RESUMO
Inhibitors of HIV protease have been shown to have antiapoptotic effects in vitro, yet whether these effects are seen in vivo remains controversial. In this study, we have evaluated the impact of the HIV protease inhibitor (PI) nelfinavir, boosted with ritonavir, in models of nonviral disease associated with excessive apoptosis. In mice with Fas-induced fatal hepatitis, Staphylococcal enterotoxin B-induced shock, and middle cerebral artery occlusion-induced stroke, we demonstrate that PIs significantly reduce apoptosis and improve histology, function, and/or behavioral recovery in each of these models. Further, we demonstrate that both in vitro and in vivo, PIs block apoptosis through the preservation of mitochondrial integrity and that in vitro PIs act to prevent pore function of the adenine nucleotide translocator (ANT) subunit of the mitochondrial permeability transition pore complex.
Assuntos
Apoptose/efeitos dos fármacos , Inibidores da Protease de HIV/farmacologia , Translocases Mitocondriais de ADP e ATP/antagonistas & inibidores , Animais , Anticorpos/administração & dosagem , Modelos Animais de Doenças , Feminino , Hepatite/tratamento farmacológico , Hepatite/patologia , Humanos , Células Jurkat , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Translocases Mitocondriais de ADP e ATP/química , Modelos Moleculares , Nelfinavir/farmacologia , Ritonavir/farmacologia , Choque Séptico/tratamento farmacológico , Choque Séptico/patologia , Transdução de Sinais/efeitos dos fármacos , Acidente Vascular Cerebral/tratamento farmacológico , Acidente Vascular Cerebral/patologiaRESUMO
The HIV protease inhibitor class of antiretroviral drug causes unpredicted adverse effects by changing elements of normal cellular metabolism. A case of QT prolongation in a patient receiving protease inhibitors made us question whether these drugs might be responsible. We identified 24 patients with QT prolongation or torsade de pointes, or both, associated with protease inhibitors, using the Food and Drug Administration's voluntary adverse event reporting system. Attending physicians thought that protease inhibitors were the most probable cause of these symptoms in 14 of the patients. Drug-induced QT prolongation is usually caused by block of human ether-a-go-go-related gene (HERG) potassium channels, and we showed that lopinavir, nelfinavir, ritonavir, and saquinavir caused dose-dependent block of HERG channels heterologously expressed in HEK293 cells in vitro. We also recorded block by lopinavir of repolarising potassium current (I(Kr)) channels in neonatal mouse cardiac myocytes. Our data show that four protease inhibitors block HERG channels, suggesting that protease inhibitors could predispose individuals to QT prolongation and torsade de pointes.
Assuntos
Proteínas de Transporte de Cátions/metabolismo , Inibidores da Protease de HIV/efeitos adversos , Canais de Potássio de Abertura Dependente da Tensão da Membrana/metabolismo , Potenciais de Ação , Animais , Linhagem Celular , Eletrocardiografia , Canais de Potássio Éter-A-Go-Go , Infecções por HIV/tratamento farmacológico , Inibidores da Protease de HIV/uso terapêutico , Coração/fisiopatologia , Humanos , Rim/metabolismo , Síndrome do QT Longo/induzido quimicamente , Síndrome do QT Longo/diagnóstico , Masculino , Camundongos , Pessoa de Meia-Idade , Miocárdio/metabolismo , Bloqueadores dos Canais de Potássio/efeitos adversos , Torsades de Pointes/induzido quimicamente , Torsades de Pointes/diagnósticoRESUMO
OBJECTIVE: To determine the effects of antiretroviral therapy on thymic output independent of HIV infection. METHODS: Thymic output was evaluated by quantifying signal joint T-cell receptor (TCR) recombination excision circles in peripheral blood lymphocytes from HIV-negative patients undergoing prophylactic antiretroviral therapy. Additionally, effects of the HIV protease inhibitor nelfinavir were assessed in vivo on TCR-induced death of murine double-positive thymocytes. RESULTS: Five out of seven HIV-negative patients undergoing prophylactic antiretroviral therapy exhibited a dramatic increase (1-3 log10) in recent thymic emigrants containing signal joint TCR recombination excision circles while their peripheral T cell compartments remained relatively unaffected. None of the patients developed subsequent HIV infections. Interestingly, nelfinavir did not have significant effects on TCR-induced apoptosis of murine thymocytes in vivo. CONCLUSION: Antiretroviral therapy augments thymic output independent of HIV. Furthermore, nelfinavir does not dramatically affect TCR-induced thymocyte death in mice, thus central tolerance remains intact.
Assuntos
Terapia Antirretroviral de Alta Atividade , Soronegatividade para HIV/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Timo/imunologia , Adulto , Animais , Apoptose/imunologia , Estudos de Casos e Controles , Infecções por HIV/prevenção & controle , Humanos , Imunofenotipagem , Leucócitos Mononucleares/imunologia , Camundongos , Pessoa de Meia-IdadeRESUMO
BACKGROUND: The process by which cardiac myocytes die during xenograft rejection is incompletely understood. The presence of cardiac myocyte apoptosis in discordant xenotransplant models has been noted, yet no investigators have examined whether a relationship between myocyte apoptosis and rejection severity exists. Thus, we chose to further investigate this observation. METHODS: Eight explanted pig-to-baboon cardiac grafts with varying severities of rejection, as determined by hematoxylin and eosin histology, were examined for apoptosis by transmission electron microscopy (TEM) and TUNEL (terminal deoxynucleotide transferase-mediated digoxigenin-dUTP nick-end labeling) immunohistochemistry. In addition, Western blot analysis for the cleavage of the apoptosis regulatory proteins pro-caspase 8 and 3 was performed. RESULTS: Transmission electron microscopy revealed that a severely rejected graft displayed widespread condensation of nuclear chromatin, which is a characteristic morphologic feature of apoptosis. TUNEL staining verified this observation and allowed for the quantification of myocyte apoptosis in each graft. Subsequent linear regression analysis of the extent of myocyte apoptosis and rejection severity revealed a direct correlation (R(2)=0.757, p=0.005). In addition, Western blot analysis demonstrated that myocyte apoptosis involves the cleavage of pro-caspase 8 and 3. CONCLUSIONS: Myocyte death in rejecting pig-to-baboon cardiac xenografts occurs through an apoptotic pathway and directly correlates with the severity of graft rejection. Further studies aimed at elucidating the apoptotic stimulus are therefore warranted. Moreover, our data suggest that antiapoptotic strategies may be of benefit in the treatment of xenograft rejection.
Assuntos
Rejeição de Enxerto/etiologia , Transplante de Coração , Papio anubis , Suínos , Transplante Heterólogo/efeitos adversos , Animais , Apoptose , Rejeição de Enxerto/patologia , Marcação In Situ das Extremidades Cortadas , Células Musculares/patologiaRESUMO
The pathophysiology of sepsis involves excessive lymphocyte apoptosis, which correlates with adverse outcomes, and disordered cytokine production, which may promote host injury. As the protease inhibitor (PI) class of antiretroviral agents is known to prevent apoptosis in vitro, we evaluated their effect on survival, lymphocyte apoptosis, and consequent cytokine production in mice with sepsis induced by cecal ligation and perforation. Mice pretreated with PIs have improved survival (67%; P<0.0005) compared with controls (17%) and a significant (P<0.05) reduction in lymphocyte apoptosis. Even mice receiving therapy beginning 4 h after perforation demonstrated improved survival (50%; P<0.05) compared with controls. PI therapy is also associated with an increase in the Th1 cytokine TNF-alpha (P<0.05) early in sepsis and a reduction in the Th2 cytokines IL-6 and IL-10 (P<0.05) late in sepsis; despite no intrinsic antibacterial effects, PI also reduced quantitative bacterial blood cultures. The beneficial effects of PI appear to be specific to lymphocyte apoptosis, as lymphocyte-deficient Rag1-/- mice did not experience benefit from treatment with PI. Thus, inhibition of lymphocyte apoptosis by PI is a candidate approach for the treatment of sepsis.