Publications

CONTEXT

HIV-infected patients on antiretroviral therapy are at increased risk for excess visceral adiposity and insulin resistance. Treatment with GH decreases visceral adiposity but worsens glucose metabolism. IGF-I, which mediates many of the effects of GH, improves insulin sensitivity in HIV-negative individuals.

OBJECTIVE

Our objective was to determine whether IGF-I, complexed to its major binding protein, IGF-binding protein-3 (IGFBP-3), improves glucose metabolism and alters body fat distribution in HIV-infected patients with abdominal obesity and insulin resistance.

METHODS

We conducted a pilot, open-label study in 13 HIV-infected men with excess abdominal adiposity and insulin resistance to assess the effect of 3 months of treatment with IGF-I/IGFBP-3 on glucose metabolism and fat distribution. Glucose metabolism was assessed by oral glucose tolerance test and hyperinsulinemic-euglycemic clamp. Endogenous glucose production (EGP), gluconeogenesis, whole-body lipolysis, and de novo lipogenesis (DNL) were measured with stable isotope infusions. Body composition was assessed by dual-energy x-ray absorptiometry and abdominal computed tomography scan.

RESULTS

Glucose tolerance improved and insulin-mediated glucose uptake increased significantly during treatment. EGP increased under fasting conditions, and suppression of EGP by insulin was blunted. Fasting triglycerides decreased significantly in association with a decrease in hepatic DNL. Lean body mass increased and total body fat decreased, whereas visceral adipose tissue did not change.

CONCLUSIONS

Treatment with IGF-I/IGFBP-3 improved whole-body glucose uptake and glucose tolerance, while increasing hepatic glucose production. Fasting triglycerides improved, reflecting decreased DNL, and visceral adiposity was unchanged.

BACKGROUND

Self-identified race or ethnic group is used to determine normal reference standards in the prediction of pulmonary function. We conducted a study to determine whether the genetically determined percentage of African ancestry is associated with lung function and whether its use could improve predictions of lung function among persons who identified themselves as African American.

METHODS

We assessed the ancestry of 777 participants self-identified as African American in the Coronary Artery Risk Development in Young Adults (CARDIA) study and evaluated the relation between pulmonary function and ancestry by means of linear regression. We performed similar analyses of data for two independent cohorts of subjects identifying themselves as African American: 813 participants in the Health, Aging, and Body Composition (HABC) study and 579 participants in the Cardiovascular Health Study (CHS). We compared the fit of two types of models to lung-function measurements: models based on the covariates used in standard prediction equations and models incorporating ancestry. We also evaluated the effect of the ancestry-based models on the classification of disease severity in two asthma-study populations.

RESULTS

African ancestry was inversely related to forced expiratory volume in 1 second (FEV(1)) and forced vital capacity in the CARDIA cohort. These relations were also seen in the HABC and CHS cohorts. In predicting lung function, the ancestry-based model fit the data better than standard models. Ancestry-based models resulted in the reclassification of asthma severity (based on the percentage of the predicted FEV(1)) in 4 to 5% of participants.

CONCLUSIONS

Current predictive equations, which rely on self-identified race alone, may misestimate lung function among subjects who identify themselves as African American. Incorporating ancestry into normative equations may improve lung-function estimates and more accurately categorize disease severity. (Funded by the National Institutes of Health and others.)

BACKGROUND

We investigated the safety and efficacy of GCSF therapy in a porcine model of ischemia-reperfusion with left ventricle ejection fraction of <45% using a clinically relevant dosing and timing regimen.

METHODS

MI was induced in pigs by a 90 min balloon occlusion of the left anterior descending coronary artery. Sixteen animals were randomized to either GCSF (IV bolus of 10 microg/kg at time of reperfusion, followed by SC injections of 5 microg/kg days 5-9 post-MI) or saline (control group). Inflammatory markers, bone marrow cell mobilization and LV function (echocardiography and pressure-volume measurements) were assessed at baseline, 1 and 6 weeks post-MI. Histopathology was performed 6 weeks post-MI.

RESULTS

GCSF therapy was associated with a significant increase in white blood cell counts. At week 6, GCSF therapy resulted in less deterioration of LVEF compared to control (38+/-2% vs. 33+/-2%, p<0.02) and improved wall motion score index (p<0.05). Histopathology revealed increased vascular density (p<0.05) and a trend toward increased areas of viable myocardium compared to control (p=0.058).

CONCLUSION

GCSF therapy prevents further deterioration of LV function in a porcine model of MI with lower EF (<45%). These results support future clinical trials with GCSF in selected patients with larger MI.