oxidants or PG-inhibitors may, in principle, influence exercise-associated immune function. Although several intervention studies have been performed, it is premature to make recommendations regarding nutritional supplementation to avoid post-exercise impairment of the immune system.

Exercise and immune function: effect of ageing and nutrition

Strenuous exercise is followed by lymphopenia, neutrophilia, impaired natural immunity, decreased lymphocyte proliferative responses to mitogens, a low level of secretory immunoglobulin A in saliva, but high circulating levels of pro- and anti-inflammatory cytokines. These exercise-induced immune changes may provide the physiological basis of altered resistance to infections. The mechanisms underlying exercise-induced immune changes are multifactorial and include neuroendocrinological and metabolic mechanisms. Nutritional supplementation with glutamine abolishes the exercise-induced decline in plasma glutamine, but does not influence post-exercise immune impairment. However, carbohydrate loading diminishes most exercise effects of cytokines, lymphocyte and neutrophils. The diminished neutrophilia and elastase (EC 3.4.21.37) responses to eccentric exercise in elderly subjects were enhanced to levels comparable with those of young subjects by fish oil or vitamin E supplements. However, although vitamin C supplementation may diminish the risk of contracting an infection after strenuous exercise, it is not obvious that this effect is linked to an effect of vitamin C on exercise-induced immune changes. In conclusion, it is premature to make recommendations regarding nutritional supplementation to avoid post-exercise impairment of the immune system.

[Pathophysiology of catabolism in undernurished elderly patients]

Malnutrition is a common finding amongst our elders. The causes of malnutrition are multifactorial and although they have been extensively studied, they are not entirely understood. Both physiological and pathological processes of aging put this population at a higher risk of being undernourished. These may be related to social, financial, psychological and/or physiological changes directly or indirectly associated to growing old. Age associated changes increase the risk of malnutrition in older individuals. These alterations range from problems in taste and smell perception, which were previously thought to be the main cause of anorexia in this population, to alterations in either the concentration or efficacy of the previously mentioned feeding modulators. Increased intestinal malabsorption together with an altered pancreatic exocrine response to different diets, further contributing to subclinical malabsorption in the elderly population aged and may account in part for the malnutrition observed in this group. Although not directly caused by the aging process, several conditions such as anorexia nervosa, cancer, infectious conditions, and inflammatory processes are associated with decreased food intake and weight loss. These conditions present with elevated levels of immunoregulatory substances known as cytokines. Each of these cytokines has multiple effects and play a leading role in the pathophysiology and maintainance of malnutrition in these situations.

Detectable serum levels of tumor necrosis factor alpha may predict early mortality in elderly institutionalized patients

OBJECTIVE

To determine if detectable serum tumor necrosis factor alpha (TNF) levels are associated with higher mortality in nursing home residents.

SUBJECTS AND METHODS

The basal serum concentrations of TNF and interleukin-1 alpha (IL-1) were measured in 129 elderly nursing home patients (mean age of 89 years), and survival in the cohort was monitored over a 13-month period.

RESULTS

At 4 months follow-up, seven out of 33 patients with detectable serum TNF levels had died (21.2%), and only three out of 96 patients with undetectable serum TNF levels had died (3.1%) (P less than 0.001). The difference in mortality remained significant up to 13 months of follow-up (P less than 0.05). Those with detectable serum TNF levels and those with undetectable levels were comparable in age, body mass index, hematocrit, lymphocyte counts, and serum level of albumin, prealbumin, and retinol-binding protein. When patients with detectable serum IL-1 levels were compared to those with undetectable levels, there were no significant differences in mortality over a 13-month period.

CONCLUSION

Detectable serum TNF levels in elderly nursing home patients may be a predictor of early mortality.