Drug-Induced Acute Kidney Injury

Medications are a common cause of AKI especially for patients admitted to hospital wards and the intensive care unit. Although drug-related kidney injury occurs through different mechanisms, this review will focus on three specific types of tubulointerstitial injury. Direct acute tubular injury develops from several medications, which are toxic to various cellular functions. Their excretory pathways through the proximal tubules contribute further to AKI. Drug-induced AKI may also develop through induction of inflammation within the tubulointerstitium. Medications can elicit a T cell-mediated immune response that promotes the development of acute interstitial nephritis leading to AKI. Although less common, a third pathway to kidney injury results from the insolubility of drugs in the urine leading to their precipitation as crystals within distal tubular lumens, causing a crystalline-related AKI. Intratubular obstruction, direct tubular injury, and localized inflammation lead to AKI. Clinicians should be familiar with the pathogenesis and clinical-pathologic manifestations of these forms of kidney injury. Prevention and treatment of AKI relies on understanding the pathogenesis and judiciously using these agents in settings where AKI risk is high.

DNA polymerase-γ hypothesis in nucleoside reverse transcriptase-induced mitochondrial toxicity revisited: A potentially protective role for citrus fruit-derived naringenin?

Nucleoside reverse transcriptase inhibitors (NRTIs) form the backbone in combination antiretroviral therapy (cARVs). They halt chain elongation of the viral cDNA by acting as false substrates in counterfeit incorporation mechanism to viral RNA-dependent DNA polymerase. In the process genomic DNA polymerase as well as mitochondrial DNA (mtDNA) polymerase-γ (which has a much higher affinity for these drugs at therapeutic doses) are also impaired. This leads to mitochondrial toxicity that manifests clinically as mitochondrial myopathy, peripheral neuropathy, hyperlactatemia or lactic acidosis and lipoatrophy. This has led to the revision of clinical guidelines by World Health Organization to remove stavudine from first-line listing in the treatment of HIV infections. Recent reports have implicated oxidative stress besides mtDNA polymerase-γ hypothesis in NRTI-induced metabolic complications. Reduced plasma antioxidant concentrations have been reported in HIV positive patients on cARVs but clinical intervention with antioxidant supplements have not been successful either due to low efficacy or poor experimental designs. Citrus fruit-derived naringenin has previously been demonstrated to possess antioxidant and free radical scavenging properties which could prevent mitochondrial toxicity associated with these drugs. This review revisits the controversy surrounding mtDNA polymerase-γ hypothesis and evaluates the potential benefits of naringenin as a potent anti-oxidant and free radical scavenger which as a nutritional supplement or therapeutic adjunct could mitigate the development of mitochondrial toxicity associated with these drugs.

Effect of monotherapy with darunavir/cobicistat on viral load and semen quality of HIV-1 patients

Many patients previously using darunavir/ritonavir (DRV/r) (800/100mg) have switched to darunavir/cobicistat (DRV/C) (800/150 mg) either as part of triple therapy (ART) or as monotherapy with DRV (mDRV). The latter approach continues to be used in some countries for patients receiving long-term treatment. However, to date, the behaviour of DRV/C in the seminal compartment has not been analysed. This study explores how the combination behaves in monotherapy, with respect to the control of viral load and seminal quality. To this end, we studied 20 patients who were treated with mDRV/C after previous treatment with mDRV/r for at least 24 weeks. A viral load control in seminal plasma similar to that published in the literature was observed after 24 weeks of treatment with mDRV/C (viral load positivity in 20% of patients). Similarly, semen quality was confirmed (70% normozoospermic) in patients treated with this formulation, as has previously been reported for ART and mDRV/r. The DRV levels measured in seminal plasma were above EC50, regardless of whether the seminal viral load was positive or negative. We conclude that this mDRV/C co-formulation behaves like mDRV/r in seminal plasma in terms of viral load control and semen quality.

HIV Protease Inhibitors Alter Amyloid Precursor Protein Processing via β-Site Amyloid Precursor Protein Cleaving Enzyme-1 Translational Up-Regulation

Mounting evidence implicates antiretroviral (ARV) drugs as potential contributors to the persistence and evolution of clinical and pathological presentation of HIV-associated neurocognitive disorders in the post-ARV era. Based on their ability to induce endoplasmic reticulum (ER) stress in various cell types, we hypothesized that ARV-mediated ER stress in the central nervous system resulted in chronic dysregulation of the unfolded protein response and altered amyloid precursor protein (APP) processing. We used in vitro and in vivo models to show that HIV protease inhibitor (PI) class ARVs induced neuronal damage and ER stress, leading to PKR-like ER kinase-dependent phosphorylation of the eukaryotic translation initiation factor 2α and enhanced translation of β-site APP cleaving enzyme-1 (BACE1). In addition, PIs induced β-amyloid production, indicative of increased BACE1-mediated APP processing, in rodent neuroglial cultures and human APP-expressing Chinese hamster ovary cells. Inhibition of BACE1 activity protected against neuronal damage. Finally, ARVs administered to mice and SIV-infected macaques resulted in neuronal damage and BACE1 up-regulation in the central nervous system. These findings implicate a subset of PIs as potential mediators of neurodegeneration in HIV-associated neurocognitive disorders.

Effect of Monotherapy with Darunavir/Ritonavir on Viral Load in Seminal Fluid, and Quality Parameters of Semen in HIV-1-Positive Patients

Patients with human immunodeficiency virus type 1 (HIV-1) who receive antiretroviral therapy (ART) often achieve increased survival and improved quality of life. In this respect, monotherapy with darunavir/ritonavir (mDRV/r) can be a useful treatment strategy. This prospective study analyses the effect of mDRV/r on sperm quality and viral load in a group of 28 patients who had previously been given conventional ART and who had recorded a viral load <20 copies/mL for at least six months. These patients were given mDRV/r at a dose of 800/100 mg for 48 weeks. At baseline (V0), CD4, CD8, FSH, LH and testosterone levels were measured, together with HIV-1 viral load in plasma and semen. In addition, seminal fluid quality was studied before mDRV/r treatment was prescribed. At week 48 (V1), HIV-1 viral load in plasma and semen and the quality of the seminal fluid were again measured. The results obtained indicate that at V0, 10% of the patients with ART had a positive viral load in seminal fluid (>20 copies/ml), and that at V1, after mDRV/r treatment, this figure had fallen to 3%. The quality of seminal fluid was close to normal in 57% of patients at V0 and in 62% at V1. We conclude that, similar to ART, mDRV/r maintains HIV-1 viral load in most patients, and that there is no worsening in seminal fluid quality.

Genome-Wide Association Study of HIV-Related Lipoatrophy in Thai Patients: Association of a DLGAP1 Polymorphism with Fat Loss

HIV-related lipoatrophy (LA) is a major adverse drug effect among HIV patients receiving the antiretroviral drug stavudine (d4T) in Southeast Asia. Although the development of LA could be observed in almost all HIV patients administered d4T for extended periods, there is considerable variation in the duration required to develop LA within this patient population. This study aimed to identify host genetic polymorphisms affecting the rate of LA onset in Thai HIV patients. We performed a genome-wide association study of HIV-related LA among patients at the Bamrasnaradura Infectious Diseases Institute, Thailand. Genotypes of HIV patients who developed LA within 2 years of treatment were compared with those of patients who did not develop LA after at least 4 years of treatment (non-LA patients). Genotypes of 49 LA and 92 non-LA patients at 578,525 single nucleotide polymorphisms (SNPs) were determined by Illumina bead arrays. The TaqMan real-time PCR method was used in a replication study. Five SNPs in the bead arrays, which showed the lowest p values in a comparison of LA with non-LA patients, were further tested in independent and sex-matched subpopulations consisting of 95 LA and 95 non-LA patients. This replication study revealed a significant association of LA with an SNP (rs12964965) in the gene encoding the Disks Large Homolog-Associated Protein 1 (DLGAP1), even after the correction for five multiple comparisons. These results strongly suggested involvement of the DLGAP1 gene product in the development of LA in Thai HIV patients.

Antiretroviral therapy: current drugs

The rapid advances in drug discovery and the development of antiretroviral therapy is unprecedented in the history of modern medicine. The administration of chronic combination antiretroviral therapy targeting different stages of the human immunodeficiency virus' replicative life cycle allows for durable and maximal suppression of plasma viremia. This suppression has resulted in dramatic improvement of patient survival. This article reviews the history of antiretroviral drug development and discusses the clinical pharmacology, efficacy, and toxicities of the antiretroviral agents most commonly used in clinical practice to date.

HIV/AIDS and lipodystrophy: implications for clinical management in resource-limited settings

Introduction

Lipodystrophy is a term used to describe a metabolic complication of fat loss, fat gain, or a combination of fat loss and gain, which is associated with some antiretroviral (ARV) therapies given to HIV-infected individuals. There is limited research on lipodystrophy in low- and middle-income countries, despite accounting for more than 95% of the burden of HIV/AIDS. The objective of this review was to evaluate the prevalence, pathogenesis and prognosis of HIV-related lipoatrophy, lipohypertrophy and mixed syndrome, to inform clinical management in resource-limited settings.

Methods

We conducted a structured literature search using MEDLINE electronic databases. Relevant MeSH terms were used to identify published human studies on HIV and lipoatrophy, lipohypertrophy, or mixed syndrome in low-, low-middle- and upper-middle-income countries through 31 March 2014. The search resulted in 5296 articles; after 1599 studies were excluded (958 reviews, 641 non-human), 3697 studies were extracted for further review. After excluding studies conducted in high-income settings (n=2808), and studies that did not meet inclusion criteria (n=799), 90 studies were included in this review.

Results and Discussion

Of the 90 studies included in this review, only six were from low-income countries and eight were from lower middle-income economies. These studies focused on lipodystrophy prevalence, risk factors and side effects of antiretroviral therapy (ART). In most studies, lipodystrophy developed after the first six months of therapy, particularly with the use of stavudine. Lipodystrophy is associated with increased risk of cardiometabolic complications. This is disconcerting and anticipated to increase, given the rapid scale-up of ART worldwide, the increasing number and lifespan of HIV-infected patients on long-term therapy, and the emergence of obesity and non-communicable diseases in settings with extensive HIV burden.

Conclusions

Lipodystrophy is common in resource-limited settings, and has considerable implications for risk of metabolic diseases, quality of life and adherence. Comprehensive evidence-based interventions are urgently needed to reduce the burden of HIV and lipodystrophy, and inform clinical management in resource-limited settings.

Decrease of mitochondrial DNA level in sperm from patients infected with human immunodeficiency virus-1 linked to nucleoside analogue reverse transcriptase inhibitors

OBJECTIVE

To study sperm parameters in patients infected with human immunodeficiency virus (HIV)-1 and to analyze mitochondrial DNA (mtDNA) in sperm according to the HIV treatment.

DESIGN

Observational study.

SETTING

University-affiliated teaching hospital.

PATIENT(S)

Thirty-two patients infected with HIV-1 and 31 noninfected healthy men provided semen samples.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

After DNA extraction, mtDNA level was assessed using real-time polymerase chain reaction (PCR) (LightCycler) in whole semen and in selected spermatozoa from 90% density centrifugation gradients. For each sample, mtDNA and β-globin gene sequences were amplified and PCR products were quantified. The mtDNA-to-β-globin ratio expressed the number of mtDNA copies per cell.

RESULT(S)

Compared with the control group, several sperm parameters were altered in patients with HIV. The number of mtDNA copies per cell in whole semen was increased in HIV-infected patients (6.3±6.3 vs. 3.5±3.2). However, there was no statistically significant difference in mtDNA copy number in the spermatozoa obtained after density gradient centrifugation. The number of nucleoside analogue reverse transcriptase inhibitors (NRTI) taken by patients during treatment significantly influenced the mtDNA level in sperm (1 NRTI 7.6±8.1, 2 NRTIs 7.0±5.1, 3 NRTIs 3.2±2.1).

CONCLUSION(S)

Using a specific method to measure sperm mtDNA, we demonstrated a decrease of mtDNA copies in spermatozoa after use of NRTIs with known mitochondrial toxicity.

Proteomic analysis identifies prohibitin down-regulation as a crucial event in the mitochondrial damage observed in HIV-infected patients

BACKGROUND

Highly active antiretroviral therapy (HAART) has largely reduced the occurrence of AIDS-related diseases and death in HIV-infected patients. However, HAART produces serious side effects mainly attributed to mitochondrial toxicity.

METHODS

To elucidate the molecular basis of HAART-related dysfunctions, we analysed the mitochondrial proteome of peripheral blood mononuclear cells from HIV-infected patients using two-dimensional gel electrophoresis and MALDI-TOF/TOF mass spectrometry. Proteomic analysis was performed on HIV patients who were either treatment-naive or under HAART therapy including zidovudine or stavudine as nucleoside reverse transcriptase inhibitors (NRTIs).

RESULTS

As compared to healthy donors, HAART-treated HIV-infected patients exhibited decreased levels of mitochondrial enzymes associated with energy production as well as mitochondrial chaperones. Moreover, significant alterations in the mitochondria-cytoskeleton network were observed. Notably, most of these changes were already detectable in untreated HIV carriers and persisted or worsened after HAART, indicating that relevant mitochondrial alterations were initially caused by HIV infection. Finally, in vitro experiments aimed at validating the proteomic results showed that down-regulation of the mitochondrial chaperone prohibitin is a causative event in NRTI-induced mitochondrial damage.

CONCLUSIONS

Our results indicate a major role of HIV infection in the mitochondrial toxicity of HAART-treated patients and identify novel candidate markers for assessing the risk of HIV- and HAART-related pathologies.

HIV-1 reverse transcriptase inhibitors

Reverse transcriptase (RT) is one of the three enzymes encoded by the human immunodeficiency virus type 1 (HIV-1), the etiological agent of AIDS. Together with protease inhibitors, drugs inhibiting the RNA- and DNA-dependant DNA polymerase activity of RT are the major components of highly active antiretroviral therapy (HAART), which has dramatically reduced mortality and morbidity of people living with HIV-1/AIDS in developed countries. In this study, we focus on RT inhibitors approved by the US Food and Drugs Administration (FDA) or in phases II and III clinical trials. RT inhibitors belong to two main classes acting by distinct mechanisms. Nucleoside RT inhibitors (NRTIs) lack a 3' hydroxyl group on their ribose or ribose mimic moiety and thus act as chain terminators. Non-NRTIs bind into a hydrophobic pocket close to the polymerase active site and inhibit the chemical step of the polymerization reaction. For each class of inhibitors, we review the mechanism of action, the resistance mechanisms selected by the virus, and the side effects of the drugs. We also discuss the main perspectives for the development of new RT inhibitors.