Circulating granulocyte-macrophage colony-stimulating factor and serum fatty acid composition in men and women

Atherosclerosis is increasingly recognized as an inflammatory disease. Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a proinflammatory cytokine, recently implicated as a prominent component of the regulatory network involved in atherogenesis. We aimed to study the relationship between circulating GM-CSF levels and serum fatty acid (FA) composition in 78 healthy subjects. The latter was analyzed by gas-liquid chromatography and GM-CSF by a high-sensitivity commercial enzyme-linked immunosorbent assay (ELISA). Among women (n = 40), serum GM-CSF levels were found to be positively associated with the proportion of palmitic acid (C16:0) and negatively with linoleic acid (C18:2omega-6), docosahexaenoic acid (DHA, C22:6omega-3), and the proportion of total essential FA. After excluding smoking women (n = 6), the associations among GM-CSF and serum linoleic acid concentration (r = -0.49, P =.003), arachidonic acid (r = -0.52, P =.001), and DHA (r = -0.34, P =.04) were strengthened. The ratio of palmitic to linoleic and DHA acids was the single best predictor of serum GM-CSF in all subjects. Together with arachidonic acid, it contributed to 22% of the GM-CSF variance in women, after taking into account the effects of age, body mass index (BMI), blood pressure, and smoking status. None of these associations were observed among men. In conclusion, serum FA composition is associated with circulating GM-CSF specifically in women. As human arterial and venous smooth muscle cells release GM-CSF, and treatment of endothelial cells with oxidized low-density lipoproteins results in a rapid expression of GM-CSF, the mechanisms involved in these associations and the sex-linked differences should be further explored.

The fat-free mass compartment influences serum leptin in men

OBJECTIVE

Recent experimental work in mice has demonstrated that leptin is synthesized by muscle cells. As this latter tissue is the main target for insulin-estimulated glucose disposal, we hypothesized that the muscular and fat-free mass (FFM) compartments might influence serum leptin levels in humans through increased insulin resistance.

DESIGN AND METHODS

We evaluated body composition (through bioelectric impedance and anthropometrical parameters), insulin resistance (using the fasting insulin resistance index (FIRI) and insulin sensitivity (S(I)) from the minimal model analysis) and leptin levels in 140 men and 114 women.

RESULTS

Serum insulin, FIRI and leptin levels were significantly increased in men in the highest quintile of FFM. Leptin levels positively correlated with FFM in men (r=0.24, P=0004) but not in women (r=0.02, P=not significant). With weight gain, however, approximately 25% of the additional weight is lean mass, so that obese people have higher fat-free mass than lean people. Hence, we performed a multiple linear regression analysis in a stepwise manner to predict leptin levels, in which fat mass (FM), FFM, and FIRI, but not age or waist-to-hip ratio (WHR) independently contributed to 32%, 6% and 3% of the variance in serum leptin levels in men. In women, FM (49%), FIRI (3.6%) and WHR (2.4%), but not FFM or age explained this variance. In a sample of 40 subjects, S(I) and leptin correlated with mid-arm muscle circumference (r=-0.51, P=0.03 and r=0.53, P=0.02) and mid-arm muscle area (r=-0.52, P=0.03 and r=0.53, P=0.02) in men (n=17) but not in women (n=23).

CONCLUSIONS

The fat-free mass compartment contributes to the variability of serum leptin levels in men. Whether insulin resistance at this level mediates an increased production of leptin merits further research.

Effect of malnutrition after acute stroke on clinical outcome

BACKGROUND AND PURPOSE

Malnutrition has received little attention in acute stroke, although it represents a risk of decreased immunity and nosocomial infections. Our objectives were to determine the prevalence of malnutrition after 1 week of hospitalization in acute stroke and to establish its relation to the stress response and neurological outcome.

METHODS

The study included 104 patients with an acute stroke of less than 24 hours' duration. Nutritional parameters (triceps skinfold thickness, midarm muscle circumference, serum albumin, and calorimetry) were evaluated at admission and after 1 week. Stress response (free urinary cortisol) was measured daily during the first week. Neurological deficit was evaluated by the Canadian Stroke Scale. Clinical outcome was estimated by the Barthel Index 1 month after the acute stroke. Patients received an oral standard diet or polymeric enteral nutrition when they had swallowing difficulties.

RESULTS

Protein-energy malnutrition was observed in 16.3% of patients at inclusion and in 26.4% after the first week, with a significant decrease in fat (P = .002) and visceral protein compartments (P = .049). Malnourished patients showed higher stress reaction and increased frequency of infections and bedsores in comparison with the appropriately nourished group. Multiple logistic regression analysis showed that malnutrition after 1 week (odds ratio, 3.5; 95% confidence interval, 1.2 to 10.2) and elevated free urinary cortisol (odds ratio, 3.3; confidence interval, 1.05 to 10.2) increased the risk of poor outcome (death or Barthel Index < or = 50 on the 30th day of follow-up) independently of age and nutritional status at admission.

CONCLUSIONS

Our findings suggest that protein-energy malnutrition after acute stroke is a risk factor for poor outcome. Early appropriate enteral caloric feeding did not prevent malnutrition during the first week of hospitalization.

Effect of total enteral nutrition on the short-term outcome of severely malnourished cirrhotics. A randomized controlled trial

Thirty-five severely malnourished cirrhotic patients were randomized to receive either enteral-tube feeding as the sole nutritional support (n = 16) or an isocaloric, isonitrogenous, low-sodium standard oral diet (n = 19). Both groups were homogeneous regarding age, sex distribution, etiology of liver cirrhosis, history of previous complications, clinical status, liver and renal function, modified Child's score, and nutritional status at admission. The enteral formula diet was energy dense, containing 40 mmol Na/day, whole protein plus branched-chain amino acids, medium- and long-chain triglycerides, and maltodextrin. It supplied 2115 kcal/day. The amount of vitamins and trace elements was at the upper limit of the recommended dietary allowances. The orally fed patients were encouraged to eat all meals served. Total enteral nutrition was well tolerated without major complications. Serum albumin and Child's score improved in the enterally fed patients but not in controls. Mortality rate while in the hospital was lower in patients on enteral feeding than in controls (12% vs 47%). These results show that total enteral nutrition is safe and effective in improving the short-term clinical outcome in severely malnourished cirrhotics.

Vitamin status in patients with inflammatory bowel disease

The status of water- and fat-soluble vitamins was prospectively evaluated in 23 patients (13 men, 10 women, mean age 33 +/- 3 yr) admitted to the hospital with acute or subacute attacks of inflammatory bowel disease. Protein-energy status was also assessed by means of simultaneous measurement of triceps skinfold thickness, mid-arm muscle circumference, and serum albumin. Fifteen patients (group A) had extensive acute colitis (ulcerative or Crohn's colitis), and eight cases (group B) had small bowel or ileocecal Crohn's disease. Eighty-nine healthy subjects (36 men, 53 women, mean age 34 +/- 2 yr) acted as controls. In both groups of patients, the levels of biotin, folate, beta-carotene, and vitamins A, C, and B1 were significantly lower than in controls (p less than 0.01). Plasma levels of vitamin B12 were decreased only in group B (p less than 0.01), whereas riboflavin was lower in group A (p less than 0.01). The percentage of patients at risk of developing hypovitaminosis was 40% or higher for vitamin A, beta-carotene, folate, biotin, vitamin C, and thiamin in both groups of patients. Although some subjects had extremely low vitamin values, in no case were clinical symptoms of vitamin deficiency observed. Only a weak correlation was found between protein-energy nutritional parameters and vitamin values, probably due to the small size of the sample studied. The pathophysiological and clinical implications of the suboptimal vitamin status observed in acute inflammatory bowel disease are unknown. Further studies on long-term vitamin status and clinical outcome in these patients are necessary.