Mechanisms for the deterioration in glucose tolerance associated with HIV protease inhibitor regimens

HIV and type 2 diabetes: An evolving story

INTRODUCTION

Diabetes is widely reported to be more common in people living with HIV (PLWH). Much of the data supporting this originated during the earlier HIV era. The perceived increased risk of type 2 diabetes is reflected in HIV clinical guidelines that recommend screening for diabetes in PLWH on anti-retroviral therapy (ART). However, international HIV clinical guidelines do not agree on the best marker of glycaemia to screen for diabetes. This stems from studies that suggest HbA1c underestimates glycaemia in PLWH.

METHODS

Within this review we summarise the literature surrounding the association of HIV and type 2 diabetes and how this has changed over time. We also present the evidence on HbA1c discrepancy in PLWH.

CONCLUSION

We suggest there is no basis to any international guidelines to restrict HbA1c based on HIV serostatus. We recommend, using the current evidence, that PLWH should be screened annually for diabetes in keeping with country specific guidance. Finally, we suggest future work to elucidate phenotype and natural history of type 2 diabetes in PLWH across all populations.

Adipose Tissue Dysfunction and Energy Balance Paradigms in People Living With HIV

Over the past 4 decades, the clinical care of people living with HIV (PLWH) evolved from treatment of acute opportunistic infections to the management of chronic, noncommunicable comorbidities. Concurrently, our understanding of adipose tissue function matured to acknowledge its important endocrine contributions to energy balance. PLWH experience changes in the mass and composition of adipose tissue depots before and after initiating antiretroviral therapy, including regional loss (lipoatrophy), gain (lipohypertrophy), or mixed lipodystrophy. These conditions may coexist with generalized obesity in PLWH and reflect disturbances of energy balance regulation caused by HIV persistence and antiretroviral therapy drugs. Adipocyte hypertrophy characterizes visceral and subcutaneous adipose tissue depot expansion, as well as ectopic lipid deposition that occurs diffusely in the liver, skeletal muscle, and heart. PLWH with excess visceral adipose tissue exhibit adipokine dysregulation coupled with increased insulin resistance, heightening their risk for cardiovascular disease above that of the HIV-negative population. However, conventional therapies are ineffective for the management of cardiometabolic risk in this patient population. Although the knowledge of complex cardiometabolic comorbidities in PLWH continues to expand, significant knowledge gaps remain. Ongoing studies aimed at understanding interorgan communication and energy balance provide insights into metabolic observations in PLWH and reveal potential therapeutic targets. Our review focuses on current knowledge and recent advances in HIV-associated adipose tissue dysfunction, highlights emerging adipokine paradigms, and describes critical mechanistic and clinical insights.

Exploring the Relation Between Diabetes and HIV: A Narrative Review

Diabetes mellitus, more usually abbreviated as DM or just diabetes, is a devastating metabolic disorder that claims many lives every year. Due to various variables, including the aging of the HIV (human immunodeficiency virus)-infected population and the high prevalence of chronic medical conditions among persons living with HIV, the crossroads of DM and HIV infection has become a significant research topic. Although the connection between HIV and diabetes is not simple, many aspects of the virus and its treatment have been connected to the onset of diabetes. The presence of inconclusive evidence that HIV is a risk factor for diabetes makes this area more challenging and debatable. This article examines the prevalence of DM in the HIV-positive community, along with its assessment, management, and treatment objectives. The most recent diabetes treatment recommendations from authoritative groups are considered in this article to give readers thorough and current advice. These guidelines emphasize the importance of tailoring pharmacological therapy and treatment goals to suit the specific needs of individuals with diabetes, including those who are also living with HIV. Individualizing treatment plans ensures that healthcare professionals consider comorbidities, medication interactions, and potential side effects when managing diabetes concerning HIV. In the later part of the article, a holistic approach is discussed to address the increased risk of cardiovascular disease and associated complications in HIV-positive individuals with diabetes. This approach aims to mitigate cardiovascular risks and improve overall health outcomes through comprehensive strategies such as lifestyle modifications, regular monitoring, medication management, and integration of multidisciplinary healthcare teams. By considering the unique challenges and considerations of individuals living with both HIV and diabetes, healthcare providers can develop targeted interventions and provide optimal care. In order to improve the life and health of persons living with HIV and diabetes, the article stresses the significance of cooperation amongst professionals in these fields.

COVID-19: Diabetes Perspective-Pathophysiology and Management

Recent evidence relating to the impact of COVID-19 on people with diabetes is limited but continues to emerge. COVID-19 pneumonia is a newly identified illness spreading rapidly throughout the world and causes many disabilities and fatal deaths. Over the ensuing 2 years, the indirect effects of the pandemic on healthcare delivery have become prominent, along with the lingering effects of the virus on those directly infected. Diabetes is a commonly identified risk factor that contributes not only to the severity and mortality of COVID-19 patients, but also to the associated complications, including acute respiratory distress syndrome (ARDS) and multi-organ failure. Diabetic patients are highly affected due to increased viral entry into the cells and decreased immunity. Several hypotheses to explain the increased incidence and severity of COVID-19 infection in people with diabetes have been proposed and explained in detail recently. On the other hand, 20-50% of COVID-19 patients reported new-onset hyperglycemia without diabetes and new-onset diabetes, suggesting the two-way interactions between COVID-19 and diabetes. A systematic review is required to confirm diabetes as a complication in those patients diagnosed with COVID-19. Diabetes and diabetes-related complications in COVID-19 patients are primarily due to the acute illness caused during the SARS-CoV-2 infection followed by the release of glucocorticoids, catecholamines, and pro-inflammatory cytokines, which have been shown to drive hyperglycemia positively. This review provides brief insights into the potential mechanisms linking COVID-19 and diabetes, and presents clinical management recommendations for better handling of the disease.

The Effects of Viruses on Insulin Sensitivity and Blood-Brain Barrier Function

In this review manuscript, we discuss the effects of select common viruses on insulin sensitivity and blood-brain barrier (BBB) function and the potential overlapping and distinct mechanisms involved in these effects. More specifically, we discuss the effects of human immunodeficiency virus (HIV), herpes, hepatitis, influenza, respiratory syncytial virus (RSV), and SARS-CoV-2 viruses on insulin sensitivity and BBB function and the proposed underlying mechanisms. These viruses differ in their ability to be transported across the BBB, disrupt the BBB, and/or alter the function of the BBB. For RSV and SARS-CoV-2, diabetes increases the risk of infection with the virus, in addition to viral infection increasing the risk for development of diabetes. For HIV and hepatitis C and E, enhanced TNF-a levels play a role in the detrimental effects. The winter of 2022-2023 has been labeled as a tridemic as influenza, RSV, and COVID-19 are all of concern during this flu season. There is an ongoing discussion about whether combined viral exposures of influenza, RSV, and COVID-19 have additive, synergistic, or interference effects. Therefore, increased efforts are warranted to determine how combined viral exposures affect insulin sensitivity and BBB function.

Metabolic Consequences of Antiretroviral Therapy

PURPOSE OF REVIEW

This review reports on published studies describing metabolic changes associated with antiretroviral therapy (ART) to treat HIV disease including a historical perspective of earlier ART agents, but with the main focus on newer ART agents currently in use.

RECENT FINDINGS

Studies from different countries around the world have shown that integrase inhibitor (INSTI)-based regimens as well as tenofovir alafenamide (TAF) are associated with weight gain, with women and people of black race at especially high risk. Some studies preliminarily suggest worsened metabolic outcomes associated with this weight gain including adverse effects on glucose homeostasis. Antiretroviral therapy can affect weight, adipose tissue, glucose, and lipids. As obesity is prevalent and increasing among people with HIV, awareness of risk factors for weight gain, including the ART medications associated with greater weight gain, are needed in order to inform prevention efforts. Further research is needed to better understand the long-term health consequences of INSTI- and TAF-associated weight increases.

Potential role of Drug Repositioning Strategy (DRS) for management of tauopathy

Tauopathy is a term that has been used to represent a pathological condition in which hyperphosphorylated tau protein aggregates in neurons and glia which results in neurodegeneration, synapse loss and dysfunction and cognitive impairments. Recently, drug repositioning strategy (DRS) becomes a promising field and an alternative approach to advancing new treatments from actually developed and FDA approved drugs for an indication other than the indication it was originally intended for. This paradigm provides an advantage because the safety of the candidate compound has already been established, which abolishes the need for further preclinical safety testing and thus substantially reduces the time and cost involved in progressing of clinical trials. In the present review, we focused on correlation between tauopathy and common diseases as type 2 diabetes mellitus and the global virus COVID-19 and how tau pathology can aggravate development of these diseases in addition to how these diseases can be a risk factor for development of tauopathy. Moreover, correlation between COVID-19 and type 2 diabetes mellitus was also discussed. Therefore, repositioning of a drug in the daily clinical practice of patients to manage or prevent two or more diseases at the same time with lower side effects and drug-drug interactions is a promising idea. This review concluded the results of pre-clinical and clinical studies applied on antidiabetics, COVID-19 medications, antihypertensives, antidepressants and cholesterol lowering drugs for possible drug repositioning for management of tauopathy.

COVID-19 and diabetes mellitus: from pathophysiology to clinical management

Initial studies found increased severity of coronavirus disease 2019 (COVID-19), caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in patients with diabetes mellitus. Furthermore, COVID-19 might also predispose infected individuals to hyperglycaemia. Interacting with other risk factors, hyperglycaemia might modulate immune and inflammatory responses, thus predisposing patients to severe COVID-19 and possible lethal outcomes. Angiotensin-converting enzyme 2 (ACE2), which is part of the renin-angiotensin-aldosterone system (RAAS), is the main entry receptor for SARS-CoV-2; although dipeptidyl peptidase 4 (DPP4) might also act as a binding target. Preliminary data, however, do not suggest a notable effect of glucose-lowering DPP4 inhibitors on SARS-CoV-2 susceptibility. Owing to their pharmacological characteristics, sodium-glucose cotransporter 2 (SGLT2) inhibitors might cause adverse effects in patients with COVID-19 and so cannot be recommended. Currently, insulin should be the main approach to the control of acute glycaemia. Most available evidence does not distinguish between the major types of diabetes mellitus and is related to type 2 diabetes mellitus owing to its high prevalence. However, some limited evidence is now available on type 1 diabetes mellitus and COVID-19. Most of these conclusions are preliminary, and further investigation of the optimal management in patients with diabetes mellitus is warranted.

Lower Cumulative Antiretroviral Exposure in People Living With HIV and Diabetes Mellitus

OBJECTIVE

People living with HIV (PLWH) are living longer and developing more non-AIDS comorbidities, which negatively impact antiretroviral therapy (ART) adherence. Tenofovir diphosphate (TFV-DP) in dried blood spots (DBS) is a novel pharmacologic measure of cumulative ART adherence that is predictive of viral suppression and future viremia. However, the relationship between non-AIDS comorbidities and this adherence measure is unknown. We aimed to evaluate the association between 3 non-AIDS comorbidities (diabetes mellitus (DM), hypertension, and hyperlipidemia) and TFV-DP in DBS in PLWH.

METHODS

Blood for TFV-DP in DBS and HIV viral load was prospectively collected from PLWH on tenofovir disoproxil fumarate for up to 3 times over 48 weeks. Non-AIDS comorbidities were recorded. Mixed effect multivariable linear regression models were used to estimate the changes in TFV-DP concentrations in DBS according to the presence of comorbidities and to estimate the percent differences in TFV-DP concentrations between these groups.

RESULTS

A total of 1144 person-visits derived from 523 participants with available concentrations of TFV-DP in DBS were included in this analysis. In univariate analysis, no significant association between non-AIDS comorbidities (categorized as having 0, 1, 2, or 3 comorbidities) and the concentrations of TFV-DP in DBS was observed (P = 0.40). Participants who had DM had 25% lower (95% confidence interval: -36% to -12%; P < 0.001) TFV-DP in DBS than participants without DM after adjusting for age, gender, race, body mass index, estimated glomerular filtration rate, CD4 T-cell count, hematocrit, ART class, patient-level medication regimen complexity index, and 3-month self-reported adherence.

CONCLUSIONS

Diabetic PLWH have lower concentrations of TFV-DP in DBS compared with those without DM. Further research is required to identify the clinical implications and biological mechanisms underlying these findings.

Correlates of fasting blood glucose among children living with hiv in a Nigerian tertiary hospital: a cross-sectional study

Background

There is growing concern as regards the emergence of metabolic disorders among children living with the Human Immunodeficiency Virus (HIV) worldwide. However, there is paucity of data on the correlates of metabolic indices among HIV-positive children in Africa.

Methods

This study examined 84 HIV-positive children on HAART recruited from the paediatric infectious diseases clinic of the University of Nigeria Teaching Hospital for blood glucose levels using finger-prick testing with an Accu-check glucose meter and test strips. Clinical information was obtained via clinical history and medical records. Data was analyzed to examine the relationship between FBG and the classes of HAART, duration of illness and treatment using analysis of variance (ANOVA).

Results

FBG was significantly associated with the classes of HAART (_x²=12.4, p = 0.017). In addition, there was a significant association between FBG and duration of illness [F(2, 81) = 6.0; P = 0.004], as well as FBG and duration on HAART [F(2, 81) = 7.9; P = 0.001]. However, duration on HAART and type of HAART were the significant predictors of FBG in this study accounting for 10.5% and 4.1% of the variance, respectively.

Conclusions

There is a greater risk of dysglycemia in paediatric patients with a longer cumulative exposure to HAART. Routine blood glucose checks among children on HAART, especially those who have received HAART for a longer duration of time may therefore be useful in their management.

Medication-induced hyperglycemia: pediatric perspective

Medication-induced hyperglycemia is a frequently encountered clinical problem in children. The intent of this review of medications that cause hyperglycemia and their mechanisms of action is to help guide clinicians in prevention, screening and management of pediatric drug-induced hyperglycemia. We conducted a thorough literature review in PubMed and Cochrane libraries from inception to July 2019. Although many pharmacotherapies that have been associated with hyperglycemia in adults are also used in children, pediatric-specific data on medication-induced hyperglycemia are scarce. The mechanisms of hyperglycemia may involve β cell destruction, decreased insulin secretion and/or sensitivity, and excessive glucose influx. While some medications (eg, glucocorticoids, L-asparaginase, tacrolimus) are markedly associated with high risk of hyperglycemia, the association is less clear in others (eg, clonidine, hormonal contraceptives, amiodarone). In addition to the drug and its dose, patient characteristics, such as obesity or family history of diabetes, affect a child's risk of developing hyperglycemia. Identification of pediatric patients with increased risk of developing hyperglycemia, creating strategies for risk reduction, and treating hyperglycemia in a timely manner may improve patient outcomes.

Factors Associated With Insulin Resistance in Adults With HIV Receiving Contemporary Antiretroviral Therapy: a Brief Update

PURPOSE OF REVIEW

This narrative review summarizes recent data on factors associated with insulin resistance (IR) in adults with HIV, including contemporary antiretroviral therapy (ART).

RECENT FINDINGS

IR remains common in persons with HIV, even those receiving contemporary ART. Generalized and abdominal obesity and ectopic fat are correlates of IR, and emerging data have identified associations with biomarkers of inflammation and immune activation. Small studies suggest associations between mitochondria and IR. In ART-naïve individuals, IR increased within 4 weeks of starting ART in persons receiving contemporary boosted protease inhibitors or an integrase inhibitor. The importance of IR in non-diabetic persons with HIV will continue to grow as the population ages and obesity increases. Non-invasive estimates of IR appear to perform well in persons with HIV, but clinically relevant cutoffs are uncertain. Unexpected metabolic effects of newer HIV integrase inhibitors have been reported; thus, careful observation for and studies of IR are still warranted.

Comparative Assessment of the Magnitude of Hyperlipidemia in HIV-Infected Patients Receiving Lopinavir/r- and Atazanavir/r-Based Antiretroviral Drugs

OBJECTIVE

To assess prevalence of hyperlipidemia in patients receiving lopinavir boosted with ritonavir (LPV/r) and atazanavir boosted with ritonavir (ATV/r) antiretroviral drugs.

METHODS

HIV-infected patients (300) were recruited in the study between December 2015 and April 2016. Lipid profile including triglycerides (TG), high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol (LDL-C) were assessed.

RESULTS

Prevalence of derangement in TG was 71.0% in patients using LPV/r compared to 44% in those using ATV/r ( P = .01). Use of LPV/r was independently associated with increased total cholesterol (TC; P = .001) and TG ( P = .0003). Females had raised levels of TC compared to males ( P = .00008). Body mass index of ≥ 25 kg/m2 was also associated with raised TC ( P = .002) and LDL-C ( P = .006).

CONCLUSION

LPV/r was significantly associated with lipid derangements, indicating the need to regularly monitor lipid profile in patients using LPV/r.

Diabetes and HIV

PURPOSE OF REVIEW

This review seeks to address the epidemiology and pathophysiological basis of the interaction between HIV infection and diabetes and the implication for treatment. Its importance stems from the current context of the growing burden of both conditions and the possible mechanisms of interactions that may exist but not yet sufficiently examined.

RECENT FINDINGS

HIV infection is associated with increased risk of insulin resistance, and ART is associated with metabolic derangement and the occurrence of type 2 diabetes. The increasing survival among people with HIV infection in developing countries is paralleled by a growing burden of chronic non-communicable diseases (NCDs) especially cardiovascular diseases and diabetes mellitus. The prevalence of diabetes mellitus is higher in HIV-positive persons compared to the general population, and especially those with associated hepatitis C virus (HCV) co-infection. Antiretroviral therapy (ART) during chronic HIV infection is the most incriminated risk factor for the development of diabetes mellitus through diverse mechanisms depending on the ART leading to insulin resistance and increased inflammatory status. A staggering 629 million of people 20-79 years are projected to have diabetes by 2045 while the world will soon enter the fourth decade of the HIV infection. Classical risk factors for diabetes such as physical inactivity and unhealthy diet may not solely explain the current trends, suggesting the role of novel risk factors including infections/inflammation. HIV and its treatment have been identified as potential contributors. Co-infections frequently observed during HIV infection also significantly influence both the epidemiological and pathophysiological of the link between HIV and diabetes. Although the relative contribution of each risk factor has not yet been quantified, several lines of evidence suggest that ART is a major contributor to hyperglycemia in HIV infection. ARTs have also led to an increase in metabolic dysfunction, including insulin resistance syndromes, dyslipidemia, and lipodystrophy. The association between ARTs and the risk of developing diabetes therefore calls for a careful choice of medication and evaluation of the risk of developing diabetes.

Examining Relationships between Metabolism and Persistent Inflammation in HIV Patients on Antiretroviral Therapy

With the advent of antiretroviral therapy (ART), HIV-infected individuals are now living longer and healthier lives. However, ART does not completely restore health and treated individuals are experiencing increased rates of noncommunicable diseases such as dyslipidemia, insulin resistance, type 2 diabetes, cardiovascular disease, and nonalcoholic fatty liver disease. While it is well known that persistent immune activation and inflammation contribute to the development of these comorbid diseases, the mechanisms underlying this chronic activation remain incompletely understood. In this review, we will discuss emerging evidence that suggests that alterations in cellular metabolism may play a central role in driving this immune dysfunction in HIV patients on ART.

Prevalence of and Risk Factors for Prediabetes in Patients Infected With HIV

BACKGROUND

The use of highly active antiretroviral therapy (HAART) has resulted in a dramatic decrease in morbidity and mortality in HIV-infected patients. Components of HAART (e.g., protease inhibitors and nucleoside reverse transcriptase inhibitors), as well as HIV infection itself, can have significant effects on developing new-onset diabetes. The goals of this study were to determine the prevalence of prediabetes and to assess risk factors associated with prediabetes in a cohort of HIV-infected patients.

METHODS

This is a retrospective, cross-sectional study of 249 HIV-infected patients in an outpatient multidisciplinary HIV clinic in a university hospital. Patients with prediabetes were identified and compared with patients without prediabetes. The association between the prevalence of prediabetes and risk factors was analyzed.

RESULTS

Among 249 HIV-infected patients, the mean age was 46.3 years, and 54% were male. Prevalence of prediabetes was approximately 30%, and BMI ≥30 kg/m² was found to be a significant risk factor for developing prediabetes.

CONCLUSION

A high prevalence of prediabetes was observed in this cohort of HIV-infected patients. Interventions targeting HIV-infected patients with increased risk of prediabetes, especially individuals with a high BMI, is needed.

Autoimmunity and dysmetabolism of human acquired immunodeficiency syndrome

Acquired immunodeficiency syndrome (AIDS) remains ill-defined by lists of symptoms, infections, tumors, and disorders in metabolism and immunity. Low CD4 cell count, severe loss of body weight, pneumocystis pneumonia, and Kaposi's sarcoma are the major disease indicators. Lines of evidence indicate that patients living with AIDS have both immunodeficiency and autoimmunity. Immunodeficiency is attributed to deficits in the skin- and mucosa-defined innate immunity, CD4 T cells and regulatory T cells, presumably relating human immunodeficiency virus (HIV) infection. The autoimmunity in AIDS is evident by: (1) overproduction of autoantibodies, (2) impaired response of CD4 cells and CD8 cells, (3) failure of clinical trials of HIV vaccines, and (4) therapeutic benefits of immunosuppression following solid organ transplantation and bone marrow transplantation in patients at risk of AIDS. Autoantibodies are generated in response to antigens such as debris and molecules de novo released from dead cells, infectious agents, and catabolic events. Disturbances in metabolic homeostasis occur at the interface of immunodeficiency and autoimmunity in the development of AIDS. Optimal treatments favor therapeutics targeting on the regulation of metabolism to restore immune homeostasis.

Diabetes, metabolic syndrome and dyslipidemia in people living with HIV in Africa: re-emerging challenges not to be forgotten

BACKGROUND

The current challenge in managing people living with human immunodeficiency virus (PLWHIV) includes the identification and monitoring for comorbid health risks associated with HIV and its treatment and longer survival. Dyslipidemia, diabetes mellitus and metabolic syndrome are increasingly seen in PLWHIV.

OBJECTIVE

In this narrative review, we aimed to summarize the current knowledge about diabetes, dyslipidemia and metabolic syndrome in PLWHIV in Africa and also to discuss the challenges that patients as well as health authorities in Africa may face.

METHODS

PubMed and Google scholar published-English literatures concerning earlier mentioned entities regardless of time limit were critically reviewed.

RESULTS

The prevalence of metabolic disorders in HIV population in Africa was estimated to range from 2.1% to 26.5% for diabetes and 20.2% to 43.5% for pre-diabetes, 13% to 58% for metabolic syndrome and 13% to 70% for dyslipidemia.

CONCLUSION

The management of metabolic disorders and cardiovascular disease risks related to HIV is complex especially in Africa due to healthcare resources, but our experience suggests that metabolic clinic is beneficial to patients and staff and should be an important part of HIV services especially as the older HIV population is increasing. In this context, cardiovascular risk assessment of HIV-infected patients will become an important component of care in developing countries in Africa and strategies are needed to deal with progressive increase in the epidemic of type 2 diabetes, dyslipidemia and metabolic syndrome.

New-onset type 2 diabetes mellitus among patients receiving HIV care at Newlands Clinic, Harare, Zimbabwe: retrospective cohort analysis

OBJECTIVE

To assess the incidence and associated factors of Type 2 Diabetes Mellitus (T2DM) among people living with HIV (PLHIV) in Zimbabwe.

METHODS

We analysed data of all HIV-infected patients older than 16 years who attended Newlands Clinic between March 1, 2004 and April 29, 2015. The clinic considers patients whose random blood sugar is higher than 11.1 mmol/l and which is confirmed by a fasting blood sugar higher than 7.0 mmol/l to have T2DM. T2DM is also diagnosed in symptomatic patients who have a RBS >11.0 mmol/l. Risk factors for developing T2DM were identified using Cox proportional hazard models adjusted for confounding. Missing baseline BMI data were multiply imputed. Results are presented as adjusted hazard ratios (aHR) with 95% confidence intervals (95% CI).

RESULTS

Data for 4,110 participants were included: 67.2% were women; median age was 37 (IQR: 31-43) years. Median baseline CD4 count was 197 (IQR: 95-337) cells/mm3 . The proportion of participants with hypertension at baseline was 15.5% (n=638). Over a median follow-up time of 4.7 (IQR: 2.1-7.2) years, 57 patients developed T2DM; the overall incidence rate was 2.8 (95% CI: 2.1-3.6) per 1000 person-years of follow-up. Exposure to PIs was associated with T2DM (HR: 1.80, 95% CI: 1.04-3.09). In the multivariable analysis, obesity (BMI>30 kg/m2 ) (aHR=2.26, 95% CI: 1.17-4.36), age >40 years (aHR=2.16, 95% CI: 1.22-3.83) and male gender, (aHR=2.13, 95% CI: 1.22-3.72) were independently associated with the risk of T2DM. HIV-related factors (baseline CD4 cell count and baseline WHO clinical stage) were not independent risk factors for developing T2DM.

CONCLUSION

Although the incidence of T2DM in this HIV cohort was lower than that has been observed in others, our results show that risk factors for developing T2DM among HIV-infected people are similar to those of the general population. HIV-infected patients in sub-Saharan Africa need a comprehensive approach to care that includes better health services for prevention, early detection and treatment of chronic diseases especially among the elderly and obese.

Improved adipose tissue function with initiation of protease inhibitor-only ART

OBJECTIVES

Use of ART containing HIV PIs has previously been associated with toxicity in subcutaneous adipose tissue (SAT), potentially contributing to the development of lipodystrophy and insulin resistance. However, the effect of PIs on SAT function in ART-naive patients independent of other ART classes is unknown. This study aimed to elucidate the effect of initiating PI-only ART on SAT function in ART-naive subjects.

METHODS

In the HIVNAT-019 study, 48 HIV-infected, ART-naive Thai adults commencing PI-only ART comprising lopinavir/ritonavir/saquinavir for 24 weeks underwent assessments of fasting metabolic parameters and body composition. In a molecular substudy, 20 subjects underwent SAT biopsies at weeks 0, 2 and 24 for transcriptional, protein, mitochondrial DNA (mtDNA) and histological analyses. ClinicalTrials.gov registration number: NCT00400738.

RESULTS

Over 24 weeks, limb fat increased (+416.4 g, P = 0.023), coinciding with larger adipocytes as indicated by decreased adipocyte density in biopsies (-32.3 cells/mm2, P = 0.047) and increased mRNA expression of adipogenesis regulator PPARG at week 2 (+58.1%, P = 0.003). Increases in mtDNA over 24 weeks (+600 copies/cell, P = 0.041), decreased NRF1 mRNA expression at week 2 (-33.7%, P < 0.001) and increased COX2/COX4 protein ratio at week 24 (+288%, P = 0.038) indicated improved mitochondrial function. Despite decreased AKT2 mRNA at week 2 (-28.6%, P = 0.002) and increased PTPN1 mRNA at week 24 (+50.3%, P = 0.016) suggesting insulin resistance, clinical insulin sensitivity [by homeostasis model assessment (HOMA-IR)] was unchanged.

CONCLUSIONS

Initiation of PI-only ART showed little evidence of SAT toxicity, the changes observed being consistent with a return to health rather than contributing to lipodystrophy.

Hyperglycemia enhances kidney cell injury in HIVAN through down-regulation of vitamin D receptors

In the present study, we evaluated the effect of short term hyperglycemia on renal lesions in a mouse model (Tg26) of HIV-associated nephropathy (HIVAN). Control and Tg26 mice in groups (n=6) were administered either normal saline (FVBN or Tg) or streptozotocin (FVBN+STZ or Tg26+STZ). After two weeks, biomarkers were collected and kidneys were harvested. FVBN+ STZ and Tg26+STZ displayed elevated serum glucose levels when compared to FVBN and Tg26 respectively. Tg26+STZ displayed elevated (P<0.05) blood urea nitrogen (BUN) levels (P<0.05) and enhanced (P<0.01) proteinuria when compared to Tg26. Tg26+STZ displayed enhanced (P<0.001) number of sclerotic glomeruli and microcysts vs. Tg26. Renal tissues of Tg26 displayed down regulation of vitamin D receptor (VDR) expression and enhanced Ang II production when compared to FVBN mice. Hyperglycemia exacerbated down regulation of VDR and production of Ang II in FVBN and Tg mice. Hyperglycemia increased kidney cell reactive oxygen species (ROS) production and oxidative DNA damage in both FVBN and Tg26 mice. In in vitro studies, HIV down regulated podocyte VDR expression and also enhanced renin angiotensin system activation. In addition, both glucose and HIV stimulated kidney cell ROS generation and DNA damage and compromised DNA repair; however, tempol (superoxide dismutase mimetic), losartan (Ang II blocker) and EB1089 (VDR agonist) provided protection against DNA damaging effects of glucose and HIV. These findings indicated that glucose activated the RAS and inflicted oxidative stress-mediated DNA damage via down regulation of kidney cell VDR expression in HIV milieu both in vivo and in vitro.

Diabetes and HIV

The co-existence of diabetes mellitus and HIV infection poses significant challenges for both patient and physician. This article reviews the clinical problems, the implications for treatment plans and potential confusions that can arise when managing patients who have both conditions.

Prevalence of insulin resistance and risk of diabetes mellitus in HIV-infected patients receiving current antiretroviral drugs

OBJECTIVE

HIV-infected patients had a higher prevalence of insulin resistance (IR) and risk of diabetes mellitus (DM) than that observed in healthy controls, but there are no data about the current prevalence considering the changes in HIV presentation and the use of newer antiretroviral drugs.

DESIGN

Longitudinal study which involved 265 HIV patients without DM, receiving first (n=71) and advanced lines of antiretroviral therapy (n=194).

METHODS

Prevalence of IR according to clinical and anthropometric variables, including dual X-ray absorptiometry (DXA) scan evaluation. IR was defined as homeostasis model assessment of IR≥3.8. Incident DM was assessed during the follow-up.

RESULTS

First-line patients had a short time of HIV infection, less hepatitis C virus coinfection, and received mainly an efavirenz-based regimen. Overall, the prevalence of IR was 21% (55 patients, 6% in first-line, 27% in pretreated). In a logistic regression analysis, significant associations were found between the waist/hip circumference ratio (RR 10; 95% CI 1.66-16; P<0.01, per unit), and central fat in percentage (RR 1.08; 95% CI 1.01-1.17; P=0.04, per unit) as evaluated by DXA, and IR. During 770.8 patient-years, DM was diagnosed in 8% (22 patients), mostly in pretreated patients (10 vs 4%; P=0.1). Thus, the overall rate of incident DM was 2.85 per 100 person-years, mostly in previous IR (10.39 vs 0.82/100 person-years; P=0.01).

CONCLUSIONS

A lower prevalence of IR is observed in the current HIV-infected patients with fewer risk factors and receiving newer antiretroviral drugs. IR continues to identify patients at high risk for developing DM in the short term.

Alteration in pancreatic islet function in human immunodeficiency virus

Molecular mechanisms behind the defects in insulin production and secretion associated with antihuman immunodeficiency virus (anti-HIV) therapy and the development of HIV-associated lipodystrophy syndrome (HALS) are discussed in this article. Data suggesting insulin resistance on the beta cell and defects in first-phase insulin release of HALS patients are presented. Hepatic extraction of insulin, nonglucose insulin secretagogues and insulin-like growth factor release may exert influence on the demand of circulating insulin and on insulin secretion in HIV-infected patients. Finally, the paucity in understanding the incretin effects in HIV and HIV therapy in relation to insulin secretion is highlighted.

Pharmacological management of cardiovascular conditions and diabetes in older adults with HIV infection

This review looks at the evidence for potential and theoretical risks of combining antiretroviral treatment with drugs prescribed for cardiovascular disease and diabetes. These conditions are common in the HIV-infected population as a result of ageing and the increased risk associated with both HIV infection and antiretroviral intake.

HIV protease inhibitors and onset of cardiovascular diseases: a central role for oxidative stress and dysregulation of the ubiquitin-proteasome system

The successful roll-out of highly active antiretroviral therapy (HAART) has extended life expectancy and enhanced the overall well-being of HIV-positive individuals. There are, however, increased concerns regarding HAART-mediated metabolic derangements and its potential risk for cardiovascular diseases (CVD) in the long-term. Here certain classes of antiretroviral drugs such as the HIV protease inhibitors (PIs) are strongly implicated in this process. This article largely focuses on the direct PI-linked development of cardio-metabolic complications, and reviews the inter-linked roles of oxidative stress and the ubiquitin-proteasome system (UPS) as key mediators driving this process. It is proposed that PIs trigger reactive oxygen species (ROS) production that leads to serious downstream consequences such as cell death, impaired mitochondrial function, and UPS dysregulation. Moreover, we advocate that HIV PIs may also directly lower myocardial UPS function. The attenuation of cardiac UPS can initiate transcriptional changes that contribute to perturbed lipid metabolism, thereby fueling a pro-atherogenic milieu. It may also directly alter ionic channels and interfere with electrical signaling in the myocardium. Therefore HIV PI-induced ROS together with a dysfunctional UPS elicit detrimental effects on the cardiovascular system that will eventually result in the onset of heart diseases. Thus while HIV PIs substantially improve life expectancy and quality of life in HIV-positive patients, its longer-term side-effects on the cardiovascular system should lead to a) greater clinical awareness regarding its benefit-harm paradigm, and b) the development and evaluation of novel co-treatment strategies.

Endocrine and metabolic abnormalities among HIV-infected patients: A current review

Multiple endocrine and metabolic abnormalities have been reported among human immunodeficiency virus (HIV) patients since the pre-antiretroviral therapy era. These abnormalities present with either subclinical or overt clinical features. Endocrine and metabolic abnormalities primarily occur due to the direct destructive effects of HIV, malignancies and opportunistic infections on the varied endocrine glands and antiretroviral therapy-associated toxicities. This article offers a broad review on the commonly encountered endocrine and metabolic abnormalities among HIV-infected patients. Timely endocrine or metabolic evaluations should be performed among patients suspected with endocrine or metabolic dysfunction and appropriate treatment instituted since the majority of these conditions pose an increased risk of mortality if undiagnosed or untreated.

Nutrition and the HIV-associated lipodystrophy syndrome

HIV-associated lipodystrophy syndrome (HALS), comprising metabolic and morphological alterations, is a known side effect of highly active antiretroviral therapy (HAART). Evidence for the role of nutrition in the management of the systemic parameters of HALS is currently limited. In the present paper we review the current knowledge base surrounding HALS, focusing particularly on the role of nutrition in mitigating the systemic parameters of the syndrome. Reported prevalence of HALS was found to vary from 9 to 83 % due to lack of a standardised definition, as well as variations in assessment methods and in the study population used. HALS is associated with both morphological (lipoatrophy, lipohypertrophy) and metabolic (dyslipidaemia, glucose intolerance, diabetes, hypertension, endothelial dysfunction and atherosclerosis) alterations, which may occur singly or in combination, and are associated with an increased risk of CVD. HAART-induced adipocyte inflammation, oxidative stress and macrophage infiltration, as well as altered adipocyte function and mitochondrial toxicity, have been shown to be central to the development of HALS. The adipocyte, therefore, represents a plausible target for treatment. Pharmacological and surgical treatment interventions have shown effect. However, their use is associated with numerous adverse effects and complications. Targeted lifestyle interventions may provide a useful alternative for managing HALS owing to their safety and tolerability. A Mediterranean-style diet has been found to be effective in improving the systemic parameters of HALS. Furthermore, the effects of n-3 PUFA supplementation are encouraging and future randomised controlled trials investigating the beneficial effects of n-3 PUFA in HALS are justified.

Relationship between leptin levels and suppressed CD4 counts in HIV patients

OBJECTIVE

To examine the relationship between serum leptin levels and suppression of CD4 count in HIV-infected individuals with highly active antiretroviral therapy (HAART).

SUBJECTS AND METHODS

Thirty seropositive HIV male patients selected from the Infectious Disease Hospital were classified into two groups according to their immunological and virological response to HAART. The first group included 15 male patients with low viral load and low CD4 counts; the second included 15 male patients with low viral load and high CD4 counts. Morning serum leptin and tumor necrosis factor-α levels of HIV patients were measured and correlated with fasting serum insulin, Homeostasis Model Assessment for Insulin Resistance (HOMA-IR), HIV viral load and CD4 count.

RESULTS

Serum leptin levels were significantly higher in patients with high CD4 counts than in patients with low CD4 counts (mean serum leptin level 47.3 vs. 10.9 ng/ml, respectively; p < 0.0001). A positive correlation was observed between serum leptin levels and CD4 counts (r = 0.697; p < 0.0001); positive correlations were also seen between leptin levels and fasting serum insulin and HOMA-IR (r = 0.633, p < 0.0001, and r = 0.537, p < 0.003, respectively).

CONCLUSION

Serum leptin level was higher in HIV patients with high CD4 count and correlated with fasting serum insulin and HOMA-IR, thereby indicating that HAART treatment could lead to decreased levels of leptin in HIV patients, which might lead to impaired immunological recovery.

HIV infection and glycemic response to newly initiated diabetic medical therapy

OBJECTIVES

Type 2 diabetes (DM2) is increasingly common in HIV-infected individuals. Antiretroviral agents and chronic inflammation may adversely affect glycemic control. However, little is known about the effectiveness of diabetic medical therapy in HIV-infected patients. The objective of this study was to compare the effectiveness of initial diabetic medical therapy in patients with and without HIV infection.

DESIGN

A retrospective cohort study was conducted among adults with DM2 initiating diabetic medications within the Centers for AIDS Research Network of Integrated Clinical Systems cohort.

METHODS

Generalized estimating equations were used to compare changes in hemoglobin A1c (HbA1c) through the year after initiation of therapy, controlling for baseline HbA1c and demographic and clinical covariates.

RESULTS

Two hundred and eighty-six HIV-infected patients and 858 age and sex-matched HIV-uninfected patients initiated diabetic medications during the study period. Overall, patients had an adjusted absolute mean reduction in HbA1c of 1.04% [95% confidence interval (CI) -0.87 to -1.22] during the first year of therapy. HIV-infected patients achieved significantly smaller reductions in HbA1c, with an absolute mean difference of -0.17% (95% CI -0.28 to -0.06; P = 0.003). On subanalyses, HIV-infected patients on a protease inhibitor-based regimen had significantly smaller reductions in HbA1c compared to HIV-uninfected patients (adjusted absolute difference -0.21%, 95% CI -0.35 to -0.08; P = 0.002).

CONCLUSION

Patients with HIV infection who initiate diabetic medical therapy achieve smaller reductions in HbA1c than patients without HIV infection in the course of routine clinical care. This less robust response may in part be related to use of antiretrovirals that exacerbate insulin resistance, specifically protease inhibitors.

The HIV-1 protease inhibitor nelfinavir activates PP2 and inhibits MAPK signaling in macrophages: a pathway to reduce inflammation

The HIV-1 PI NFV has off-target effects upon host enzymes, including inhibition of the 20S proteasome, resulting in activation of PP1. HIV-1-associated monocyte/macrophage activation, in part a result of systemically elevated levels of microbial products including LPS, is associated with risk of mortality, independent of viremia or CD4 T cell loss. This study tested the hypothesis that activation of protein phosphatases by NFV would reduce activation of monocytes/macrophages through dephosphorylation of signal transduction proteins. NFV uniquely blocked LPS-induced production by human monocyte-derived macrophages of the inflammatory cytokines TNF and IL-6, as well as sCD14. Although NFV failed to modulate NF-κB, NFV treatment reduced phosphorylation of AKT and MAPKs. Inhibition of PP2 with okadaic acid blocked the anti-inflammatory effect of NFV, whereas the PP1 inhibitor calyculin A failed to counter the anti-inflammatory effects of NFV. For in vivo studies, plasma sCD14 and LPS were monitored in a cohort of 31 pediatric HIV-1 patients for over 2 years of therapy. Therapy, including NFV, reduced sCD14 levels significantly compared with IDV or RTV, independent of ΔLPS levels, VL, CD4 T cell frequency, or age. The hypothesis was supported as NFV induced activation of PP2 in macrophages, resulting in disruption of inflammatory cell signaling pathways. In vivo evidence supports that NFV may offer beneficial effects independent of antiviral activity by reducing severity of chronic innate immune activation in HIV-1 infection.

Measurement of insulin action: a tribute to Sir Harold Himsworth

Sir Harold Himsworth was a renowned clinician and researcher. Among his myriad of accomplishments, he was the first to differentiate diabetes mellitus into 'insulin-sensitive' and 'insulin-insensitive' forms. To help distinguish these two types, he developed the first test to measure insulin sensitivity, the insulin-glucose test. This article reviews Himsworth's pioneer methods and subsequent advances in the measurement of insulin action. The advantages and limitations of commonly used methods to assess insulin sensitivity are also examined.

South Asian Consensus Guidelines for the rational management of diabetes in human immunodeficiency virus/acquired immunodeficiency syndrome

As newer methods of management are made available, and accessible, survival rates with human immunodeficiency virus (HIV) are increasing. This means that chronic, metabolic complications of HIV are becoming more frequent in clinical practice, as acute morbidity is controlled. Management of HIV/acquired immunodeficiency syndrome (AIDS) is gradually expanding to include these chronic and metabolic complications of the disease, and the adverse effects associated with its treatments, including diabetes. Unfortunately, no guidelines are available to help the medical practitioners choose appropriate therapy for patients with these conditions. The aim of the South Asian Consensus Guidelines is to provide evidence-based recommendations to assist healthcare providers in the rational management of type 2 diabetes mellitus in patients with HIV. The development of these guidelines used systematic reviews of available evidence to form its key recommendations. These guidelines and associated review of literature represent a compilation of available knowledge regarding rational management of diabetes in HIV. Patients of diabetes with concomitant HIV infection are managed optimally with insulin therapy and judicious use of highly active antiretroviral therapy with suitable alternatives is also recommended. These guidelines should prove helpful to physicians, not only in South Asia, but also across the globe, while managing patients with coexistent HIV and diabetes.

Molecular mechanisms for insulin resistance in treated HIV-infection

Identification and characterization of the molecular mechanisms contributing to the high incidence of insulin resistance in HIV infected patients treated with combined antiretroviral therapy remains a critically important goal in the quest to improve the safety of antiretroviral treatment regimens. The use of in vitro model systems together with the investigation of drug-mediated effects on glucose homeostasis in animals and healthy human volunteers has provided important insight into the contribution of individual drugs to insulin resistance and affected cellular pathways. HIV protease inhibitor mediated blockade of glucose transport and nucleoside reverse transcriptase inhibitor mediated mitochondrial toxicity have been well characterized. Together with growing understanding of mediators of insulin resistance in non-HIV metabolic syndrome, additional cellular effects including the induction of endoplasmic reticulum and oxidative stress, altered adipocytokine secretion, and lipotoxicity have been integrated into this developing picture. Further elucidation of these mechanisms provides potential for the continued development of safer antiviral drugs and targeted treatment of insulin resistance in affected patients.

Type B insulin resistance syndrome associated with an immune reconstitution inflammatory syndrome in an HIV-infected woman

CONTEXT

Type B insulin resistance syndrome is a rare condition characterized by the presence of autoantibodies directed against the insulin receptor. It has been reported in association with autoimmune diseases such as systemic lupus erythematosus.

OBJECTIVE

We report a case of type B insulin resistance syndrome in a patient with HIV infection on highly active antiretroviral therapy (HAART).

PATIENT AND METHODS

A 27-yr-old African woman with ketosis-prone diabetes and HIV infection developed severe insulin resistance after the initiation of HAART. Standard oral glucose tolerance tests using 75 g of glucose performed 1, 2, and 3 months after the initiation of HAART showed severe hyperinsulinemia and hypoglycemia. Six months later, she developed symptomatic hyperglycemia resistant to high-dose insulin therapy. To determine the cause of insulin resistance, we assayed the titer of insulin receptor autoantibodies in the serum of the patient.

RESULTS

Plasma insulin receptor autoantibodies were present at the time of marked hyperglycemia and insulin resistance, confirming the diagnosis of type B insulin resistance syndrome. Simultaneously the diagnosis of immune reconstitution inflammatory syndrome was established according to increased CD4 T cell count, decreased plasma HIV1-RNA level, and tuberculosis reactivation, shortly after institution of HAART. Corticosteroid therapy improved insulin resistance and hyperglycemia.

CONCLUSION

We report the first case of type B insulin resistance syndrome associated with immune reconstitution inflammatory syndrome in an HIV-infected patient.

The effects of enfuvirtide therapy on body composition and metabolic parameters over 48 weeks in the TORO body imaging substudy

OBJECTIVE

The aim of the study was to compare the metabolic and morphological effects of enfuvirtide plus an optimized background (OB) regimen vs. OB alone (control group) in treatment-experienced patients in the T-20 vs. Optimized Regimen Only (TORO) studies.

METHODS

Body composition and metabolic changes were investigated in patients over 48 weeks, based on fasting chemistries, body weight, and other anthropometric measurements. Dual-energy X-ray absorptiometry (DEXA) and computed tomography (CT) scans were performed in a patient subgroup (n=155) at baseline and at weeks 24 and 48.

RESULTS

At week 48, mean changes from baseline were similar between treatment groups for glucose, insulin, C-peptide, total cholesterol, low-density lipoprotein (LDL) cholesterol, very low density lipoprotein (VLDL) cholesterol, high-density lipoprotein (HDL) cholesterol and triglyceride levels. The enfuvirtide group experienced a significant increase in body weight [mean change from baseline +0.99 kg; 95% confidence interval (CI) +0.54, +1.44] and, in those who had body scans, there was a significant increase in truncal fat (by DEXA: median change +419.4 g; 95% CI+71.3, +767.5) and total fat [visceral adipose tissue (VAT)+subcutaneous adipose tissue (SAT) by single-slice abdominal CT scan: median change +25.5 cm(2) ; 95% CI+8.9, +42.0] over 48 weeks; significant increases in these parameters were not seen in the control group. There was no significant change in truncal:peripheral fat ratio in either the enfuvirtide or the control group.

CONCLUSION

The addition of enfuvirtide to an OB regimen does not appear to have unfavourable effects on fat distribution or metabolic parameters.

Understanding diabetes in patients with HIV/AIDS

This paper reviews the incidence, pathogenetic mechanisms and management strategies of diabetes mellitus in patients with human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS). It classifies patients based on the aetiopathogenetic mechanisms, and proposes rational methods of management of the condition, based on aetiopathogenesis and concomitant pharmacotherapy.

Glyceroneogenesis is inhibited through HIV protease inhibitor-induced inflammation in human subcutaneous but not visceral adipose tissue

Glyceroneogenesis, a metabolic pathway that participates during lipolysis in the recycling of free fatty acids to triglycerides into adipocytes, contributes to the lipid-buffering function of adipose tissue. We investigated whether glyceroneogenesis could be affected by human immunodeficiency virus (HIV) protease inhibitors (PIs) responsible or not for dyslipidemia in HIV-infected patients. We treated explants obtained from subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) depots from lean individuals. We observed that the dyslipidemic PIs nelfinavir, lopinavir and ritonavir, but not the lipid-neutral PI atazanavir, increased lipolysis and decreased glyceroneogenesis, leading to an increased release of fatty acids from SAT but not from VAT. At the same time, dyslipidemic PIs decreased the amount of perilipin and increased interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) secretion in SAT but not in VAT. Parthenolide, an inhibitor of the NFκB pathway, counteracted PI-induced increased inflammation and decreased glyceroneogenesis. IL-6 (100 ng) inhibited the activity of phosphoenolpyruvate carboxykinase, the key enzyme of glyceroneogenesis, in SAT but not in VAT. Our data show that dyslipidemic but not lipid-neutral PIs decreased glyceroneogenesis as a consequence of PI-induced increased inflammation in SAT that could have an affect on adipocytes and/or macrophages. These results add a new link between fat inflammation and increased fatty acids release and suggest a greater sensitivity of SAT than VAT to PI-induced inflammation.

What is type 2 diabetes?

Type 2 diabetes is a common metabolic disorder characterized by chronic hyperglycaemia. It is associated with a reduced life expectancy owing to a greater risk of heart disease, stroke, peripheral neuropathy, renal disease, blindness and amputation. At present, the best predictors of increased diabetes risk and progression to diabetes are an elevated fasting plasma glucose, an abnormal glucose tolerance test, obesity and evidence of impaired insulin action. However, the mechanisms by which people with impaired fasting glucose and/or abnormal glucose tolerance `progress' to overt type 2 diabetes are not completely understood. Moreover, type 2 diabetes is defined in a `negative' sense (hyperglycaemia occurring in the absence of evidence of autoimmune destruction of islet cells). This has two consequences - one is the heterogeneity of the disease, the other is that the disease is identified purely in terms of hyperglycaemia, to a certain extent ignoring the underlying mechanisms that lead to the disease. In this review, we explore some of these mechanisms in an attempt to remind readers that hyperglycaemia is one of many abnormalities in type 2 diabetes.

Effects of the HIV protease inhibitor ritonavir on GLUT4 knock-out mice

HIV protease inhibitors acutely block glucose transporters (GLUTs) in vitro, and this may contribute to altered glucose homeostasis in vivo. However, several GLUT-independent mechanisms have been postulated. To determine the contribution of GLUT blockade to protease inhibitor-mediated glucose dysregulation, the effects of ritonavir were investigated in mice lacking the insulin-sensitive glucose transporter GLUT4 (G4KO). G4KO and control C57BL/6J mice were administered ritonavir or vehicle at the start of an intraperitoneal glucose tolerance test and during hyperinsulinemic-euglycemic clamps. G4KO mice exhibited elevated fasting blood glucose compared with C57BL/6J mice. Ritonavir impaired glucose tolerance in control mice but did not exacerbate glucose intolerance in G4KO mice. Similarly, ritonavir reduced peripheral insulin sensitivity in control mice but not in G4KO mice. Serum insulin levels were reduced in vivo in ritonavir-treated mice. Ritonavir reduced serum leptin levels in C57BL/6J mice but had no effect on serum adiponectin. No change in these adipokines was observed following ritonavir treatment of G4KO mice. These data confirm that a primary effect of ritonavir on peripheral glucose disposal is mediated through direct inhibition of GLUT4 activity in vivo. The ability of GLUT4 blockade to contribute to derangements in the other molecular pathways that influence insulin sensitivity remains to be determined.

Management of the Metabolic Syndrome in Patients With Human Immunodeficiency Virus

Patients with human immunodeficiency virus (HIV) are an increasing subpopulation of patients seen in endocrine/ diabetes clinics. This article explores evidence-based treatment recommendations for patients with metabolic syndrome who are also positive for HIV. Patients infected with HIV may manifest metabolic abnormalities. They often present with low high-density lipoprotein (HDL-C), hypertension, visceral adiposity, and insulin resistance, among other symptoms consistent with features of the metabolic syndrome. The etiologies of the metabolic abnormalities are not completely understood. The role of highly active antiretroviral therapy (HAART) and the separate effect of HIV on patients who are surviving longer may contribute to the increased incidence of the development of the metabolic syndrome. The role of the health care team is to provide patient education to patients with HIV concerning lifestyle modification in order to prevent complications related to the metabolic syndrome.

The protease inhibitor combination lopinavir/ritonavir does not decrease insulin secretion in healthy, HIV-seronegative volunteers

BACKGROUND

HIV protease inhibitors have been shown to worsen glucose and lipid metabolism. Recent studies have suggested that protease inhibitors can impair insulin secretion in HIV-infected patients. We studied the effects of the protease inhibitor combination lopinavir and ritonavir on insulin secretion, insulin sensitivity, and lipid metabolism in HIV-negative persons.

METHODS

A combination dose of lopinavir 400 mg and ritonavir 100 mg was given twice daily to eight HIV-seronegative men for 4 weeks. Fasting glucose, insulin, lipid, and lipoprotein profiles; oral glucose tolerance; insulin secretion and insulin-mediated glucose disposal by hyperglycemic clamp; and body composition by dual energy X-ray absorptiometry were determined before and after lopinavir/ritonavir administration.

RESULTS

There was no change in first-phase insulin secretion (2.82 +/- 0.30 versus 2.71 +/- 0.31 nmol/l; P = 0.60), as well as fasting insulin and glucose levels, oral glucose tolerance, or insulin-mediated glucose disposal after 4 weeks administration of lopinavir/ritonavir. However, there were significant increases in fasting triglycerides (1.02 +/- 0.13 versus 2.20 +/- 0.31 mmol/l; P = 0.001), total cholesterol (4.42 +/- 0.30 versus 5.70 +/- 0.60 mmol/l; P = 0.007), and apo B-100 levels (0.86 +/- 0.07 versus 1.07 +/- 0.11 g/l; P = 0.0009). High-density lipoprotein cholesterol decreased (0.99 +/- 0.11 versus 0.82 +/- 0.10 mmol/l; P = 0.005). There were no changes in body composition, weight, or body fat.

CONCLUSION

Although administration of lopinavir/ritonavir to healthy, HIV-seronegative volunteers for 4 weeks resulted in increased triglyceride and decreased high-density lipoprotein cholesterol levels, there was no change in first-phase insulin secretion during the hyperglycemic clamp. The reported effects of protease inhibitor on insulin secretion in HIV-infected individuals may be due to changes in HIV-related factors and not a direct drug effect.

HIV protease inhibitors and insulin resistance: lessons from in-vitro, rodent and healthy human volunteer models

PURPOSE OF REVIEW

Although the use of HIV protease inhibitors is linked to the development of insulin resistance and other metabolic changes that greatly increase the risk for cardiovascular disease, the molecular mechanisms responsible remain incompletely understood. This review summarizes recent advances that have been made in understanding the relative contributions of individual protease inhibitors to both acute and chronic insulin resistance together with newly identified cellular mediators.

RECENT FINDINGS

Individual protease inhibitors, alone and in combination, have differing propensities to induce insulin resistance, reflecting relative differences in both affinities for identified molecular targets and pharmacokinetic profiles. Several of the most recent protease inhibitors approved for clinical use or in development appear to be less likely to induce insulin resistance. In addition to direct effects on glucose transporter-4 activity, induction of oxidative stress, proteosome inhibition, alteration of adipokine levels, and changes in suppressors of cytokine signaling-1 have been implicated.

SUMMARY

A better understanding of the propensity of individual HIV protease inhibitors to produce insulin resistance will allow the tailoring of individual treatment plans based upon overall risk for diabetes. The elucidation of the molecular mechanisms for alterations in glucose homeostasis will facilitate the development of newer generations of HIV protease inhibitors that maintain their clinical efficacy without contributing to the development of diabetes mellitus and other proatherogenic effects.