Long Noncoding RNAs Hepatocyte Nuclear Factor 4A Antisense RNA 1 and Hepatocyte Nuclear Factor 1A Antisense RNA 1 Are Involved in Ritonavir-Induced Cytotoxicity in Hepatoma Cells.

Ritonavir (RTV), a pharmacoenhancer used in anti-HIV regimens, can induce liver damage. RTV is primarily metabolized by cytochrome P450 3A4 (CYP3A4) in the liver. HNF4A antisense RNA 1 (HNF4A-AS1) and HNF1A antisense RNA 1 (HNF1A-AS1) are long noncoding RNAs that regulate the expression of pregnane X receptor (PXR) and CYP3A4. This study investigated the role and underlying mechanisms of HNF4A-AS1 and HNF1A-AS1 in RTV-induced hepatotoxicity. HNF4A-AS1 and HNF1A-AS1 were knocked down by small hairpin RNAs in Huh7 and HepG2 cells. Lactate dehydrogenase and reactive oxygen species assays were performed to assess RTV-induced hepatotoxicity. Chromatin immunoprecipitation quantitative real-time polymerase chain reaction was used to detect PXR enrichment and histone modifications in the CYP3A4 promoter. HNF4A-AS1 knockdown increased PXR and CYP3A4 expression and exacerbated RTV-induced cytotoxicity, whereas HNF1A-AS1 knockdown generated the opposite phenotype. Mechanistically, enrichment of PXR and trimethylation of histone 3 lysine 4 (H3K4me3) in the CYP3A4 promoter was increased, and trimethylation of histone 3 lysine 27 (H3K27me3) was decreased after HNF4A-AS1 knockdown. However, PXR and H3K4me3 enrichment decreased after HNF1A-AS1 knockdown. Alterations in RTV-induced hepatotoxicity caused by decreasing HNF4A-AS1 or HNF1A-AS1 were reversed by knockdown or overexpression of PXR. Increased susceptibility to RTV-induced liver injury caused by the PXR activator rifampicin was attenuated by HNF4A-AS1 overexpression or HNF1A-AS1 knockdown. Taken together, these results revealed that HNF4A-AS1 and HNF1A-AS1 modulated RTV-induced hepatotoxicity by regulating CYP3A4 expression, primarily by affecting the binding of PXR and histone modification status in the CYP3A4 promoter. SIGNIFICANCE STATEMENT: HNF4A-AS1 and HNF1A-AS1, transcribed separately from neighboring antisense genes of the human transcription factor genes HNF4A and HNF1A, were identified as long noncoding RNAs that can affect RTV-induced hepatotoxicity and susceptibility to RTV-induced hepatotoxicity caused by rifampicin exposure, mainly by affecting the expression of CY3A4 via alterations in PXR enrichment and histone modification status in the CYP3A4 promoter. This discovery provides directions for further research on the mechanisms of RTV-induced liver injury.

Quantification of the pharmacokinetic-toxicodynamic relationship of oral docetaxel co-administered with ritonavir.

Introduction Oral formulations of docetaxel have successfully been developed as an alternative for intravenous administration. Co-administration with the enzyme inhibitor ritonavir boosts the docetaxel plasma exposure. In dose-escalation trials, the maximum tolerated doses for two different dosing regimens were established and dose-limiting toxicities (DLTs) were recorded. The aim of current analysis was to develop a pharmacokinetic (PK)-toxicodynamic (TOX) model to quantify the relationship between docetaxel plasma exposure and DLTs. Methods A total of 85 patients was included in the current analysis, 18 patients showed a DLT in the four-week observation period. A PK-TOX model was developed and simulations based on the PK-TOX model were performed. Results The final PK-TOX model was characterized by an effect compartment representing the toxic effect of docetaxel, which was linked to the probability of developing a DLT. Simulations of once-weekly, once-daily 60 mg and once-weekly, twice-daily 30 mg followed by 20 mg of oral docetaxel suggested that 14% and 34% of patients, respectively, would have a probability >25% to develop a DLT in a four-week period. Conclusions A PK-TOX model was successfully developed. This model can be used to evaluate the probability of developing a DLT following treatment with oral docetaxel and ritonavir in different dosing regimens.

Case Report: Retinal Toxicity Secondary to Ritonavir.

SIGNIFICANCE: Because patients with HIV have increased life expectancies with the advent of new drug therapies, complications from iatrogenic syndromes such as drug toxicity can occur. Ritonavir-induced retinal toxicity is one such complication but has rarely been reported in the literature. PURPOSE: This case report describes a patient with bilateral maculopathy and bone spicule-like pigmentary changes in the midperipheral retina due to ritonavir use. In addition, novel optical coherence tomography findings are described. CASE REPORT: A 53-year-old man presented with gradual-onset blurry vision and difficulty seeing at night. He had been diagnosed as having HIV infection 19 years prior and had previously taken ritonavir for 7 years as part of highly active antiretroviral therapy. Best-corrected acuities were 20/30 in the right eye and 20/25 in the left eye. Clinical examination revealed a subtle annular pattern of retinal pigment epithelium mottling around the fovea and bone spicule-like pigment changes in the midperiphery of both retinas. Optical coherence tomography imaging revealed abnormal subfoveal hyperreflectivity of the ellipsoid zone with relative attenuation centrally, annular parafoveal ellipsoid zone loss, and punctate hyperreflectivity within the ellipsoid zone more eccentrically. Fundus autofluorescence in both eyes showed annular hyperautofluorescence in the parafoveal region, geographic hyperautofluorescence in the areas underlying the midperipheral pigmentary changes, and discrete patches of hyperautofluorescence along the far inferotemporal arcades in areas that appeared normal with biomicroscopy. A diagnosis of retinal toxicity secondary to ritonavir use was made based on the patient's history and clinical examination. CONCLUSIONS: Ritonavir retinal toxicity seems to be an uncommon adverse event that can cause decreased visual function. This case report provides further evidence of the retinal toxicity and reviews the reported clinical and optical coherence tomography manifestations of the disease.

A Direct Comparison of the Effects of the Antiretroviral Drugs Stavudine, Tenofovir and the Combination Lopinavir/Ritonavir on Bone Metabolism in a Rat Model.

Antiretroviral (ARV) treatment may induce metabolic complications in HIV patients on long-term therapy that can affect bone health. In this study, the effects of the ARVs Stavudine (d4T), Tenofovir (TDF) and Lopinavir/ritonavir (LPV/r) on bone metabolism and lipodystrophy were directly compared in rats to negate the consequences of HIV-associated confounding factors. Healthy 12-14-week-old male Wistar rats (n = 40) were divided into four treatment groups and received an oral animal equivalent dose of either Stavudine (6.2 mg/kg/day), TDF (26.6 mg/kg/day), LPV/r (70.8 mg/kg/day) or water (Control 1.5 mL water/day) for a period of 9 weeks. Whole-body DXA measurements, a biomechanical three-point breaking test and histomorphometric analysis were performed on the femurs and tibias at the end of the treatment period. Stavudine monotherapy was found to be associated with decreased femoral bone mineral density that translated into reduced bone strength, whereas histomorphometric analysis demonstrated that Stavudine induces an imbalance in bone metabolism at tissue level, evident in higher resorption (eroded surfaces, osteoclast surfaces and osteoclast number) and lower formation parameters (osteoblast surfaces and osteoid surfaces). This was less clear in the rats treated with either TDF or LPV/r. Furthermore, both Stavudine and TDF treatment resulted in significant bone marrow adiposity, although no significant redistribution of body fat was noted in the treated rats compared to controls. The data from this study suggest that in the absence of HIV-associated factors, LPV/r is less detrimental to bone metabolism compared to Stavudine and TDF.

Chronic action of lamivudine and ritonavir on maternal and fetal liver and kidney of albino pregnant rats (Rattus norvegicus albinus, Rodentia, Mammalia): morphological and biochemical aspects.

PURPOSE: To investigate the morphological and biochemical effects of lamivudine associated with ritonavir on maternal and fetal livers and kidneys throughout the pregnancy of albino rats. MATERIALS AND METHODS: Forty pregnant rats were divided into four numerically equal groups: control (C), experiment 1 (E1), experiment 2 (E2), and experiment 3 (E3). Only distilled water was given to the control group, while groups E1, E2, and E3 received, respectively, 5, 15 and 45 mg/kg of lamivudine associated with 20, 60, and 180 mg/kg of ritonavir, per day, throughout the pregnancy. On the 20th day of the pregnancy, the histological structure of the maternal and fetal livers and kidneys was analyzed by means of optical microscopy, along with the blood concentrations of AST, ALT, urea, and matrix creatinine. The numerical variables were analyzed using the Kruskal-Wallis test and Dunn's multiple comparison test. RESULTS: The histological alterations occurred in both the maternal livers and the maternal kidneys, particularly in group E3, which received the greatest therapeutic dosage (nine times). The blood levels ofALT in group E3 were significantly lower than in the other groups (p = 0.0037). The urea and creatinine levels in the blood were significantly lower in group E1 (p = 0.0420 andp = 0.0108, respectively). CONCLUSIONS: rhe association of lamivudine and ritonavir affected the histological structure of the kidneys of the matrices of group E3. There was a significant decrease in the blood values of urea e creatinine in group El.

Human immunodeficiency virus protease inhibitors interact with ATP binding cassette transporter 4/multidrug resistance protein 4: a basis for unanticipated enhanced cytotoxicity.

Human immunodeficiency virus (HIV) pharmacotherapy, by combining different drug classes such as nucleoside analogs and HIV protease inhibitors (PIs), has increased HIV-patient life expectancy. Consequently, among these patients, an increase in non-HIV-associated cancers has produced a patient cohort requiring both HIV and cancer chemotherapy. We hypothesized that multidrug resistance protein 4/ATP binding cassette transporter 4 (MRP4/ABCC4), a widely expressed transporter of nucleoside-based antiviral medications as well as cancer therapeutics might interact with PIs. Among the PIs evaluated (nelfinavir, ritonavir, amprenavir, saquinavir, and indinavir), only nelfinavir both effectively stimulated MRP4 ATPase activity and inhibited substrate-stimulated ATPase activity. Saos2 and human embryonic kidney 293 cells engineered to overexpress MRP4 were then used to assess transport and cytotoxicity. MRP4 expression reduced intracellular accumulation of nelfinavir and consequently conferred survival advantage to nelfinavir cytotoxicity. Nelfinavir blocked Mrp4-mediated export, which is consistent with its ability to increase the sensitivity of MRP4-expressing cells to methotrexate. In contrast, targeted inactivation of Abcc4/Mrp4 in mouse cells specifically enhanced nelfinavir and 9-(2-phosphonylmethoxyethyl) adenine cytotoxicity. These results suggest that nelfinavir is both an inhibitor and substrate of MRP4. Because nelfinavir is a new MRP4/ABCC4 substrate, we developed a MRP4/ABCC4 pharmacophore model, which showed that the nelfinavir binding site is shared with chemotherapeutic substrates such as adefovir and methotrexate. Our studies reveal, for the first time, that nelfinavir, a potent and cytotoxic PI, is both a substrate and inhibitor of MRP4. These findings suggest that HIV-infected cancer patients receiving nelfinavir might experience both enhanced antitumor efficacy and unexpected adverse toxicity given the role of MRP4/ABCC4 in exporting nucleoside-based antiretroviral medications and cancer chemotherapeutics.

Mg supplementation attenuates ritonavir-induced hyperlipidemia, oxidative stress, and cardiac dysfunction in rats.

Use of protease inhibitors (PI) in HIV patients is associated with hyperlipidemia and increased risk of coronary heart disease. Chronic systemic and cardiac effects of ritonavir (RTV), a universal PI booster, and Mg supplementation were examined. RTV was administered (75 mg·kg(-1)·day(-1) po) to Lewis × Brown-Norway hybrid (LBNF1) rats for up to 8 wk; significant increases in plasma triglyceride and cholesterol occurred from 8 days to 8 wk. At 5 wk, the expression of selected hepatic genes (CYP7A1, CITED2, G6PC, and ME-1), which are key to lipid catabolism/synthesis, were altered toward lipogenesis. Dietary Mg supplementation (six-fold higher) completely reversed the altered expression of these genes and attenuated both hypertriglyceridemia and hypercholesterolemia. Neutrophils isolated from the RTV-treated rats displayed a three-fold higher basal and a twofold higher stimulated superoxide production; plasma isoprostane and red blood cell (RBC) GSSG levels were elevated two- to three-fold. All oxidative indices were normalized by Mg supplementation. After 5 wk, RTV caused significant decreases in cardiac left ventricular (LV) shortening fraction and LV ejection fraction; mitral valve early/late atrial ventricular filling (E/A) ratio was reduced accompanied by LV posterior wall thinning. Immunohistochemical staining revealed significant white blood cell (WBC) infiltration (5 wk) and prominent fibrosis (8 wk) in the RTV hearts. Mg supplementation attenuated RTV-induced declines in systolic and diastolic (improved mitral valve E/A ratio) function (>70%), lessened LV posterior wall thinning (by 75%), and substantially decreased the pathological markers. The known clinical hyperlipidemia effects of RTV can be mimicked in the LBNF1 rats; in association, systemic oxidative stress and progressive cardiac dysfunction occurred. Remarkably, Mg supplementation alone suppressed RTV-mediated hyperlipidemia, oxidative stress, and cardiac dysfunction.

Human immunodeficiency virus protease inhibitors modulate Ca2+ homeostasis and potentiate alcoholic stress and injury in mice and primary mouse and human hepatocytes.

UNLABELLED: A portion of human immunodeficiency virus (HIV)-infected patients undergoing protease inhibitor (PI) therapy concomitantly consume or abuse alcohol leading to hepatic injury. The underling mechanisms are not known. We hypothesize that HIV PIs aggravate alcohol-induced liver injury through an endoplasmic reticulum (ER) stress mechanism. To address this, we treated mice, primary mouse hepatocytes (PMHs), and primary human hepatocytes (PHHs) with alcohol and the HIV PIs ritonavir (RIT) and lopinavir (LOP). In mice, RIT and LOP induced mild ER stress and inhibition of sarco/ER calcium-ATPase (SERCA) without significant increase in serum alanine aminotransferase (ALT) levels. However, a single dose of alcohol plus the two HIV PIs caused a more than five-fold increase in serum ALT, a synergistic increase in alcohol-induced liver lipid accumulation and ER stress response, and a decrease of SERCA. Mice treated with chronic HIV PIs and alcohol developed moderate liver fibrosis. In PMHs, the HIV drugs plus alcohol also inhibited SERCA expression and increased expression of glucose-regulated protein 78, C/EBP homologous protein, sterol regulatory element-binding protein 1c, and phosphorylated c-Jun N-terminal kinase 2, which were accompanied by a synergistic increase in cell death compared with alcohol or the HIV drugs alone. In PHHs, treatment with RIT and LOP or alcohol alone increased messenger RNA of spliced X box-binding protein 1 and decreased SERCA, which were accompanied by reduced levels of intracellular calcium. Alcohol combined with the HIV drugs significantly reduced intracellular calcium levels and potentiated cell death, which was comparable to the cell death caused by the SERCA inhibitor thapsigargin. CONCLUSION: Our findings suggest the possibility that HIV PIs potentiate alcohol-induced ER stress and injury through modulation of SERCA and maintaining calcium homeostasis could be a therapeutic aim for better care of HIV patients.

Administration of lopinavir/ritonavir association during rat pregnancy: maternal and fetal effects.

PURPOSE: To evaluate the effects of the association of lopinavir and ritonavir administered during the whole period of rat pregnancy. METHODS: 62 Wistar rats of the EPM-1 variant weighing about 200 g were randomly divided into five groups: two controls (Ctrl = stress control, n = 10; and Ctr2 = drug vehicle control, n = 10) and three experimental ones which were treated with an oral solution of lopinavir/ritonavir (Exp1 = 12.8/3.2 mg/kg b.w., n = 14; Exp2 = 38.4/9.6 mg/kg b.w., n = 14; Exp3 = 115.2/28.8 mg/kg b.w., n = 14) from 'day 0' up to the 20th day of pregnancy. Maternal body weight was recorded at the start of the experiment and on the 7th, 14th and 20th day thereafter. At term (20th day), upon laparotomy and hysterotomy, the rats were anesthetized and the amount of implantations, reabsorptions, living fetuses, placentae and intrauterine deaths were recorded. The collected fetuses and placentae were weighed and the concepts were examined under a stereoscope microscope for external malformations. RESULTS: An apparent dose-unrelated lethal effect of the antiviral association on the pregnant rats was observed; notwithstanding, the body weight gain of the surviving rats had no changes, independent of the considered group. It was noted that the quantitative and qualitative intrauterine content of living term rats was indistinguishable from that of the controls. CONCLUSION: There was some degree of deleterious effects of the administration of the lopinavir/ritonavir association on pregnant rats; such effects eventually led to maternal death. However, neither the surviving rats showed toxicity nor did their concepts present any detectable change which could be related to the drug association.

Revealing the toxicity of lopinavir- and ritonavir-containing water and wastewater treated by photo-induced processes to Danio rerio and Allivibrio fischeri.

In coronavirus disease 2019 (COVID-19), among many protocols, lopinavir and ritonavir in individual or combined forms with other drugs have been used, causing an increase in the concentration of antiviral drugs in the wastewater and hospital effluents. In conventional wastewater treatment plants, the removal efficiency of various antiviral drugs is estimated to be low (<20%). The high values of predicted no-effect concentration (PNEC) for lopinavir and ritonavir (in ng∙L-1) reveal their high chronic toxicity to aquatic organisms. This indicates that lopinavir and ritonavir are current priority antiviral drugs that need to be thoroughly monitored and effectively removed from any water and wastewater samples. In this study, we attempt to explore the impacts of two photo-induced processes (photolysis and photocatalysis) on the toxicity of treated water and wastewater samples containing lopinavir and ritonavir to zebrafish (Danio rerio) and marine bacteria (Allivibrio fischeri). The obtained results reveal that traces of lopinavir in water under photo-induced processes may cause severe problems for Danio rerio, including pericardial edema and shortening of the tail, affecting its behavior, and for Allivibrio fischeri as a result of the oxygen-depleted environment, inflammation, and oxidative stress. Hence, lopinavir must be removed from water and wastewater before being in contact with light. In contrast, the photo-induced processes of ritonavir-containing water and wastewater reduce the toxicity significantly. This shows that even if the physicochemical parameters of water and wastewater are within the standard requirements/limits, the presence of traces of antiviral drugs and their intermediates can affect the survival and behavior of Danio rerio and Allivibrio fischeri. Therefore, the photo-induced processes and additional treatment of water and wastewater containing ritonavir can minimize its toxic effect.

Reproductive toxicity of ritonavir in male: Insight into mouse sperm capacitation.

Since COVID-19 began in 2019, therapeutic agents are being developed for its treatment. Among the numerous potential therapeutic agents, ritonavir (RTV), an anti-viral agent, has recently been identified as an important element of the COVID-19 treatment. Moreover, RTV has also been applied in the drug repurposing of cancer cells. However, previous studies have shown that RTV has toxic effects on various cell types. In addition, RTV regulates AKT phosphorylation within cancer cells, and AKT is known to control sperm functions (motility, capacitation, and so on). Although deleterious effects of RTV have been reported, it is not known whether RTV has male reproduction toxicity. Therefore, in this study, we aimed to investigate the effects of RTV on sperm function and male fertility. In the present study, sperm collected from the cauda epididymis of mice were incubated with various concentrations of RTV (0, 0.1, 1, 10, and 100 µM). The expression levels of AKT, phospho-AKT (Thr308 and Ser473), and phospho-tyrosine proteins, sperm motility, motion kinematics, capacitation status, and cell viability were assessed after capacitation. The results revealed that AKT phosphorylation at Thr308 and Ser473 was significantly increased, and the levels of tyrosine-phosphorylated proteins (at approximately 25 and 100 kDa) were significantly increased in a dose-dependent manner. In addition, RTV adversely affected sperm motility, motion kinematics, and cell viability. Taken together, RTV may have negative effects on sperm function through an abnormal increase in tyrosine phosphorylation and phospho-AKT levels. Therefore, individuals taking or prescribing RTV should be aware of its reproductive toxicity.

Reproductive and developmental safety of nirmatrelvir (PF-07321332), an oral SARS-CoV-2 Mpro inhibitor in animal models.

Nirmatrelvir (PF-07321332; NMV) the antiviral component of PAXLOVID™ is a potent and selective inhibitor of the SARS-CoV-2 main protease (Mpro), which plays a critical role in viral replication. PAXLOVID, comprised of nirmatrelvir and ritonavir (used as a pharmacokinetic enhancer), is an oral therapy currently in development as a therapeutic option for those infected with SARS-CoV-2 to prevent progression to severe disease, hospitalization, and death. PAXLOVID has been shown to be efficacious against hospitalization and death in two Phase 2/3 clinical studies that evaluated non hospitalized patients both with and without high risk factors for progression to severe illness. Given that males and females of reproductive age are included in the intended patient population, we assessed the potential effects of NMV up to the limit dose of 1000 mg/kg/day in ICH guideline embryo-fetal development studies in rats and rabbits, and a fertility and early embryonic development study in rats. There were no effects on male and female fertility or early embryonic development in rats, and no severe manifestations of developmental toxicity in rats or rabbits. The lack of adverse findings reported here in nonclinical species is consistent with the intended therapeutic target of NMV (a virus specific protein not present in mammalian cells), the favorable off-target selectivity profile, and lack of genetic toxicity. The results of these nonclinical studies with NMV along with existing ritonavir safety information indicate that there are no clinically relevant risks associated with PAXLOVID administration during pregnancy and in males and females of reproductive age.

Metabolomic screening and identification of the bioactivation pathways of ritonavir.

Ritonavir-boosted protease inhibitor regimens are widely used for HIV chemotherapy. However, ritonavir causes multiple side effects, and the mechanisms are not fully understood. The current study was designed to explore the metabolic pathways of ritonavir that may be related to its toxicity. Metabolomic analysis screened out 26 ritonavir metabolites in mice, and half of them are novel. These novel ritonavir metabolites include two glycine conjugated, two N-acetylcysteine conjugated, and three ring-open products. Accompanied with the generation of ritonavir ring-open metabolites, the formation of methanethioamide and 2-methylpropanethioamide were expected. Upon the basis of the structures of these novel metabolites, five bioactivation pathways are proposed, which may be associated with sulfation and epoxidation. By using Cyp3a-null mice, we confirmed that CYP3A is involved in four pathways of RTV bioactivation. In addition, all these five bioactivation pathways were recapitulated in the incubation of ritonavir in human liver microsomes. Further studies are suggested to determine the role of CYP3A and these bioactivation pathways in ritonavir toxicity.

Drug-induced liver injury associated with lopinavir-ritonavir in patients with COVID-19: a disproportionality analysis of U.S. food and drug administration adverse event reporting system (FAERS) data.

Background Liver injury has been documented independently in novel coronavirus disease 2019 (COVID-19) patients and patients treated with lopinavir-ritonavir. Objective to investigate the drug-induced liver injury associated with lopinavir-ritonavir among the patients with COVID-19. Methods We conducted a disproportionality analysis of US Food and Drug Administration Adverse Event Reporting System (FAERS) between 2020Q1 and 2021Q1 to evaluate the association between lopinavir-ritonavir and risk of drug-induced liver injury (or severe drug-induced liver injury) and calculated their reporting odds ratios (RORs) with 95% confidence intervals (CIs). Results A total of 3,425 cases of drug-induced liver injury were reported in 19,782 patients with COVID-19. The ROR for drug-induced liver injury was 2.99 (2.59-3.46), 3.16 (2.68-3.73), and 5.39 (4.63-6.26) when comparing lopinavir-ritonavir with all other drugs, hydroxychloroquine/chloroquine only, and remdesivir, respectively. For severe drug-induced liver injury, RORs for lopinavir-ritonavir provided evidence of an association compared with all other drugs (3.98; 3.15-5.05), compared with hydroxychloroquine/chloroquine only (5.33; 4.09-6.94), and compared with remdesivir (3.85; 3.03-4.89). Conclusions In the FAERS, we observed a disproportional signal for drug-induced liver injury associated with lopinavir-ritonavir in patients with COVID-19.

Acipimox, an inhibitor of lipolysis, attenuates atherogenesis in LDLR-null mice treated with HIV protease inhibitor ritonavir.

OBJECTIVE: The advent of HIV protease inhibitors has greatly extended the life span of AIDS patients. With an aging HIV(+) population, the cardiometabolic side effects of these drugs are becoming increasingly important clinical concerns. The purpose of this study was to test the hypothesis that inhibition of adipose lipolysis will retard atherogenic lesion development induced by the antiviral protease inhibitors. METHODS AND RESULTS: LDLR-null mice receiving ritonavir were compared with those receiving ritonavir plus lipolysis inhibitor acipimox or vehicle alone to determine how acipimox would affect ritonavir-induced atherogenesis. Intermittent high-fat high-cholesterol diet was used to facilitate optimal atheromatous lesion development. Drug effects were assessed as changes in aortic lesion score, plasma lipid and lipoprotein profile, body fat mass, and insulin-induced suppression of plasma fatty acid concentrations. Ritonavir increased aortic lesions, in association with decreased body fat mass, impaired antilipolysis action of insulin, and increased proatherogenic plasma lipoproteins. All these adverse effects were attenuated by cotreatment with acipimox. CONCLUSIONS: Our results provide the first direct evidence that supports the hypothesis that dysregulation of adipose lipolysis is an important contributor to the proatherogenic role of selected HIV protease inhibitors.

Identification of proteasome gene regulation in a rat model for HIV protease inhibitor-induced hyperlipidemia.

Patients treated with highly active antiretroviral therapy may develop metabolic side effects such as hyperlipidemia, insulin resistance, lipoatrophy and lactic acidosis. The pathophysiology of these metabolic abnormalities is unknown, although some, e.g., lactic acidosis and lipoatrophy, are more associated with nucleoside use while protease inhibitors (PIs) have been shown to contribute to hyperlipidemia and insulin resistance. Identifying new PIs that are not associated with dyslipidemia has been hindered by the lack of mechanistic information and the unavailability of relevant animal models. In order to understand the molecular mechanism behind the hyperlipidemia associated with other protease inhibitors, and to develop a more effective, faster screen for compounds with this liability, we have analyzed expression profiles from PI-treated animals. Previously, we have shown that treatment of rats with ritonavir results in increases in the expression of proteasomal subunit genes in the liver. We show this increase is similar in rats treated with bortezomib, a proteasome inhibitor. In addition, we have treated rats with additional protease inhibitors, including atazanavir, which is associated with lower rates of lipid elevations in the clinic when administered in the absence of ritonavir. Our results indicate a strong correlation between proteasomal induction and lipid elevations, and have allowed us to develop a rapid screen for identifying novel PIs that do not induce the proteasome.

High Dietary Fat Modulates Neurobehavioural Effect of Lopinavir/ Ritonavir in Mice.

BACKGROUND: Lopinavir/Ritonavir (LR) is a protease inhibitor used human immunodeficiency virus infection management. There have been issues regarding the effects of fat on LR efficacy and the possibility of neurological deficits following prolonged use, there is however a dearth of research examining this. AIMS: The effects of LR administered with normal or High-Fat Diet (HFD) on neurobehaviour, neurochemistry and oxidative stress in healthy mice were examined. METHODS: Mice were randomly-assigned into eight groups of ten (n=10) animals each. The groups were normal control [Standard Diet, (SD)], HFD control, 3 groups of LR incorporated into SD (100/25, 200/50 and 400/100 mg/kg of feed), and 3 groups of LR with HFD (100/25, 200/50 and 400/100 mg/kg of feed). Mice were fed daily for six weeks, following which open field, elevated-plus maze (EPM), radial-arm maze and Y-maze behaviours were scored. Twenty-four hours after tests, mice were euthanised and brains were homogenised for estimation of oxidative stress, L-glutamate level and acetylcholinesterase activity. RESULTS: LR was associated with a reduction in HFD-induced weight gain, suppression of open-field behaviours with SD, and counteraction of HFD-induced changes in working-memory, open-field and anxiety-related behaviours. Also, LR causes increased lipid peroxidation and superoxide dismutase activity; and a decrease in brain glutamate, irrespective of dietary composition. Increased fat catabolism leading to increased oxidative stress could possibly account for the weight changes, while a decrease in brain glutamate could account for the changes in open-field behaviours in mice fed SD. CONCLUSION: LR alters neurobehaviour, oxidative stress and brain glutamate in mice; however, only its effects on neurobehaviour are affected by diet.

The dual protease inhibitor lopinavir/ritonavir (LPV/r) exerts genotoxic stress on lung cells.

The Sub-Saharan countries, particularly South Africa has the largest number of people living with HIV, accompanied by the largest antiretroviral treatment (ART) programme in the world. The Highly Active Antiretroviral Treatment (HAART) is the most effective regimen against HIV/AIDS and has improved the lifespan and quality of life of HIV positive patients. HAART has also led to a decrease in the incidence of AIDS defining cancers (ADCs) while there is an increased incidence of the non-AIDS Defining Cancers (NADCs), such as lung cancer in the HAART era. The association between lung tumourigenesis and the use of HAART components such as the dual protease inhibitor (PI) lopinavir/ritonavir (LPV/r) is poorly understood. Using cell and molecular biological approaches, this study aimed at elucidating the effects of LPV/r on the regulation of the cell cycle related genes in normal (MRC-5) and adenocarcinoma (A549) lung cells. Initially, the nuclear integrity of these cells in response to LPV/r was determined using DAPI staining. The effect of LPV/r on cell cycle genes was evaluated through the use of a RT2 PCR gene array of 84 genes related to the cell cycle signaling pathway. The PCR array data was validated by Real-Time Quantification PCR (RT-qPCR). Ingenuity Pathway Analysis (IPA) bio-informatics tool was employed to disclose the molecular mechanism/s observed at cellular and gene expression levels. Loss of nuclear integrity and the upregulation of the p53 DNA damage response (DDR) pathway was revealed by DAPI staining, differential gene expression and IPA core analysis. Furthermore, MAD2L2 and AURKB which also play a role in the DDR pathway were shown to be differentially expressed. The activation of the CASP3 gene in response to LPV/r in A549 cells was also observed. The findings of this study suggest genotoxic properties of LPV/r in healthy normal lung fibroblasts cells and anti-tumour properties in the A549 cells.