Metabolic abnormalities and body fat redistribution in HIV-1 infected patients: the lipodystrophy syndrome

Photoperiod-Induced Increases in Bone Mineral Apposition Rate in Siberian Hamsters and the Involvement of Seasonal Leptin Changes

The adipokine leptin regulates energy balance, appetite, and reproductive maturation. Leptin also acts on bone growth and remodeling, but both osteogenic and anti-osteogenic effects have been reported depending on experimental conditions. Siberian hamsters (Phodopus sungorus) have natural variation in circulating leptin concentrations, where serum leptin is significantly decreased during the short day (SD)-induced winter state. In summer long day (LD) photoperiods, appetite and body adiposity increase with associated central leptin insensitivity. This natural change in leptin secretion was exploited to investigate leptin's effect on bone growth. Hamsters were injected with calcium-chelating fluorescent dyes to measure bone mineral apposition rate (MAR). Measurements were initially obtained from 5-week and 6-month-old animals maintained in low leptin (SD) or high leptin (LD) states. A further study investigated effects of chronic administration of recombinant mouse leptin to hamsters housed in SD and LD conditions; growth plate thickness and bone density were also assessed. As expected, a reduction in body mass was seen in hamsters exposed to SD, confirming the phenotype change in all studies. Serum leptin concentrations were significantly reduced in SD animals in all studies. MAR was reproducibly and significantly increased in the femurs of SD animals in all studies. Vitamin D and growth plate thickness were significantly increased in SD animals at 6 months. No effect on bone density was observed in any study. Taken together these data suggest that bone growth is associated with the low leptin, winter, lean state. In leptin-treated animals, there was a significant interaction effect of leptin and photoperiod. In comparison to their vehicle counterparts, SD animals had decreased and LD animals had increased MAR, which was not apparent prior to leptin administration. In conclusion, increased MAR was associated with low serum leptin levels in early life and sustained over 6 months, implying that leptin has a negative effect on bone growth in this model. The unexpected finding that MAR increased after peripheral leptin administration in LD suggests that leptin exerts different effects on bone growth dependent on initial leptin status. This adds further weight to the hypothesis that leptin-treated LD animals display central leptin resistance.

Second generation HIV protease inhibitors against resistant virus

BACKGROUND

The AIDS epidemic has spread around the world at an alarming rate. Although the first generation of HIV protease inhibitors, including indinavir, nelfinavir, saquinavir, ritonavir and amprenavir, were initially effective against HIV infection, the fast emerging resistance to these agents has been a substantial and persistent problem in the treatment of AIDS. Attempts to address the resistance issue with 'salvage therapy' consisting of high doses of multiple protease inhibitors have only been moderately successful owing to the high level of cross-resistance and toxicities associated with the protease inhibitors.

OBJECTIVE

To study the second generation HIV protease inhibitors against resistant virus.

METHOD

This review highlights new developments achieved by various organizations to address the challenge of high level resistance of current therapies since 2000.

CONCLUSION

All second generation protease inhibitors used in patients who experienced extensive treatment require ritonavir as a pharmacological boosting agent to increase the drug level in the plasma, but there is toxicity associated with such a practice. Accordingly, there remains a need for new protease inhibitors with improved effectiveness against the resistant viral variants. A third generation protease inhibitor will require no boosting agent while maintaining high potency against resistant virus.

Iron status in HIV-1 infection: implications in disease pathology

BACKGROUND

There had been conflicting reports with levels of markers of iron metabolism in HIV infection. This study was therefore aimed at investigating iron status and its possible mediation of severity of HIV- 1 infection and pathogenesis.

METHOD

Eighty (80) anti-retroviral naive HIV-1 positive and 50 sero-negative controls were recruited for the study. Concentrations of serum total iron, transferrin, total iron binding capacity (TIBC), CD4+ T -lymphocytes, vitamin C, zinc, selenium and transferrin saturation were estimated.

RESULTS

The mean CD4+ T-lymphocyte cell counts, serum iron, TIBC, transferrin saturation for the tests and controls were 319 ± 22, 952 ± 57 cells/μl (P < 0.001), 35 ± 0.8, 11.8 ± 0.9 μmol/l (P < 0.001), 58.5 ± 2.2, 45.2 ± 2.4 μmol/l (P < 0.005) and 68.8 ± 3.3, 27.7 ± 2.2%, (P <0.001), respectively, while mean concentrations of vitamin C, zinc and selenium were 0.03 ± 0.01, 0.3 ± 0.04 (P < 0.001), 0.6 ± 0.05, 11.9 ± 0.26 μmol/l (P < 0.001) and 0.1 ± 0.01, 1.2 ± 0.12 μmol/l (P < 0.001) respectively. Furthermore, CD4+ T-lymphocyte cell count had a positive correlation with levels of vitamin C (r = 0.497, P < 0.001), zinc (r = 0.737, P < 0.001), selenium (r = 0.639, P < 0.001) and a negative correlation with serum iron levels (r = -0.572, P < 0.001).

CONCLUSION

It could be inferred that derangement in iron metabolism, in addition to oxidative stress, might have contributed to the depletion of CD4+ T cell population in our subjects and this may result in poor prognosis of the disease.

Lipomatous disorder of the peri-trochanteric soft tissue: case report and review

Disorders of fatty tissue metabolism and body contour are frequently described in the literature. Several different syndromes have been ascribed to recurring characteristics of fatty deposition with similar underlying etiologies. These syndromes can generally be classified into the lipomatoses (abnormal accumulations of fat) and the lipodystrophies (abnormal fat atrophy). The authors describe a case of isolated symmetrical lipomatosis of the soft tissue overlying the trochanters that developed a recurrence after treatment with liposuction. They have attempted to match this patient's disorder into 1 of several reported syndromes, with benign symmetric lipomatosis and acquired partial lipodystrophy at the top of the differential diagnosis. However, some characteristics of this patient may warrant a separate categorization for her condition. In this case report, the current literature on disorders of fatty tissue metabolism is reviewed and a discussion of relevant factors and issues surrounding their clinical significance and management is provided.

Intrathoracic fat in HIV-infected patients

BACKGROUND

The impact of HIV infection or antiretroviral therapy on the intrathoracic fat compartment is unknown.

METHODS

Consecutive clinically stable HIV-infected adult patients, irrespective of exposure to antiretroviral therapy, and non-HIV-infected healthy volunteers, both without clinical evidence of body fat changes consistent with lipodystrophy and adjusted for age, gender and body mass index, were recruited for this study. Thoracic and abdominal fat was assessed by computed tomography and compared between patients and controls.

RESULTS

There were nine women (33%) and 18 men (67%) in each group. Nineteen patients (70%) had been taking antiretrovirals for a median of 8 months (interquartile range: 6-11). Among the HIV-infected patients, intrathoracic fat (median; interquartile range) did not differ significantly between treated (6.7 cm(2); 4.5-8.3 cm(2)) and untreated (6.9 cm(2); 5.7-10.9 cm(2)) individuals (P=0.288). However, intrathoracic fat content (median; interquartile range) was higher in HIV-infected patients (6.8 cm(2); 5.6-10.5 cm(2)) than in controls (5.6 cm(2); 3.9-6.7 cm(2)) (P=0.025). Intrathoracic fat was positively correlated with intra-abdominal fat both in patients (rho=0.6, P=0.002) and in controls (rho=0.7, P=0.004).

CONCLUSION

In HIV-infected adults without clinical evidence of lipodystrophy, intrathoracic fat content was higher than in healthy persons and positively correlated with intra-abdominal fat content.

Increased risk of pre-eclampsia and fetal death in HIV-infected pregnant women receiving highly active antiretroviral therapy

BACKGROUND

Pre-eclampsia and/or fetal death have increased sharply in HIV-infected pregnant women receiving HAART.

METHODS

The occurrence of pre-eclampsia or fetal death was analysed in women who delivered after at least 22 weeks of gestation for all women (January 2001 until July 2003) and for HIV-infected women (November 1985 until July 2003).

RESULTS

In 2001, 2002 and 2003, the rates per 1000 deliveries of pre-eclampsia and fetal death, respectively, remained stable in all pregnant women at 25.4, 31.9 and 27.7 (P = 0.48) and 4.8, 5.8, and 5.0 (P = 0.89) (n = 8768). In 1985-2000 (n = 390) to 2001-2003 (n = 82), rates per 1000 deliveries in HIV-infected women rose from 0.0 to 109.8 (P < 0.001) for pre-eclampsia and from 7.7 to 61.0 (P < 0.001) for fetal death. In all pregnant women, factors associated with pre-eclampsia or fetal death were multiple gestation [adjusted odds ratio (OR) 3.6; 95% confidence interval (CI), 2.3-5.6; P < 0.001], HIV infection (adjusted OR, 4.9; 95% CI, 2.4-10.1; P < 0.001), multiparity (adjusted OR, 0.76; 95% CI, 0.58-0.98; P = 0.040) and tobacco smoking (adjusted OR, 0.65; 95% CI, 0.46-0.90; P = 0.010). The use of HAART prior to pregnancy (adjusted OR, 5.6; 95% CI, 1.7-18.1; P = 0.004) and tobacco smoking (adjusted OR, 0.183; 95% CI, 0.054-0.627; P = 0.007) were risk factors in HIV-infected women.

CONCLUSIONS

HIV infection treated with HAART prior to pregnancy was associated with a significantly higher risk for pre-eclampsia and fetal death.

Substitution of nevirapine or efavirenz for protease inhibitor versus lipid-lowering therapy for the management of dyslipidaemia

OBJECTIVES

To evaluate simplified protease inhibitor (PI)-sparing antiretroviral treatment versus lipid-lowering therapy for the management of highly active antiretroviral therapy (HAART)-induced hyperlipidaemia.

DESIGN

Randomized, open-label clinical trial assessing the efficacy on hyperlipidaemia of a switching therapy from PI to non-nucleoside reverse transcriptase inhibitor (NNRTI) nevirapine or efavirenz versus a hypolipidaemic treatment (with pravastatin or bezafibrate) added to current, unchanged antiretroviral combination.

METHODS

All HIV-infected patients on their first HAART regimen, with stable immuno-virological features, naive to all NNRTIs, and with mixed hyperlipidaemia, were randomized to replace PI with nevirapine (arm A) or efavirenz (arm B), or to receive pravastatin (arm C) or bezafibrate (arm D) with unchanged HAART regimen, and were followed-up for 12 months.

RESULTS

One hundred and thirty patients were evaluated: 29 patients were randomized to arm A, 34 to arm B, 36 to arm C, and 31 to arm D. At the end of the 12-month follow-up, a reduction of 25.2, 9.4, 41.2 and 46.6% in mean triglyceridaemia versus respective baseline values was reported in groups A, B, C and D, respectively, with statistically significant difference between arms A-B and C-D (P < 0.01). Similar results were reported for total and low-density lipoprotein cholesterol levels. Viro-immunological efficacy and tolerability profile were comparable in all considered arms.

CONCLUSION

Pravastatin and bezafibrate proved significantly more effective in the management of HAART-related hyperlipidaemia than the switching therapy from PI to nevirapine or efavirenz.

Prevalence of fat redistribution and metabolic disorders in human immunodeficiency virus-infected children

In this study we assessed the prevalence of fat redistribution and metabolic disorders in a population of HIV-infected children on antiretroviral treatment. To make associations with epidemiological parameters, clinical-immune status, viral load and highly active antiretroviral therapy (HAART), we performed a cross-sectional study in HIV-infected children. Epidemiological parameters (age, sex, family history), clinical and immune status, viral load, and duration of antiretroviral treatment (ART) and HAART, including protease inhibitors, were recorded. Presence of clinical signs of fat redistribution and lipid, glucose and lactic acid levels were evaluated. A total of 56 HIV-infected children, including 30 boys (54%), aged between 21 months and 18 years (mean 9.5 years) were studied. In all, 49 patients (87.5%) were receiving ART (mean duration 4 years) and 43 (77%) were receiving HAART (mean duration 3.6 years). Fat redistribution or lipodystrophy was present in 14 patients (25%); seven had lipohypertrophy (12.5%), two lipoatrophy (3.5%) and five a mixed pattern (8.9%). Fat redistribution was higher in children older than 11 years (50%). Of the lipodystrophic patients, 71.4% presented hypertriglyceridaemia (> 130 mg/dl) and 57% hypercholesterolaemia (> 180 mg/dl). We found significant associations between lipodystrophy and age, ART and HAART duration and hypertriglyceridaemia ( P < 0.001, 0.002, 0.016 and < 0.001, respectively), but no significant association with sex, family history, clinical or immune status and viral load.

CONCLUSION

The prevalence of lipodystrophy was 25% (95% confidence interval 14.8-34.6) with lipohypertrophy being the commonest pattern. Clinical fat redistribution was significantly associated with older age, duration of antiretroviral treatment and highly active antiretroviral therapy and hypertriglyceridaemia.

Lipodystrophy Syndrome: The Morphologic and Metabolic Effects of Antiretroviral Therapy in HIV Infection

Widespread use of highly active antiretroviral therapy (HAART) to manage HIV infection is now associated with the development of lipodystrophy syndrome. This syndrome is a combination of such morphologic and metabolic changes as hyperlipidemia, fat redistribution, and insulin resistance. Although many of the long-term effects of HAART have not been fully recognized, it is thought that lipodystrophy syndrome may now contribute to early-onset hypercholesterolemia, heart disease, and diabetes, and may have a negative psychological impact on the individual living with HIV infection.

Serum adiponectin and metabolic parameters in HIV-1-infected patients after substitution of nevirapine for protease inhibitors

BACKGROUND

In the context of HIV infection and antiretroviral therapy, adiponectin concentrations have been shown to be related to lipodystrophy, metabolic alterations and HIV-protease inhibitor (PI) use. The replacement of PI by nevirapine has improved the lipid profile of patients under antiretroviral therapy. The aim of the present study was to examine whether adiponectin concentration or insulin sensitivity level correlate with the modifications of lipid parameters after the switch of PI by nevirapine.

MATERIAL AND METHODS

The evolution of metabolic parameters before and after 6 months of substitution of nevirapine for protease inhibitors was evaluated in a cohort of 55 HIV-1 infected patients. Adiponectin concentration, insulin sensitivity, lipid profile, cholesterol ester transfer protein (CETP) mass concentration and triglyceride enrichment of HDL were determined before and after the replacement of PI by nevirapine. Insulin sensitivity was evaluated by the HOMA model assessment.

RESULTS

Twenty-four weeks of treatment with nevirapine improved significantly the lipid profile with a significant reduction of apoB (from 0.98 to 0.92 g L(-1); P = 0.005) and triglyceride (from 2.02 to 1.66 mmol L(-1); P = 0.02). HDL cholesterol and apoA1 increased significantly (from 0.99 to 1.19 mmol L(-1); P = 0.001 and from 1.40 to 1.57 g L(-1); P < 0.001, respectively). The triglyceride enrichment of HDL significantly decreased after the replacement of PI by nevirapine (from 0.248 +/- 0.092 to 0.213 +/- 0.093; P = 0.003). At baseline, and after 24 weeks of nevirapine treatment, we observed significant correlations between adiponectin level and lipid parameters [(HDL-cholesterol (r = 0.66, P = 0.001 and r = 0.69, P = 0.001); triglycerides (r = -0.42, P = 0.002 and r = -0.57, P = 0.001), and triglyceride enrichment of HDL (r = -0.43, P = 0.005 and r = -0.53, P = 0.005)]. Twenty-four weeks of treatment with nevirapine did not significantly change adiponectin concentrations (from 984 to 1086 micro g L(-1), P = 0.22), CETP mass and insulin sensitivity.

CONCLUSION

This study shows that even though a strong correlation was found between adiponectin and some metabolic parameters at baseline and after 24 weeks of treatment by nevirapine, the improvement of lipid profile observed after the replacement of PI by nevirapine was not in relation to the change of plasma adiponectin concentration. The significant decrease of triglyceride enrichment of HDL after the replacement of PI by nevirapine probably leads to a decreased catabolism of HDL lipoprotein, and consequently explains the increase of plasma HDL concentration observed in this study.

[Is there an increased risk for cardiovascular disease in HIV-infected patients on antiretroviral therapy?]

There is a growing concern about an increased risk for cardiovascular disease in HIV infected patients receiving antiretroviral therapy (ART). This risk could be related to metabolic abnormalities associated with long-term use of antiretroviral drugs. In fact, well recognized cardiovascular risk factors such as hypertension, dyslipidaemia, diabetes mellitus and central fat deposition are increasingly seen in HIV patients on ART. These factors can also be associated with non reversible risk factors, such as male sex, age greater than 40 years and family history of premature coronary artery disease. In addition, cigarette smoking and sedentary lifestyle may predispose these patients to significant cardiovascular disease. A direct atherogenic effect of HIV infection itself or antiretroviral drugs is unlikely. Epidemiological studies have suggested an increased risk for coronary artery disease in HIV infected persons; nevertheless, only long term follow-up could confirm this statement. Despite these uncertainties, it seems reasonable to identify and manage cardiovascular risk factors in HIV infected patients.

Increased VLDL-apoB and IDL-apoB production rates in nonlipodystrophic HIV-infected patients on a protease inhibitor-containing regimen: a stable isotope kinetic study

The aim of this study was to identify the first abnormalities of apolipoprotein B (apoB) metabolism in HIV-infected patients treated by antiretroviral therapy (ART) with protease inhibitors (PIs). The influence of ART on the metabolism of apoB in VLDL, IDL, and LDL was investigated in six patients receiving dual nucleoside reverse transcriptase inhibitors (NRTIs) and PI, and in five patients receiving NRTI and nevirapine. None of the patients had lipodystrophy. The study was performed in the fed state. Each subject received an intravenous injection of a 0.7 mg.kg-1 bolus of l-[1-13C]leucine, immediately followed by a 16 h constant infusion at 0.7 mg.kg-1.h-1. The VLDL- and IDL-apoB concentrations were significantly higher in PI-treated patients compared to non-PI-treated patients. The VLDL-apoB and IDL-apoB production rates were markedly higher in PI-treated patients compared to non-PI-treated patients (54.5 +/- 30.1 vs. 30.9 +/- 8.4 mg.kg-1.d-1, P = 0.04; and 43.5 +/- 20.0 vs. 18.7 +/- 7.8 mg.kg-1.d-1, P = 0.04, respectively). In conclusion, our study shows that patients receiving ART with PI present altered metabolism of the VLDL-IDL-LDL chain compared with patients treated without PI. These data confirm that PI therapy is associated with a physiopathological mechanism for dyslipidemia in addition to the effect of lipodystrophy on lipid metabolism.

Hyperlipidaemia in patients with HIV-1 infection receiving highly active antiretroviral therapy: epidemiology, pathogenesis, clinical course and management

A wide range of abnormalities of lipid metabolism have been recently described in HIV-infected patients receiving a protease inhibitor (PI)-based highly active antiretroviral therapy, including hypertriglyceridaemia and hypercholesterolaemia. The increase of plasma lipid concentrations may involve up to 70-80% of HIV-positive subjects treated with a PI-containing regimen and are frequently (but not always) associated with the fat redistribution or the lipodystrophy syndrome. Multiple pathogenetic mechanisms by which antiretroviral agents lead to dyslipidaemia have been hypothesized, but they are still controversial. The potential clinicopathological consequences of HIV-associated hyperlipidaemia are not completely known, but several anecdotal observations report an increased risk of premature coronary artery diseases in young HIV-positive individuals receiving PIs, besides peripheral atherosclerosis and acute pancreatitis. A limited-to-significant improvement of increased triglyceride and cholesterol plasma levels was described in patients who replaced PIs with nevirapine, efavirenz or abacavir, but the risks of long-term toxicity and virological relapse of this treatment switching are not completely defined. A hypolipidaemic diet and regular physical exercise may act favorably on dyslipidaemia, but pharmacological therapy becomes necessary when hyperlipidaemia is severe or persists for a long time. The choice of hypolipidaemic drugs is problematic because of potential pharmacological interactions with antiretroviral compounds and other antimicrobial agents, associated with an increased risk of toxicity and intolerance. Statins are considered the first-line therapy for the PI-related hypercholesterolaemia, while fibrates are the cornerstone of drug therapy when predominant hypertriglyceridaemia is of concern.

Statins and fibrates for the treatment of hyperlipidaemia in HIV-infected patients receiving HAART

OBJECTIVES

The aim of our work is to evaluate the role of statins and fibrates in the management of hyperlipidaemia in HIV-infected patients receiving highly active antiretroviral therapy.

DESIGN

Open-label, randomized, prospective study of the efficacy and safety of bezafibrate, gemfibrozil, fenofibrate, pravastatin and fluvastatin as pharmacologic treatment for protease inhibitor-related dyslipidaemia.

METHODS

Plasma lipid levels of 656 HIV-infected patients who referred to our tertiary care centre and were on protease inhibitor-based antiretroviral therapy for at least 12 months have been evaluated. All patients had HIV viral load < 50 copies/ml and presented with hypertriglyceridaemia of at least 6 months duration that was unresponsive to a hypolipidaemic diet; all have been treated with bezafibrate, gemfibrozil, fenofibrate, pravastatin, or fluvastatin for 12 months.

RESULTS

Of the 656 patients observed 113 (17.2%) received pharmacological therapy, while seven patients were excluded from evaluation due to early drop-out. Of the 106 evaluable subjects, bezafibrate was used in 25 cases, gemfibrozil in 22, fenofibrate in 22, pravastatin in 19, and fluvastatin in 18. At the close of 1-year follow-up, fibrates led to a reduction of 40.7% and 21.9% versus baseline triglyceridaemia and cholesterolaemia, respectively (P < 0.001), and statins led to a reduction of 34.8% and 25.2% versus baseline triglyceride and total cholesterol levels, respectively (P < 0.001), without significant differences according to each different administered hypolipidaemic drug.

CONCLUSIONS

All administered statins and fibrates revealed a similar, significant efficacy in the treatment of diet-resistant hyperlipidaemia, and showed a favourable tolerability profile.

Effect of highly active antiretroviral therapy (HAART) and hepatitis C Co-infection on hyperlipidemia in HIV-infected patients: a retrospective longitudinal study

BACKGROUND

Lipid abnormalities are among the most frequent treatment-limiting adverse events during HAART in HIV-infected individuals. Lipid disturbances have also been associated with hepatitis C virus (HCV) chronic infection in HIV-uninfected participants. HAART-induced lipid abnormalities may then have peculiar features in HIV-HCV co-infected individuals.

PURPOSE

To estimate the prevalence and incidence rates of hypertriglyceridemia and hypercholesterolemia and to identify associated factors in a large clinic population of HIV patients after HAART has been initiated.

DESIGN

We performed a retrospective longitudinal follow-up study in a large cohort of HIV patients on their first HAART.

PATIENTS AND METHOD

The clinical databases of two major clinical centers in Italy participating in the MASTER study were merged. Treatment-emerging metabolic disorders in patients on their first HAART regimen (PI-based or NNRTI-based) who were stable for at least 4 months were prospectively analyzed by baseline parameters, drug regimens, and viroimmunological outcome of therapy. Follow-up was continued for 24 months or until drug discontinuation, whichever came first.

RESULTS

Two hundred and eighty two (282) HIV-infected patients undergoing HAART (203 PI + 79 NNRTI; 65 including stavudine [d4T]) met inclusion criteria and were enrolled in the study from 1997 to 2001. Mean follow-up was 18.5 +/- 6.7 months. After HAART had been initiated, a statistically significant mean increase in total cholesterol over time was observed in comparison to baseline (p <.0001), without difference between treatment groups (PI vs. NNRTI, with or without d4T). In the univariate analysis, predictive factors for HAART-induced hypercholesterolemia were baseline total plasma cholesterol and triglycerides values and CD4+ cell count differential increase over time, while a negative correlation was found with zalcitabine-including regimens and baseline HCV seropositivity. At multivariate analysis, only high baseline total plasma cholesterol and triglycerides values retained their predictive value and baseline HCV seropositivity was significantly associated with lower increase in total cholesterol values under HAART, regardless of treatment groups (p <.001).

CONCLUSION

HCV co-infection is an independent factor preventing the emergence of treatment-limiting total cholesterol increase under any HAART regimen, possibly reflecting impaired total cholesterol synthesis in the liver or total cholesterol hypercatabolism. On the contrary, no HCV influence on triglycerides plasma levels was noted. Our data do not suggest any favoring role of specific treatment or drugs (PI and/or d4T) on total cholesterol and triglycerides increase under HAART.

Body composition changes in protease inhibitor-naive HIV-infected patients treated with two nucleoside reverse transcriptase inhibitors

OBJECTIVES

In the era of highly active antiretroviral treatment (HAART), there are insufficient data regarding lipodystrophy syndromes in HIV-1-infected patients treated with regimens that do not include protease inhibitors (PIs). We studied changes in body composition in HIV-1-infected patients before and 2 years after starting a non-PI-containing antiretroviral treatment regimen.

METHODS

We studied retrospectively the whole body dual energy X-ray absorptiometry (DEXA) scans of 23 PI-naive HIV-1-infected patients (17 males, six females), aged 37.4 +/- 9.3 years with mean CD4 count 401 +/- 130 cells/microL. Thirteen patients were on zidovudine (ZDV) + lamivudine (3TC) and 10 on ZDV + didanosine (ddI). Subjects were evaluated before the beginning of antiretroviral treatment and approximately 24 months later. For each patient body weight, CD4 T-cell counts, bone mineral content (BMC), bone mineral density (BMD) and whole body as well as regional fat and lean body mass were evaluated.

RESULTS

A significant decrease in BMC was observed, although the T scores remained within the normal limits. Our patients also exhibited a significant decrease in body weight due almost exclusively to fat loss, while lean mass was minimally affected. Fat loss was statistically significant in the arms and legs, but not in the trunk. The above changes were most prominent in the ZDV + 3TC treatment group; in this group of patients, fat loss was also evident in the trunk. Patients on ZDV + ddI, on the other hand, only showed a significant increase in their legs' lean mass; they preserved their total fat mass and exhibited no other significant changes between the two assessments.

CONCLUSIONS

Dual NRTI therapy contributes to fat loss and reduction of bone mineral content in otherwise healthy, clinically stable, PI-naive HIV-infected adults. Compared with patients on ZDV + ddI, patients on ZDV + 3TC had a more prominent fat loss in all body regions.

Coronary heart disease associated with the use of human immunodeficiency virus (HIV)-1 protease inhibitors: report of four cases and review

Four cases of human immunodeficiency virus (HIV)-infected patients who developed coronary heart disease (CHD) while under treatment with a protease inhibitor (PI) are described, and the epidemiologic and clinical features of 18 cases reported in the literature are analyzed. Cardiac manifestations mostly included myocardial infarctions. Smoking and hyperlipidemia were the most common risk factors for CHD, reported in 72 and 81% of the patients, respectively. Hypercholesterolemia was observed in 75% of the cases at the time of the cardiovascular event. Ninety percent of the patients with pretreatment normal lipid values experienced a rise in the plasma lipid levels during PI therapy. Although a definite relationship between the development of CHD and HIV PIs can not be made, this analysis suggests that PI-induced hyperlipidemia may play a role in accelerating coronary atherosclerosis in patients with concomitant risk factors. Evaluation and control of risk factors for CHD should be performed in each patient for whom treatment with a PI is indicated.

Strategies for treating HIV-related lipodystrophy

HIV-related lipodystrophy has emerged as one of the most prevalent problems for patients with HIV, since this infection can now be seen as a chronic disease. Despite its growing importance, crucial issues such as aetiopathogenesis, diagnosis, prevention and therapy remain largely unknown and unexplored. Current evidence suggests that aetiology is multifactorial. HIV infection, antiretroviral therapy and patient-related factors probably all contribute to the development of lipodystrophy. The lack of a formal definition and the nature of wasting syndromes that affect HIV-infected patients can hinder the diagnosis and treatment of lipodystrophy. Body fat changes have a major negative impact on the quality of life of patients. Metabolic abnormalities are also well known cardiovascular risk factors that can increase the morbidity and mortality due to cardiovascular disorders in a relatively young population. As yet, we do not know whether lipodystrophy is preventable or reversible. Several therapeutic approaches have been tested with limited success, however potential complications must be considered. These therapeutic approaches include general health measures (diet, exercise and discontinuation of smoking), switching antiretrovirals (from protease inhibitors to non-nucleoside reverse transcriptase inhibitors or abacavir, or from stavudine to other nucleoside reverse transcriptase inhibitors) and use of drugs with metabolic effects (metformin, thiazolidinediones, recombinant growth hormone and anabolic steroids). A judicious use of available data, and opting for an individualised approach seems the best option for management of this problem at present.

The HIV protease inhibitor indinavir impairs sterol regulatory element-binding protein-1 intranuclear localization, inhibits preadipocyte differentiation, and induces insulin resistance

Protease inhibitors used in the treatment of HIV infection have been causally associated with lipodystrophy and insulin resistance and were shown to alter adipocyte differentiation in cultured cells. We aimed to delineate the mechanism by which indinavir impaired adipocyte function. We report that indinavir altered neither the growth nor insulin sensitivity of 3T3-F442A preadipocytes, nor did it alter the initial step of their differentiation, i.e., clonal proliferation. However, adipose conversion was inhibited by indinavir (by 50-60%), as shown by 1) the decrease in the number of newly formed adipocytes; 2) the lower level of the adipogenic protein markers, sterol regulatory element-binding protein-1 (SREBP-1), peroxisome proliferator-activated receptor-gamma (PPAR-gamma), and the insulin receptor (IR); and 3) the lack of SREBP-1 and PPAR-gamma immunoreactivity in the nucleus of most indinavir-treated cells. Partial adipose conversion also correlated with an accumulation of SREBP-1 at the nuclear periphery and an alteration in its electrophoretic mobility. Defective expression and nuclear localization of PPAR-gamma probably resulted from the decreased level of nuclear SREBP-1. Indinavir also rendered 3T3-F442A adipocytes resistant to insulin for mitogen-activated protein kinase activation at a step distal to IR substrate-1 tyrosine phosphorylation. Hence, indinavir impairs differentiation at an early step of adipose conversion probably involving the process controlling SREBP-1 intranuclear localization.

Disorders of lipid metabolism in patients with HIV disease treated with antiretroviral agents: frequency, relationship with administered drugs, and role of hypolipidaemic therapy with bezafibrate

OBJECTIVES

To assess the correlation between antiretroviral treatment and dyslipidaemia in HIV-infected patients, and the role of bezafibrate as a lipid-lowering agent.

METHODS

We retrospectively compared serum lipid levels of five groups of 40 patients, each of them treated with either saquinavir hard gel, indinavir, or ritonavir (associated with two nucleoside analogues), or dual nucleoside reverse transcriptase inhibitors (NRTI) with or without a non-nucleoside reverse transcriptase inhibitor (NNRTI), or not treated with antiretrovirals, randomly selected from nearly 1000 HIV-infected patients followed-up for >or= 12 months, while on the relevant therapy. Hypertriglyceridaemia was defined by triglyceride levels >or= 172 mg/dl, and hypercholesterolaemia by cholesterol levels >or= 200 mg/dl. All patients with triglyceridaemia > 300 mg/dl and cholesterolaemia > 220 mg/dl for at least 6 months, and unresponsive to a >or= 3-month diet, started bezafibrate (400 mg/day), and were prospectively followed-up at a <or= 3-month interval, evaluating both efficacy and tolerability of the hypolipidaemic treatment, provided that they did not change their protease inhibitor treatment for reasons other than metabolic abnormalities.

RESULTS

Hypertrygliceridaemia occurred in 75 patients out of 200 (37.5%), but was significantly more frequent and severe with ritonavir vs. indinavir (P<0.001), and in subjects given indinavir vs. all remaining patients (either treated or not) (P<0.001), while isolated saquinavir use was associated with higher tri glyceride levels than NRTI-NNRTI treatment alone, or no antiretroviral therapy (P<0.03). Hypercholesterolaemia was found in 27 subjects (13.5%), and a significantly higher frequency and severity was shown in patients treated with indinavir and ritonavir vs. saquinavir, NRTI-NNRTI, and no anti-HIV therapy (P<0.05 to P<0.001). No appreciable difference was found between patients undergoing NRTI-NNRTI and untreated controls, for all evaluated variables. Bezafibrate was administered once daily for 6-18 months to 49 patients with elevated and diet-resistant hyperlipidaemia due to ritonavir or indinavir (27 and 22 subjects, respectively), and reduced triglyceride and cholesterol levels by 35% and 25%, respectively over 6 months, without differences between the underlying protease inhibitor regimen. Thirty-three patients (67.3%) reached a normal triglyceridaemia after 6-9 months, and normal cholesterol levels were obtained in all subjects. Bezafibrate proved safe and well tolerated.

CONCLUSIONS

Careful monitoring of the serum lipid profile is needed during antiretroviral therapy, including protease inhibitors, to identify the need for a diet and/or an hypolipidaemic treatment, and to prevent clinical sequelae related to long-term dyslipidaemia. Specific guidelines for the management of disorders of lipid metabolism in HIV-infected patients are needed.

Risk of lipodystrophy in HIV-1-infected patients treated with protease inhibitors: a prospective cohort study

BACKGROUND

Risk factors for lipodystrophy in patients infected with HIV-1 treated with highly active antiretroviral therapy (HAART) containing HIV-1 protease inhibitors are poorly understood. We aimed to identify the risk factors for lipodystrophy in antiretroviral-naive HIV-1-infected adults on HAART.

METHODS

Moderate or severe body-fat changes were clinically assessed and categorised as subcutaneous lipoatrophy, central obesity, or both, in all consecutive antiretroviral-naïve HIV-1-infected adults who began HAART with two nucleoside reverse transcriptase inhibitors plus at least one protease inhibitor from October, 1996, to September, 1999. A person-years analysis was used to calculate the incidence of types of lipodystrophy, and Cox proportional hazards models were used to describe the univariate and multivariate factors associated with progression to any lipodystrophy.

FINDINGS

After a median follow-up of 18 months, 85 (17%) of the 494 patients developed some type of lipodystrophy. The incidences of any lipodystrophy, lipodystrophy with subcutaneous lipoatrophy, and lipodystrophy with central obesity were 11.7 (95% CI 9.2-14.2), 9.2 (7.0-11.4), and 7.7 (5.7-9.7) per 100 patient-years. An increased risk for any lipodystrophy was found among women as compared with men (relative hazard 1.87 [1.07-3.28]), heterosexuals (2.86 [1.50-5.48]), and homosexuals (2.17 [1.07-4.42]) as compared with intravenous drug users, with increasing age (1.33 per 10 years older [1.08-1.62]), and with the duration of exposure to antiretroviral therapy (1.57 per 6 months extra [1.30-1.88]) but not with any individual antiretroviral agent. The factors associated with an increased risk for lipodystrophy with subcutaneous lipoatrophy or lipodystrophy with central obesity were very similar to those associated with any lipodystrophy. The duration of indinavir use may represent an additional contribution for the development of lipodystrophy with central obesity (1.26 per 6 months extra [0.99-1.60]); p=0.064).

INTERPRETATION

Risk factors associated with development of any lipodystrophy, lipodystrophy with subcutaneous lipoatrophy, and tipodystrophy with central obesity in patients infected with HIV-1 who were receiving HAART containing protease inhibitors are multifactorial and overlapping, and cannot be exclusively ascribed to the duration of exposure to an particular antiretroviral agent.

Lipodystrophy Syndrome in Patients with HIV Infection

Current antiretroviral therapy has lead to longer survival in patients infected with HIV, but it is also associated with new and important problems. Body fat redistribution and metabolic abnormalities, the so-called lipodystrophy syndrome, are among the most prevalent and worrisome ones. While an increasing number of patients infected with HIV are becoming affected by this syndrome, the pathogenesis of this syndrome and how to prevent and treat the problem all remain largely unknown. Body fat changes stigmatise the bodies of patients infected with HIV giving them a similar look to that seen in patients some years ago when the wasting syndrome was more prevalent and HIV infection was ultimately fatal. The psychological impact of body fat changes may be severe enough to affect a patients' desire to continue with antiretroviral therapy. Metabolic abnormalities, probably with the exception of symptomatic diabetes mellitus and hypertriglyceridaemia-induced pancreatitis, do not have an immediate impact on the quality of the lives of patients with HIV. However, their potential long term cardiovascular and bone consequences may increase the morbidity and the mortality of patients infected with HIV through noninfectious diseases. The impact of lipodystrophy on patients infected with HIV is not readily captured with the classic instruments used to measure quality of life and hence it is necessary to modify them urgently. Though treating lipodystrophy seems fully justified, there is no proven treatment for this problem, although a number of treatments have been used with varying success. Despite the recognition that lipodystrophy may have important psychological repercussions, the best psychological approach for this problem is not known at present. Although lipodystrophy has its own peculiarities, existing knowledge about how to psychologically help other patients with deforming body changes might be of help for patients infected with HIV, or at least may act as a starting point.

Management of dyslipidemia in patients with HIV disease

The epidemiological, etiopathogenetic, laboratory and clinical features of serum lipid abnormalities occurring in the course of HIV disease are still poorly understood (especially when the supporting role of single antiretroviral compounds is considered), while limited literature data are to date available regarding the management of HIV-related dyslipidemia, as well as the efficacy and safety of dietary-exercise programs, and that of selected hypolipidemic agents. At this time, a careful monitoring of serum lipid profile is needed during combination antiretroviral therapy including protease inhibitors, in order to suggest a diet and hypolipidemic treatment when applicable, and to prevent clinical sequelae related to long-term dyslipidemia. The selection of an appropriate hypolipidemic agent is difficult, since no controlled studies are available in this field, and possibly increased risks of pharmacologic interactions, toxicity and impaired patient's adherence should be taken into consideration. Waiting for specific guidelines for the treatment of hypertriglyceridemia and hypercholesterolemia in the setting of HIV infection, all available literature reports dealing with the management of HIV-associated hyperlipidemia are briefly discussed, on the basis of personal clinical experience.

Clinical manifestations and management of antiretroviral nucleoside analog-related mitochondrial toxicity

OBJECTIVES

This article reviews the clinical manifestations of mitochondrial toxicity associated with the use of nucleoside analog reverse transcriptase inhibitors (NRTIs) and outlines strategies to manage these sequelae.

BACKGROUND

NRTIs are the key components of the antiretroviral combinations used in the management of patients infected with HIV. The available NRTIs differ in their convenience of administration, frequency of dosing, resistance profiles, and side-effect profiles. NRTIs act as competitive inhibitors of the RNA/DNA polymerase reverse transcriptase of HIV and cause chain termination in the growing viral DNA chain. Many of the important and treatment-limiting side effects of NRTIs may be related to the effect of these agents on human DNA polymerases, in particular, mitochondrial DNA polymerase gamma. Depletion of mitochondrial DNA during chronic NRTI therapy may lead to cellular respiratory dysfunction and generalized and tissue- and drug-specific toxicities, including myopathy, peripheral neuropathy, and lactic acidosis. Recently, it has been proposed that the fat redistribution syndrome, or lipodystrophy, reported during chronic antiretroviral therapy is a manifestation of the differential impact of at least some NRTIs on peripheral and visceral adipocytes. Management of potential mitochondrial toxicity during NRTI therapy remains a challenge. A range of nutritional supplements, both as treatments and prophylaxes, have been proposed, and some have been investigated in vitro; no in vivo studies have yet been conducted.

METHODS

The information in this review was compiled using MEDLINE and AIDSLINE searches of the literature, including conference abstracts.

CONCLUSIONS

At present, interruption of NRTI therapy or substitution of the probable causative agent with alternative NRTIs that appear to be better tolerated represents the mainstay of management for mitochondrial toxicity and its clinical manifestations.

Absence of association between individual thymidine analogues or nonnucleoside analogues and lipid abnormalities in HIV-1-infected persons on initial therapy

Changes in levels of triglycerides and cholesterol during antiretroviral therapy raise concerns regarding an increased future risk of atherogenic disease and may precede the appearance of fat redistribution. Hypotheses regarding the impact of nucleoside analogues on adipocytes provide a possible explanation for metabolic and clinical fat disturbances. It is unclear whether the choice of nucleoside analogue combination or coadministration of nonnucleoside agents influences change in lipids. We performed a cross-sectional analysis of 135 persons receiving their first nucleoside analogue plus nonnucleoside-based combination antiretroviral regimen for at least 1 month and for whom cholesterol and triglyceride values were available on therapy. Univariate and multivariate regression models were used to explore the relation between cholesterol and triglycerides, as continuous variables with other variables. Both significant and nonsignificant variables from univariate analyses were evaluated in multivariate models to limit possible confounders. No association with drug choice was observed, either when comparing thymidine analogues (stavudine or zidovudine), all nucleoside analogue combinations or choice of either efavirenz or nevirapine as nonnucleoside. Age and triglyceride levels were found in a multivariate analysis to be associated with higher cholesterol. Only higher cholesterol was associated with higher triglyceride levels. In conclusion, no differences were observed between choice of drug or combination on cholesterol or triglyceride values during therapy. Older individuals may be more likely to have elevated cholesterol values.

Targeting the HIV-protease in AIDS therapy: a current clinical perspective

This review deals with clinical applications of compounds that inhibit the action of the protease encoded within the genome of human immunodeficiency virus (HIV). The HIV-protease is essential for viral maturation and represents an important therapeutic target in the fight against AIDS. Following a brief overview of the enzyme structure and function, the article focuses on a number of peptide and non-peptide based HIV-protease inhibitors that are in current clinical use. These drugs are discussed both with respect to their efficacy in treatment of AIDS, and to problems related to insurgence of viral resistance and side effects seen to date in patient populations.

Mitochondrial toxicity of nucleoside analogue reverse transcriptase inhibitors: a looming obstacle for long-term antiretroviral therapy?

Nucleoside reverse transcriptase inhibitors suppress HIV replication by blocking reverse transcriptase, an RNA-dependent DNA polymerase. These drugs can also affect cellular and mitochondrial DNA polymerases. Mitochondrial DNA polymerase gamma is particularly sensitive to nucleoside reverse transcriptase inhibitors, and the majority of adverse effects caused by nucleoside reverse transcriptase inhibitors are most likely caused by mitochondrial dysfunction. This article reviews the recent clinical implications of nucleoside reverse transcriptase inhibitor-induced mitochondrial toxicity and discusses options for management.