Progenitor cell types in HIV-1 infection: bioactivity and emerging targets for treatment.

HIV-1 exerts its most profound effects through destruction of the host's immune responses specifically through targeting of the T-lymphocyte populations. In addition to its primary immune target, HIV-1 also targets cells of the nervous, skeletal and vascular system. There is emerging evidence to suggest that HIV-1 may, in part at least, affect these diverse tissues by impairing the homeostatic production of terminally differentiated cells from stem and progenitor cell populations. The interaction between HIV-1 and stem cell populations may serve to underpin the diverse non-immunological effects of HIV-1. This review deals with the effect of HIV-1 infection on a number of progenitor cell types, with emphasis on delineating mechanisms of HIV's destructive effect on the body. Modification of these effects may represent novel avenues for exploration in our search for clinical interventions.

Sub-optimal CD4 recovery on long-term suppressive highly active antiretroviral therapy is associated with favourable outcome.

OBJECTIVES: To examine risk factors for sub-optimal CD4 recovery on suppressive highly active antiretroviral therapy (HAART) and assess long-term clinical and immunological outcomes. METHODS: Retrospective analysis of 286 HIV-positive patients from a university clinic who initiated HAART with CD4 count <350 cells/microL between January 1996 and July 2006 and achieved > or =52 weeks of viral suppression (VS). Sub-optimal and optimal CD4 count recovery were defined by gains of <150 and > or =150 cells/microL during the first year of VS, respectively. Risk factors were analysed by multivariate logistic regression and markers of immune maturation and activation were evaluated prospectively for a sub-group of patients with prolonged (>5 years) VS. RESULTS: One hundred and two (36%) patients had sub-optimal CD4 recovery. Male gender, lower pre-HAART viral load, HAART toxicity and use of opportunistic infection (OI) prophylaxis were independent risk factors on multivariate analysis (P<0.05). Outcomes of duration of VS on HAART (4 years), new OI events (1%) and mortality (5%) were similar between groups. Markers of immune maturation and activation were higher among patients with sub-optimal CD4 recovery (P<0.05). CONCLUSIONS: Among HIV-positive patients with long-term VS, sub-optimal CD4 recovery was common but morbidity and mortality remained low. In addition, persistent CD4 T-cell activation appeared to blunt long-term CD4 gains.

European AIDS Clinical Society (EACS) guidelines on the prevention and management of metabolic diseases in HIV.

BACKGROUND: Metabolic diseases are frequently observed in HIV-infected persons and, as the risk of contracting these diseases is age-related, their prevalence will increase in the future as a consequence of the benefits of antiretroviral therapy (ART). SUMMARY OF GUIDELINES: All HIV-infected persons should be screened at regular intervals for a history of metabolic disease, dyslipidaemia, diabetes mellitus, hypertension and alteration of body composition; cardiovascular risk and renal function should also be assessed. Efforts to prevent cardiovascular disease will vary in intensity depending on an individual's absolute risk of ischaemic heart disease and should be comprehensive in nature. Lifestyle interventions should focus on counselling to stop smoking, modify diet and take regular exercise. A healthy diet, exercise and maintaining normal body weight tend to reduce dyslipidaemia; if not effective, a change of ART should be considered, followed by use of lipid-lowering medication in high-risk patients. A pre-emptive switch from thymidine analogues is recommended to reduce the risk of development or progression of lipoatrophy. Intra-abdominal fat accumulation is best managed by exercise and diet. Prevention and management of type 2 diabetes mellitus and hypertension follow guidelines used in the general population. When using medical interventions to prevent and/or treat metabolic disease(s), impairment of the efficacy of ART should be avoided by considering the possibility of pharmacokinetic interactions and compromised adherence. Specialists in HIV and specialists in metabolic diseases should consult each other, in particular in difficult-to-treat cases. CONCLUSION: Multiple and relatively simple approaches exist to prevent metabolic diseases in HIV-infected persons; priority should be given to patients at high risk of contracting these diseases.

Post-exercise heart rate recovery in HIV-positive individuals on highly active antiretroviral therapy. Early indicator of cardiovascular disease?

BACKGROUND: HIV infection and its treatment, specifically protease inhibitor (PI) therapy, have been associated with an increased risk for cardiovascular disease. Heart rate recovery (HRR) following peak exercise is predictive of future cardiovascular events and mortality in the general population. Nothing is known regarding HRR in individuals infected with HIV on highly active antiretroviral therapy (HAART). SUBJECTS AND METHODS: HIV-positive subjects on HAART that included a PI (HIV+PI, n=19), HIV-positive subjects on HAART that did not include a PI (HIV+noPI, n=19) and HIV-seronegative age, gender and body mass index (BMI) matched controls (Cntl, n=15) underwent a graded maximal exercise test on a cycle ergometer to volitional exhaustion. A continuous electrocardiogram was recorded and HRR was monitored every 30 s for 2 min post exercise. RESULTS: HRR at 1.5 and 2 min was significantly delayed in HIV-positive subjects both on and not on PI-based HAART compared with controls (P<0.01). CONCLUSION: HRR is impaired in HIV-positive individuals on HAART, whether or not the HAART includes a PI, compared with age, gender, BMI, and activity level matched HIV-seronegative controls. Abnormal HRR may reflect cardio-autonomic dysfunction and may be an independent risk factor for future cardiac events in HIV-positive individuals that receive HAART.

Predictors of immunity after hepatitis A vaccination in HIV-infected persons.

Hepatitis A virus (HAV) infection remains a health risk for human immunodeficiency virus (HIV)-infected persons. While the inactivated HAV vaccine affords protection to immunocompetent persons >95% of the time, rates of developing protective antibody (anti-HAV) in HIV+ persons are considerably lower. Although low CD4+ T-cell counts have previously been reported to be correlated with this poor response, the effect of HIV viraemia on HAV vaccine response has not previously been reported. The medical records of HIV-infected patients who had received at least one dose of HAV vaccine (Havrix, 1440 EIU) were reviewed for factors associated with the development of a protective anti-HAV response. Serological data with regard to anti-HAV status after vaccination were available in 238 patients with 133 individuals (49.6%) developing immunity after vaccination. In a logistic regression model, the only factors associated with a protective antibody response were an HIV plasma RNA level <1000 copies/mL at the time of vaccination (P = 0.011) and male gender (P = 0.016). Neither nadir CD4+ T cell count nor CD4+ T-cell count at time of vaccination were predictive of the development of anti-HAV. Suppression of HIV replication at time of vaccination is associated with a protective antibody response to HAV vaccination in HIV-infected adults. The low rate of response warrants further research in alternative strategies for HAV vaccination among HIV-infected persons.

Persistent low-level viraemia and virological failure in HIV-1-infected patients treated with highly active antiretroviral therapy.

OBJECTIVE: To assess the prognostic significance of persistent low-level viraemia (PLV, defined as persistent plasma viral loads of 51-1000 HIV-1 RNA copies/mL for at least 3 months) in patients who had achieved viral suppression on antiretroviral therapy (ART). METHODS: A retrospective cohort of HIV-infected patients who received ART, were followed-up for > or =12 months, made regular visits to the clinic during which blood tests were performed for an ultrasensitive HIV RNA assay every 3 months, and achieved viral loads <50 copies/mL were evaluated. Virological failure was defined as two consecutive viral load measurements >1000 copies/mL. RESULTS: Of 362 patients, 78 (27.5%) experienced PLV. The demographics of patients with and without PLV were similar. PLV occurred at a mean (+/-standard deviation) of 22.6+/-16.9 months after ART initiation and lasted for 6.4+/-3.4 months. During a median follow-up of 29.5 months, patients with PLV had a higher rate of virological failure (39.7% vs 9.2%; P < 0.001). The median time to failure was 68.4 months [95% confidence interval (CI) 37.0-99.7] for patients with PLV and >72 months for patients without PLV (log rank test, P < 0.001). By Cox regression, patients with PLV had a greater risk of virological failure [hazard ratio (HR) 3.8; 95% CI 2.2-6.4; P < 0.001]. Among patients with PLV, a PLV of >400 copies/mL (HR 3.3; 95% CI 1.5-7.1; P = 0.003) and a history of ART (HR 2.4; 95% CI 1.0-5.7; P = 0.042) predicted virological failure. CONCLUSIONS: PLV is associated with virological failure. Patients with a PLV >400 copies/mL and a history of ART experience are more likely to experience virological failure. Patients with PLV should be considered for treatment optimization and interventional studies.

Alterations in liver, muscle, and adipose tissue insulin sensitivity in men with HIV infection and dyslipidemia.

Dyslipidemia is common in patients with HIV infection. In this study, a two-stage euglycemic hyperinsulinemic clamp, with infusion of stable isotopically labeled tracers, was used to evaluate insulin action in skeletal muscle, liver, and adipose tissue in HIV-infected men with dyslipidemia (HIV-DL; plasma triglyceride >250 mg/dl and HDL <45 mg/dl; n=12), HIV-infected men without dyslipidemia (HIV w/o DL; n=12), and healthy men (n=6). Basal rates of glucose production (glucose R(a)), glucose disposal (glucose R(d)), and lipolysis (palmitate R(a)) were similar between groups. The relative suppression of glucose R(a) (63+/- 4, 77+/- 2, and 78+/- 3%, P=0.008) and palmitate R(a) (49+/-4, 63+/-3, and 68+/-3%, P=0.005) during ow-dose insulin infusion (plasma insulin approximately 30 microU/ml), and the relative stimulation of glucose R(d) (214+/-21, 390+/-25, and 393+/-46%, P=0.001) during high-dose insulin infusion (plasma insulin approximately 75 microU/ml) were lower in HIV-DL than in HIV w/o DL and healthy volunteers, respectively. Suppression of basal glucose R(a) correlated with plasma adiponectin (r=0.44, P=0.02) and inversely with plasma IL-6 (r=-0.49, P<0.001). Stimulation of glucose R(d) correlated directly with adiponectin (r=0.48, P<0.01) and inversely with IL-6 (r=-0.49, P=0.02). We conclude that dyslipidemia in HIV-infected men is indicative of multiorgan insulin resistance, and circulating adipokines may be important in the pathogenesis of impaired insulin action.

Addressing current challenges in haemophilia care: consensus recommendations of a European Interdisciplinary Working Group.

Current challenges facing haemophilia care were identified and reviewed by an interdisciplinary group of experts in haemostasis and thrombosis, infectious disease, epidemiology, pharmacoeconomics and public health who met in February 2005 in Brussels. The outcome of this meeting was a series of consensus recommendations proposed to address the following three challenges: (i) developing the next generation of haemophilia specialists; (ii) reducing the risk that emerging pathogens present to safe haemophilia care and (iii) providing haemophilia care in an environment of cost constraint. It is intended that these consensus recommendations will form the basis of a concerted effort by leading haemophilia clinicians to secure future resources for the development and improvement of haemophilia care throughout Europe.

Alterations in lipid kinetics in men with HIV-dyslipidemia.

Hypertriglyceridemia is common in individuals with human immunodeficiency (HIV) infection, but the mechanisms responsible for increased plasma triglyceride (TG) concentrations are not clear. We evaluated fatty acid and VLDL-TG kinetics during basal conditions and during a glucose infusion that resulted in typical postprandial plasma glucose and insulin concentrations in six men with HIV-dyslipidemia [body mass index (BMI): 28 +/- 2 kg/m2] and six healthy men (BMI: 26 +/- 2 kg/m2). VLDL-TG secretion and palmitate rate of appearance (Ra) in plasma were measured by using stable-isotope-labeled tracer techniques. Basal palmitate Ra and VLDL-TG secretion rates were greater (P < 0.01 for both) in men with HIV-dyslipidemia (1.04 +/- 0.07 micromol palmitate x kg-1 x min-1 and 5.7 +/- 0.6 micromol VLDL-TG x l plasma-1 x min-1) than in healthy men (0.67 +/- 0.08 micromol palmitate. kg-1 x min-1 and 3.0 +/- 0.5 micromol VLDL-TG x l plasma-1 x min-1). Basal VLDL-TG plasma clearance was lower in men with HIV-dyslipidemia (13 +/- 1 ml/min) than in healthy men (19 +/- 2 ml/min; P < 0.05). Glucose infusion decreased palmitate Ra (by approximately 50%) and the VLDL-TG secretion rate (by approximately 30%) in both groups, but the VLDL-TG secretion rate remained higher (P < 0.05) in subjects with HIV-dyslipidemia. These findings demonstrate that increased secretion of VLDL-TG and decreased plasma VLDL-TG clearance, during both fasting and fed conditions, contribute to hypertriglyceridemia in men with HIV-dyslipidemia. Although it is likely that increased free fatty acid release from adipose tissue contributes to the increase in basal VLDL-TG concentration, other factors must be involved, because insulin-induced suppression of lipolysis and systemic fatty acid availability did not normalize the VLDL-TG secretion rate.

An objective case definition of lipodystrophy in HIV-infected adults: a case-control study.

BACKGROUND: Lipodystrophy (peripheral lipoatrophy, central fat accumulation, and lipomatosis) is a common and disfiguring problem in adult patients with HIV-1 infection on antiretrovirals. However, an objective, validated definition of the disorder does not exist. We aimed to develop an objective, sensitive, specific, and broadly applicable case definition of HIV lipodystrophy. METHODS: In a case-control study, 1081 consecutive, HIV-infected, adult outpatients (261 [15%] women) without active AIDS were recruited from 32 sites worldwide. We classed patients with at least one moderate or severe subjective lipodystrophic feature, identified by lipodystrophy-specific physical examination and patient questionnaire, and apparent to both doctor and patient as cases (n=417). We classed patients with no such feature as controls (n=371), and patients without a clear diagnosis as non-assigned. We used objective clinical, metabolic, and body composition measurements to construct a logistic regression model with a subset of randomly selected cases and controls. The model was validated in the remaining patients. FINDINGS: A model including age, sex, duration of HIV infection, HIV disease stage, waist to hip ratio, anion gap, serum HDL cholesterol concentration, trunk to peripheral fat ratio, percentage leg fat, and intra-abdominal to extra-abdominal fat ratio had 79% (95% CI 70-85) sensitivity and 80% (95% CI 71-87) specificity for diagnosis of lipodystrophy. Models that incorporated only clinical, or only clinical and metabolic variables had lower sensitivity and specificity than the inclusive model. Models for lipoatrophy, fat accumulation, and lipomatosis could not be developed since pure phenotypes occurred in fewer than 10% of patients with clinical diagnoses of these disorders. INTERPRETATION: Our objective case definition of HIV-associated lipodystrophy should improve assessment of lipodystrophy prevalence, risk factors, and pathogenesis; prevention and treatment approaches; and assist in diagnosis.

Increasing prevalence of resistance mutations in antiretroviral-naïve individuals with established HIV-1 infection from 1996-2001 in St. Louis.

BACKGROUND: Transmission of drug-resistant virus in HIV-1 infected individuals is well documented, particularly in patients with primary infection. Prevalence in chronically infected antiretroviral-naïve patients is reportedly low. Routine genotyping in this population is not recommended. PURPOSE: The purpose of this study was to evaluate resistance profiles in patients with established HIV infection in St. Louis. METHOD: We selected specimens from drug-naïve individuals (CD4 >300 cells/mL and VL >1000 copies/mL) with established HIV infection between 1996-2001. 62 of 75 specimens were available for genotyping. We excluded patients with evidence of acute HIV infection and long-term nonprogressors. RESULTS: The overall prevalence of resistance was 11% (7/62). From 1996 to 1998, a prevalence of 4% was observed (1/27 individuals). During the subsequent period from 1999 to 2001, the frequency increased to 17% (6/35 participants; p =.08; 95% CI 5-29%). CONCLUSION: The results suggest that the prevalence of primary resistance is increasing in our region to the point that it justifies genotypic testing in all individuals before the initiation of antiretroviral therapy. This has to be considered when designing antiretroviral clinical trials.

Long-term exposure to lifelong therapies.

Three categories of highly active antiretroviral therapy (HAART)-associated major toxic effects have been identified: nucleoside-related toxic effects (e.g., neuropathy, myopathy, pancreatitis, hepatic steatosis, lactic acidosis, and possibly lipoatrophy), metabolic complications (e.g., fat redistribution, insulin resistance, and hyperlipidemia), and bone disease (e.g., osteopenia and/or osteoporosis). The toxic effects caused by nucleosides are hypothesized to be a result of mitochondrial injury and include myopathy, pancreatitis, liver failure, and lactic acidosis. Alterations in lactic acid metabolism range from common instances of asymptomatic lactic acidemia to rare occurrences of life-threatening lactic acidosis with hepatic steatosis. A metabolic syndrome consisting of lipodystrophy (i.e., fat redistribution), hyperlipidemia and insulin resistance has been observed, particularly with protease inhibitor treatment. Some additive interaction between protease inhibitors and nucleosides has also been described. The potential relationship of these metabolic abnormalities to increased risk of cardiovascular disease and diabetes has broad implications on long-term patient management. Lipodystrophy associated with HAART is generally accompanied by potentially serious abnormalities, including dyslipidemia (i.e., hypercholesterolemia and hypertriglyceridemia) and altered glucose metabolism (i.e., insulin resistance). Regimens of HAART may have adverse effects on bone metabolism, as indicated by emerging reports of osteopenia, osteoporosis, and avascular necrosis.

Treatment of acute cryptococcal disease.

Successful treatment outcome for cryptococcal disease has been available since the introduction of the polyene antifungal, amphotericin B. Over the past 15-20 years, treatment of acute cryptococcal disease has dramatically improved. Several therapeutic strategies have been introduced which improve overall outcome of therapy and help decrease the duration of treatment. Not surprisingly, most data now exists on the treatment of AIDS-associated cryptococcal disease, especially cryptococcal meningitis. Currently, amphotericin B with or without flucytosine is regarded as the best initial therapy for patients with meningitis or more severe illness, although, the azoles and other formulations of amphotericin B can considered in other situations. The choice of treatment for cryptococcal disease depends on both the anatomic sites of involvement and the host's immune status, all of which will be addressed in this article.

A prospective study of discontinuing primary and secondary Pneumocystis carinii pneumonia prophylaxis after CD4 cell count increase to > 200 x 106 /l.

OBJECTIVE: To assess the incidence of Pneumocystis carinii pneumonia (PCP) after discontinuation of either primary or secondary prophylaxis. DESIGN: This was a prospective, non-randomized, non-blinded study. SETTING: Twenty-five University-based AIDS Clinical Trials Group units. PARTICIPANTS: Participants either had a CD4 cell count < or = 100 x 106/l at any time in the past and no history of confirmed PCP (group I; n = 144), or had a confirmed episode of PCP > or = 6 months prior to study entry (group II; n = 129). All subjects had sustained CD4 cell counts > 200 x 106/l in response to antiretroviral therapy. INTERVENTIONS: Subjects discontinued PCP prophylaxis within 3 months or at the time of study entry. Evaluations for symptoms of PCP and CD4 cell counts were performed every 8 weeks. Prophylaxis was resumed if two consecutive CD4 cell counts were < 200 x 106/l. MAIN OUTCOME MEASURE(S): The main outcome was development of PCP. RESULTS: No cases of PCP occurred in 144 subjects (median follow-up, 82 weeks) in group I or in the 129 subjects (median follow-up, 63 weeks) in group II (95% upper confidence limits on the rates of 1.3 per 100 person-years and 1.96 per 100 person-years for groups I and II, respectively). Eight subjects (five in group I and three in group II) resumed PCP prophylaxis after two consecutive CD4 cell counts < 200 x 106/l. CONCLUSIONS: The risk of developing initial or recurrent PCP after discontinuing prophylaxis is low in HIV-infected individuals who have sustained CD4 cell count increases in response to antiretroviral therapy. Neither lifelong primary nor secondary PCP prophylaxis is necessary.

The changing face of mycoses in patients with HIV/AIDS.

The current era of effective antiretroviral therapy has led to a marked reduction in opportunistic infections (OIs) in those countries where such therapies are available. Opportunistic fungal infections are no exception, and the incidence of such infections is now 20% to 25% of that seen in the mid-1990s. Infections associated with very advanced HIV disease, such as azole-resistant candidiasis and aspergillosis, are also rarely seen, reflecting the improvement in immune function. Indeed, the most common issue now is whether patients who have had a systemic mycosis require life-long therapy as had been recommended. Preliminary data from small studies suggest that as with other OIs, it may be possible to stop suppressive therapy in patients with a history of mycosis whose CD4+ lymphocyte count rises with antiretroviral therapy. Thus, it appears that the future of HIV-associated mycoses is linked to the future of effective treatment for HIV itself.

Timing of antiretroviral therapy. Use of Markov modeling and decision analysis to evaluate the long-term implications of therapy.

BACKGROUND: The timing of initiation of antiretroviral therapy is controversial. Current guidelines are heavily based on the principle of 'hit early, hit hard', although the long-term implications of this approach are unknown. METHODS: Using Markov modeling and decision analysis we modeled the virologic outcomes over 10 years in a hypothetical population of 10 000 HIV-infected patients in which therapy (with the possibility of three sequential regimens before the development of multidrug-resistant virus) is started immediately versus starting progressively at rates of 5, 10, 15, 20 or 30% of the original population each year. The model used inputs from available clinical trial data: virologic success rate and durability of the response of the first and subsequent regimens. We performed one-way and two-way sensitivity analysis to evaluate changes in the input variables. RESULTS: If therapy is started immediately in all patients, by 10 years 57% would be undetectable, but 38% would have detectable multidrug-resistant virus. In contrast, the population as a whole would have had better virologic outcomes if one waited before starting treatment at any progression rate; for example, initiating therapy in 10% of the subjects per year results in 64% of patients being undetectable and 24% with multidrug-resistant virus. Two-way sensitivity analysis demonstrates that immediate initiation should be at least 15 to 20% better than delayed antiretroviral therapy to justify immediate initiation of therapy over a wide range of success rates of the delayed start. CONCLUSION: Our analysis, utilizing optimistic outcomes based on short-term clinical trials, provides a theoretical basis for questioning the current aggressive early use of therapy and should help prompt studies that look at when and how to start antiretroviral therapy.

Elevated lactate levels in hospitalized persons with HIV infection.

Lactic acidosis has been described in persons with HIV infection particularly in association with the use of nucleoside reverse transcriptase inhibitors (NRTIs). Little is known about the epidemiology of this problem. We reviewed the records of all HIV-infected adults with elevated lactate levels admitted to Barnes-Jewish hospital from 1996 to 1998. There were 37 patients identified with elevated lactate levels. The annual rate of elevated lactate levels was 22.6, 33.9, and 30.8 per 1,000 admissions in 1996, 1997, and 1998, respectively. The median age of the patients was 40.4 years; median CD4(+) count was 148 cells/mm(3); and the median HIV-1 RNA level was 4,401 copies/ml. The median lactate level was 4.5 mmol/liter (range, 2.2-19 mmol/liter). Twenty-nine patients (78%) had elevated lactate levels at admission. Elevated lactate levels were associated with sepsis (48.7%), pancreatitis (13.5%), liver failure (8.1%), multiorgan failure (8.1%), and other conditions. Five patients had lactic acidosis associated with the use of antiretroviral medications; one patient with unexplained lactic acidosis and four patients with pancreatitis. The mortality rate was 45.9% (17/37). Higher lactate levels were associated with increased mortality. In conclusion, elevated lactate levels were uncommon but not rare in hospitalized patients with HIV infection. Sepsis was the most commonly associated condition and antiretroviral medications were the second most frequently associated factor. There was no significant increase in the annual rate of lactic acidosis during this 3-year period.

Resistance exercise training reduces hypertriglyceridemia in HIV-infected men treated with antiviral therapy.

Hypertriglyceridemia, peripheral insulin resistance, and trunk adiposity are metabolic complications recently recognized in people infected with human immunodeficiency virus (HIV) and treated with highly active antiretroviral therapy (HAART). These complications may respond favorably to exercise training. Using a paired design, we determined whether 16 wk of weight-lifting exercise increased muscle mass and strength and decreased fasting serum triglycerides and adipose tissue mass in 18 HIV-infected men. The resistance exercise regimen consisted of three upper and four lower body exercises done for 1-1.5 h/day, 4 days/wk for 64 sessions. Dual-energy X-ray absorptiometry indicated that exercise training increased whole body lean mass 1.4 kg (P = 0.005) but did not reduce adipose tissue mass (P = NS). Axial proton-magnetic resonance imaging indicated that thigh muscle cross-sectional area increased 5-7 cm(2) (P < 0.005). Muscle strength increased 23-38% (P < 0.0001) on all exercises. Fasting serum triglycerides were decreased at the end of training (281-204 mg/dl; P = 0.02). These findings imply that resistance exercise training-induced muscle hypertrophy may promote triglyceride clearance from the circulation of hypertriglyceridemic HIV-infected men treated with antiviral therapy.