NIELS OLSEN SARAIVA CAMARA
Projetos de Pesquisa
Unidades Organizacionais
BMI, ICB - Docente
LIM/05 - Laboratório de Poluição Atmosférica Experimental, Hospital das Clínicas, Faculdade de Medicina
LIM/05 - Laboratório de Poluição Atmosférica Experimental, Hospital das Clínicas, Faculdade de Medicina
4 resultados
Resultados de Busca
Agora exibindo 1 - 4 de 4
- Pathogenic role of innate immunity in a model of chronic NO inhibition associated with salt overload(2019) ZAMBOM, Fernanda Florencia Fregnan; OLIVEIRA, Karin Carneiro; FORESTO-NETO, Orestes; FAUSTINO, Viviane Dias; AVILA, Victor Ferreira; ALBINO, Amanda Helen; ARIAS, Simone Costa Alarcon; VOLPINI, Rildo Aparecido; MALHEIROS, Denise Maria Avancini Costa; CAMARA, Niels Olsen Saraiva; ZATZ, Roberto; FUJIHARA, Clarke KazueNitric oxide inhibition with N-omega-nitro-L-arginine methyl ester (L-NAME), along with salt overload, leads to hypertension, albuminuria, glomerulosclerosis, glomerular ischemia, and interstitial fibrosis, characterizing a chronic kidney disease (CKD) model. Previous findings of this laboratory and elsewhere have suggested that activation of at least two pathways of innate immunity, Toll-like receptor 4 (TLR4)/NF-kappa B and nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain containing 3 (NLRP3) inflammasome/IL-1 beta, occurs in several experimental models of CKD and that progression of renal injury can be slowed with inhibition of these pathways. In the present study, we investigated whether activation of innate immunity, through either the TLR4/NF-kappa B or NLRP3/IL-1 beta pathway, is involved in the pathogenesis of renal injury in chronic nitric oxide inhibition with the salt-overload model. Adult male Munich-Wistar rats that received L-NAME in drinking water with salt overload (HS + N group) were treated with allopurinol (ALLO) as an NLRP3 inhibitor (HS + N + ALLO group) or pyrrolidine dithiocarbamate (PDTC) as an NF-kappa B inhibitor (HS + N + PDTC group). After 4 wk, HS + N rats developed hypertension, albuminuria, and renal injury along with renal inflammation, oxidative stress, and activation of both the NLRP3/IL-1 beta and TLR4/NF-kappa B pathways. ALLO lowered renal uric acid and inhibited the NLRP3 pathway. These effects were associated with amelioration of hypertension, albuminuria, and interstitial inflammation/fibrosis but not glomerular injury. PDTC inhibited the renal NF-kappa B system and lowered the number of interstitial cells staining positively for NLRP3. PDTC also reduced renal xanthine oxidase activity and uric acid. Overall, PDTC promoted a more efficient anti-inflammatory and nephroprotective effect than ALLO. The NLRP3/IL-1 beta and TLR4/NF-kappa B pathways act in parallel to promote renal injury/inflammation and must be simultaneously inhibited for best nephroprotection.
- Chronic environmental hypoxia attenuates innate immunity activation and renal injury in two CKD models(2023) ZAMBOM, Fernanda Florencia Fregnan; ALBINO, Amanda Helen; TESSARO, Helena Mendonca; FORESTO-NETO, Orestes; MALHEIROS, Denise Maria Avancini Costa; CAMARA, Niels Olsen Saraiva; ZATZ, RobertoTissue hypoxia has been pointed out as a major pathogenic factor in chronic kidney disease (CKD). However, epidemiological and experimental evidence inconsistent with this notion has been described. We have previously reported that chronic exposure to low ambient Po-2 promoted no renal injury in normal rats and in rats with 5/6 renal ablation (Nx) unexpectedly attenuated renal injury. In the present study, we investigated whether chronic exposure to low ambient Po-2 would also be renoprotective in two additional models of CKD: adenine (ADE) excess and chronic nitric oxide (NO) inhibition. In both models, normobaric ambient hypoxia attenuated the development of renal injury and inflammation. In addition, renal hypoxia limited the activation of NF-?B and NOD-like receptor family pyrin domain containing 3 inflammasome cascades as well as oxidative stress and intrarenal infiltration by angiotensin II-positive cells. Renal activation of hypoxia-inducible factor (HIF)-2a, along with other adaptive mechanisms to hypoxia, may have contributed to these renoprotective effects. The present findings may contribute to unravel the pathogenesis of CKD and to the development of innovative strategies to arrest its progression.
- Chronic exposure to hypoxia attenuates renal injury and innate immunity activation in the remnant kidney model(2019) REMPEL, Lisienny Campoli Tono; FAUSTINO, Viviane Dias; FORESTO-NETO, Orestes; FANELLI, Camilla; ARIAS, Simone Costa Alarcon; MOREIRA, Gizely Cristina da Silva; NASCIMENTO, Thalita Fabiana; AVILA, Victor Ferreira; MALHEIROS, Denise Maria Avancini Costa; CAMARA, Niels Olsen Saraiva; FUJIHARA, Clarice Kazue; ZATZ, RobertoHypoxia is thought to influence the pathogenesis of chronic kidney disease, but direct evidence that prolonged exposure to tissue hypoxia initiates or aggravates chronic kidney disease is lacking. We tested this hypothesis by chronically exposing normal rats and rats with 5/6 nephrectomy (Nx) to hypoxia. In addition, we investigated whether such effect of hypoxia would involve activation of innate immunity. Adult male Munich-Wistar rats underwent Nx (n = 54) or sham surgery (sham; n = 52). Twenty-six sham rats and 26 Nx rats remained in normoxia, whereas 26 sham rats and 28 Nx rats were kept in a normobaric hypoxia chamber (12% O-2) for 8 wk. Hypoxia was confirmed by immunohistochemistry for pimonidazole. Hypoxia was confined to the medullary area in sham + normoxia rats and spread to the cortical area in sham + hypoxia rats, without changing the peritubular capillary density. Exposure to hypoxia promoted no renal injury or elevation of the content of IL-1 beta or Toll-like receptor 4 in sham rats. In Nx, hypoxia also extended to the cortical area without ameliorating the peritubular capillary rarefaction but, unexpectedly, attenuated hypertension, inflammation, innate immunity activation, renal injury, and oxidative stress. The present study, in disagreement with current concepts. shows evidence that hypoxia exerts a renoprotective effect in the Nx model instead of acting as a factor of renal injury. The mechanisms for this unexpected beneficial effect are unclear and may involve NF-kappa B inhibition, amelioration of oxidative stress, and limitation of angiotensin II production by the renal tissue.
- NF-kappa B blockade during short-term L-NAME and salt overload strongly attenuates the late development of chronic kidney disease(2020) OLIVEIRA, Karin Carneiro; ZAMBOM, Fernanda Florencia Fregnan; ALBINO, Amanda Helen; ARIAS, Simone Costa Alarcon; AVILA, Victor Ferreira; FAUSTINO, Viviane Dias; MALHEIROS, Denise Maria Avancini Costa; CAMARA, Niels Olsen Saraiva; FUJIHARA, Clarice Kazue; ZATZ, RobertoNitric oxide synthase inhibition by N-omega-nitro-L-arginine methyl ester (L-NAME) plus a high-salt diet (HS) is a model of chronic kidney disease (CKD) characterized by marked hypertension and renal injury. With cessation of treatment, most of these changes subside, but progressive renal injury develops, associated with persistent low-grade renal inflammation. We investigated whether innate immunity. and in particular the NF-kappa B system, is involved in this process. Male Munich-Wistar rats received HS + L-NAME (32 mg.kg(-1).day(-1)), whereas control rats received HS only. Treatment was ceased after week 4 when 30 rats were studied. Additional rats were studied at week 8 (n = 30) and week 28 (n = 30). As expected, HS + L-NAME promoted severe hypertension, albuminuria, and renal injury after 4 wk of treatment, whereas innate immunity activation was evident. After discontinuation of treatments, partial regression of renal injury and inflammation occurred, along with persistence of innate immunity activation at week 8. At week 28, glomerular injury worsened, while renal inflammation persisted and renal innate immunity remained activated. Temporary administration of the NF-kappa B inhibitor pyrrolidine dithiocarbamate, in concomitancy with the early 4-wk HS + L-NAME treatment, prevented the development of late renal injury and inflammation, an effect that lasted until the end of the study. Early activation of innate immunity may be crucial to the initiation of renal injury in the HS + L-NAME model and to the autonomous progression of chronic nephropathy even after cessation of the original insult. This behavior may be common to other conditions leading to CKD.