c-peptide and HIV-Infections

In healthy, nondiabetic individuals with insulin resistance, fasting insulin is inversely correlated to the posthepatic insulin clearance rate (MCRi) and the hepatic insulin extraction (HEXi). We investigated whether similar early mechanisms to facilitate glucose homeostasis exist in nondiabetic, human immunodeficiency virus (HIV)-infected patients with and without lipodystrophy. We studied 18 HIV-infected patients with lipodystrophy (LIPO) on antiretroviral therapy and 25 HIV-infected patients without lipodystrophy (controls) of whom 18 were on antiretroviral therapy and 7 were not. Posthepatic insulin clearance rate was estimated as the ratio of posthepatic insulin appearance rate to steady-state plasma insulin concentration during a euglycemic hyperinsulinemic clamp (40 mU.m-2 .min-1). Posthepatic insulin appearance rate during the clamp was calculated, taking into account the remnant endogenous insulin secretion, which was estimated by deconvolution of C-peptide concentrations. Hepatic extraction of insulin was calculated as 1 minus the ratio of fasting posthepatic insulin delivery rate to fasting endogenous insulin secretion rate. Compared with controls, LIPO displayed increased fasting insulin (130%, P < .001), impaired insulin sensitivity index (M value, -29%, P < .001), and reduced MCRi (-17%, P < .01). Hepatic extraction of insulin was similar between groups (LIPO, 55%; controls, 57%; P > .8). In LIPO, HEXi and MCRi correlated inversely with fasting insulin (r = -0.56, P < .02 and r = -0.68, P < .002) and positively with M value (r = 0.63, P < .01 and r = 0.65, P < .004). In controls, MCRi correlated inversely with fasting insulin (r = -0.47, P < .02) and positively with M value (r = 0.57, P < .004); however, the correlations between HEXi and these parameters were insignificant (P > .1). Our data suggest that HEXi and MCRi are decreased in proportion to the degree of insulin resistance in nondiabetic HIV-infected patients with lipodystrophy.

Topics: Adipose Tissue; Adult; Algorithms; Antiretroviral Therapy, Highly Active; Body Composition; C-Peptide; Fatty Acids, Nonesterified; Female; Glucose Clamp Technique; HIV Infections; Humans; Insulin; Insulin Resistance; Kinetics; Lipodystrophy; Liver; Male

We examined whether plasma concentrations of nonglucose insulin secretagogues are associated with prehepatic insulin secretion rates (ISR) in nondiabetic, insulin-resistant, human immunodeficiency virus (HIV)-infected, lipodystrophic patients (LIPO). Additionally, the negative feedback of insulin on ISR was evaluated. ISR were estimated by deconvolution of plasma C-peptide concentrations during fasting (basal) and during the last 30 min of a 120-min euglycemic insulin clamp (40 mU.m(-2).min(-1)). Eighteen normoglycemic LIPO were compared with 25 normoglycemic HIV-infected patients without lipodystrophy (controls). Thirty minutes before start of the clamp, a bolus of glucose was injected intravenously to stimulate endogenous insulin secretion. Insulin sensitivity index (SiRd) was estimated from glucose tracer analysis. LIPO displayed increased basal ISR (69%), clamp ISR (114%), basal insulin (130%), and clamp insulin (32%), all P < or = 0.001, whereas SiRd was decreased (57%, P < 0.001). In LIPO, ISRbasal correlated significantly with basal insulin, alanine, and glucagon (all r > 0.65, P < 0.01), but not with glucose. In control subjects, ISR(basal) correlated significantly with insulin, glucagon, and glucose (all r > 0.41, P < 0.05), but not with alanine. In LIPO, ISRclamp correlated significantly with clamp free fatty acids (FFA), alanine, triglyceride, and glucagon (all r > 0.51, P < 0.05). In control subjects, ISRclamp correlated with clamp triglyceride (r = 0.45, P < 0.05). Paradoxically, in LIPO, ISRclamp correlated positively with clamp insulin (r = 0.68, P < 0.01), which suggests an absent negative feedback of insulin on ISR. Our data support evidence that lipodystrophic, nondiabetic, HIV-infected patients exhibit increased ISR, which can be partially explained by an impaired negative feedback of insulin on beta-cells and an increased stimulation of ISR by FFA, alanine, triglyceride, and glucagon.

Topics: Adipose Tissue; Adult; Alanine; Anthropometry; Blood Glucose; Body Composition; Body Mass Index; C-Peptide; Feedback; Glucagon; HIV Infections; HIV-Associated Lipodystrophy Syndrome; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Male; Middle Aged; Triglycerides

In spite of indisputable benefits, the use of antiretroviral therapy is associated with multiple metabolic complications. Switching to simpler regimens might maintain viral suppression, improve metabolic side effects, and provide insight into the pathogenesis of these complications. Our objective was to carefully characterize the virological and metabolic effects of switching from a successful protease inhibitor (PI)-based antiretroviral regimen to a nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen with nevirapine (NVP). Forty patients, taking their first successful (less than 40 HIV RNA copies/ml) PI-based regimen, switched their PI to NVP. If patients did not tolerate NVP, substitution with efavirenz was allowed. The duration of the study was 48 weeks. At 12 weeks intervals subjects had multiple virological and metabolic parameters including glucose, insulin, C-peptide, glucagon, proinsulin, blood lipids, and lipoproteins. A subgroup of 18 patients also had body composition evaluations with DEXA scans and MRIs of the abdomen and the thighs as well as insulin tolerance tests. Ninety-five percent of the patients maintained viral suppression (95% CI 88-100%); only one patient failed and another developed hepatitis. There were improvements in glucose (decreased fasting glucose, insulin, and improved insulin tolerance) and lipid metabolism (decreased triglycerides and increased HDL), but no changes in body composition and bone mineral density. Our study supports a pathogenic role for PIs in the development of hypertriglyceridemia and insulin resistance, but a more limited role in the fat redistribution syndrome.

Topics: Alkynes; Anti-HIV Agents; Benzoxazines; Blood Glucose; Body Composition; Bone Density; C-Peptide; Cyclopropanes; Drug Therapy, Combination; Female; Glucagon; HIV; HIV Infections; HIV Protease Inhibitors; Humans; Insulin; Insulin Resistance; Lipids; Lipoproteins; Male; Nevirapine; Oxazines; Pilot Projects; RNA, Viral; Viral Load

Intravenous pentamidine induces hypo- and hyperglycaemia (dose-dependent toxicity on islet beta cells), pancreatitis and nephrotoxicity. Conversely, aerosolized pentamidine (AP) is usually devoid of systemic side-effects: few reports of hypo- or hyperglycaemia have been published. Our study aimed to assess the influence on glucose homeostasis and insulin secretion of long-term exposure to AP used for prophylaxis of Pneumocystis carinii pneumonia in HIV-positive patients, and to compare the impact on insulin secretion of AP, whether administered for the first time or after prolonged monthly exposure.. Retrospective cross-sectional controlled study (main objective) and non-randomized prospective controlled study.. We compared glucose homeostasis and C peptide response to 1 mg intravenous glucagon in patients who had previously inhaled > or = 10 prophylactic aerosols (group 1, n = 21) and in HIV-positive controls (groups 2 and 3, n = 28) who had received none. Both groups were comparable for age and body-mass index, but CD4 T-lymphocyte counts and Karnofsky scores were both significantly higher in the control group.. Fasting (T0) blood glucose, fructosamine and response to the first glucagon test were similar in both groups, but postprandial glucose, glycated haemoglobin and fasting C peptide were significantly higher (P < 0.05) in the pentamidine group. A second glucagon test was performed on the same day, 3 h (T3) after AP inhalation in 35 patients (in 21 after > or = 10 aerosols, group 1; in 14 after the first, group 2) and in 14 HIV-positive controls (group 3). The only significant difference between the three groups in C peptide response to this second test was a lower peak T3/peak T0 ratio in group 1. Plasma amylase and creatinine were not altered by the aerosol.. Long-term prophylactic exposure to AP had minor but significant effects on glucose homeostasis and insulin secretion but did not modify pancreatic and renal function. The detrimental effects induced by long-term exposure to AP found in our study are probably not clinically relevant, but a more prolonged exposure to AP might conceivably induce more severe alterations.

Topics: Administration, Inhalation; Adult; Aerosols; AIDS-Related Opportunistic Infections; C-Peptide; Cross-Sectional Studies; Female; Glucose; HIV Infections; Homeostasis; Humans; Insulin; Insulin Secretion; Islets of Langerhans; Male; Pentamidine; Pneumonia, Pneumocystis; Prospective Studies; Retrospective Studies; Time Factors

Early-life metabolic derangements in HIV-exposed uninfected (HEU) infants have been reported.. Pregnant women with HIV and HIV-uninfected pregnant women were enrolled with their newborns in a US cohort from 2011 to 2015. We measured cord insulin, C-peptide, and metabolic cytokines of HEU and HIV-unexposed uninfected (HUU) newborns using ELISA and metabolites, lipid subspecies, and eicosanoids via liquid chromatography/mass spectrometry. Linear regression was employed to assess the association of intrauterine HIV/ART with insulin and C-peptide. Graphical lasso regression was used to identify differences between metabolite/lipid subspecies networks associated with C-peptide.. Of 118 infants, 56 were HEU, ART exposed. In adjusted analyses, mean cord insulin (β = 0.295, p = 0.03) and C-peptide (β = 0.522, p < 0.01) were significantly higher in HEU vs. HUU newborns. HEU neonates exhibited primarily positive associations between complex lipids and C-peptide, indicative of fuel storage, and augmented associations between cord eicosanoids and cytokines. HUU neonates exhibited negative associations with lipids and C-peptide indicative of increased fuel utilization.. Higher cord insulin and C-peptide in HEU vs. HUU newborns as well as differences in cord metabolites, metabolic-related cytokines, and eicosanoids may reflect a propensity for fuel storage and an inflammatory milieu suggestive of fetal metabolic changes associated with in utero HIV/ART exposure.. There is a paucity of studies assessing cord blood and neonatal metabolic health in HIV-exposed uninfected (HEU) newborns, an increasing population worldwide. Compared to HIV-unexposed uninfected (HUU) newborns, HEU newborns exhibit alterations in fuel homeostasis and an inflammatory milieu associated with in utero HIV/antiretroviral therapy (ART) exposure. The long-term implications of these neonatal findings are as yet unknown, but merit continued evaluation as this important and growing population ages into adulthood.

Topics: Adipokines; Adult; Anti-Retroviral Agents; C-Peptide; Cytokines; Female; Fetal Blood; HIV Infections; Humans; Infant; Infant, Newborn; Lipidomics; Lipids; Pregnancy; Pregnancy Complications, Infectious

To determine the association of insulin sensitivity and metabolic status with declining cognition in HIV-infected individuals.. We conducted targeted clinical and metabolic measures in longitudinal plasma samples obtained from HIV-infected patients enrolled in the Central Nervous System HIV Anti-Retroviral Therapy Effects Research Study (CHARTER). Findings were validated with plasma samples from the Multicenter AIDS Cohort Study (MACS). Patients were grouped according to longitudinally and serially assessed cognitive performance as having stably normal or declining cognition.. Patients with declining cognition exhibited baseline hyperinsulinemia and elevated plasma c-peptide levels with normal c-peptide/insulin ratios, suggesting that insulin production was increased, but insulin clearance was normal. The association of hyperinsulinemia with worsening cognition was further supported by low high-density lipoprotein (HDL), high low-density lipoprotein/HDL ratio, and elevated cholesterol/HDL ratio compared to patients with stably normal cognition.. These findings suggest that hyperinsulinemia and impaired insulin sensitivity are associated with cognitive decline in antiretroviral therapy-treated HIV-infected patients.

Topics: Adult; Anti-HIV Agents; C-Peptide; Case-Control Studies; Cognition; Cognitive Dysfunction; Cohort Studies; Female; HIV Infections; Humans; Hyperinsulinism; Insulin Resistance; Lipoproteins; Male; Middle Aged

HIV infection has been associated with increased diabetes risk, but prior work has mostly focused on insulin resistance, as opposed to beta cell effects, or included patients on antiretroviral therapies (ART) directly linked to metabolic toxicity. In this analysis, we measured markers of glucose homeostasis and beta cell function, stress, and death in fasting sera from a cross section of HIV+ individuals off ART (n = 43), HIV+ individuals on ART (n = 23), and HIV- controls (n = 39). Markers included glucose, HOMA%S, HOMA%B, proinsulin:C-peptide ratio (PI:C ratio), and circulating preproinsulin (INS) DNA. We performed multiple linear regressions with adjustments for age, sex, race, BMI, and smoking status. Compared to HIV- controls, HIV+ participants off ART exhibited similar beta cell function and insulin sensitivity, without increases in markers of beta cell stress or death. Specifically, in HIV+ participants with CD4 counts <350 cells/μL, PI:C ratios were lower than in HIV- controls (p<0.01), suggesting a reduction in intrinsic beta cell stress among this group. By contrast, HIV+ participants on ART had higher fasting glucose (p<0.0001) and lower HOMA%B (p<0.001) compared to HIV- controls. Among the entire HIV+ population, higher HIV RNA correlated with lower fasting glucose (r = -0.57, p<0.001), higher HOMA%B (r = 0.40, p = 0.001), and lower PI:C ratios (r = -0.42, p<0.001), whereas higher CD4 counts correlated with higher PI:C ratios (r = 0.2, p = 0.00499). Our results suggest that HIV seropositivity in the absence of ART does not worsen beta cell function or glucose homeostasis, but immune reconstitution with ART may be associated with worsened beta cell function.

Topics: Adult; Age Factors; Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Biomarkers; Blood Glucose; Body Mass Index; C-Peptide; Case-Control Studies; CD4 Lymphocyte Count; Cell-Free Nucleic Acids; Fasting; Female; HIV Infections; Humans; Immune Reconstitution; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Proinsulin; Protein Precursors; Sex Factors; Smoking

Gene therapeutic strategies for human immunodeficiency virus type 1 (HIV-1) infection could potentially overcome the limitations of standard antiretroviral drug therapy (ART). However, in none of the clinical gene therapy trials published to date, therapeutic levels of genetic protection have been achieved in the target cell population for HIV-1. To improve systemic antiviral efficacy, C peptides, which are efficient inhibitors of HIV-1 entry, were engineered for high-level secretion by genetically modified cells. The size restrictions for efficient peptide export through the secretory pathway were overcome by expressing the C peptides as concatemers, which were processed into monomers by furin protease cleavage. These secreted antiviral entry inhibitory (SAVE) peptides mediated a substantial protective bystander effect on neighboring nonmodified cells, thus suppressing virus replication even if only a small fraction of cells was genetically modified. Accordingly, these SAVE peptides may provide a strong benefit to AIDS patients in future, and, if applied by direct in vivo gene delivery, could present an effective alternative to antiretroviral drug regimen.

Topics: Blotting, Western; C-Peptide; Cell Line; Flow Cytometry; Gammaretrovirus; Genetic Therapy; HIV Infections; Humans; Immunoprecipitation; Peptides; Transduction, Genetic

The C-peptides used to prevent HIV infection, such as T20 and C34, are chemically synthesized, making them costly drugs. The sensitivity of peptides to protease also restricts their clinical application. We showed previously that C52L, a recombinant peptide produced in bacteria, is a potent anti-HIV C-peptide, although most of the peptide accumulates in inclusion bodies. Here we applied leucine and glutamine scanning mutagenesis to the heptad-repeat of C52L to produce an optimized variant of C52L that is potent and soluble when expressed in bacteria. We present that the substitution of Asn656 and Glu659 with leucine (peptide L14 and L15, respectively) can increase the helical content of this peptide. These substitutions also result in soluble expression. We measured the inhibitory activities of these mutant peptides against laboratory-adapted HIV-1 strains and found that L15 and its parental peptide C52L have equivalent anti-HIV activities. Moreover, L15 was found to be more stable to proteinase K digestion than C52L. Thus, we show that the L15 peptide can be expressed in a soluble state and exhibits potent anti-HIV activity. This peptide may be further developed as an anti-HIV therapeutic and/or microbicide for the prevention of HIV sexual transmission.

Topics: Amino Acid Sequence; Amino Acid Substitution; C-Peptide; Escherichia coli; Gene Expression; HIV Fusion Inhibitors; HIV Infections; HIV-1; Humans; Leucine; Molecular Sequence Data; Protein Structure, Secondary; Recombinant Proteins; Solubility

Cell membrane-anchored (ma) antiviral peptides derived from the C-terminal heptad repeat of the HIV-1 transmembrane glycoprotein gp41 (C-peptides) and expressed from retroviral vectors were shown to efficiently inhibit HIV-1 entry into target cells. Here, we analyzed the influence of the vector backbone, the scaffold modules that anchor the peptide to the membrane and the length of the C-peptide on expression level and antiviral activity. In general, antiviral activity was determined primarily by the density of the C-peptide on the cell surface. By influencing expression levels, the scaffold elements indirectly also determined antiviral activity. Additional direct effects of the scaffold on antiviral activity were minor. At comparable expression levels, the elongated C-peptide (maC46) was found to be more potent than the shorter maC36. On the basis of these findings, a dose-response assay was established that quantifies antiviral activity relative to the expression level of the antiviral gene product. Taken together, these data demonstrate the importance of analyzing the efficacy of therapeutic genes relative to the dose of the gene product.

Topics: Amino Acid Sequence; Antiviral Agents; C-Peptide; Cell Line; Cell Membrane; Dose-Response Relationship, Drug; Genetic Vectors; HIV Infections; Humans; Molecular Sequence Data; Proteins; Retroviridae; Transgenes; Virus Internalization

Low-dose growth hormone (GH) administration has been suggested as a treatment for HIV-lipodystrophy.. Postglucose GH-secretion, kinetics of insulin-like growth factors (IGFs), insulin, and glucose metabolism were examined in six male HIV-infected lipodystrophic patients (two normal-weight patients with normal glucose-tolerance (NGT), two normal-weight with impaired glucose-tolerance (IGT), and two obese patients with diabetes (DM)) during a 16 weeks open-labelled pilot-study of low-dose GH, 0.7 mg/day.. DM, compared to NGT and IGT, displayed an impaired rebound of GH during a 5h oral glucose-tolerance test. Near lower normal limits in all patients before GH-therapy, total and free IGF-I increased between 87 and 152% during the GH-therapy (P<0.001), approaching upper normal limits in all patients with the highest incremental percentages shown in DM. A slight and temporary reduction in insulin sensitivity was caused by a reduction in non-oxidative glucose metabolism (n=5). GH-administration reduced hepatic extraction of insulin alleviating the demand for insulin secretion (n=5). No adverse effects of GH were detected.. As judged from effects on circulating IGF-I, glucose metabolism, and insulin kinetics, 0.7 mg/day of GH may be expedient for treatment of HIV-infected males with lipodystrophy. Whether the patients' glucose metabolic status matters for the IGF-response to low-dose GH-therapy awaits further investigation.

Topics: Antiretroviral Therapy, Highly Active; C-Peptide; Fatty Acids, Nonesterified; Glucose; Glucose Tolerance Test; Growth Hormone; HIV Infections; HIV-Associated Lipodystrophy Syndrome; Humans; Insulin; Insulin Secretion; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Male; Middle Aged; Oxidation-Reduction; Time Factors

Highly active antiretroviral therapy has been associated with lipodystrophy in adults. Much is unknown about its characteristics, especially in children.. To obtain an objective case definition of the lipodystrophy syndrome.. This was a cross-sectional study. One investigator rated clinical lipodystrophy. Body composition was measured using body mass index, skin fold thickness and circumference of arm, leg, waist and hip. Samples for human immunodeficiency virus (HIV)-1 RNA, CD4 cell count, fasting lipids and glucose variables were drawn. HIV-infected children with lipodystrophy were compared with HIV-infected children without lipodystrophy (controls).. Thirty-four children were included: 28 controls, 2 nonassigned, and 4 with the lipoatrophic phenotype. Lipohypertrophy or mixed syndrome were not observed. All children with lipoatrophy were pubertal; they had used stavudine and didanosine longer. Children with lipoatrophy had significantly smaller arm and leg circumference, and their skin folds were thinner. The torso-to-arm ratio was 3 times higher in lipoatrophic children, but the difference did not reach significance. The waist-to-hip ratio was higher (P = 0.005). None of the laboratory values differed significantly between the two groups, but all children with lipoatrophy had an increased C-peptide level above the upper limit of normal. All children with lipoatrophy could be distinguised from controls by an increased C-peptide level, a waist-to-hip ratio z score of 1 standard deviation or higher and a sum of skin folds z score below -1 standard deviation.. All children with lipoatrophy can be distinguished by using anthropometric measurements and C-peptide measurement in serum. This method is simple, readily available and inexpensive.

Topics: Adolescent; Anthropometry; Antiretroviral Therapy, Highly Active; Body Composition; C-Peptide; Child; Child, Preschool; Female; HIV Infections; HIV-Associated Lipodystrophy Syndrome; Humans; Infant; Male

We aimed to investigate whether the insulin precursors, intact (IP) and 32-33 split proinsulin (SP), which are elevated in states of insulin resistance and predict type 2 diabetes, would be elevated in human immunodeficiency virus (HIV)-infected patients with lipodystrophy (LIPO).. Forty-three normoglycaemic HIV-infected patients [18 LIPO and 18 without lipodystrophy (NONLIPO) receiving antiretroviral drugs, and seven patients naïve to antiretroviral drugs (NAIVE)] were examined. Insulin precursors were measured during fasting, during an intravenous glucose tolerance test and during a hyperinsulinaemic-euglycaemic clamp, respectively. Insulin secretion rates (ISR) were determined by deconvolution of C-peptide concentrations. Disposition index (DI) was calculated as insulin sensitivity (Si(RD)) multiplied by the first-phase insulin response to intravenous glucose.. LIPO exhibited increased fasting IP and SP (P < 0.05), a higher proportion of elevated fasting IP (3.1 pmol L(-1), 66% vs. 33% and 28%, P < 0.05) and SP (7.2 pmol L(-1), 50%, 11% and 0%, P < 0.01), reduced Si(RD) (> 50%, P < 0.001) and increased ISR (P < 0.001) compared with NONLIPO and NAIVE. Fasting SP and IP correlated positively with ISR (P < 0.001) and inversely and hyperbolically with Si(RD) (P < 0.001). Fasting SP/insulin ratio correlated inversely with Si(RD) (P < 0.05). Incremental IP + SP/insulin ratio after an intravenous glucose bolus correlated inversely with DI (P < 0.01), but did not differ between study groups.. Proinsulin appeared to be increased in HIV-lipodystrophy, but no more than caused by the increased ISR. Nevertheless, the inverse correlations between SP/insulin ratio versus Si(RD) and incremental total proinsulin/insulin ratio versus DI may argue for a subtle beta-cell dysfunction in those patients with insulin resistance and low DI.

Topics: Adult; Antiretroviral Therapy, Highly Active; Blood Glucose; Body Composition; C-Peptide; Fasting; Glucose Tolerance Test; HIV Infections; HIV-1; HIV-Associated Lipodystrophy Syndrome; Humans; Hyperlipidemias; Insulin; Insulin Resistance; Male; Middle Aged; Proinsulin

We investigated whether the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), which are major regulators of glucose tolerance through the stimulation of insulin secretion, contribute to impaired glucose tolerance (IGT) among HIV-infected patients on highly active antiretroviral therapy (HAART).. Eighteen HIV-infected male patients (six lipodystrophic and 12 nonlipodystrophic) with normal glucose tolerance (NGT) were compared with 10 HIV-infected male patients (eight lipodystrophic and two nonlipodystrophic) with IGT. Plasma concentrations of GLP-1 and GIP were determined frequently during a 3-h, 75-g glucose tolerance test. Insulin secretion rates (ISRs) were calculated by deconvolution of C-peptide concentrations.. The incremental area under the curve (incrAUC) for GLP-1 was increased by 250% in IGT patients compared with NGT patients (1455+/-422 vs. 409+/-254 pmol/L/180 min, respectively; P<0.05), whereas the incrAUC for GIP did not differ between the study groups (7689+/-1097 vs. 8041+/-998 pmol/L/180 min, respectively; not significant). In pooled study groups, the GIP incrAUC correlated positively with the ISR incrAUC without adjustment (r=0.38, P<0.05) and following adjustment for glucose incrAUC (r=0.49, P<0.01).. Our data suggest: (1) that glucose-intolerant, HIV-infected male patients may display enhanced GLP-1 responses to oral glucose compared with normal glucose-tolerant HIV-infected male patients, which may represent a compensatory mechanism rather than explain the IGT; (2) that the GIP response may be associated with ISR independently of plasma glucose in nondiabetic HIV-infected males on HAART.

Topics: Adult; Analysis of Variance; Antiretroviral Therapy, Highly Active; Antiviral Agents; Area Under Curve; Blood Glucose; Body Composition; C-Peptide; Gastric Inhibitory Polypeptide; Glucagon; Glucagon-Like Peptide 1; Glucose; Glucose Intolerance; Glucose Tolerance Test; HIV Infections; HIV-Associated Lipodystrophy Syndrome; Humans; Male; Peptide Fragments; Protein Precursors

The pancreatic endocrine system normally guarantees a quick and efficient response to daily metabolic perturbations, but associated data for human immunodeficiency virus (HIV)-infected patients are lacking. A prospective study was performed to evaluate pancreatic endocrine secretion and its possible association with failure to thrive among HIV-infected children.. Fourteen well-nourished, prepubertal, HIV-infected children (6 boys and 8 girls; age range, 5-11 years), none of whom were receiving protease inhibitors, and 16 clinically healthy sex- and age-matched children formed the patient group and the control group, respectively. At yearly follow-up examinations, insulin, glucagon, C-peptide, and glucose levels were measured; the ratio of insulin to glucose, the ratio of insulin to glucagon, and the homeostasis model assessment (HOMA) index were calculated; the glucagon test was administered; and growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, cortisol, and lipid patterns were evaluated.. Insulin, glucagon, C-peptide, glucose, and HOMA measurements were significantly higher among patients, compared with control subjects, at all 3 follow-ups performed to date. The glucagon test revealed a normal glycemic response in all the healthy control subjects and a significantly impaired response in 11 patients. A significant correlation emerged between the ratio of insulin to glucagon and the growth velocity of HIV-infected children.. To our knowledge, the present study provides the first evidence of altered pancreatic endocrine secretion and its association with growth failure among HIV-infected children.

Topics: Blood Glucose; C-Peptide; Child; Female; Glucagon; Growth Disorders; HIV Infections; Homeostasis; Hormones; Humans; Insulin; Lipids; Male; Pancreas; Prospective Studies

Human immunodeficiency virus (HIV)-lipodystrophy is associated with impaired growth hormone (GH) secretion. It remains to be elucidated whether insulin-like growth factors (IGFs), IGF-binding proteins (IGFBPs), IGFBP-3 protease, and GH-binding protein (GHBP) are abnormal in HIV-lipodystrophy. These parameters were measured in overnight fasting serum samples from 16 Caucasian males with HIV-lipodystrophy (LIPO) and 15 Caucasian HIV-infected males without lipodystrophy (NONLIPO) matched for age, weight, duration of HIV infection, and antiretroviral therapy. In LIPO, abdominal fat mass and insulin concentration were increased (>90%, P < .01) and insulin sensitivity (Log10ISI(composite)) was decreased (-50%, P < .001). Total and free IGF-I, IGF-II, IGFBP-3, and IGFBP-3 protease were similar between groups (all P > .5), whereas, in LIPO, IGFBP-1 and IGFBP-2 were reduced (-36%, P < .05 and -50%, P < .01). In pooled groups, total IGF-I, free IGF-I, total IGF-II, and IGFBP-3, respectively, correlated inversely with age (all P < .01). In pooled groups, IGFBP-1 and IGFBP-2 correlated positively with insulin sensitivity (age-adjusted all P < .05). IGFBP-3 protease correlated with free IGF-I in pooled groups (r(p) = 0.47, P < .02), and in LIPO (r(p) = 0.71, P < .007) controlling for age, total IGF-I, and IGFBP-3. GHBP was increased, whereas GH was decreased in LIPO (all P < .05). GH correlated inversely with GHBP in pooled groups (P < .05). Taken together the similar IGFs and IGFBP-3 concentrations between study groups, including suppressed GH, and increased GHBP in LIPO, argue against GH resistance of GH-sensitive tissues in LIPO compared with NONLIPO; however, this notion awaits examination in dose-response studies. Furthermore, our data suggest that IGFBP-3 protease is a significant regulator of bioactive IGF-I in HIV-lipodystrophy.

Topics: Age Factors; Blood Glucose; Body Composition; Body Constitution; Body Mass Index; C-Peptide; Carrier Proteins; Endopeptidases; HIV Infections; Humans; Insulin; Insulin-Like Growth Factor Binding Proteins; Linear Models; Lipodystrophy; Male; Middle Aged; Somatomedins

The mechanisms responsible for the deterioration in glucose tolerance associated with protease inhibitor-containing regimens in HIV infection are unclear. Insulin resistance has been implicated as a major factor, but the affected tissues have not been identified. Furthermore, beta-cell function has not been evaluated in detail. The present study was therefore undertaken to assess the effects of protease inhibitor-containing regimens on hepatic, muscle, and adipose tissue insulin sensitivity as well as pancreatic beta-cell function. We evaluated beta-cell function in addition to glucose production, glucose disposal, and free fatty acid (FFA) turnover using the hyperglycemic clamp technique in combination with isotopic measurements in 13 HIV-infected patients before and after 12 weeks of treatment and in 14 normal healthy volunteers. beta-Cell function and insulin sensitivity were also assessed by homeostasis model assessment (HOMA). Treatment increased fasting plasma glucose concentrations in all subjects (P < 0.001). Insulin sensitivity as assessed by HOMA and clamp experiments decreased by approximately 50% (P < 0.003). Postabsorptive glucose production was appropriately suppressed for the prevailing hyperinsulinemia, whereas glucose clearance was reduced (P < 0.001). beta-Cell function decreased by approximately 50% (P = 0.002), as assessed by HOMA, and first-phase insulin release decreased by approximately 25%, as assessed by clamp data (P = 0.002). Plasma FFA turnover and clearance both increased significantly (P < 0.001). No differences at baseline or in responses after treatment were observed between drug naïve patients who were started on a nucleoside reverse transcriptase inhibitor (NRTI) plus a protease inhibitor and patients who had been on long-term NRTI treatment and had a protease inhibitor added. The present study indicates that protease inhibitor-containing regimens impair glucose tolerance in HIV-infected patients by two mechanisms: 1) inducement of peripheral insulin resistance in skeletal muscle and adipose tissue and 2) impairment of the ability of the beta-cell to compensate.

Topics: Adipose Tissue; Adult; Blood Glucose; Body Composition; Body Constitution; C-Peptide; CD4 Lymphocyte Count; Fatty Acids, Nonesterified; Female; Glucagon; Glucose Clamp Technique; Glucose Intolerance; Glycated Hemoglobin; Glycerol; HIV Infections; HIV Protease Inhibitors; Homeostasis; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Lipids; Liver; Male; Middle Aged; Muscle, Skeletal; Proinsulin; Viral Load

To determine the extent and degree of abnormalities of serum lipids, glucose homeostasis and abdominal adipose tissue distribution in protease inhibitor (PI)-treated and PI-naive HIV-infected children.. A cross-sectional study involving HIV-infected children, 3-18 years of age, in a paediatric tertiary care centre.. Total, HDL and LDL-cholesterol, triglycerides, glucose, insulin, proinsulin and C-peptide were determined in the fasting state. Insulin resistance was assessed using the homeostatic model assessment-insulin resistance (HOMA-IR). Abdominal adipose tissue distribution was determined by single-slice computed tomography at the umbilical level.. Thirty PI-treated and 20 PI-naive children were evaluated (76% prepubertal). PI-treated children had significantly higher total cholesterol (P = 0.0021), LDL-cholesterol (P = 0.019) and triglycerides (P = 0.0018). Serum glucose, insulin, proinsulin and C-peptide, the insulin : glucose ratio, HOMA-IR and abdominal adipose tissue distribution were similar in the two groups. Clinical and immunological HIV categories, viral load, CD4 cell count and stavudine therapy were not significantly associated with serum lipids, insulin resistance or abdominal adipose tissue distribution. The predictor variable most strongly associated with fasting serum insulin and HOMA-IR was the Tanner stage. Age was the most significant predictor variable of the visceral : subcutaneous adipose tissue ratio.. In this cohort of predominantly prepubertal HIV-infected children, PI therapy was associated with an atherogenic dyslipidemia but not with insulin resistance or abnormal abdominal adipose tissue distribution. The results suggest that children, particularly prepubertal children, are less susceptible than adults to PI-induced changes in glucose homeostasis and abdominal adipose tissue distribution.

Topics: Abdomen; Adipose Tissue; Adolescent; Antiretroviral Therapy, Highly Active; Blood Glucose; C-Peptide; Case-Control Studies; Chi-Square Distribution; Child; Child, Preschool; Cholesterol; Cholesterol, HDL; Cholesterol, LDL; Cross-Sectional Studies; Female; HIV Infections; Homeostasis; Humans; Insulin; Lipids; Male; Multivariate Analysis; Proinsulin; Protease Inhibitors; Regression Analysis; Tomography, X-Ray Computed; Triglycerides

Changes in glucose and fat metabolism associated with human immunodeficiency virus (HIV) infection have received attention because of the development of glucose intolerance, dyslipidemia, and lipodystrophy associated with protease inhibitor (PI) therapy. The response to ingested [13C]glucose (1.4 g/kg) was determined in 9 asymptomatic male HIV patients before and after 4.8 months of PI therapy (nelfinavir, 2,250 mg/d) compared with 9 matched seronegative HIV controls. No significant difference was observed for basal plasma glucose, insulin, and C-peptide concentrations between controls and patients before PI therapy. After 4.8 months of PI therapy, basal plasma glucose concentration was slightly, but significantly, increased (approximately 15%) compared with controls or HIV patients prior to receiving PI therapy. Over the first hour following ingestion of the glucose load, plasma glucose and insulin concentrations were higher in HIV patients than in controls, both before (approximately 15% and approximately 29%, respectively) and after (approximately 32% and approximately 43%, respectively) PI therapy. In addition, plasma C-peptide concentration was approximately 61% higher after PI therapy. The oxidation rate of fat, endogenous, and exogenous glucose was computed from the VO2 and respiratory exchange ratio corrected for protein oxidation and from 13C/12C in expired CO2. The only difference between controls and patients both before and after PI therapy was observed over the first 120 minutes following ingestion of the glucose load, when HIV patients oxidized approximately 18% more glucose and approximately 19% less fat than controls. This was not due to a larger oxidation rate of exogenous glucose, but to a larger oxidation rate of endogenous glucose (approximately 50%) in patients compared with controls. These data indicate that HIV infection is associated with minor changes in glucose metabolism, and that PI therapy with nelfinavir for 4.8 months only slightly further impairs glucose metabolism as assessed in response to a large oral glucose load. However, the larger stimulation of total and endogenous glucose oxidation and the larger reduction in fat oxidation, observed in the metabolic response to the glucose load in HIV patients, over time, could result in the accumulation of body fat and could contribute to lipodystrophy.

Topics: Adult; Blood Glucose; C-Peptide; Calorimetry, Indirect; Carbon Isotopes; Fats; Fatty Acids, Nonesterified; Glucose; Glycogen; HIV Infections; HIV Protease Inhibitors; HIV Seronegativity; Humans; Insulin; Longitudinal Studies; Male; Nelfinavir; Oxidation-Reduction; Time Factors; Urea

Topics: Adult; Antiviral Agents; C-Peptide; Diabetes Mellitus; Glycated Hemoglobin; HIV Infections; HIV-1; Humans; Hyperglycemia; Insulin; Male; Protease Inhibitors

Fasting hyperglycemia has been associated with HIV protease inhibitor (PI) therapy.. To determine whether absolute insulin deficiency or insulin resistance with relative insulin deficiency and an elevated body mass index (BMI) contribute to HIV PI-associated diabetes.. Cross-sectional evaluation.. 8 healthy seronegative men, 10 nondiabetic HIV-positive patients naive to PI, 15 nondiabetic HIV-positive patients receiving PI (BMI = 26 kg/m2), 6 nondiabetic HIV-positive patients receiving PI (BMI = 31 kg/m2), and 8 HIV-positive patients with diabetes receiving PI (BMI = 34 kg/m2). All patients on PI received indinavir.. Fasting concentrations of glucoregulatory hormones. Direct effects of indinavir (20 microM) on rat pancreatic beta-cell function in vitro.. In hyperglycemic HIV-positive subjects, circulating concentrations of insulin, C-peptide, proinsulin, glucagon, and the proinsulin/insulin ratio were increased when compared with those of the other 4 groups (p < .05). Morning fasting serum cortisol concentrations were not different among the 5 groups. Glutamic acid decarboxylase (GAD) antibody titers were uncommon in all groups. High BMI was not always associated with diabetes. In vitro, indinavir did not inhibit proinsulin to insulin conversion or impair glucose-induced secretion of insulin and C-peptide from rat beta-cells.. The pathogenesis of HIV PI-associated diabetes involves peripheral insulin resistance with insulin deficiency relative to hyperglucagonemia and a high BMI. Pancreatic beta-cell function was not impaired by indinavir. HIV PI-associated diabetes mirrors that of non-insulin-dependent diabetes mellitus and impaired insulin action in the periphery.

Topics: Adult; Animals; Anti-HIV Agents; C-Peptide; Cells, Cultured; Cross-Sectional Studies; Diabetes Mellitus, Type 1; Glucagon; HIV Infections; HIV Protease Inhibitors; Humans; Indinavir; Insulin; Insulin Resistance; Islets of Langerhans; Male; Phospholipases A; Proinsulin; Rats; Rats, Sprague-Dawley

To test whether clinically stable human immunodeficiency virus (HIV) infection, like other infections, is associated with insulin resistance and increased insulin clearance, we measured the sensitivity to insulin and insulin clearance using the euglycemic insulin clamp technique in 10 clinically stable outpatients with symptomatic HIV infection (Centers for Disease Control [CDC] group IV) and 10 healthy controls. During administration of 0.8 and 4 mU insulin.kg-1.min-1, HIV-infected men had 40% (P less than .02) and 83% (P less than .01) higher rates of insulin clearance when compared with healthy controls. Despite significantly lower steady-state insulin concentrations (42 +/- 2 v 52 +/- 4 microU/mL, P less than .05, and 255 +/- 17 v 392 +/- 14 microU/mL, P less than .001, patients v controls), patients and controls had similar total glucose uptake (7.99 +/- 0.81 v 7.92 +/- 0.44 mg.kg-1.min-1 and 14.00 +/- 0.81 v 13.65 +/- 0.65 mg.kg-1.min-1, patients v controls). In the postabsorptive state, no differences were found between patients and controls in insulin levels (7 +/- 1 microU/mL in both) and endogenous glucose production (2.52 +/- 0.07 and 2.24 +/- 0.17 mg.kg-1.min-1, respectively), but plasma glucose levels in the patients (5.02 +/- 0.15 mmol/L) were significantly lower when compared with controls (5.46 +/- 0.14 mmol/L, P less than .05). The results indicate that HIV-infected men have increased rates of insulin clearance and increased sensitivity of peripheral tissues to insulin, which makes HIV infection unique with regard to glucose and insulin metabolism.

Topics: Adult; Blood Glucose; C-Peptide; Epinephrine; Glucagon; Glucose; Growth Hormone; HIV Infections; Humans; Hydrocortisone; Insulin; Insulin Infusion Systems; Insulin Resistance; Male; Metabolic Clearance Rate; Middle Aged; Norepinephrine; Reference Values