Monitoring insulin-like growth factors in HIV infection and AIDS

Renal Impairment Impact and Survival Analysis in a Romanian Cohort of HIV-1(F1)-Infected Children and Adolescents

Human immunodeficiency virus (HIV) is a lentivirus that is transmissible through blood and other body fluids. During the late 1980s and early 1990s, an estimated 10,000 Romanian children were infected with HIV-1 subtype F nosocomially through contaminated needles and untested blood transfusions. Romania was a special case in the global acquired immunodeficiency syndrome (AIDS) pandemic, displaying the largest population of HIV-infected children by parental transmission between 1987–1990. In total, 205 HIV-infected patients from the western part of Romania were analyzed in this retrospective study. Over 70% of them had experienced horizontal transmission from an unknown source, while vertical transmission was identified in only five cases. Most patients had a moderate to severe clinical manifestation of HIV infection, 77.56% had undergone antiretroviral (ARV) treatment, most of them (71.21%) had experienced no adverse reactions and many of those with HIV (90.73%) had an undetectable viral load. Renal impairment was detected in one third of patients (34.63%). Patients born before 1990, male patients, patients diagnosed with HIV before the age of 10, and those undernourished or with renal impairment had a shorter average survival time than the group born after 1990, female patients, patients receiving ARV treatment, patients with a normal body mass index (BMI) and those without renal impairment. Periodical monitoring of the estimated glomerular filtration rate (eGFR) level, as well as the detection of protein excretion, should be taken into consideration worldwide when monitoring HIV-positive patients; this in order to detect even asymptomatic chronic kidney disease (CKD), and to manage these patients and prolong their lives.

The Endocannabinoid System as a Potential Therapeutic Target for HIV-1-Associated Neurocognitive Disorder

Background: Despite the successful introduction of combined antiretroviral therapy, the prevalence of mild to moderate forms of HIV-associated neurocognitive disorders (HAND) remains high. It has been demonstrated that neuronal injury caused by HIV is excitotoxic and inflammatory, and it correlates with neurocognitive decline in HAND. Endocannabinoid system (ECS) protects the body from excitotoxicity and neuroinflammation on demand and presents a promising therapeutic target for treating HAND. Here, we firstly discuss the potential pathogenesis of HAND. We secondly discuss the structural and functional changes in the ECS that are currently known among HAND patients. We thirdly discuss current clinical and preclinical findings concerning the neuroprotective and anti-inflammatory properties of the ECS among HAND patients. Fourth, we will discuss the interactions between the ECS and neuroendocrine systems, including the hypothalamic-pituitary-adrenocortical (HPA) and hypothalamic-pituitary-gonadal (HPG) axes under the HAND conditions. Materials and Methods: We have carried out a review of the literature using PubMed to summarize the current state of knowledge on the association between ECS and HAND. Results: The ECS may be ideally suited for modulation of HAND pathophysiology. Direct activation of presynaptic cannabinoid receptor 1 or reduction of cannabinoid metabolism attenuates HAND excitotoxicity. Chronic neuroinflammation associated with HAND can be reduced by activating cannabinoid receptor 2 on immune cells. The sensitivity of the ECS to HIV may be enhanced by increased cannabinoid receptor expression in HAND. In addition, indirect regulation of the ECS through modulation of hormone-related receptors may be a potential strategy to influence the ECS and also alleviate the progression of HAND due to the reciprocal inhibition of the ECS by the HPA and HPG axes. Conclusions: Taken together, targeting the ECS may be a promising strategy to alleviate the inflammation and neurodegeneration caused by HIV-1 infection. Further studies are required to clarify the role of endocannabinoid signaling in HIV neurotoxicity. Strategies promoting endocannabinoid signaling may slow down cognitive decline of HAND are proposed.

The delicate balance between neurotoxicity and neuroprotection in the context of HIV-1 infection

Human immunodeficiency virus type-1 (HIV-1) causes a spectrum of neurological impairments, termed HIV-associated neurocognitive disorder (HAND), following the infiltration of infected cells into the brain. Even though the implementation of antiretroviral therapy reduced the systemic viral load, the prevalence of HAND remains unchanged and infected patients develop persisting neurological disturbances affecting their quality of life. As a result, HAND have gained importance in basic and clinical researches, warranting the need of developing new adjunctive treatments. Nonetheless, a better understanding of the molecular and cellular mechanisms remains necessary. Several studies consolidated their efforts into elucidating the neurotoxic signaling leading to HAND including the deleterious actions of HIV-1 viral proteins and inflammatory mediators. However, the scope of these studies is not sufficient to address all the complexity related to HAND development. Fewer studies focused on an altered neuroprotective capacity of the brain to respond to HIV-1 infection. Neurotrophic factors are endogenous polyproteins involved in neuronal survival, synaptic plasticity, and neurogenesis. Any defects in the processing or production of these crucial factors might compose a risk factor rendering the brain more vulnerable to neuronal damages. Due to their essential roles, they have been investigated for their diverse interplays with HIV-1 infection. In this review, we present a complete description of the neurotrophic factors involved in HAND. We discuss emerging concepts for their therapeutic applications and summarize the complex mechanisms that down-regulate their production in favor of a neurotoxic environment. For certain factors, we finally address opposing roles that rather lead to increased inflammation.

Insulin-Like Growth Factor Is Associated with Changes in Body Composition with Antiretroviral Therapy Initiation

Growth hormone (GH)/insulin-like growth factor (IGF)-1 axis abnormalities have been associated with body composition changes among HIV-infected persons with wasting or lipodystrophy. Little is known of GH/IGF-1 axis alterations with antiretroviral therapy (ART) initiation or differing ART therapies. The AIDS Clinical Trials Group Prospective Evaluation of Antiretrovirals in Resource-Limited Settings (PEARLS) study was a prospective, randomized clinical trial of ART initiation with emtricitabine/tenofovir + efavirenz (FTC/TDF+EFV) versus lamivudine/zidovudine + efavirenz (3TC/ZDV+EFV) in HIV-1-infected individuals from resource-diverse settings. IGF-1 was measured from baseline, week 48, and week 96 stored serum samples. Multivariate models were constructed. 415 participants were included: 170 (41%) were randomized to FTC/TDF+EFV and 245 (59%) to 3TC/ZDV+EFV. The mean age was 35 years, 60% were black, 42% women. The mean IGF-1 level did not change significantly from baseline to week 96 (-0.65 ng/ml; 95% confidence interval (CI) -5.18-3.87), p = .78 and there were no differences by treatment arm at week 96, p = .74. Lower baseline IGF-1 was associated with age, non-white race, greater waist-hip ratio (WHR), low CD4 count, and lower baseline albumin (all p < .01) but not plasma HIV-1 RNA, body mass index, or treatment arm. Greater change in IGF-1 from baseline to 96 weeks was associated with female sex, smaller WHR change, lower baseline albumin, and higher baseline HIV-1 RNA (all p < .01). ART initiation with either ZDV or TDF did not significantly impact overall IGF-1 levels. Baseline and on-treatment changes in IGF-1 with ART initiation may be related to the body composition changes that occur after ART initiation.

Insulin-like growth factors and related proteins in plasma and cerebrospinal fluids of HIV-positive individuals

Background

Clinically significant dysregulation of the insulin-like growth factor (IGF) family proteins occurs in HIV-infected individuals, but the details including whether the deficiencies in IGFs contribute to CNS dysfunction are unknown.

Methods

We measured the levels of IGF1, IGF2, IGFBP1, IGFBP2, and IGF2 receptor (IGF2R) in matching plasma and cerebrospinal fluid (CSF) samples of 107 HIV+ individuals from CNS HIV Antiretroviral Therapy Effects Research (CHARTER) and analyzed their associations with demographic and disease characteristics, as well as levels of several soluble inflammatory mediators (TNFα, IL-6, IL-10, IL-17, IP-10, MCP-1, and progranulin). We also determined whether IGF1 or IGF2 deficiency is associated with HIV-associated neurocognitive disorder (HAND) and whether the levels of soluble IGF2R (an IGF scavenging receptor, which we also have found to be a cofactor for HIV infection in vitro) correlate with HIV viral load (VL).

Results

There was a positive correlation between the levels of IGF-binding proteins (IGFBPs) and those of inflammatory mediators: between plasma IGFBP1 and IL-17 (β coefficient 0.28, P = 0.009), plasma IGFBP2 and IL-6 (β coefficient 0.209, P = 0.021), CSF IGFBP1 and TNFα (β coefficient 0.394, P < 0.001), and CSF IGFBP2 and TNF-α (β coefficient 0.14, P < 0.001). As IGFBPs limit IGF availability, these results suggest that inflammation is a significant factor that modulates IGF protein expression/availability in the setting of HIV infection. However, there was no significant association between HAND and the reduced levels of plasma IGF1, IGF2, or CSF IGF1, suggesting a limited power of our study. Interestingly, plasma IGF1 was significantly reduced in subjects on non-nucleoside reverse transcriptase inhibitor-based antiretroviral therapy (ART) compared to protease inhibitor-based therapy (174.1 ± 59.8 vs. 202.8 ± 47.3 ng/ml, P = 0.008), suggesting a scenario in which ART regimen-related toxicity can contribute to HAND. Plasma IGF2R levels were positively correlated with plasma VL (β coefficient 0.37, P = 0.021) and inversely correlated with current CD4+ T cell counts (β coefficient −0.04, P = 0.021), supporting our previous findings in vitro.

Conclusions

Together, these results strongly implicate (1) an inverse relationship between inflammation and IGF growth factor availability and the contribution of IGF deficiencies to HAND and (2) the role of IGF2R in HIV infection and as a surrogate biomarker for HIV VL.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-015-0288-6) contains supplementary material, which is available to authorized users.

HIV therapy, metabolic and cardiovascular health are associated with glomerular hyperfiltration among men with and without HIV infection

OBJECTIVE

Diabetes and hypertension, common conditions in antiretroviral-treated HIV-infected individuals, are associated with glomerular hyperfiltration, which precedes the onset of proteinuria and accelerated kidney function decline. In the Multicenter AIDS Cohort Study, we examined the extent to which hyperfiltration is present and associated with metabolic, cardiovascular, HIV and treatment risk factors among HIV-infected men.

DESIGN

Cross-sectional cohort using direct measurement of glomerular filtration rate by iohexol plasma clearance for 367 HIV-infected men and 241 HIV-uninfected men who were free of chronic kidney disease.

METHODS

Hyperfiltration was defined as glomerular filtration rate above 140-1 ml/min per 1.73 m per year over age 40. Multivariate logistic regression was used to estimate the odds ratios (ORs) of prevalent hyperfiltration for metabolic, cardiovascular, HIV and cumulative antiretroviral exposure factors.

RESULTS

Among individuals without chronic kidney disease, the prevalence of hyperfiltration was higher for HIV-infected participants (25%) compared to uninfected participants (17%; P = 0.01). After adjustment, HIV infection remained associated with hyperfiltration [OR 1.70, 95% confidence interval (CI) 1.11-2.61] and modified the association between diabetes and hyperfiltration, such that the association among HIV-uninfected men (OR 2.56, 95% CI 1.33-5.54) was not observed among HIV-infected men (OR 1.19, 95% CI 0.69-2.05). These associations were independent of known risk factors for hyperfiltration. Indicators of hyperglycemia and hypertension were also associated with hyperfiltration as was cumulative zidovudine exposure.

CONCLUSION

Hyperfiltration, a potential modifiable predictor of kidney disease progression, is significantly higher among antiretroviral-treated HIV-infected men. Furthermore, HIV-infection nullifies the association of diabetes and hyperfiltration present in HIV-uninfected men.

Insulin-like growth factor 1 and 2 (IGF1, IGF2) expression in human microglia: differential regulation by inflammatory mediators

BACKGROUND

Recent studies in experimental animals show that insulin-like growth factor 1 (IGF1) plays a trophic role during development and tissue injury and that microglia are important sources of IGF1. However, little information is available regarding the expression, regulation, and function of IGF1 and related proteins in human brain cells. In the current study, we examined the expression of IGF1 and IGF2 in human microglia in vivo and in vitro.

METHODS

Expression of IGF1 and IGF2 was examined by immunohistochemistry in post-mortem human brain sections derived from HIV+ and HIV- brains. In primary cultures of human fetal microglia, IGF1 and IGF2 mRNA and protein expression was examined by Q-PCR, ELISA, and Western blot analysis. Additionally, the role of IGF1 and IGF2 in neuroprotection was examined in primary human neuronal glial cultures.

RESULTS

Immunohistochemistry of human brain tissues showed that nonparenchymal cells (vessels and meninges), as well as parenchymal microglia and macrophages were positive for IGF1, in both HIV encephalitis and control brains, while IGF2 was undetectable. Cultured microglia expressed IGF1 mRNA and produced pg/ml levels of IGF1 protein; this was significantly suppressed by proinflammatory mediators, such as lipopolysaccharide (LPS), poly(I:C), and IFNγ. The Th2 cytokines IL-4 and IL-13 had no significant effect, but the cAMP analog (dibutyryl cAMP) significantly increased IGF1 production. In contrast, microglial IGF2 mRNA and protein (determined by Western blot) were upregulated by LPS. IGF1 receptor (IGF1R) immunoreactivity was predominantly expressed by neurons, and both IGF1 and IGF2 significantly protected neurons from cytokine (IL-1/IFNγ) induced death.

CONCLUSIONS

Our study in human brain tissues and cells indicates that microglia are important sources of neurotrophic growth factors IGF1 and IGF2, and that microglial activation phenotypes can influence the growth factor expression. Importantly, our results suggest that chronic neuroinflammation and upregulation of proinflammatory cytokines could lead to neurodegeneration by suppressing the production of microglia-derived neuronal growth factors, such as IGF1.

Human conditions of insulin-like growth factor-I (IGF-I) deficiency

Insulin-like growth factor I (IGF-I) is a polypeptide hormone produced mainly by the liver in response to the endocrine GH stimulus, but it is also secreted by multiple tissues for autocrine/paracrine purposes. IGF-I is partly responsible for systemic GH activities although it possesses a wide number of own properties (anabolic, antioxidant, anti-inflammatory and cytoprotective actions). IGF-I is a closely regulated hormone. Consequently, its logical therapeutical applications seems to be limited to restore physiological circulating levels in order to recover the clinical consequences of IGF-I deficiency, conditions where, despite continuous discrepancies, IGF-I treatment has never been related to oncogenesis. Currently the best characterized conditions of IGF-I deficiency are Laron Syndrome, in children; liver cirrhosis, in adults; aging including age-related-cardiovascular and neurological diseases; and more recently, intrauterine growth restriction. The aim of this review is to summarize the increasing list of roles of IGF-I, both in physiological and pathological conditions, underlying that its potential therapeutical options seem to be limited to those proven states of local or systemic IGF-I deficiency as a replacement treatment, rather than increasing its level upper the normal range.

Growth hormone and HIV infection: contribution to disease manifestations and clinical implications

In untreated HIV patients growth hormone deficiency contributes to loss of lean and fat mass. Pharmacologic doses of growth hormone successfully reverse this wasting process. In patients responding to antiretroviral therapies several non AIDS-related complications usually common among older, uninfected persons now occur more frequently in younger HIV patients. Among these conditions are cardiovascular disease and metabolic disorders. Although their etiology is multifactorial, changes in growth hormone biology reflecting relative growth hormone deficiency occur and may be involved. In these patients truncal obesity, and associated dyslipidemia and glucose homeostasis changes contribute to impaired quality of life and increased cardiovascular risk. Treatment with growth hormone and growth hormone releasing factor leads to short-term improvement of some of these abnormalities. This paper will review abnormalities of growth hormone biology and the use of growth hormone and growth hormone releasing factor as therapeutic agents in HIV patients.

Immunoneuroendocrine alterations in patients with progressive forms of chronic Chagas disease

We studied the features of parallel immunoneuroendocrine responses in patients with different degrees of chronic Chagas myocarditis (indeterminate, mild/moderate or severe). A systemic inflammatory scenario was evident in patients with severe myocarditis compared to healthy subjects. This was paralleled by a disrupted activation of the hypothalamus-pituitary-adrenal axis, characterized by decreased concentrations of dehydroepiandrosterone-sulfate (DHEA-s) and an unbalanced cortisol/DHEA-s ratio, reinforcing the view that severe Chagas disease is devoid of an adequate anti-inflammatory milieu, likely involved in pathology. Our study constitutes the first demonstration of neuroendocrine disturbances, in parallel to a systemic inflammatory profile, during progressive human Chagas disease.

Human immunodeficiency virus and highly active antiretroviral therapy-associated metabolic disorders and risk factors for cardiovascular disease

The successful introduction of highly active antiretroviral therapy (HAART), a combination of potent antiretroviral agents, including protease inhibitors, nucleoside reverse transcriptase inhibitors, and nonnucleoside reverse transcriptase inhibitors, has impacted positively on morbidity and mortality among human immunodeficiency virus (HIV)-positive patients. Over time, HAART has been associated with a number of metabolic and anthropometric abnormalities, including dyslipidemia and insulin resistance as well as subcutaneous fat loss and abdominal obesity, potentially contributing to cardiovascular risk. Recent studies have more firmly established that both HIV infection and HAART might increase the risk of clinical cardiovascular events. Furthermore, whereas HIV/HAART is associated with multiple aspects of endocrine dysfunction, there has been less focus on bone disease, although some studies indicate a higher prevalence of osteoporosis among HIV-positive subjects compared to HIV-negative controls. The relationship between bone and fat metabolism under HIV-positive conditions deserves further attention, and available data suggest the possibility of an intriguing connection. In the future, an increasing population of aging HIV-positive patients with a spectrum of antiretroviral therapies and accumulation of endocrine abnormalities and conventional cardiovascular risk factors will present preventive and therapeutic challenges to our health-care system.

Cellular and molecular mechanisms of memory T-cell survival

Long-term maintenance of the memory T-cell response is the hallmark of immune protection and, hence, constitutes one of the most important objectives of vaccine-development strategies. Persistent memory T cells, developed after vaccination or microbial infections, ensure the generation of an antimicrobial response upon re-exposure to the pathogen through rapid clonal proliferation and activation of effector functions. However, in the context of many pathogen infections, these memory T cells fail to persist and die. In this review, we will highlight recent exciting findings in studies of memory T cells, their generation, their lineage relationships and their survival pathways; indeed, survival of memory T cells and maintenance of their functionality are key features of the immune response in its quest to control disease progression and in the development of vaccines to persistent microbial infections.

Proteomic profiling of amniotic fluid in preterm labor using two-dimensional liquid separation and mass spectrometry

OBJECTIVE

Simultaneous analysis of the protein composition of biological fluids is now possible. Such an approach can be used to identify biological markers of disease and to understand the pathophysiology of disorders that have eluded classification, diagnosis, and treatment. The purpose of this study was to analyze the differences in protein composition of the amniotic fluid of patients in preterm labor.

STUDY DESIGN

Amniotic fluid was obtained by amniocentesis from three groups of women with preterm labor and intact membranes: (1) women without intra-amniotic infection/inflammation (IAI) who delivered at term, (2) women without IAI who delivered a preterm neonate, and (3) women with IAI. Intra-amniotic infection was defined as a positive amniotic fluid culture for microorganisms. Intra-amniotic inflammation was defined as an elevated amniotic fluid interleukin (IL)-6 (> or =2.3 ng/mL). Two-dimensional (2D) chromatography was used for analysis. The first dimension separated proteins by isoelectric point, while the second, by the degree of hydrophobicity. 2D protein maps were generated using different experimental conditions (reducing agents as well as protein concentration). The maps were used to discern subsets of isoelectric point/hydrophobicity containing differentially expressed proteins. Protein identification of differentially expressed fractions was conducted with mass spectrometry. Enzyme-linked immunosorbent assays (ELISA) as well as surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS)-based on-chip antibody capture immunoassays were also used for confirmation of a specific protein that was differentially expressed.

RESULTS

(1) Amniotic fluid protein composition can be analyzed using a combination of 2D liquid chromatography and mass spectrometry for the identification of proteins differentially expressed in patients in preterm labor. (2) While total insulin-like growth factor-binding protein-1 (IGFBP-1) concentration did not change, IGFBP-1 fragments at about 13.5 kDa were present in patients with IAI. (3) Proteins that were over-expressed in group 1 included von Ebner gland protein precursor, IL-7 precursor, apolipoprotein A1, tropomyosin sk1 (TPMsk1) fragment, ribosomal protein S6 kinase alpha-3, and alpha-1-microglobulin/bikunin precursor (AMBP). (4) Proteins that were over-expressed in group 3 included fibrinopeptide B, transferrin, major histocompatibility complex (MHC) class 1 chain-related A antigen fragment, transcription elongation factor A, sex-determining region Y (SRY) box 5 protein, Down syndrome critical region 2 protein (DSCR2), and human peptide 8 (HP8). (5) One protein, retinol-binding protein, was over-expressed in women who delivered preterm, regardless of the presence of IAI.

CONCLUSIONS

A combination of techniques involving 2D chromatography, mass spectrometry, and immunoassays allows identification of proteins that are differentially regulated in the amniotic fluid of patients with preterm labor. Specifically, the amount of the IGFBP-1 fragments at approximately 13.5 kDa was found to be increased in patients with IAI, while the amount of the intact form of IGFBP-1 was decreased.

O papel do hormônio de crescimento no tratamento dos distúrbios endócrino-metabólicos do paciente com a síndrome da imunodeficiência adquirida (Aids)

As primeiras descrições da síndrome da imunodeficiência adquirida (Aids) associavam-se à síndrome de emaciamento, e os distúrbios metabólicos às alterações na composição corporal. Após a introdução da terapia anti-retroviral altamente ativa (HAART), houve declínio na desnutrição, e surge a lipodistrofia como importante distúrbio metabólico. A Aids também se caracteriza por distúrbios hormonais, principalmente no eixo hormônio de crescimento/fator de crescimento insulina-like tipo 1 (GH/IGF-1). O uso do GH recombinante humano (hrGH) foi inicialmente indicado na síndrome de emaciamento, a fim de aumentar a massa muscular. Embora também não existam dúvidas quanto aos efeitos do hrGH na lipodistrofia, a diminuição na sensibilidade à insulina limita o seu uso, o qual ainda não está oficialmente aprovado. A diversidade nos esquemas de tratamento é outro limitante do uso dessa medicação em pacientes com Aids. Esta revisão apresenta os principais distúrbios endócrino-metabólicos associados à Aids e ao uso do hrGH nessas condições.

Innate Immunity in the Female Reproductive Tract: Role of Sex Hormones in Regulating Uterine Epithelial Cell Protection Against Pathogens

The mucosal immune system in the upper female reproductive tract is uniquely prepared to maintain a balance between the presence of commensal bacteria, sexually transmitted bacterial and viral pathogens, allogeneic spermatozoa, and an immunologically distinct fetus. At the center of this dynamic system are the epithelial cells that line the Fallopian tubes, uterus, cervix and vagina. Epithelial cells provide a first line of defense that confers continuous protection, by providing a physical barrier as well as secretions containing bactericidal and virucidal agents. In addition to maintaining a state of ongoing protection, these cells have evolved to respond to pathogens, in part through Toll-like receptors (TLRs), to enhance innate immune protection and, when necessary, to contribute to the initiation of an adaptive immune response. Against this backdrop, epithelial cell innate and adaptive immune function is modulated to meet the constraints of procreation. The overall goal of this review is to focus on the dynamic role of epithelial cells in the upper reproductive tract, with special emphasis on the uterus, to define the unique properties of these cells as they maintain homeostasis in preparation for successful fertilization and pregnancy while at the same time confer protection against sexually transmitted infections, which threaten to compromise women's reproductive health and survival. By understanding the nature of this protection and the ways in which innate and adaptive immunity are regulated by sex hormones, these studies provide the opportunity to contribute to the foundation of information essential for ensuring reproductive health.

Associations of insulin-like growth factor (IGF)-I and IGF-binding protein-3 with HIV disease progression in women

BACKGROUND

The insulin-like growth factor (IGF) axis has been hypothesized to influence the rate of human immunodeficiency virus (HIV) disease progression. This premise is based largely on laboratory models showing that IGF-I stimulates thymic growth and increases lymphocyte numbers and that IGF-binding protein (IGFBP)-3 has an opposing effect, inhibiting hematopoietic stem cell development.

METHODS

We studied 1422 HIV-infected women enrolled in a large cohort that entailed semiannual follow-up (initiated in 1994). Baseline serum samples were tested for IGF-I and IGFBP-3 to determine their associations with incident clinical acquired immunodeficiency syndrome (AIDS) and CD4+ T cell count decline prior to April 1996 (before the era of highly active antiretroviral therapy [HAART]).

RESULTS

Low IGF-I levels (Ptrend= .02) and high IGFBP-3 levels (Ptrend= .02) were associated with rapid CD4+ T cell count decline. Only IGFBP-3, however, was significantly associated with AIDS incidence (hazard ratio for highest vs. lowest quartile, 2.65 [95% confidence interval, 1.30-5.42]; Ptrend= .02) in multivariable models.

CONCLUSIONS

These findings suggest that serum levels of IGFBP-3 (and possibly IGF-I) are associated with the rate of HIV disease progression in women and, more broadly, that interindividual heterogeneity in the IGF axis may influence HIV pathogenesis. If correct, the IGF axis could be a target for interventions to slow HIV disease progression and extend the time before use of HAART becomes necessary.

Clinical utility of measurements of insulin-like growth factor 1

Plasma insulin-like growth factor 1 (IGF-I) concentrations are regulated by genetic factors, nutrient intake, growth hormone (GH) and other hormones such as T4, cortisol and sex steroids. The accuracy of IGF-I measurement in diagnosing GH deficiency or excess depends, in part, on the relative contributions of each of these variables. Since their respective influence may vary widely between individuals, the establishment of well-defined normal ranges is necessary, which requires adequate numbers of normal individuals, in order for IGF-I measurements to have maximum utility. In states of GH deficiency, the influence of these non-GH-related factors predominates. Although IGF-I levels have utility as a screening test in children and young adults, they cannot be used as a stand-alone test for the diagnosis of GH deficiency. By contrast, in acromegaly, GH is the predominant determinant of IGF-I levels and, therefore, measurement of IGF-I is a very useful diagnostic test. In acromegaly, IGF-I levels are useful for assessing the relative degree of GH excess, because changes in IGF-I correlate with changes in symptoms and soft-tissue growth. IGF-I is also very useful in monitoring the symptomatic response to therapy.