Chronic hyperlactatemia in HIV-infected patients taking antiretroviral therapy

Exploring the relationship between hyperlactatemia and anemia

Hyperlactatemia and anemia commonly coexist and their crosstalk is a longstanding mystery with elusive mechanisms involved in physical activities, infections, cancers, and genetic disorders. For instance, hyperlactatemia leads to iron restriction by upregulating hepatic hepcidin expression. Increasing evidence also points to lactate as a crucial signaling molecule rather than merely a metabolic byproduct. Here, we discuss the mutual influence between anemia and hyperlactatemia. This opinion calls for a reconsideration of the multifaceted roles of lactate and lactylation in anemia and emphasizes the need to fill knowledge gaps, including the dose dependence of lactate's effects, its sources, and its subcellular localization.

Management of Human Immunodeficiency Virus in the Emergency Department

Over the past 30 years, significant advances have transformed the landscape of human immunodeficiency virus (HIV) care in the emergency department. Diagnosis and management of HIV has improved, resulting in a decline in the incidence of acquired immunodeficiency syndrome (AIDS)-defining infections. Advances in pharmacology have led to fewer serious medication toxicities and more tolerable regimens. Emergency providers have played an increasingly important role in HIV screening and diagnosis of acute infection. Provision of postexposure prophylaxis is expanding from a focus on occupational exposure to include all high-risk cases.

Evaluation of antiretroviral effect on mitochondrial DNA depletion among HIV-infected patients in Bali

Background

Nucleoside reverse transcriptase inhibitors (NRTIs) are the cornerstone of highly active antiretroviral therapy combination regimens for HIV infection. Unfortunately, NRTIs have been noticeably associated with many adverse effects related to mitochondrial toxicity leading to mitochondrial deoxyribonucleic acid (mtDNA) depletion. However, similar mitochondrial dysfunction has recently been found even in antiretroviral therapy-naïve patients, suggesting HIV itself could contribute to this abnormality. In this study, we determine whether mtDNA depletion was present in either antiretroviral therapy-naïve or NRTI-treated patients at Sanjiwani Hospital, Bali, Indonesia.

Patients and methods

A cross-sectional study was conducted from the peripheral blood mononuclear cells of HIV patients. Specifically, the relative content of mtDNA (mtRNR1 gene) to nuclear DNA (ASPOLG gene) was determined by real-time polymerase chain reaction. Data were analyzed with SPSS 16.0 software and GraphPad Prism 7.02.

Results

A total of 84 samples (67 on NRTIs and 17 HIV-naïve) were suitable for analysis. We identified 21.4% of the samples (18/84) with mtDNA:nDNA ratio <1. Although it was not significant (P=0.121), the median mtDNA:nDNA ratio of HIV-naïve group was slightly higher (median 1.8; interquartile range [IQR]: 1.1-2.1) than NRTI-treated patients (median 1.5; IQR: 1.3-2.85). Tenofovir-based NRTI was more frequently used (73.13%) than zidovudine-based NRTI (26.86%). The period for which NRTI was used probably contributed to the ratio of mtDNA:nDNA. The median ratio of mtDNA:nDNA zidovudine-treated patients was slightly lower (median 1.2; IQR: 1.08-1.98) when compared to tenofovir-based NRTI (median 1.6; IQR: 1.05-2.10), with the median period of former treatment being significantly longer (P<0.001). Although these data overall indicate that NRTI treatment had no effect on mtDNA:nDNA ratios, patients who undergo more than 12 months of NRTIs treatment show a decrease in the ratio; however, further study is required.

Conclusion

Almost one-fourth of the samples showed a lower mtDNA:nDNA ratio. The decreasing of the ratio mtDNA:nDNA was most likely present after 12 months of NRTI treatment.

Risk Factors for Hyperlactataemia in HIV-Infected Patients, Aquitaine Cohort, 1999–2003

The objectives of our study were to describe the characteristics of a subset of patients who had been prescribed serum lactate in clinical practice within a large cohort of HIV-infected patients and to determine the factors associated with hyperlactataemia. Hyperlactataemia (⩾T2 mmol/l) was found in 219 [29% (95% confidence interval: 25.3–31.7)] of the 768 HIV-infected participants. In multivariate analysis (logistical regression), an increased risk of hyperlactataemia was associated with increasing age, CD4 count <500/mm3, triglycerides >2.2 mmol/L, lipoatrophy and stavudine use. In a second model coding for the NRTI-based drug combinations, only those including stavudine were associated with an increased risk of hyperlactataemia. In a third model including exposure duration to NRTIs, we estimated a 20% increased risk of hyperlactataemia per year of exposure to didanosine or stavudine. The risk of hyperlactataemia could increase over time in patients treated with these drugs and is also closely associated with increased age, decreased CD4 count, lipodystrophy and increased plasma triglycerides. It could be proposed that patients having one or more of these risk factors undergo regular monitoring of plasma lactate and renal function to prevent lactic acidosis.

Intracellular expression of Tat alters mitochondrial functions in T cells: a potential mechanism to understand mitochondrial damage during HIV-1 replication

Background

HIV-1 replication results in mitochondrial damage that is enhanced during antiretroviral therapy (ART). The onset of HIV-1 replication is regulated by viral protein Tat, a 101-residue protein codified by two exons that elongates viral transcripts. Although the first exon of Tat (aa 1–72) forms itself an active protein, the presence of the second exon (aa 73–101) results in a more competent transcriptional protein with additional functions.

Results

Mitochondrial overall functions were analyzed in Jurkat cells stably expressing full-length Tat (Tat101) or one-exon Tat (Tat72). Representative results were confirmed in PBLs transiently expressing Tat101 and in HIV-infected Jurkat cells. The intracellular expression of Tat101 induced the deregulation of metabolism and cytoskeletal proteins which remodeled the function and distribution of mitochondria. Tat101 reduced the transcription of the mtDNA, resulting in low ATP production. The total amount of mitochondria increased likely to counteract their functional impairment. These effects were enhanced when Tat second exon was expressed.

Conclusions

Intracellular Tat altered mtDNA transcription, mitochondrial content and distribution in CD4+ T cells. The importance of Tat second exon in non-transcriptional functions was confirmed. Tat101 may be responsible for mitochondrial dysfunctions found in HIV-1 infected patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12977-015-0203-3) contains supplementary material, which is available to authorized users.

Chronic liver disease in the human immunodeficiency virus patient

There are an estimated 40 million HIV infected individuals worldwide, with chronic liver disease being the 2nd leading cause of mortality in this population. Elevated liver functions are commonly noted in HIV patients and the etiologies are varied. Viral hepatitis B and C, fatty liver and drug induced liver injury are more common. Treatment options for viral hepatitis C are rapidly evolving and are promising, but treatments are limited for the other conditions and is primarily supportive. Opportunistic infections of the liver are now uncommon. Irrespective of etiology, management requires referral to specialized centers and with due diligence mortality can be reduced.

A review of the toxicity of HIV medications

Antiretroviral therapy has changed human immunodeficiency virus (HIV) infection from a near-certainly fatal illness to one that can be managed chronically. More patients are taking antiretroviral drugs (ARVs) for longer periods of time, which naturally results in more observed toxicity. Overdose with ARVs is not commonly reported. The most serious overdose outcomes have been reported in neonates who were inadvertently administered supratherapeutic doses of HIV prophylaxis medications. Typical ARV regimens include a "backbone" of two nucleoside reverse transcriptase inhibitors (NRTI) and a "base" of either a protease inhibitor (PI) or nonnucleoside reverse transcriptase inhibitor. New classes of drugs called entry inhibitors and integrase inhibitors have also emerged. Older NRTIs were associated with mitochondrial toxicity, but this is less common in the newer drugs, emtricitabine, lamivudine, and tenofovir. Mitochondrial toxicity results from NRTI inhibition of a mitochondrial DNA polymerase. Mitochondrial toxicity manifests as myopathy, neuropathy, hepatic failure, and lactic acidosis. Routine lactate assessment in asymptomatic patients is not indicated. Lactate concentration should be obtained in patients taking NRTIs who have fatigue, nausea, vomiting, or vague abdominal pain. Mitochondrial toxicity can be fatal and is treated by supportive care and discontinuing NRTIs. Metabolic cofactors like thiamine, carnitine, and riboflavin may be helpful in managing mitochondrial toxicity. Lipodystrophy describes changes in fat distribution and lipid metabolism that have been attributed to both PIs and NRTIs. Lipodystrophy consists of loss of fat around the face (lipoatrophy), increase in truncal fat, and hypertriglyceridemia. There is no specific treatment of lipodystrophy. Clinicians should be able to recognize effects of chronic toxicity of ARVs, especially mitochondrial toxicity.

Mid-ATR-FTIR spectroscopic profiling of HIV/AIDS sera for novel systems diagnostics in global health

Global health, whether in developed or developing countries, is in need of robust systems diagnostics for major diseases, such as HIV/AIDS, impacting the world populations. Fourier transform Infrared (FTIR) spectroscopy of serum is a quick and reagent-free methodology with which to analyze metabolic alterations such as those caused by disease or treatment. In this study, Attenuated Total Reflectance Fourier-Transform (ATR-FTIR) Spectroscopy was investigated as a means of distinguishing HIV-infected treatment-experienced (HIV(pos) ART(pos), n=39) and HIV-infected-treatment-naïve (HIV(pos) ART(neg), n=16) subjects from uninfected control subjects (n=30). Multivariate pattern recognition techniques, including partial least squares discriminant analysis (PLS-DA) and orthogonal partial least squares discriminant analysis (OPLS-DA), successfully distinguished sample classes, while univariate approaches identified significant differences (p<0.05) after Benjamini-Hochberg corrections. OPLS-DA discriminated between all groups with sensitivity, specificity, and accuracy of >90%. Compared to uninfected controls, HIV(pos) ART(pos) and HIV(pos) ART(neg) subjects displayed significant differences in spectral regions linked to lipids/fatty acids (3010 cm(-1)), carbohydrates (1299 cm(-1); 1498 cm(-1)), glucose (1035 cm(-1)), and proteins (1600 cm(-1); 1652 cm(-1)). These are all molecules shown by conventional biochemical analysis to be affected by HIV/ART interference. The biofluid metabolomics approach applied here successfully differentiated global metabolic profiles of HIV-infected patients and uninfected controls and detected potential biomarkers for development into indicators of host response to treatment and/or disease progression. Our findings therefore contribute to ongoing efforts for capacity-building in global health for robust omics science and systems diagnostics towards major diseases impacting population health.

Blood lactate in HIV-infected children on antiretroviral therapy in rural South Africa

We studied blood lactate levels in 253 South African children on antiretroviral therapy. The prevalence of hyperlactatemia was 68% and severity was mild in most cases (69%). There was no association of symptoms and/or signs with hyperlactatemia. Independent predictors were lipo-dystrophy, time on antiretroviral therapy and baseline CD4 count. Increased awareness of hyperlactatemia in African children on antiretroviral therapy is warranted.

Hyperlactatemia in a group of HIV patients living in Yaounde-Cameroon

Background and aim

Prolonged exposure to highly active antiretroviral therapy (HAART) is associated with adverse effects such as hyperlactatemia. We determined the prevalence and risk factors for developing hyperlactatemia among human immunodeficiency virus (HIV)-infected cameroonians on antiretroviral therapy (ART).

Methods

We conducted a cross-sectional study from January to April 2012 involving 91 HIV-infected patients receiving ART for at least 12 months and 30 HIV-infected patients who have never received ART (ART-naïve patients). Plasma lactate levels were determined after at least 12 hours of overnight fasting and hyperlactatemia defined as lactate concentrations ≥ 3 mmol/L. The prevalence of hyperlactatemia was determined and the risk factors were analyzed by a multivariate logistic regression model.

Results

The mean lactataemia was significantly higher in the group of HIV patients currently taking ART than in the ART-naïve one (2.3 ± 1.3 and 1.7 ± 0.7 mmol/L respectively, p = 0.002). Patients on first line ART regimens had significantly higher lactatemia than those on second line regimens (2.5 ± 1.5 and 1.9 ± 0.7 mmol/L respectively, p = 0.014). The prevalence of hyperlactatemia in HIV patients receiving ART and in ART-naïve HIV patients was respectively 18.7 and 6.7% (p = 0.095). ART-exposure (adjusted odds ratio (aOR) 5.44, 95% confidence interval (CI) 1.06 – 27.84; p = 0.042) and being on a first line regimen (aOR 16.22, 95% CI 1.57 – 167.91; p = 0.019) were independent strong predictors of hyperlactatemia.

Conclusion

Hyperlactatemia was not rare in our study population. Being on a first line regimen constitutes an important risk factor for developing hyperlactatemia. Measurement of plasma lactate may be useful in optimizing the management of HIV-positive persons on ART.

Longitudinal lactate levels from routine point-of-care monitoring in adult Malawian antiretroviral therapy patients: associations with stavudine toxicities

Introduction

Stavudine is still widely used in under-resourced settings such as Malawi due to its low price. It frequently causes peripheral neuropathy and lipodystrophy and increases the risk of lactic acidosis and other high lactate syndromes.

Methods

We studied the association of longitudinal lactate levels, obtained by routine, 3-monthly point-of-care monitoring, with peripheral neuropathy, lipodystrophy and high lactate syndromes in adult Malawians who were in the second year of stavudine containing antiretroviral therapy (ART).

Results

Point-of-care lactate measurements were feasible in a busy urban ART clinic. Of 1170 lactate levels collected from 253 patients over the course of one year, 487 (41.8%) were elevated (>2.2mg/dl), 58 (5.0%) were highly elevated (>3.5mg/dl). At least one elevated lactate level occurred in 210 (83.0%) of patients and sustained hyperlactatemia in 65 (26.4%). In random effects analyses lipodystrophy and peripheral neuropathy were associated with higher lactate levels. Only five patients developed high lactate syndromes (one lactic acidosis) of whom no preceding lactate measurements were available because events had started before enrolment. Lactate levels significantly decreased over time and no high lactate syndromes were observed after the 15th month on ART.

Conclusion

Lipodystrophy and peripheral neuropathy were associated with higher lactate levels. Lactate levels decreased over time, coinciding with absence of new high lactate syndromes after the 15th month on ART.

Management of persons infected with human immunodeficiency virus requiring admission to the intensive care unit

Rates of admission to the intensive care unit (ICU) for persons infected with human immunodeficiency virus (HIV) remain relatively unchanged in the modern era despite advances in antiretroviral therapy (ART) and improvements in ICU survival. Critical care may be required for patients with HIV because of severe opportunistic infections or malignancy, antiretroviral drug toxicity, or critical illness seemingly unrelated to HIV, and each of these scenarios may present different management challenges. In this article, the epidemiology of HIV-related ICU admission is reviewed and key management issues are discussed.

Fatigue-related gene networks identified in CD(14)+ cells isolated from HIV-infected patients: part I: research findings

PURPOSE

Human immunodeficiency virus (HIV)-related fatigue (HRF) is multicausal and potentially related to mitochondrial dysfunction caused by antiretroviral therapy with nucleoside reverse transcriptase inhibitors (NRTIs).

METHODOLOGY

The authors compared gene expression profiles of CD14(+) cells of low versus high fatigued, NRTI-treated HIV patients to healthy controls (n = 5/group). The authors identified 32 genes predictive of low versus high fatigue and 33 genes predictive of healthy versus HIV infection. The authors constructed genetic networks to further elucidate the possible biological pathways in which these genes are involved. RELEVANCE FOR NURSING PRACTICE: Genes including the actin cytoskeletal regulatory proteins Prokineticin 2 and Cofilin 2 along with mitochondrial inner membrane proteins are involved in multiple pathways and were predictors of fatigue status. Previously identified inflammatory and signaling genes were predictive of HIV status, clearly confirming our results and suggesting a possible further connection between mitochondrial function and HIV. Isolated CD14(+) cells are easily accessible cells that could be used for further study of the connection between fatigue and mitochondrial function of HIV patients.

IMPLICATION FOR PRACTICE

The findings from this pilot study take us one step closer to identifying biomarker targets for fatigue status and mitochondrial dysfunction. Specific biomarkers will be pertinent to the development of methodologies to diagnosis, monitor, and treat fatigue and mitochondrial dysfunction.

Audiological monitoring for ototoxic tuberculosis, human immunodeficiency virus and cancer therapies in a developing world setting

Ototoxic drugs are widely used in the developing world, without audiological monitoring. Epidemiological data on ototoxic deafness are lacking for developing countries. The public health aspect of ototoxicity is often overlooked, to the detriment of the individual patient. This paper reviews ototoxic hearing loss, particularly in sub-Saharan Africa, and also assesses the impact of treatments for tuberculosis, cancer and human immunodeficiency virus (the latter including highly active antiretroviral therapy) on ototoxic hearing loss. The paper also discusses obstacles to audiological monitoring for ototoxicity in the developing world, and the potential of audiology screening using applications for mobile devices.

Hyperlactataemia in HIV-infected subjects initiating antiretroviral therapy in a large randomized study (a substudy of the INITIO trial)

OBJECTIVE

The aim of the study was to evaluate the predictive value of clinical and molecular risk factors, including peripheral blood mononuclear cell (PBMC) mitochondrial DNA (mtDNA) and mitochondrial RNA (mtRNA), for the development of lactic acidosis (LA) and symptomatic hyperlactataemia (SHL).

METHODS

In a substudy of a large multicentre, randomized trial of three antiretroviral regimens, all containing didanosine (ddI) and stavudine (d4T), in antiretroviralnaïve, HIV-1-infected patients, patients with LA/SHL ('cases') were compared with those without LA/SHL in a univariate analysis, with significant parameters analysed in a multivariate model. In a molecular substudy, PBMC mtDNA and mtRNA from cases and matched controls at baseline and time of event were examined.

RESULTS

In 911 subjects followed for a median of 192 weeks, 24 cases were identified (14 SHL and 10 LA). In univariate analysis, cases were more likely to be female (P=0.05) and to have a high body mass index (BMI) (P=0.02). In multivariate analyses, only BMI remained an independent predictor of the development of LA/SHL (P=0.03). Between cases and controls there was no significant difference in mtDNA copy number at baseline (389 vs. 411 copies/cell, respectively; P=0.60) or at time of event (329 vs. 474 copies/cell, respectively; P=0.21), in the change in mtDNA copy number from baseline to event (-65 vs. +113 copies/cell, respectively; P=0.12), in mtRNA expression at baseline or time of event, or in the change in mtRNA expression from baseline to event.

CONCLUSION

The development of LA/SHL was associated with increased BMI, but PBMC mtDNA and mtRNA did not predict LA/SHL. This demonstrates the ineffectiveness of routine measurement of PBMC mtDNA in patients on ddI and d4T as a means of predicting development of LA/SHL.

Cost-effectiveness of antiretroviral regimens in the World Health Organization's treatment guidelines: a South African analysis

OBJECTIVE

the World Health Organization (WHO) recently changed its first-line antiretroviral treatment guidelines in resource-limited settings. The cost-effectiveness of the new guidelines is unknown.

DESIGN

comparative effectiveness and cost-effectiveness analysis using a model of HIV disease progression and treatment.

METHODS

using a simulation of HIV disease and treatment in South Africa, we compared the life expectancy, quality-adjusted life expectancy, lifetime costs, and cost-effectiveness of five initial regimens. Four are currently recommended by the WHO: tenofovir/lamivudine/efavirenz; tenofovir/lamivudine/nevirapine; zidovudine/lamivudine/efavirenz; and zidovudine/lamivudine/nevirapine. The fifth is the most common regimen in current use: stavudine/lamivudine/nevirapine. Virologic suppression and toxicities determine regimen effectiveness and cost-effectiveness.

RESULTS

choice of first-line regimen is associated with a difference of nearly 12 months of quality-adjusted life expectancy, from 135.2 months (tenofovir/lamivudine/efavirenz) to 123.7 months (stavudine/lamivudine/nevirapine). Stavudine/lamivudine/nevirapine is more costly and less effective than zidovudine/lamivudine/nevirapine. Initiating treatment with a regimen containing tenofovir/lamivudine/nevirapine is associated with an incremental cost-effectiveness ratio of $1045 per quality-adjusted life year compared with zidovudine/lamivudine/nevirapine. Using tenofovir/lamivudine/efavirenz was associated with the highest survival, fewest opportunistic diseases, lowest rate of regimen substitution, and an incremental cost-effectiveness ratio of $5949 per quality-adjusted life year gained compared with tenofovir/lamivudine/nevirapine. Zidovudine/lamivudine/efavirenz was more costly and less effective than tenofovir/lamivudine/nevirapine. Results were sensitive to the rates of toxicities and the disutility associated with each toxicity.

CONCLUSION

among the options recommended by WHO, we estimate only three should be considered under normal circumstances. Choice among those depends on available resources and willingness to pay. Stavudine/lamivudine/nevirapine is associated with the poorest quality-adjusted survival and higher costs than zidovudine/lamivudine/nevirapine.

Risk factors for fatality in HIV-infected patients with dideoxynucleoside-induced severe hyperlactataemia or lactic acidosis

BACKGROUND

Lactic acidosis (LA) and severe hyperlactataemia (HL) are infrequent but serious complications of antiretroviral therapy that have been associated with a high fatality rate.

METHODS

In a multinational retrospective cohort study, LA was defined as arterial blood pH<7.35, bicarbonate <20 mmol/l and lactate above normal, and HL as confirmed blood lactate >5 mmol/l. Logistic regression was used to identify factors associated with fatality. Sensitivity and specificity of different case definitions as predictors of death were compared.

RESULTS

The overall case-fatality rate was 19/110 (17.3%), but among acidotic patients it was 33% (16/49 cases). There were 10 asymptomatic patients and none of them died as a consequence of the event. The median lactate for fatal, non-fatal and all patients was 8.3 mmol/l (IQR 7.2-13.1), 6.4 mmol/l (IQR 5.4-7.8) and 6.7 mmol/l (IQR 5.5-8.1), respectively. After adjusting for age and current CD4(+) T-cell count, lactate >7 mmol/l (OR 6.27, 95% CI 1.13-34.93), blood bicarbonate <12 mmol/l (OR 10.02 relative to >18 mmol/l, 95% CI 1.33-75.65) and concurrent opportunistic infections (OR 8.69, 95% CI 1.45-52.22) were independently associated with case fatality. Blood lactate >7 mmol/l showed a sensitivity of 84% for fatality with a specificity of 60%, whereas bicarbonate <12 mmol/l showed a better specificity (85%) but a poorer sensitivity (42%). Bicarbonate <18 mmol/l appears to be as good as lactate <7 mmol/l at predicting death (sensitivity 90% and specificity 54%).

CONCLUSIONS

Our data suggest that blood lactate >7 mmol/l and blood bicarbonate <18 mmol/l appear to predict death and might help clinicians in selecting patients who may benefit from more intense monitoring.

Transient elastography: A non-invasive tool for assessing liver fibrosis in HIV/HCV patients

AIM: To assess the prevalence of advanced liver fibrosis (ALF) in human immunodeficiency virus (HIV), hepatitis C virus (HCV) and HIV/HCV patients using transient elastography, and to identify factors associated with ALF.

METHODS: Between September 2008 and October 2009, 71 HIV mono-infected, 57 HIV/HCV co-infected and 53 HCV mono-infected patients on regular follow-up at our Center were enrolled in this study. Alcohol intake, the main parameters of liver function, presence of HCV-RNA, HIV-RNA, duration of highly active anti-retroviral therapy (HAART) and CD4 cell count were recorded. ALF was defined as liver stiffness (LS) ≥ 9.5 kPa. To estimate liver fibrosis (LF) a further 2 reliable biochemical scores, aspartate aminotransferase platelet ratio index (APRI) and FIB-4, were also used.

RESULTS: LS values of co-infected patients were higher than in either HIV or HCV mono-infected patients (χ²_MH = 4, P < 0.04). In fact, LS ≥ 9.5 was significantly higher in co-infected than in HIV and HCV mono-infected patients (χ² = 5, P < 0.03). Also APRI and the FIB-4 index showed more LF in co-infected than in HIV mono-infected patients (P < 0.0001), but not in HCV mono-infected patients. In HIV⁄HCV co-infected patients, the extent of LS was significantly associated with alcohol intake (P < 0.04) and lower CD4+ cell count (P < 0.02). In HCV patients, LS was correlated with alcohol intake (P < 0.001) and cholesterol levels (P < 0.03). Body mass index, diabetes, HCV- and HIV-viremia were not significantly correlated with LS. In addition, 20% of co-infected patients had virologically unsuccessful HAART; in 50% compliance was low, CD4+ levels were < 400 cells/mm³ and LS was > 9.5 kPa. There was no significant correlation between extent of LF and HAART exposure or duration of HAART exposure, in particular with specific dideoxynucleoside analogues.

CONCLUSION: ALF was more frequent in co-infected than mono-infected patients. This result correlated with lower CD4 levels. Protective immunological effects of HAART on LF progression outweigh its hepatotoxic effects.

Nucleoside reverse transcriptase inhibitor toxicity and mitochondrial DNA

IMPORTANCE OF THE FIELD

HIV/AIDS is a worldwide epidemic. While there remains no cure for the HIV-1 infection, nucleoside reverse transcriptase inhibitors (NRTIs) have helped transform the HIV-1 infection from a lethal disease into a chronic illness. Though NRTIs inhibit HIV-1 replication, they exhibit side effects in human tissues that appear to result from NRTI inhibition of human mitochondrial polymerase γ (pol γ).

AREAS COVERED IN THIS REVIEW

this review discusses the current knowledge of NRTI-induced toxicity, specifically the inhibition of pol γ and the mitochondrial toxicity from incorporation of NRTIs into mitochondrial DNA. Details are discussed about general mechanisms of NRTI toxicity and how specific tissue toxicities in mitochondria relate to clinical manifestation.

WHAT THE READER WILL GAIN

a detailed knowledge of the mitochondrial toxicity resulting from NRTI-inclusive therapies and related tissue toxicities are provided. This review presents both the molecular effects of NRTI usage on mitochondrial genetic homeostasis and energy metabolism as well as the clinical manifestations associated with NRTI toxicities.

TAKE HOME MESSAGE

NRTIs remain a critical component of current HIV-1 treatment regimens. Future NRTIs should provide higher specificity for HIV-RT and lower incorporation by pol γ to minimize mitochondrial toxicity. Alternatively, therapeutic interventions to prevent or alleviate mitochondrial toxicity should be addressed.

The effect of aging, nutrition, and exercise during HIV infection

Medical advances continue to change the face of human immunodeficiency virus- acquired immunodeficiency syndrome (HIV/AIDS). As life expectancy increases, the number of people living with HIV rises, presenting new challenges for the management of a chronic condition. Aging, nutrition, and physical activity can influence outcomes in other chronic conditions, and emerging data show that each of these factors can impact viral replication and the immune system in HIV. HIV infection results in a decline of the immune system through the depletion of CD4+ T cells. From initial infection, viral replication is a continuous phenomenon. Immunosenescence, a hallmark of aging, results in an increased susceptibility to infections secondary to a delayed immune response, and this phenomenon may be increased in HIV-infected patients. Optimal nutrition is an important adjunct in the clinical care of patients with HIV. Nutritional interventions may improve the quality and span of life and symptom management, support the effectiveness of medications, and improve the patient's resistance to infections and other disease complications by altering immunity. Moderate physical activity can improve many immune parameters, reduce the risk of acute infection, and combat metabolic abnormalities. As people with HIV age, alternative therapies such as nutrition and physical activity may complement medical management.

Clinical syndromes and consequences of antiretroviral-related hepatotoxicity

Highly active antiretroviral therapy (HAART)-related hepatotoxicity complicates the management of patients infected with human immunodeficiency virus (HIV), increases medical costs, alters the prescription patterns, and affects the guideline recommendations. Among the clinical consequences derived from HAART-related liver toxicity, hypersensitivity reactions and lactic acidosis are recognized as acute events with potential to evolve into fatal cases, whereas there seems to be other syndromes not as well characterized but of equal concern as possible long-term liver complications. Belonging to the latter category of syndrome, HAART-related nonalcoholic steatohepatitis, liver fibrosis, portal hypertension, and nodular regenerative hyperplasia are discussed in this review. Updated information on liver toxicity of current antiretroviral drugs, including the most recently licensed, is provided. Management and prevention of liver toxicity among HIV-infected patients treated with HAART are reviewed as well.

Short communication: Severe symptomatic hyperlactatemia among HIV type 1-infected adults on antiretroviral therapy in Côte d'Ivoire

Stavudine is no longer recommended for use in first-line antiretroviral therapy (ART), but it remains in high demand worldwide because it is affordable. We report the clinical presentation and incidence of severe hyperlactatemia (SL) in HIV-infected adults who initiated ART between April 2005 and May 2009 in Côte d'Ivoire, West Africa. In a prospective cohort study at the HIV care center affiliated with the National Centre for Blood Transfusion, we used standardized forms to record baseline and follow-up data. We measured serum lactate levels for all adults on ART who showed signs of hyperlactatemia. SL was defined as serum lactate >2.5 mmol/liter. Overall, 806 adults initiated ART. Among the 591 patients (73%) on stavudine-containing regimens, 394 were women (67%); the median pre-ART CD4 count was 150/mm3 and the median body mass index was 20.9 kg/m2. These patients were followed for a median of 28 months. We detected SL only among patients taking stavudine. The incidence of SL was 0.55/100 person-years (PY) (95% CI 0.47-0.63) overall and 0.85/100 PY among women (95% CI 0.75-0.95). Among the eight patients with SL, 100% lost >9% of body weight before diagnosis, 100% had serum lactate >4 mmol/liter (range 4.2-12.1), 50% had pre-ART BMI >25 kg/m2, and three patients died (38%), accounting for 6.4% of deaths among patients taking stavudine. As long as HIV clinicians continue to use stavudine in sub-Saharan Africa, they should watch out for acute unexplained weight loss in patients taking ART, particularly among women and patients with high pre-ART BMI.

Hepatic non-Hodgkin's lymphoma with lactic acidosis in HIV-infected patients: report of 2 cases

We report 2 patients with HIV-associated non-Hodgkin's lymphoma with massive hepatic involvement and lactic acidosis. The lactic acidosis was likely caused by excessive tumor lactate production coupled with impaired hepatic clearance. Although 1 patient died rapidly, the other survived for 7 months after receiving urgent combination chemotherapy. Clinicians should be aware of this condition and the importance of its early diagnosis and treatment.

Stavudine-induced hyperlactatemia/lactic acidosis at a tertiary communicable diseases clinic in South Africa

OBJECTIVES

To determine the incidence, presentation, and outcome of hyperlactatemia and lactic acidosis. DESIGN AND METHODS SETTING: Grey's Hospital, a tertiary level referral institution.

STUDY POPULATION

A chart review of 1719 patients commenced on highly active antiretroviral therapy (HAART) between August 1, 2004, and July 31, 2006. A total of 1000 patients (615 females) received stavudine (d4T)/lamivudine (3TC)/efavirenz (EFV), 719 patients (598 females) received d4T/ 3TC/nevirapine (NVP).

RESULTS

Of the 1719 patients, 152 (8.84%) had an elevated plasma venous lactate (>2.2 mmol/L), 45 patients required admission for lactic acidosis. The overall incidence rate was 13.5 cases per 1000 patient years. The most common presenting symptoms were loss of weight (95%), abdominal pain (78.9%), loss of appetite, and paresthesias (63.8%). The median body mass index (BMI) at commencement of HAART and at onset of symptoms was 24.5 and 26, respectively. A median serum lactate level of 6.08 mmol/L (range 2.3-19.7 mmol/L) was observed at the onset of symptoms.

CONCLUSIONS

High BMI at treatment initiation did not always predict hyperlactatemia. All patients who died had a baseline CD4 count <10 cells/mm(3) at HAART initiation.

Adverse drug reactions to antiretroviral therapy (ART): an experience of spontaneous reporting and intensive monitoring from ART centre in India

PURPOSE

To assess the nature, severity, predictability and preventability of adverse drug reactions (ADRs) and to identify risk factors for antiretroviral ADRs.

METHODS

Enrolled ambulatory patients were intensively monitored for ADRs. Spontaneously reported ADRs by clinicians were also included. Predictability was assessed based on history of previous exposure to the drug or literature incidence of ADRs. Preventability was assessed using Schumock and Thornton criteria and severity was assessed using modified Hartwig and Siegel scale. Bivariate analysis and subsequently multivariate logistic regression were used to identify the risk factors for ADRs. Data from spontaneous reporting was assessed using Bayesian neural network method for possible ADR signals.

RESULTS

Monitoring by active surveillance indentified 159 (52.82%) ADRs from 400 patients. One hundred and forty-two (47.17%) reactions were spontaneously reported. Anaemia and vomiting were the most commonly observed ADRs. The ADRs were severe in 10.9% of cases. A total of 88% ADRs were definitely/probably preventable. Use of Zidovudine+Lamivudine with Nevirapine or Efavirenz, CD4 <200 cells/microl, female gender, tuberculosis and illiteracy were observed as risk factors for ADRs by bivariate analysis. Concurrent tuberculosis was the only influential risk factor for development of ADRs identified by multivariate logistic regression.

CONCLUSION

Prevalence of ADRs in intensively monitored patients was found to be 39.7%. Tuberculosis in HIV patients is an influential risk factor for occurrence of ADRs. With the increasing access to antiretrovirals in India, ADRs to antiretrovirals require monitoring and reporting.

Apoptosis: a clinically useful measure of antiretroviral drug toxicity?

Antiretroviral therapy (ART) has improved life expectancy with HIV infection, but long-term toxicities associated with these medications are now a major global disease burden. There is a clear need to develop useful methods for monitoring patients on antiretroviral drugs for early signs of toxicity. Assays with predictive utility -- allowing therapy to be changed before serious end organ damage occurs -- would be ideal. Attempts to develop biochemical methods of monitoring ART toxicity have concentrated on the mitochondrial toxicity of nucleoside analogue reverse transcriptase inhibitors and have not generally lead to assays with widespread clinical applications. For example, plasma lactate and peripheral blood measurements of mitochondrial DNA associate with exposure to potentially toxic nucleoside analogue reverse transcriptase inhibitors but have not reliably predicted clinical toxicity. Better assays are needed, including markers of toxicity from additional drug classes. Apoptosis may be a potential marker of ART toxicity. Increased apoptosis has been demonstrated both in vitro and in vivo in association with various antiretroviral drug classes and a range of clinical toxicities. However, quantifying apoptosis on biopsy specimens of tissue (such as adipose tissue) is impractical for patient monitoring. Novel assays have been described that can quantify apoptosis using minute tissue samples and initial results from clinical samples suggest peripheral blood may have utility in predicting ART toxicities. The limitations and potential of such techniques for monitoring patients for drug side effects will be discussed.

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.

Risk factors for and clinical characteristics of severe hyperlactataemia in patients receiving antiretroviral therapy: a case-control study

BACKGROUND

Symptomatic hyperlactataemia and lactic acidosis (SHLA) are potentially life-threatening complications associated with stavudine (d4T), an antiretroviral therapy (ART) drug widely used in developing countries.

METHODS

Cases comprised all symptomatic patients with measured lactates >or= 5 mmol/L referred to a South African hospital between August 2003 and November 2005. Matched controls were selected according to facility and duration on ART.

RESULTS

Seventy-one cases and 142 controls were included in the study. The majority of cases presented between 6 and 18 months on ART. Female sex [adjusted odds ratio (AOR) 23.4; 95% confidence interval (CI) 4.0-136.6], a baseline weight between 60 and 75 kg (AOR 4.5; 95% CI 1.4-14.1) or, in particular, >or= 75 kg (AOR 19.4; 95% CI 4.1-82.5) at ART initiation and gaining >or= 6 kg in the first 3 months on therapy (AOR 3.5; 95% CI 1.3-9.5) were independent risk factors identifying patients who may subsequently develop SHLA. Weight loss of >or= 2 kg (AOR 6.1; 95% CI 2.0-18.3), a rise in alanine aminotransferase (ALT) >or= 10 U/L (AOR 3.1; 95% CI 1.1-8.9), the presence of at least one of three major symptoms (vomiting, nausea and abdominal pains) of SHLA (AOR 12.6; 95% CI 3.3-47.2) and peripheral neuropathy (AOR 3.4; 95% CI 1.1-9.8) were the clinical parameters that were most able to identify patients with early manifestations of SHLA.

CONCLUSIONS

This is the first case-control study for SHLA in Southern Africa. Given these findings, we advise that stavudine is avoided in overweight women. Weight loss, a rise in ALT, peripheral neuropathy and/or gastrointestinal symptoms should prompt healthcare workers to assess for SHLA, especially at between 6 and 18 months on ART.

Facilitated mitochondrial import of antiviral and anticancer nucleoside drugs by human equilibrative nucleoside transporter-3

Human equilibrative nucleoside transporter-3 (hENT3) was recently reported as a pH-dependent, intracellular (lysosomal) transporter capable of transporting anti-human immunodeficiency virus (HIV) dideoxynucleosides (ddNs). Because most anti-HIV ddNs (e.g., zidovudine, AZT) exhibit clinical mitochondrial toxicity, we investigated whether hENT3 facilitates transport of anti-HIV ddNs into the mitochondria. Cellular fractionation and immunofluorescence microscopy studies in several human cell lines identified a substantial presence of hENT3 in the mitochondria, with additional presence at the cell surface of two placental cell lines (JAR, JEG3). Mitochondrial or cell surface hENT3 expression was confirmed in human hepatocytes and placental tissues, respectively. Unlike endogenous hENT3, yellow fluorescent protein (YFP)-tagged hENT3 was partially directed to the lysosomes. Xenopus oocytes expressing NH2-terminal-deleted hENT3 (expressed at the cell surface) showed pH-dependent interaction with several classes of nucleosides (anti-HIV ddNs, gemcitabine, fialuridine, ribavirin) that produce mitochondrial toxicity. Transport studies in hENT3 gene-silenced JAR cells showed significant reduction in mitochondrial transport of nucleosides and nucleoside drugs. Our data suggest that cellular localization of hENT3 is cell type dependent and the native transporter is substantially expressed in mitochondria and/or cell surface. hENT3-mediated mitochondrial transport may play an important role in mediating clinically observed mitochondrial toxicity of nucleoside drugs. In addition, our finding that hENT3 is a mitochondrial transporter is consistent with the recent finding that mutations in the hENT3 gene cause an autosomal recessive disorder in humans called the H syndrome.

Mitochondrial oxidative phosphorylation protein levels in peripheral blood mononuclear cells correlate with levels in subcutaneous adipose tissue within samples differing by HIV and lipoatrophy status

Depletion of mitochondrial DNA (mtDNA) and mtDNA-encoded respiratory chain proteins in subcutaneous (SC) fat from patients with HIV lipoatrophy have clearly demonstrated the role of mitochondrial dysfunction in this syndrome. Research in HIV lipoatrophy, however, has been severely hampered by the lack of a suitable surrogate marker in blood or other easily obtained clinical specimens as fat biopsies are invasive and mtDNA levels in peripheral blood mononuclear cells (PBMC) do not consistently correlate with the disease process. We used a simple, rapid, quantitative 2-site dipstick immunoassay to measure OXPHOS enzymes Complex I (CI) and Complex IV (CIV), and rtPCR to measure mtDNA in 26 matched SC fat and PBMC specimens previously banked from individuals on potent antiretroviral (ARV) therapy with HIV lipoatrophy, on similar ARV therapy without lipoatrophy, and in HIV seronegative controls. Significant correlations were found between the respective PBMC and fat levels for both CI (r = 0.442, p = 0.024) and for CIV (r = 0.507, p = 0.008). Both CI and CIV protein levels were also significantly reduced in both PBMCs and fat in lipoatrophic subjects compared to HIV seronegative controls (p < or = 0.05), while a comparative reduction in mtDNA levels in lipoatrophic subjects was observed only in fat. We conclude that CI and CIV levels in PBMCs correlate to their respective levels in fat and may have utility as surrogate markers of mitochondrial dysfunction in lipoatrophy.

Co-factors for abnormal lactate levels among persons with HIV disease at a tertiary HIV care setting in South India

BACKGROUND

The co-factors underlying abnormal lactate level remains to be determined in resource-limited settings. In a cross-sectional study conducted between January 2004 and July 2006, we determined the proportion of HIV-infected persons with abnormal lactate levels and correlated the association of certain co-factors of abnormal lactate levels at a tertiary HIV care centre in Chennai, Southern India.

METHODS

Lactate was estimated by the enzymatic method using an Olympus AU 400 autoanalyzer. Absolute CD4+T lymphocyte count was determined by the Guava personal cell analyser (Guava Technologies Inc., Hayward, CA, USA). Subjects were classified to have normal or abnormal values of lactate based on the reference interval (0.3-2.2 mmol/L). A p value 0.05 was considered statistically significant.

RESULTS

A total of 225 HIV-infected individuals (HAART experienced 213 (95%) and HAART naïve (5%)) were included in the analysis. Mean age was 34+/-8 and 36+/-9 years for the individuals with normal and abnormal lactate levels respectively. Of these 185 (82%) had normal (0.3-2.2 mmol/L) and 40 (18%) had abnormal (>2.2 mmol/L) lactate levels. Significant difference in relation to female gender was observed between the normal and abnormal groups (p=0.03). Among the abnormal group, 39 (97.5%) subjects were HAART experienced compared to 174 (94.1%) normal group. Among the abnormal group, 24 (60%) individuals had a CD4 count of <200 cells/microL as compared to 76 (41.1%) normal subjects.

CONCLUSION

Female gender should be carefully monitored with respect to their clinical, laboratory and biological data to diminish the occurrence of lactic acidosis.

Safety of stavudine in the treatment of HIV infection with a special focus on resource-limited settings

BACKGROUND

Western randomized trials and prospective cohorts in resource-limited settings have proven virological success with stavudine-based highly active antiretroviral therapy. However, stavudine is no longer recommended in first-line treatments in these two settings due to its intrinsic toxicities and side effects. Yet it remains a cornerstone of treatment in resource-limited settings, due to lack of alternatives and its availability in generic fixed-dose combinations.

OBJECTIVE

To review the toxic effects of stavudine and their prevention and management strategies, especially in resource-limited settings.

METHODS

Data from clinical and pharmacological trials in Western countries, as well as prospective cohorts in resource-limited settings, were reviewed.

CONCLUSION

Initiating or switching to less toxic nucleoside analogues whenever possible, or lowering stavudine doses to 30 mg b.i.d., is strongly recommended.

Risk factors for mortality in symptomatic hyperlactatemia among HIV-infected patients receiving antiretroviral therapy in a resource-limited setting

OBJECTIVES

To determine the mortality rate and risk factors after experiencing symptomatic hyperlactatemia in HIV-infected patients receiving antiretroviral therapy (ART).

METHODS

A retrospective cohort study was conducted among patients who were diagnosed with symptomatic hyperlactatemia (lactate >2.5mmol/l) between January 2004 and April 2006. All patients were followed until 3 months after the diagnosis.

RESULTS

One hundred and twenty-five patients were included in the study. The mean+/-standard deviation (SD) age was 39.9+/-10.1 years and body weight was 58.2+/-16.9kg; 60.8% were male. Symptomatic hyperlactatemia in 114 (91.2%) was associated with receiving d4T, in five (4.0%) with d4T+ddI, in four (3.2%) with ZDV+ddI, and in two (1.6%) with ddI (d4T, stavudine; ddI, didanosine; ZDV, zidovudine). The median duration of ART was 13 months. Nine (7.2%) patients died. Patients who died had a higher mean lactate level (8.0 vs. 5.1mmol/l) and mean alanine aminotransferase (ALT; 164 vs. 48U/l) at the time of diagnosis when compared to those who survived (p<0.05). Patients who died had a lower mean weight than those who survived (48 vs. 59kg, p=0.008). By logistic regression, mortality was associated with patients whose body weight was <45kg (p=0.014, odds ratio (OR) 9.090, 95% confidence interval (CI) 1.575-52.632) and whose serum lactate was >10mmol/l (p=0.004, OR 20.372, 95% CI 2.610-159.001).

CONCLUSIONS

The mortality rate of symptomatic hyperlactatemia among HIV-infected patients receiving ART is substantial. Almost all patients received d4T. Patients who have a low body weight and high serum lactate level are at a higher risk of mortality.

Therapy insight: Body-shape changes and metabolic complications associated with HIV and highly active antiretroviral therapy

Increasingly effective therapies for HIV infection are now available. These treatments, referred to collectively as highly active antiretroviral therapy, comprise various combinations of anti-HIV drugs from different drug classes. Recently, a range of metabolic complications have emerged as important toxicities in treated patients. Complications present as abnormalities of body-fat mass distribution in association with an often significant dyslipidemia and glucose homeostasis dysregulation. The body-shape changes, manifesting as peripheral lipoatrophy or central lipohypertrophy, can have a negative impact on quality of life and consequently on adherence to treatment. The combination of central lipohypertrophy, dyslipidemia and insulin resistance is associated with accelerated rates of atherosclerosis and other potentially significant long-term effects. The pathogenesis of these effects is complex and is still being actively investigated. Possible contributing factors relate to host characteristics, HIV viral parameters and specific effects of anti-HIV drugs on adipose-tissue biology and on intermediary metabolism. Management of these complications involves manipulation of the anti-HIV drugs using an understanding of their particular effects on lipid and glucose metabolism, in association with standard therapeutic interventions. Individualized approaches, taking into consideration quality-of-life issues, and assessment of potential cardiovascular risks, are now an important component of effective care of HIV-infected patients.

Higher-than-expected rates of lactic acidosis among highly active antiretroviral therapy-treated women in Botswana: preliminary results from a large randomized clinical trial

BACKGROUND

The ability of nucleoside reverse transcriptase inhibitors (NRTIs) to inhibit human mitochondrial polymerase-gamma results in impaired synthesis of mitochondrial enzymes that generate adenosine triphosphate (ATP) by oxidative phosphorylation. This has been associated with several long-term mitochondrial toxicities, which include lactic acidosis and pancreatitis, peripheral neuropathy, and lipoatrophy.

METHODS

Enrolled highly active antiretroviral therapy (HAART)-treated adults have completed nearly 2 years of follow-up as part of the ongoing randomized clinical trial Adult Antiretroviral Treatment and Drug Resistance (Tshepo) study. All patients were intensively screened for the presence of ARV-related toxicities.

RESULTS

Six hundred fifty adults (69% female) were initiated on NRTI-based HAART. Overall, 2.0% of patients developed moderate to severe symptomatic hyperlactatemia, with 7 (1.0%), all female, diagnosed with lactic acidosis. Female gender (P = 0.008) and being overweight, namely having a body mass index (BMI) of greater than 25 (P = 0.001), were predictive for the development of moderate to severe symptomatic hyperlactatemia or lactic acidosis. Older age (age >40 years) showed a statistical trend (P = 0.053) as a predictor for the development of toxicity, whereas exposure to d4T and/or ddI for 6 or more months was not predictive (P = 0.102). Those diagnosed with lactic acidosis had a mean BMI of 32.38 (interquartile range [IQR] = 29.4 to 35) at the time of toxicity and had been receiving HAART for a mean of 12.1 months (IQR = 7 to 20.8). Four of the 7 (57%) died of lactic acidosis and/or hemorrhagic pancreatitis; these 4 patients also had a comorbid diagnosis of severe clinical pancreatitis with grade 3/4 lipase elevations and abdominal symptoms at the time of their demise.

CONCLUSIONS

Rates of lactic acidosis appear to be higher in southern Africa when compared with rates previously described elsewhere. Risk factors for the development of moderate to severe symptomatic hyperlactatemia or lactic acidosis appear to be multifactorial but include female gender and having a BMI of greater than 25. Additional studies are ongoing to evaluate for other possible risk factors, such as host genetic differences.

Risk factors for lactic acidosis and severe hyperlactataemia in HIV-1-infected adults exposed to antiretroviral therapy

BACKGROUND

Severe hyperlactataemia and lactic acidosis are rare serious complications of antiretroviral therapy (ART).

METHODS

Lactic acidosis was defined as pH < 7.35, bicarbonate < 20 mmol/l and raised lactate; hyperlactataemia as two consecutive lactates > 5 mmol/l. The case-control study of 110 cases and 220 controls(two randomly selected from treated patients by centre and calendar year) from centres in 10 countries included 40 (36.4%) female cases and 40 female controls (18.2%) (P < 0.001). Median age was 42.4 years [interquartile range (IQR, 36.0-52.5] for cases and 40 (IQR, 35.0-47.1) for controls (P = 0.013). More cases were nonwhite (41.9%) than controls (31.2%) (P = 0.032). Cases had a shorter duration of exposure to dideoxynucleosides.

RESULTS

After adjusting for age, gender and current CD4 cell count, hyperlactataemia/lactic acidosis remained associated with exposure to didanosine in every category of exposure duration but was most strongly associated with exposure < 12 months. In a separate multivariable model, apart from exposure to stavudine, didanosine, or even more strongly both, age above 40 years [odds ratio (OR), 2.6; 95% confidence interval (CI), 1.08-6.29], female gender (OR, 5.97; 95% CI, 1.92-18.5) and advanced immunosuppression were independent associations (CD4 cell count 200-349, 100-199 and < 100 cells/mul: OR, 3.89, 7.58 and 8.11, respectively).

INTERPRETATION

Hyperlactataemia/lactic acidosis was associated with exposure to dideoxynucleosides, female gender, advanced immunosuppression and possibly ethnicity. This has important consequences for choice of ART in resource-limited settings. The association with shorter duration of exposure may support the hypothesis of susceptibility in a small proportion of patients.

Limitation of exercise capacity in nucleoside-treated HIV-infected patients with hyperlactataemia

BACKGROUND

Inhibition of DNA polymerase gamma by nucleoside reverse transcriptase inhibitors (NRTIs) can cause mitochondrial dysfunction and cellular toxicity. Hyperlactataemia, which is a consequence of a shift in the metabolism of pyruvate, is an indicator of nucleoside-related mitochondrial toxicity.

METHODS

We evaluated exercise and oxidative capacities as well as circulatory and ventilatory responses to exercise in 24 HIV-infected patients on NRTIs presenting hyperlactataemia [mean (+/-standard deviation) fasted lactate=3.5+/-1.1 mmol/L]; 27 NRTI-treated patients with normal baseline lactate concentrations were used as controls (mean fasted lactate=1.6+/-0.3 mmol/L).

RESULTS

In the patients with hyperlactataemia, the average peak work capacity (1.7+/-0.6 W/kg) and peak oxygen consumption (VO(2)) (21+/-4 mL/kg/min) were significantly lower (P<0.01) than in control subjects (work, 2.1+/-0.4 W/kg; VO(2), 25+/-4 mL/kg/min). The capacity to increase oxygen extraction during exercise was significantly diminished in the hyperlactataemia group, as shown by a low peak systemic arteriovenous oxygen difference (a-vO(2)) difference compared with controls (11+/-3 vs 14+/-3 mL/dL; P=0.008), and as indicated by a linear correlation between VO(2) and systemic a-vO(2) difference (r(2)=0.76). During exercise, the increases in cardiac output relative to VO(2) (mean Delta cardiac output (Q)/DeltaVO(2)=8+/-3.6) and ventilation (mean Delta ventilation (VE)/DeltaVO(2)=48.6+/-13.2) were significantly higher in hyperlactataemia patients compared with controls (mean cardiac output Delta(Q)/DeltaVO(2)=6+/-2; mean DeltaVE/DeltaVO(2)=42+/-12.7; P=0.03).

CONCLUSIONS

The degree of exercise limitation in patients with nucleoside-related mitochondrial toxicity correlates directly with the severity of impaired muscle oxidative phosphorylation, as indicated by the capacity for muscle oxygen extraction. Exaggerated circulatory and ventilatory responses to exercise are direct consequences of the level of impaired muscle oxidative phosphorylation.

Mitochondrial disease in the offspring as a result of antiretroviral therapy

Nucleoside analogue reverse transcriptase inhibitors (NRTIs) have substantially lowered the risk of the mother-to-child transmission of HIV. Evidence of mitochondrial toxicity in vitro, in animal models and in adult HIV-infected patients, has raised concern about the perinatal safety of these antiretrovirals. In zidovudine-exposed, but HIV-uninfected infants, transient anaemia and additional long-term blood abnormalities (neutropenia, thrombopenia and lymphopenia) and hyperlactatemia have been documented. The overall risk of mortality and congenital abnormalities does not appear to be increased, but rare mitochondrial events cannot be excluded for lack of statistical power. French data suggest an above background incidence of mitochondrial symptomatology. Preclinical data demonstrate zidovudine also to be a carcinogen. Long-term systematic follow-up of exposed babies in large cohorts is needed, as are randomised trials with NRTIs carrying a lower risk of mitochondrial toxicity.

Mitochondrial Toxicity of Tenofovir, Emtricitabine and Abacavir Alone and in Combination with Additional Nucleoside Reverse Transcriptase Inhibitors

Background

Some nucleoside/nucleotide reverse transcriptase inhibitor (NRTI) combinations cause additive or synergistic interactions in vitro and in vivo.

Methods

We evaluated the mitochondrial toxicity of tenofovir (TFV), emtricitabine (FTC) and abacavir as carbovir (CBV) alone, with each other, and in combination with additional NRTIs. HepG2 human hepatoma cells were incubated with TFV, FTC, CBV, didanosine (ddI), stavudine (d4T), lamivudine (3TC) and zidovudine (AZT) at concentrations equivalent to 1 and 10x clinical steady-state peak plasma levels (Cmax). NRTIs were also used in double and triple combinations. Cell growth, lactate production, intracellular lipids, mtDNA and the mtDNA-encoded respiratory chain subunit II of cytochrome c oxidase (COXII) were monitored for 25 days.

Results

TFV and 3TC had no or minimal toxicity. FTC moderately reduced hepatocyte proliferation independent of effects on mtDNA. ddI and d4T induced a time- and dose-dependent loss of mtDNA and COXII, decreased cell growth and increased levels of lactate and intracellular lipids. CBV and AZT strongly impaired hepatocyte proliferation and increased lactate and lipid production, but did not induce mtDNA depletion. The dual combination of TFV plus 3TC had only minimal toxicity; TFV plus FTC slightly reduced cell proliferation without affecting mitochondrial parameters. All other combinations exhibited more pronounced adverse effects on mitochondrial endpoints. Toxic effects on mitochondrial parameters were observed in all combinations with ddI, d4T, AZT or CBV. TFV and 3TC both attenuated ddI-related cytotoxicity, but worsened the effects of CBV and AZT.

Conclusions

The data demonstrate unpredicted interactions between NRTIs with respect to toxicological endpoints and provide an argument against the liberal use of NRTI cocktails without first obtaining data from clinical trials.

Drug-induced liver injury associated with HIV medications

Antiretroviral therapy (ART) for HIV infection frequently has been associated with elevated liver enzyme levels. Determining the cause of elevated liver enzyme levels in patients who have HIV is difficult because ART usually consists of three different drugs, patients may be taking additional hepatotoxic medications and patients who have HIV often suffer from other liver diseases. Several agents, however, are recognized as having noteworthy and specific patterns of toxicity. This article reviews the different HIV drug classes, incidence of elevated liver enzyme values by class and by individual drug, risk factors, specific toxicities, and possible mechanisms of injury.

A High Incidence of Lactic Acidosis and Symptomatic Hyperlactatemia in Women Receiving Highly Active Antiretroviral Therapy in Soweto, South Africa

BACKGROUND

Lactic acidosis and symptomatic hyperlactatemia may complicate nucleoside reverse-transcriptase inhibitor use. Females may be at increased risk for such complications. Our study evaluated the incidence of lactic acidosis and symptomatic hyperlactatemia by sex, analyzed clinical features, and described the safety of reintroducing highly active antiretroviral therapy (HAART) with zidovudine replacing stavudine.

METHODS

A retrospective cohort analysis was performed for 1735 adults (63% of whom were female) who initiated HAART from April 2004 through August 2005 in Soweto, South Africa, with follow-up until February 2006. Patients with lactate levels > or =4.5 mmol/L and no potential cause of elevated lactic acidosis other than receipt of HAART were included in the study.

RESULTS

A total of 23 patients (22 of whom were female) experienced lactic acidosis. The overall incidence was 10.6 cases per 1000 patient-years; the incidence was 16.1 cases per 1000 patient-years in female patients and 1.2 cases per 1000 patient-years in male patients. Seven (30.4%) of the patients died. Eight (34.8%) of the patients were obese (body mass index [calculated as weight in kilograms divided by the square of height in meters], >30) at HAART initiation. Forty-four patients (37 of whom were female) had symptomatic hyperlactatemia. The overall incidence was 20.2 cases per 1000 patient-years, with an incidence of 27.0 cases per 1000 patient-years in female patients and 8.7 cases per 1000 patient-years in male patients. None of the patients died. Nine (20.4%) of the patients were obese at HAART initiation. Sixty-six of 67 patients were receiving stavudine, and 5 patients were receiving didanosine. Among 56 patients who restarted HAART with zidovudine for a cumulative nucleoside reverse-transcriptase inhibitor reexposure of 44.6 patient-years--including 41 patients who received treatment for > or =9 months--there were no relapses.

CONCLUSION

Women in Soweto, South Africa, have a higher frequency of symptomatic hyperlactatemia and lactic acidosis than has been reported for patients in other study groups. In cases associated with stavudine use, restarting HAART with zidovudine seemed to be safe and effective for patients with limited nucleoside reverse-transcriptase inhibitor alternatives.

Tratamiento antirretroviral y toxicidad mitocondrial

The introduction of highly active antiretroviral therapy for the treatment of human immunodeficiency virus (HIV) infection has led to substantial reduction in morbidity and near-complete suppression of HIV-1 replication. This progress has been tempered by a growing number of new adverse effects. Mitochondrial toxicity is one aspect of these long-term toxicities of antiretroviral drugs, with the role of nucleoside analogs being particularly underlined. Some cases of impaired mitochondrial function have been clearly identified, such as pancreatitis, neuropathy, miopathy and lactic acidosis. Beyond the inhibition of DNA polymerase-g using nucleoside analogs, it appears that several physiopathologic mechanisms interact to explain the observed toxicity. At present there is no reliable method to detect subclinical mitochondrial toxicity. There is no proven effective therapy for antiretroviral therapy-associated mitochondrial toxicity other than ceasing the implicated agent, and even with this strategy, resolution of symptoms may be incomplete. Therefore, investigation of mitochondrial toxicity of new compounds or new combinations is of growing interest for the clinical application of antiretroviral agents.

Gender and long-term metabolic toxicities from antiretroviral therapy in HIV-1 infected persons

Gender differences in a large population-based cohort of HIV-1 infected patients (245 women and 723 men) were examined with respect to the incidence of metabolic and morphologic alterations after initiation of highly active antiretroviral therapy (HAART). Patients initiated HAART between January 1996 and December 2003. The outcome measures were the incidence of hyperglycemia, hypercholesterolemia, symptomatic lactic acidosis, treatment-limiting lipodystrophy, and hypersensitivity reaction. Cox proportional hazards models were used to estimate the crude and adjusted hazard ratios of reaching the endpoints for exposures and covariates. Women were younger than men (35 +/- 9.8 vs. 40 +/- 8.2 years, P < 0.001) and more frequently from Haiti or Africa (59%), whereas 76% of men were Canadian-born. Type of initial HAART regimen did not differ between women and men. There were no gender differences in the overall incidence of hyperglycemia, hypercholesterolemia, or treatment-limiting lipodystrophy, even after adjusting for age, CD4 cell count, viral load, time since HIV diagnosis, history of AIDS-defining illness and year of HAART initiation. In contrast, women had significantly higher risk of developing lactic acidosis than men (P = 0.0009). Hypersensitivity reactions were also more frequent in women than men (adjusted hazard ratio = 4.4 (95% CI: 2.1-9.3)). Collectively, these data suggest that metabolic toxicities after HAART do not differ by gender but that lactic acidosis and hypersensitivity reactions are more frequent in women than men.