Kinetics of lactate metabolism after submaximal ergometric exercise in HIV-infected patients

Combined Physical Training Increases Plasma Brain-Derived Neurotropic Factor Levels, But Not Irisin in People Living with HIV/AIDS

This study evaluated plasma levels of brain-derived neurotropic factor (BDNF), irisin, and lactate in people living with HIV/AIDS who completed a combined physical training program. Nineteen HIV+ participants (age: 39.60 ± 10.96 years; carrier time: 7.75 ± 7.88 years; time of ART: 6.41 ± 5.93 years) performed strength/aerobic training (combined physical training) in the same session for 8 weeks and levels of BDNF, irisin, and lactate were assessed. BDNF (pg/mL) was higher post-CPT (Pre: 1258.73 ± 372.30; Post: 1504.17 ± 322.30; p < 0.001). Irisin (ng/mL) showed no change (Pre: 115.61 ± 72.41; Post: 125.87 ± 81.14; p = 0.973). There was positive correlation between irisin and lactate (mmol/L) pre (r = 0.55, p = 0.04), and lactate values were higher in the group with the highest value of irisin (3.65 ± 0.69 × 2.82 ± 0.59, p = 0.02). Combined physical training results in increased basal BDNF in people living with HIV/AIDS, this finding suggests that increased concentration of BDNF may be associated with decreased chances of developing cognitive disorders or HIV-associated dementia. Further studies involving molecular mechanisms on this subject are necessary.

Combined Exercise Modulates Cortisol, Testosterone, and Immunoglobulin A Levels in Individuals Living With HIV/AIDS

BACKGROUND

Combined exercise (CE) has been recommended for individuals living with HIV/AIDS (ILWHA) under antiretroviral therapy. However, depending on the intensity and duration, physical exercise may occasionally increase inflammatory parameters and reduce immunological responses that if not reversed, cause health injury specifically in this population. Information about immunological and hormonal responses after CE in ILWHA has not been completely elucidated. Therefore, the aim is to verify the acute effects of CE on cortisol, testosterone, immunoglobulin A, and pro-inflammatory and anti-inflammatory cytokines over 24 hours in ILWHA.

METHODS

Noninfected individuals and ILWHA undergone 5 sessions of CE prior to the acute assessment session. Seventy-two hours after the last session, the subjects were submitted to one session of CE (aerobic exercise: 25 min at 60-70% reserve heart rate and resistance exercise: 3 sets of 15 maximum repetitions of 6 exercises). Saliva samples were collected before, immediately, 6 and 24 hours after CE.

RESULTS

CE reduced cortisol (6 h: 2.54 [0.58] vs 0.65 [0.22] pg·mL-1; P = .02), increased testosterone (all moments) and immunoglobulin A levels (24 h: 255.3 [44.7] vs 349.2 [41.9] μm·mL-1; P = .01) without significant difference in cytokines levels in ILWHA.

CONCLUSION

CE modulates cortisol, testosterone, and immunoglobulin A levels without the change in immunological parameters in ILWHA.

RESPOSTAS AGUDAS DO EXERCÍCIO FÍSICO EM PESSOAS INFECTADAS PELO HIV: UMA REVISÃO SISTEMÁTICA

RESUMO O treinamento físico é uma estratégia importante para a saúde de pessoas que vivem com HIV/AIDS; contudo, suas respostas a curto prazo ainda não foram amplamente estudadas, o que limita o entendimento dos efeitos e da segurança da prescrição do treinamento para essa população. Portanto, objetivou-se revisar sistematicamente as respostas agudas decorrentes do exercício físico em pessoas com HIV sobre variáveis fisiológicas e imunológicas. Para isso, foi realizada uma revisão sistemática a partir de trabalhos indexados nas seguintes bases de dados: Medline, Lilacs, Scielo, Web of Science e Science Direct. Os descritores utilizados foram: acquired immunodeficiency syndrome, HIV, AIDS, seropositive, acute session, short, physical activity, exercise, training. As buscas foram realizadas em fevereiro de 2015 e atualizadas em dezembro de 2015 e foram conduzidas sem restrição de datas de publicação ou idioma específico. Foram incluídos para esta revisão artigos que avaliaram as respostas agudas decorrentes de algum modelo de prescrição de treinamento físico envolvendo exercícios aeróbicos, com pesos ou combinados (exercícios aeróbicos e com pesos) relacionados com variáveis fisiológicas e imunológicas em pessoas infectadas pelo HIV. Foram encontrados 2.422 títulos, dos quais, após exclusão das duplicatas e a aplicação dos critérios de elegibilidade, foram selecionados sete artigos para síntese qualitativa. De acordo com os resultados reportados pelos estudos há evidências de que, imediatamente após a realização do exercício físico, ocorre um aumento do número de células circulantes, incluindo leucócitos totais, neutrófilos, monócitos e linfócitos T CD8+ em pessoas infectadas pelo HIV. Além disso, também se observaram alterações significantes nas concentrações de lactato, triglicerídeos, epinefrina e norepinefrina imediatamente após a realização do treinamento aeróbico, independentemente do uso de TARV e/ou de hiperlactatemia. No entanto, não há evidências suficientes para afirmar que o treinamento físico seja totalmente seguro e eficaz para esta população.

[(13)C]Methionine breath test as a marker for hepatic mitochondrial function in HIV-infected patients

Metabolic disturbances such as dyslipidemia, lipodystrophy syndrome, visceral obesity, hyperlactatemia, diabetes mellitus, and hepatic steatosis have been recognized as serious complications in long-term antiretroviral-treated HIV-infected patients. The oxidative capacity of liver mitochondria plays a central role in their pathogenesis and can be analyzed using the [(13)C]methionine breath test. We analyzed hepatic mitochondrial function using the [(13)C]methionine breath test in antiretrovirally treated and untreated HIV-infected patients as well as HIV-negative controls. Patients with hepatic steatosis, hypertriglyceridemia, lipohypertrophy, and older age showed reduced methionine metabolism. Hepatic mitochondrial function is impaired in antiretroviral-treated HIV-infected patients with disturbances of lipid metabolism.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The Influence of HIV Infection and Antiretroviral Therapy on the Mitochondrial Membrane Potential of Peripheral Mononuclear Cells

Objectives

Clinical disorders occurring in HIV-infected patients on antiretroviral therapy (ART) have been linked to mitochondrial dysfunction, for example, lactic acidosis and lipodystrophy. Mitochondrial membrane potential (ΔΨm) is the most direct measure of the state of energization of the mitochondria. We analysed ΔΨm of peripheral blood mononuclear cells (PBMCs) in HIV-negative, healthy subjects ( n=8), HIV-infected, treatment-naive patients ( n=30), and HIV-infected patients on ART ( n=58). The influence of ART was analysed in six patients who started their first regimen.

Methods

The ΔΨm of PBMC was measured by flow cytometry using the dye JC-1.

Results

The ΔΨm was significantly lower in HIV-infected patients than in HIV-negative controls. This difference was detected in both treated ( P=0.0001) and untreated patients ( P=0.001). The ΔΨm of PBMCs was highly correlated with CD4+ T-cell count in therapy-naive patients ( P=0.002, r=0.546) and in treated patients ( P=0.028, r=0.288). The ΔΨm increased significantly in therapy-naive patients after starting ART ( P=0.001). Patients with lipoatrophy had significantly lower ΔΨm than patients without lipodystrophy or with lipohypertrophy ( P=0.023).

Conclusions

In HIV-infected persons ΔΨm is significantly reduced. Patients with lipoatrophy have significantly reduced ΔΨm. This is the first study showing that the ΔΨm of PBMCs is highly correlated with CD4+ T-cell count in HIV infection.

Glucose production, oxidation and disposal correlate with plasma lactate levels in HIV-infected patients on HAART

OBJECTIVES

Hyperlactatemia is prevalent in HIV-infected patients on highly active antiretroviral therapy (HAART) and may be associated with depletion of mitochondrial DNA. However, the correlation between fasting lactate and mitochondrial DNA may be weak or absent, implicating that other factors e.g. glucose turnover may contribute to hyperlactatemia.

METHODS

HIV-infected patients receiving HAART who had lipodystrophy (LIPO, n=18) or were without lipodystrophy (NONLIPO, n=18) were investigated. Insulin sensitivity (M-value), glucose oxidation rate (GOX) and fasting endogenous glucose production (EGP) were determined by hyperinsulinemic euglycemic clamp, indirect calorimetry and glucose tracer technique, respectively.

RESULTS

Fasting p-lactate (median 1.2 mmol/L; range 0.6-4.3, n=36) tended to be increased in LIPO (P=0.12); 6 patients (4 LIPO) had lactate > or =2.0 mmol/L. Fasting lactate correlated inversely with M-value (P<0.001) and positively with fasting EGP (P<0.05) and fasting GOX (P<0.05), together explaining 51% (R2, n=36) of the variation in fasting lactate. Lactate increased in NONLIPO (P<0.05) but not in LIPO (P>0.5) during clamp. Incremental (clamp minus fasting value) GOX (P<0.01) was decreased and incremental insulin (P<0.01) was increased in LIPO.

CONCLUSIONS

Fasting EGP, GOX and insulin resistance may be major determinants of fasting lactate levels in HIV-infected patients on HAART. Insulin levels per se may not determine plasma lactate in such patients.

Toxic metabolic syndrome associated with HAART

Acquired fat redistribution, that is, peripheral fat loss often accompanied by central fat accumulation in patients with HIV infection is the most common form of lipodystrophy in man. Approximately 30 - 50% of HIV-infected individuals after > or = 12 months on highly active antiretroviral therapy (HAART) may encounter the HIV-associated lipodystrophy syndrome (HALS), which attenuates patient compliance to this treatment. HALS is characterised by impaired glucose and lipid metabolism and other risk factors for cardiovascular disease. This review depicts the metabolic abnormalities associated with HAART by describing the key cell and organ systems that are involved, emphasising the role of insulin resistance. An opinion on the remedies available to treat the metabolic abnormalities and phenotype of HALS is provided.

Muscle and Liver Lactate Metabolism in Haart-Treated and Naive HIV-Infected Patients: The Mitovir Study

Objective

To assess the impact of nucleoside analogue reverse transcriptase inhibitor (NRTI) combination therapy on muscle and liver lactate metabolism in HIV-infected patients.

Methods

This cross-sectional study involved HIV-infected patients who were either antiretroviral-naive (Group 1) or were receiving either a stable triple-drug combination including at least one d-drug (zidovudine, zalcitabine, stavudine, didanosine; Group 2) or a backbone of abacavir and lamivudine (Group 3). Lactataemia was measured at rest. Muscle lactate metabolism was assessed during a standardized exercise test and liver lactate metabolism during intravenous lactate infusion. Mitochondrial DNA was quantified in peripheral blood mononuclear cells.

Results

A total of 65 patients were enrolled (16, 31 and 18 patients in Group 1, Group 2 and Group 3, respectively). None of the patients had symptoms of hyperlactataemia. Patients in Group 3 had received d-drugs for a median of seven years before switching to abacavir and lamivudine. Median baseline lactataemia, although within the normal range, was significantly higher in both treatment groups than in the naive patients (Group 2: 1.4, Group 3: 1.5, and Group 1: 1.0 mmol/l, P=0.005). Muscle lactate clearance was significantly lower in both treatment groups than in naive patients (Group 2: 1.6, Group 3: 1.8, and Group 1: 2.1, P=0.01). Lactate liver metabolism and mitochondrial DNA levels did not differ among the three groups.

Conclusions

In HIV-infected patients without symptomatic hyperlactataemia, all NRTI-containing HAART regimens appear to cause muscle mitochondrial damage but to spare the liver. Absence of difference between Group 2 and Group 3 raises questions about the potential reversibility of muscle mitochondrial dysfunction, and/or the ability of abacavir and lamivudine to induce such mitochondrial damage.