RESUMO
PURPOSE: Retinal photocoagulation and nondamaging laser therapy are used for treatment of macular disorders, without understanding of the response mechanism and with no rationale for dosimetry. To establish a proper titration algorithm, we measured the range of tissue response and damage threshold. We then evaluated safety and efficacy of nondamaging retinal therapy (NRT) based on this algorithm for chronic central serous chorioretinopathy (CSCR) and macular telangiectasia (MacTel). METHODS: Retinal response to laser treatment below damage threshold was assessed in pigmented rabbits by expression of the heat shock protein HSP70 and glial fibrillary acidic protein (GFAP). Energy was adjusted relative to visible titration using the Endpoint Management (EpM) algorithm. In clinical studies, 21 eyes with CSCR and 10 eyes with MacTel were treated at 30% EpM energy with high spot density (0.25-diameter spacing). Visual acuity, retinal and choroidal thickness, and subretinal fluid were monitored for 1 year. RESULTS: At 25% EpM energy and higher, HSP70 was expressed acutely in RPE, and GFAP upregulation in Müller cells was observed at 1 month. Damage appeared starting at 40% setting. Subretinal fluid resolved completely in 81% and partially in 19% of the CSCR patients, and visual acuity improved by 12 ± 3 letters. Lacunae in the majority of MacTel patients decreased while preserving the retinal thickness, and vision improved by 10 letters. CONCLUSIONS: Heat shock protein expression in response to hyperthermia helps define the therapeutic window for NRT. Lack of tissue damage enables high-density treatment to boost clinical efficacy, therapy in the fovea, and retreatments to manage chronic diseases.
Assuntos
Terapia a Laser/métodos , Macula Lutea/cirurgia , Degeneração Macular/cirurgia , Acuidade Visual , Animais , Modelos Animais de Doenças , Análise de Elementos Finitos , Angiofluoresceinografia , Seguimentos , Fundo de Olho , Proteínas de Choque Térmico HSP72/biossíntese , Humanos , Imuno-Histoquímica , Macula Lutea/metabolismo , Macula Lutea/patologia , Degeneração Macular/diagnóstico , Degeneração Macular/metabolismo , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Coelhos , Fatores de Tempo , Tomografia de Coerência Óptica , Resultado do TratamentoRESUMO
OBJECTIVES: Oxidative stress plays critical roles in the pathogeneses of diabetes, hypertension, and atherosclerosis, but its effect on fat accumulation is still unclear. In this study, we analyzed the role of the well-known antioxidant and a glutathione (GSH) precursor N-acetylcysteine (NAC) in fat accumulation and the expression of obesity-associated proteins. METHODS: We studied the effects of 10 µM NAC on obesity-related protein expression in cultured 3T3-L1 preadipocytes, which are able to differentiate into mature adipocytes and accumulate lipids. RESULTS: NAC treatment inhibited fat accumulation and reduced the expression of obesity-related proteins, including monoamine oxidase A, heat shock protein 70 (HSP70), aminoacylase -1 (ACY-1), and transketolase. DISCUSSION: Our results suggest that the effects of NAC on triglycerides (Tgs) and protein expression are correlated. In support of this, we showed that NAC treatment affected both the Tg synthesis pathway and the expression levels of proteins implicated in human obesity.
Assuntos
Acetilcisteína/farmacologia , Adipócitos/metabolismo , Adipogenia/efeitos dos fármacos , Células 3T3-L1 , Adipócitos/efeitos dos fármacos , Amidoidrolases/biossíntese , Animais , Diferenciação Celular/fisiologia , Proteínas de Ligação a Ácido Graxo/biossíntese , Proteínas de Choque Térmico HSP72/biossíntese , Camundongos , Monoaminoxidase/biossíntese , Estresse Oxidativo/efeitos dos fármacos , Transcetolase/biossíntese , Triglicerídeos/metabolismoRESUMO
BACKGROUND/AIM: Nitric oxide (NO) modulates the expression of the chaperone Hsp72 in the heart, and exercise stimulates both NO production and myocardial Hsp72 expression. The main purpose of the study was to investigate whether NO interferes with an exercise-induced myocardial Hsp72 expression. METHODS: Male Wistar rats (70-100 days) were divided into control (C, n=12), L-NAME-treated (L, n=12), exercise (E, n=13) and exercise plus L-NAME-treated (EL, n=20) groups. L-NAME was given in drinking water (700 mg·L(-1)) and the exercise was performed on a treadmill (15-25 m·min(-1), 40-60 min.day(-1)) for seven days. Left ventricle (LV) protein Hsp content, NOS and phosphorylated-NOS (p-NOS) isoforms were measured using Western blotting. The activity of NOS was assayed in LV homogenates by the conversion of [(3)H]L-arginine to [(3)H]L-citrulline. RESULTS: Hsp72 content was increased significantly (223%; p < 0.05) in the E group compared to the C group, but exercise alone did not alter the NOS content, p-NOS isoforms or NOS activity. Contrary to our expectation, L-NAME enhanced (p < 0.05) the exercise-induced Hsp72 content (EL vs. C, L and E groups = 1019%, 548% and 457%, respectively). Although the EL group had increased stimulatory p-eNOS(Ser1177) (over 200%) and decreased inhibitory p-nNOS(Ser852) (ñ50%) compared to both the E and L groups (p < 0.05), NOS activity was similar in all groups. CONCLUSIONS: Our results suggest that exercise-induced cardiac Hsp72 expression does not depend on NO. Conversely, the in vivo L-NAME treatment enhances exercise-induced Hsp72 production. This effect may be due to an increase in cardiac stress.
Assuntos
Proteínas de Choque Térmico HSP72/biossíntese , Ventrículos do Coração/enzimologia , Atividade Motora/fisiologia , Miocárdio/enzimologia , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico Sintase Tipo III/biossíntese , Óxido Nítrico Sintase Tipo I/biossíntese , Óxido Nítrico/metabolismo , Animais , Arginina/metabolismo , Western Blotting , Citrulina/metabolismo , Ventrículos do Coração/efeitos dos fármacos , Hemodinâmica/efeitos dos fármacos , Masculino , Atividade Motora/efeitos dos fármacos , Fosforilação , Ratos , Ratos Wistar , Trítio/análise , Trítio/metabolismoRESUMO
The cell response of human HepG2 cells exposed to hypothermia with rewarming was analyzed. Ultrastructural findings in hypothermic stressed cells showed swollen mitochondria, dispersed chromatin, vacuoles and ring-shape nucleolar reorganization. These changes were coupled with significative differences in the induction of Hsp60, inducible Hsp70 and monomeric Hsfl in all treated samples, but not in Hsc 70 expression. Cellular response to hypothermia could be associated with the synergistic induction of Hsp expression.
Assuntos
Carcinoma Hepatocelular/patologia , Chaperonina 60/biossíntese , Temperatura Baixa , Proteínas de Ligação a DNA/biossíntese , Regulação Neoplásica da Expressão Gênica , Proteínas de Choque Térmico HSP72/biossíntese , Neoplasias Hepáticas/patologia , Proteínas de Neoplasias/biossíntese , Fatores de Transcrição/biossíntese , Linhagem Celular Tumoral/metabolismo , Linhagem Celular Tumoral/ultraestrutura , Chaperonina 60/genética , Temperatura Baixa/efeitos adversos , Proteínas de Ligação a DNA/genética , Proteínas de Choque Térmico HSP72/genética , Fatores de Transcrição de Choque Térmico , Humanos , Mitocôndrias/ultraestrutura , Proteínas de Neoplasias/genética , Reaquecimento , Temperatura , Fatores de Transcrição/genéticaRESUMO
BACKGROUND: Physical exercise induces hemodynamic stress. OBJECTIVE: To evaluate if voluntary running and forced running induced different levels of stress protein (Hsp72) in the myocardium of female Wistar rats. METHODS: Female rats were randomly assigned to the following groups: forced treadmill running group (FR; n= 6), voluntary running group (VR; n=6) and control group (C; n=6). VR group animals had free access to running wheels, and those from FR group underwent a running program on a treadmill (18 m/min, 60 min/day, 5 days/wk) for 8 weeks. Left ventricle (LV) and right ventricle (RV) fragments were collected at sacrifice, and the relative immunoblot contents of stress protein (Hsp72) were determined. RESULTS: VR animals ran on average 4.87 km/wk, and FR rats ran 4.88 km/wk. Animals from VR and FR groups had less body weight gain (p<0.05) than those from C group (81.67 +/- 11.95g vs 81.17 +/- 10.18g vs 111.50 +/- 2.26g, respectively). Heart weight/body weight ratio was not significantly different (p>0.05) among VR, FR and C groups (4.54 +/- 0.79 mg/g vs 4.94 +/- 0.89 mg/g vs 4.34 +/- 0.87 mg/g, respectively). FR group animals had levels of Hsp72 (p<0.05) higher than those from VR, both in LV (287.45 +/- 35.86 % vs 135.59 +/- 5.10 %, respectively) and RV (241.31 +/- 25.83 % vs 137.91 +/- 45.20 %, respectively). CONCLUSION: Voluntary running and forced running induced different levels of Hsp72 in the myocardium of female Wistar rats.
Assuntos
Proteínas de Choque Térmico HSP72/biossíntese , Miocárdio/metabolismo , Esforço Físico/fisiologia , Corrida/fisiologia , Animais , Peso Corporal/fisiologia , Métodos Epidemiológicos , Feminino , Ventrículos do Coração/patologia , Modelos Animais , Miocárdio/patologia , Tamanho do Órgão/fisiologia , Condicionamento Físico Animal/fisiologia , Ratos , Ratos WistarRESUMO
Regions of low oxygen tension are common features of inflamed and infected tissues and provide physiologic selective pressure for the expansion of cells with enhanced hypoxia tolerance. The aim of this study was to investigate whether macrophages resistant to death induced by hypoxia were accompanied by functional alterations. A mouse macrophage cell line (J774 cells) was used to obtain subpopulations of death-resistant macrophages induced by long-term exposure to severe hypoxia (<1% O(2)). The results indicated that exposing J774 macrophages to periods of severe hypoxia results in the selection of cells with phenotypes associated with the modulation of heat-shock protein 70 kDa (HSP70) expression, tumor necrosis factor-alpha (TNF-alpha), and nitric oxide (NO) production and reduced susceptibility to parasite Leishmania infection. Thus, we suggest that hypoxia-selected macrophages may influence the outcome of inflammation and infection.