The wasting syndrome in AIDS: mechanisms and implications

Effect of early chemoprophylaxis with co-trimoxazole on nutritional status evolution in HIV-1-infected adults in Abidjan, Côte d'Ivoire

BACKGROUND

In sub-Saharan Africa, malnutrition is a major complication of HIV disease. Measuring accurately the nutritional benefits of a therapeutic intervention could be an easy-to-monitor secondary outcome.

METHODS

Anthropometric data were analysed from patients participating in a placebo-controlled trial of co-trimoxazole prophylaxis in adults recruited at early stages of HIV-1 infection in Côte d'Ivoire (COTRIMO-CI ANRS 059 trial). Body mass index (BMI), arm muscle circumference (AMC) and percentage of fat mass (FM) were measured at baseline and quarterly during the follow up. Percentage of variation from the baseline value was compared between treatment groups and within the groups using Student t-test.

RESULTS

An improvement of all anthropometric indicators was observed in the first 3 months of follow up in both treatment groups, significant in the co-trimoxazole group (P < or = 0.0006) but not in the placebo group (P > or = 0.06). In the co-trimoxazole group, this improvement was maintained for up to 24 months for BMI (P = 0.007), 21 months for AMC (P = 0.02) and only up to 12 months for FM (P = 0.04). The placebo group had a stable anthropometric status up to the end of the trial. Differences between treatment groups were significant for up to 15 months for BMI and AMC and 12 months for FM.

CONCLUSION

As co-trimoxazole prophylaxis is now recommended in Africa as part of a minimum package of care for HIV-infected symptomatic subjects, the short-term improvement of these anthropometric indicators in adults who start co-trimoxazole prophylaxis should be considered as an effective clinical outcome.

Association of severe insulin resistance with both loss of limb fat and elevated serum tumor necrosis factor receptor levels in HIV lipodystrophy

HIV-lipodystrophy (HIV-LD) is characterized by the loss of body fat from the limbs and face, an increase in truncal fat, insulin resistance, and hyperlipidemia, factors placing affected patients at increased risk for vascular disease. This study evaluated insulin sensitivity and inflammatory status associated with HIV-LD and provides suggestions about its etiology. Insulin sensitivity and immune activation markers were assessed in 12 control subjects and 2 HIV-positive groups, 14 without and 15 with LD syndrome. Peripheral insulin sensitivity (mostly skeletal muscle) was determined with the hyperinsulinemic-euglycemic clamp. Circulating insulin-like growth factor (IGF) binding protein-1 (IGFBP-1) and free fatty acid (FFA) levels, and their response to insulin infusion were indicative of insulin responsiveness of liver and adipose tissue, respectively. Serum levels of soluble type 2 tumor necrosis factor-alpha (TNF-alpha) receptor (sTNFR2) were used as an indicator of immune activation. HIV-LD study subjects had significantly reduced (twofold) peripheral insulin sensitivity, but normal levels of FFA and reduced levels of IGFBP-1, relative to the nonlipodystrophy groups, indicating that the loss of insulin sensitivity was more pronounced in skeletal muscle than in liver or fat. The significant loss of peripheral fat in the HIV-LD group (34%; p <.05) closely correlated with the reduced peripheral insulin sensitivity (p =. 0001). Levels of sTNFR2 were elevated in all HIV-infected study subjects, but they were significantly higher in those with lipodystrophy than without, and sTNFR2 levels strongly correlated with the reduction in insulin sensitivity (p =.0001). Loss of peripheral fat, normal levels of FFA, and reduced levels of IGFBP-1 indicate that insulin resistance in HIV-LD is distinct from type 2 diabetes and obesity. The relationship between the degree of insulin resistance and sTNFR2 levels suggests an inflammatory stimulus is contributing to the development of HIV-associated lipodystrophy.

Cytokine-driven inflammatory response is associated with the hypermetabolism of AIDS patients with opportunistic infections

BACKGROUND

To assess a possible role of systemic inflammation in the resting metabolic response in AIDS patients with active secondary infections.

METHODS

Fifty-two patients with AIDS-defined criteria and concomitant active infections and 19 healthy subjects were studied. Measurements were as follows: body composition assessed by bioelectrical impedance; resting energy expenditure (REE) by 30-minute indirect calorimetry; cytokine concentrations (IL-6, IFNalpha, TNFalpha, sTNF-R1) by ELISA; C-reactive protein (CRP), erythrocyte sedimentation rate, fibrinogen, and nutritional parameters by standard techniques.

RESULTS

REE adjusted for fat-free mass (REEFFM) was significantly increased in AIDS patients despite 39% of them not being hypermetabolic. The patients were undernourished and were found to have increased levels of acute-phase proteins and increased concentrations of IL-6 and sTNF-R1 relative to controls. REE parameters were positively related to CRP, ESR, ferritin, IL-6, and sTNF-R1 and negatively related to albumin, prealbumin, and transferrin. CRP was an independent predictor of REEFFM in AIDS patients and explained 25% of its variability. Patients with severe inflammation (CRP > or = 37 mg/dL) were significantly hypermetabolic with respect to patients without inflammation (CRP < 6 mg/dL) and had higher levels of IL-6 and sTNF-R1 and lower levels of albumin and prealbumin. Although no significant differences were observed with respect to the infection type, patients with tuberculosis and Pneumocystis carinii infections had higher resting metabolic and inflammatory responses, whereas patients with recurrent bacterial pneumonia were normometabolic and had lower levels of inflammatory markers.

CONCLUSIONS

Resting hypermetabolism observed in AIDS patients with concurrent active infections is related to the presence and severity of systemic cytokine-driven inflammatory response, which could reflect the type of secondary infection.