ANTONIO CARLOS SEGURO
Projetos de Pesquisa
Unidades Organizacionais
Instituto Central, Hospital das Clínicas, Faculdade de Medicina - Médico
LIM/12 - Laboratório de Pesquisa Básica em Doenças Renais, Hospital das Clínicas, Faculdade de Medicina - Líder
LIM/12 - Laboratório de Pesquisa Básica em Doenças Renais, Hospital das Clínicas, Faculdade de Medicina - Líder
9 resultados
Resultados de Busca
Agora exibindo 1 - 9 de 9
- Cathelicidin protects mice from Rhabdomyolysis-induced Acute Kidney Injury(2021) SILVA, Beatriz Helena Cermaria Soares da; ARIGA, Suely Kubo; BARBEIRO, Hermes Vieira; VOLPINI, Rildo Aparecido; BARBEIRO, Denise Frediani; SEGURO, Antonio Carlos; SILVA, Fabiano Pinheiro daBackground: Cathelicidins are ancient and well-conserved antimicrobial peptides (AMPs) with intriguing immunomodulatory properties in both infectious and non-infectious inflammatory diseases. In addition to direct antimicrobial activity, cathelicidins also participate in several signaling pathways inducing both pro-inflammatory and anti-inflammatory effects. Acute kidney injury (AKI) is common in critically ill patients and is associated with high mortality and morbidity. Rhabdomyolysis is a major trigger of AKI. Objectives: Here, we investigated the role of cathelicidins in non-infectious Acute kidney Injury (AKI). Method: Using an experimental model of rhabdomyolysis, we induced AKI in wild-type and cathelicidin-related AMP knockout (CRAMP(-/-)) mice. Results: We previously demonstrated that CRAMP(-/-) mice, as opposed wild-type mice, are protected from AKI during sepsis induced by cecal ligation and puncture. Conversely, in the current study, we show that CRAMP(-/-) mice are more susceptible to the rhabdomyolysis model of AKI. A more in-depth investigation of wild-type and CRAMP(-/-) mice revealed important differences in the levels of several inflammatory mediators. Conclusion: Cathelicidins can induce a varied and even opposing repertoire of immune-inflammatory responses depending on the subjacent disease and the cellular context.
bookPart Fisiologia Renal(2021) GOIS, Pedro Henrique França; CAMARGO, Leonardo Figueiredo; HACHMANN, Jean Carlo Tibes; SEGURO, Antonio Carlos- High blood pressure induced by vitamin D deficiency is associated with renal overexpression and hyperphosphorylation of Na+-K+-2Cl-cotransporter type 2(2021) LUCHI, Weverton M.; CRAJOINAS, Renato O.; MARTINS, Flavia L.; CASTRO, Paulo de C.; VENTURINI, Gabriela; SEGURO, Antonio C.; GIRARDI, Adriana C. C.Objectives: Clinical and epidemiological studies have suggested a correlation between vitamin D deficiency (VDD) and high blood pressure (BP). This study aimed to test the hypothesis that high BP induced by VDD is associated with altered expression and covalent modification of apical sodium transporters along the nephron. The contributions of the intrarenal renin-angiotensin system (RAS) and oxidative stress were also investigated. Methods: Male Wistar rats were fed a vitamin D-free (n = 26) or standard diet (n = 25) for 30 days. BP was recorded using noninvasive and invasive procedures. The expression levels of total and phosphorylated apical sodium transporters in rat renal cortex and medulla were evaluated by immunoblotting. Intrarenal RAS components were assessed by immunoblotting and ELISA. Renal oxidative stress was analyzed by measuring the concentrations of thiobarbituric acid reactive substances and reduced glutathione. Results: Higher BP levels in VDD rats than controls were accompanied by overexpression and hyperphosphorylation of renal cortical and medullary Na+-K+-2Cl- cotransporter type 2, enhanced levels of phosphorylated Na+/H+ exchanger type 3, and reduced expression levels of total and phosphorylated Na+/Cl- cotransporter. Changes in intrarenal RAS induced by VDD vs. controls included the marked elevation of medullary renin expression, higher expression of cortical angiotensinogen, higher urinary angiotensinogen excretion, and higher cortical and medullary angiotensin II content. VDD rats displayed higher thiobarbituric acid reactive substances/glutathione ratios in the renal cortex and medulla than controls. Conclusion: These results suggest that the molecular mechanisms underlying the effects of VDD on BP may include the upregulation of Na+-K+-2Cl- cotransporter type 2 and activation of intrarenal RAS and oxidative stress.
- Changes in the renal function after acute mercuric chloride exposure in the rat are associated with renal vascular endothelial dysfunction and proximal tubule NHE3 inhibition(2021) VIEIRA, Joao Vitor dos Anjos; MARQUES, Vinicius Bermond; VIEIRA, Luiza Valli; CRAJOINAS, Renato de Oliveira; SHIMIZU, Maria Heloisa Massola; SEGURO, Antonio Carlos; CARNEIRO, Maria Tereza Weitzel Dias; GIRARDI, Adriana Castello Costa; VASSALLO, Dalton Valentim; SANTOS, Leonardo dosMercury is an environmental pollutant and a threat to human health. Mercuric chloride (HgCl2)-induced acute renal failure has been described by several reports, but the mechanisms of renal dysfunction remain elusive. This study tested the hypothesis that HgCl2 directly impairs renal vascular reactivity. Additionally, due to the mercury toxicity on the proximal tubule, we investigated whether the HgCl2-induced natriuresis is accompanied by inhibition of Na+/H+ exchanger isoform-3 (NHE3). We found that 90-min HgCl2 infusion (6.5 mu g/kg i.v.) remarkably increased urinary output, reduced GFR and renal blood flow, and increased vascular resistance in rats. ""In vitro"" experiments of HgCl2 infusion in isolated renal vascular bed demonstrated an elevation of perfusion pressure in a concentration- and time-dependent manner, associated with changes on the endothelium-dependent vasodilatation and the flow-pressure relationship. Moreover, by employing ""in vivo"" stationary microperfusion of the proximal tubule, we found that HgCl2 inhibits NHE3 activity and increases the phosphorylation of NHE3 at serine 552 in the renal cortex, in line with the HgCl2-induced diuresis. Changes in renal proximal tubular function induced by HgCl2 were parallel to increased urinary markers of proximal tubular injury. Besides, atomic spectrometry showed that mercury accumulated in the renal cortex. We conclude that acute HgCl2 exposure causes renal vasoconstriction that is associated with reduced endothelial vasodilator agonistand flow-mediated responses and inhibition of NHE3-mediated sodium reabsorption. Thus, our data suggest that HgCl2-induced acute renal failure may be attributable at least in part by its direct effects on renal hemodynamics and NHE3 activity.
- The Restoration of Vitamin D Levels Slows the Progression of Renal Ischemic Injury in Rats Previously Deficient in Vitamin D(2021) SANTOS, Michele Santiago dos; CANALE, Daniele; BERNARDO, Desiree Rita Denelle; SHIMIZU, Maria Heloisa Massola; SEGURO, Antonio Carlos; VOLPINI, Rildo Aparecido; BRAGANCA, Ana Carolina deChronic kidney disease (CKD) remains a global public health problem. The initial damage after ischemia/reperfusion (I/R) injury plays an important role in the pathogenesis of acute kidney injury (AKI) and predisposition to CKD. Several studies have been showing that nontraditional risk factors such as AKI and hypovitaminosis D could also be involved in CKD progression. Vitamin D deficiency (VDD) is associated with hemodynamic changes, activation of inflammatory pathways and renal disease progression (RDP) following I/R-AKI. Strategies for prevention and/or slowing RDP have been determined and the sufficiency of vitamin D has been emerging as a renoprotective factor in many diseases. Therefore, we investigated the effect of the restoration of vitamin D levels in the progression of I/R injury (IRI) in rats previously deficient in vitamin D. On day 30, male Wistar rats were submitted to bilateral 45 min IRI and divided into three groups: IRI, standard diet for 120 days; VDD+IRI, vitamin D-free diet for 120 days; and VDD+IRI+R, vitamin D-free diet in the first 30 days and just after I/R, we reintroduced the standard diet in the last 90 days. After the 120-day protocol, VDD+IRI+R rats presented an improvement in the renal function and renal protein handling followed by a smaller fractional interstitial area. Furthermore, those animals exhibited a reestablishment regarding the hemodynamic parameters and plasma levels of aldosterone, urea and PTH. In addition, the restoration of vitamin D levels reestablished the amount of MCP1 and the renal expressions of CD68+ and CD3+ cells in the VDD+IRI+R rats. Also, VDD+IRI+R rats showed a restoration regarding the amount of collagen type III and renal expressions of fibronectin, vimentin and alpha-SMA. Such changes were also accompanied by a reestablishment on the renal expression of VDR, Klotho, JG12, and TGF-beta 1. Our findings indicate that the restoration of vitamin D levels not only improved the renal function and hemodynamics but also reduced the inflammation and fibrosis lesions observed in I/R-AKI associated with VDD. Thus, monitoring of vitamin D status as well as its replacement in the early stages of kidney injury may be a therapeutic alternative in the mitigation of renal disease progression.
- Acute kidney injury induced by glycerol is worsened by orchiectomy and attenuated by testosterone replacement(2021) SOUZA, Samira Itana de; ROCHA, Edilene Candido; FERRAZ, Halanna Rocha; DIAS, Jessica Afonso; SEGURO, Antonio Carlos; VOLPINI, Rildo Aparecido; CANALE, Daniele; BRAGANCA, Ana Carolina de; SHIMIZU, Maria Heloisa Massola; MARQUES, Lucas Miranda; MAGALHAES, Amelia Cristina Mendes de; COIMBRA, Terezila Machado; SOARES, Telma de JesusAlthough several studies have demonstrated that the male gender represents an independent risk factor for renal disease, evidence shows that androgens exert renal protective actions. The findings are controversial and no studies have evaluated the effects of orchiectomy and testosterone replacement on glycerol-induced renal injury. Male Wistar rats were submitted to orchiectomy or sham surgery and divided into four groups: SC, sham control rats injected with NaCl; SG, sham rats injected with glycerol; OG, orchiectomized rats injected with glycerol; OGT, orchiectomized rats injected with glycerol and testosterone. Testosterone was administered daily for 14 days in the OGT group. After 11 days of testosterone replacement in the OGT group, SC rats were submitted to a saline injection, while SG, OG and OGT rats received glycerol. All rats were euthanized three days after injections. OG rats presented higher serum creatinine and urea, and sodium excretion, compared to SC and SG, while testosterone attenuated these changes. Acute tubular necrosis was also mitigated by testosterone. Renal immunostaining for macrophages, lymphocytes and NF-kappa B was higher in OG compared to SC and SG. In addition, renal interleukin-1 beta, Caspase 3 and AT1 gene expression was higher in OG rats compared to SG. Testosterone attenuated these alterations, except the NF-kappa B immunostaining. The renal NO was lower in OG rats compared to SG. Only the OG rats presented decreases in serum NO and renal HO-1, and increased TNF-alpha, angiotensinogen and AT1 expression compared to SC. We conclude that orchiectomy worsened glycerol-induced kidney injury, while testosterone attenuated this renal damage.
- The Blockade of TACE-Dependent EGF Receptor Activation by Losartan-Erlotinib Combination Attenuates Renal Fibrosis Formation in 5/6-Nephrectomized Rats Under Vitamin D Deficiency(2021) GONCALVES, Janaina Garcia; CANALE, Daniele; BRAGANCA, Ana Carolina de; SEGURO, Antonio Carlos; SHIMIZU, Maria Heloisa Massola; VOLPINI, Rildo AparecidoChronic kidney disease (CKD) has been considered a major public health issue. In addition to cardiovascular diseases and infections, hypovitaminosis D has been considered a non-traditional aggravating factor for CKD progression. Interstitial fibrosis is a hallmark of CKD strongly correlated with deterioration of renal function. Transforming growth factor beta (TGF-beta) is the major regulatory profibrotic cytokine in CKD. Many injurious stimuli converge on the TGF-beta pathway, which has context-dependent pleiotropic effects and interacts with several related renal fibrosis formation (RFF) pathways. Epidermal growth factor receptor (EGFR) is critically involved in CKD progression, exerting a pathogenic role in RFF associated with TGF-beta-related fibrogenesis. Among others, EGFR pathway can be activated by a disintegrin and a metalloproteinase known as tumor necrosis factor alpha-converting enzyme (TACE). Currently no effective therapy is available to completely arrest RFF and slow the progression of CKD. Therefore, we investigated the effects of a double treatment with losartan potassium (L), an AT1R antagonist, and the tyrosine kinase inhibitor erlotinib (E) on the alternative pathway of RFF related to TACE-dependent EGFR activation in 5/6-nephrectomized rats under vitamin D deficiency (D). During the 90-day protocol, male Wistar rats under D, were submitted to 5/6 nephrectomy (N) on day 30 and randomized into four groups: N+D, no treatment; N+D+L, received losartan (50 mg/kg/day); N+D+E, received erlotinib (6 mg/kg/day); N+D+L+E received losartan+erlotinib treatment. N+D+L+E data demonstrated that the double treatment with losartan+erlotinib not only blocked the TACE-dependent EGF receptor activation but also prevented the expression of TGF-beta, protecting against RFF. This renoprotection by losartan+erlotinib was corroborated by a lower expression of ECM proteins and markers of phenotypic alteration as well as a lesser inflammatory cell infiltrate. Although erlotinib alone has been emerging as a renoprotective drug, its association with losartan should be considered as a potential therapeutic strategy on the modulation of RFF.
- Urinary DPP4 correlates with renal dysfunction, and DPP4 inhibition protects against the reduction in megalin and podocin expression in experimental CKD(2021) BENETTI, Acaris; MARTINS, Flavia Leticia; SENE, Leticia Barros; SHIMIZU, Maria Heloisa M.; SEGURO, Antonio C.; LUCHI, Weverton M.; GIRARDI, Adriana C. C.This study investigated the molecular mechanisms underlying the antiproteinuric effect of DPP4 inhibition in 5/6 renal ablation rats and tested the hypothesis that the urinary activity of DPP4 correlates with chronic kidney disease (CKD) progression. Experiments were conducted in male Wistar rats who underwent 5/6 nephrectomy (Nx) or sham operation followed by 8 wk of treatment with the DPP4 inhibitor (DPP4i) sitagliptin or vehicle. Proteinuria increased progressively in Nx rats throughout the observation period. This increase was remarkably mitigated by sitagliptin. Higher levels of proteinuria in Nx rats compared to control rats were accompanied by higher urinary excretion of retinol-binding protein 4, a marker of tubular proteinuria, as well as higher urinary levels of podocin, a marker of glomerular proteinuria. Retinol-binding protein 4 and podocin were not detected in the urine of Nx + DPP4i rats. Tubular and glomerular proteinuria was associated with the reduced expression of megalin and podocin in the renal cortex of Nx rats. Sitagliptin treatment partially prevented this decrease. Besides, the angiotensin II renal content was significantly reduced in the Nx rats that received sitagliptin compared to vehicle-treated Nx rats. Interestingly, both urinary DPP4 activity and abundance increased progressively in Nx rats. Additionally, urinary DPP4 activity correlated positively with serum creatinine levels, proteinuria, and blood pressure. Collectively, these results suggest that DPP4 inhibition ameliorated both tubular and glomerular proteinuria and prevented the reduction of megalin and podocin expression in CKD rats. Furthermore, these findings suggest that urinary DPP4 activity may serve as a biomarker of renal disease and progression.
- Renal Inflammation and Innate Immune Activation Underlie the Transition From Gentamicin-Induced Acute Kidney Injury to Renal Fibrosis(2021) ALBINO, Amanda Helen; ZAMBOM, Fernanda Florencia Fregnan; FORESTO-NETO, Orestes; OLIVEIRA, Karin Carneiro; AVILA, Victor Ferreira; ARIAS, Simone Costa Alarcon; SEGURO, Antonio Carlos; MALHEIROS, Denise Maria Avancini Costa; CAMARA, Niels Olsen Saraiva; FUJIHARA, Clarice Kazue; ZATZ, RobertoSubjects recovering from acute kidney injury (AKI) are at risk of developing chronic kidney disease (CKD). The mechanisms underlying this transition are unclear and may involve sustained activation of renal innate immunity, with resulting renal inflammation and fibrosis. We investigated whether the NF-kappa B system and/or the NLRP3 inflammasome pathway remain activated after the resolution of AKI induced by gentamicin (GT) treatment, thus favoring the development of CKD. Male Munich-Wistar rats received daily subcutaneous injections of GT, 80 mg/kg, for 9 days. Control rats received vehicle only (NC). Rats were studied at 1, 30, and 180 days after GT treatment was ceased. On Day 1, glomerular ischemia (ISCH), tubular necrosis, albuminuria, creatinine retention, and tubular dysfunction were noted, in association with prominent renal infiltration by macrophages and myofibroblasts, along with increased renal abundance of TLR4, IL-6, and IL1 beta. Regression of functional and structural changes occurred on Day 30. However, the renal content of IL-1 beta was still elevated at this time, while the local renin-angiotensin system remained activated, and interstitial fibrosis became evident. On Day 180, recurring albuminuria and mild glomerulosclerosis were seen, along with ISCH and unabated interstitial fibrosis, whereas macrophage infiltration was still evident. GT-induced AKI activates innate immunity and promotes renal inflammation. Persistence of these abnormalities provides a plausible explanation for the transition of AKI to CKD observed in a growing number of patients.