Cytoprotective role of heme oxygenase-1 and heme degradation derived end products in liver injury

The activation of heme oxygenase-1 (HO-1) appears to be an endogenous defensive mechanism used by cells to reduce inflammation and tissue damage in a number of injury models. HO-1, a stress-responsive enzyme that catabolizes heme into carbon monoxide (CO), biliverdin and iron, has previously been shown to protect grafts from ischemia/reperfusion and rejection. In addition, the products of the HO-catalyzed reaction, particularly CO and biliverdin/bilirubin, have been shown to exert protective effects in the liver against a number of stimuli, as in chronic hepatitis C and in transplanted liver grafts. Furthermore, the induction of HO-1 expression can protect the liver against damage caused by a number of chemical compounds. More specifically, the CO derived from HO-1-mediated heme catabolism has been shown to be involved in the regulation of inflammation; furthermore, administration of low concentrations of exogenous CO has a protective effect against inflammation. Both murine and human HO-1 deficiencies have systemic manifestations associated with iron metabolism, such as hepatic overload (with signs of a chronic hepatitis) and iron deficiency anemia (with paradoxical increased levels of ferritin). Hypoxia induces HO-1 expression in multiple rodent, bovine and monkey cell lines, but interestingly, hypoxia represses expression of the human HO-1 gene in a variety of human cell types (endothelial cells, epithelial cells, T cells). These data suggest that HO-1 and CO are promising novel therapeutic molecules for patients with inflammatory diseases. In this review, we present what is currently known regarding the role of HO-1 in liver injuries and in particular, we focus on the implications of targeted induction of HO-1 as a potential therapeutic strategy to protect the liver against chemically induced injury.FAPESP (Fundação de Apoio à Pesquisa do Estado de São Paulo), 07/07139-3FAPESP (Fundação de Apoio à Pesquisa do Estado de São Paulo), 10/02024-6CNP

Butyrate Attenuates Lung Inflammation by Negatively Modulating Th9 Cells

Th9 cells orchestrate allergic lung inflammation by promoting recruitment and activation of eosinophils and mast cells, and by stimulating epithelial mucus production, which is known to be mainly dependent on IL-9. These cells share developmental pathways with induced regulatory T cells that may determine the generation of one over the other subset. In fact, the FOXP3 transcription factor has been shown to bind il9 locus and repress IL-9 production. The microbiota-derived short-chain fatty acids (SCFAs) butyrate and propionate have been described as FOXP3 inducers and are known to have anti-inflammatory properties. While SCFAs attenuate lung inflammation by inducing regulatory T cells and suppressing Th2 responses, their effects on Th9 cells have not been addressed yet. Therefore, we hypothesized that SCFAs would have a protective role in lung inflammation by negatively modulating differentiation and function of Th9 cells. Our results demonstrated that butyrate is more effective than propionate in promoting FOXP3 expression and IL-9 repression. In addition, propionate was found to negatively impact in vitro differentiation of IL-13-expressing T cells. Butyrate treatment attenuated lung inflammation and mucus production in OVA-challenged mice, which presented lower frequency of lung-infiltrated Th9 cells and eosinophils. Both Th9 cell adoptive transfer and IL-9 treatment restored lung inflammation in butyrate-treated OVA-challenged mice, indicating that the anti-inflammatory effects of butyrate may rely on suppressing Th9-mediated immune responses

The immunomodulatory role of carbon monoxide during transplantation

The number of organ and tissue transplants has increased worldwide in recent decades. However, graft rejection, infections due to the use of immunosuppressive drugs and a shortage of graft donors remain major concerns. Carbon monoxide (CO) had long been regarded solely as a poisonous gas. Ultimately, physiological studies unveiled the endogenous production of CO, particularly by the heme oxygenase (HO)-1 enzyme, recognizing CO as a beneficial gas when used at therapeutic doses. The protective properties of CO led researchers to develop uses for it, resulting in devices and molecules that can deliver CO in vitro and in vivo. The resulting interest in clinical investigations was immediate. Studies regarding the CO/HO-1 modulation of immune responses and their effects on various immune disorders gave rise to transplantation research, where CO was shown to be essential in the protection against organ rejection in animal models. This review provides a perspective of how CO modulates the immune system to improve transplantation and suggests its use as a therapy in the field.This work was supported by CNPq (CNPq/Inserm, INCT Complex Fluids, MCT/CNPq/FINEP 559887/2010-8 PNPD 159018/2011-0) and FAPESP (12/02270-2)

Gut microbial metabolite increases skeletal muscle regeneration through epigenetic mechanisms

Introduction: Reduction in skeletal muscle regeneration capacity, such as in inflammatory muscle diseases and aging, leads to progressive muscle strength decrement, which impairs mobility and increases risk of falls and mortality, with a negative impact of quality of life. This reduction in skeletal muscle regeneration has been associated with an impaired function of the skeletal muscle stem cells, namely, the satellite cells. These cells are localized beneath basal lamina in a quiescence state and can be activated and differentiated into new myofibers after muscle damage. Indeed, satellite cells need to exit the cell cycle for differentiation. Therefore, the search for biological tools that can improve activation/differentiation of satellite cells is of great interest to regenerative medicine. In this regard, butyrate, a gut microbial metabolite, which can induce cell cycle arrest through histone deacetylase inhibition, has emerged as a therapeutic tool in some diseases, such as cancer. Then, we hypothesize that butyrate could improve skeletal muscle regeneration by accelerating satellite cellsdifferentiation into myofibers through epigenetics mechanisms related to cell cycle exit. Objectives: To assess whether butyrate could improve skeletal muscle regeneration after barium chloride damage and its epigenetics mechanisms. Methods: Twenty C57Bl/6 male mice (CEUA: 133/2014), with 8 weeks of age, were grouped as follows: (1) control group with no injury + saline (C-Sal); (2) control group with no injury + butyrate (CBut); (3) injury with saline (I-Sal);and (4) injury + butyrate (I-But). The muscle injury was performed with the injection of 50 μL of barium chloride (1.2%) in both tibialis anterior and the muscles were harvested six and twelve days after injury for histological and molecular analyses. Butyrate were injected intraperitoneally (400 mg/kg) for 6 days. For in vitro assays, primary satellite cells were isolated and cultured as myoblasts. Myoblasts were treated with 300 μM of butyrate during proliferation and differentiation conditions in order to assess cell cycle molecules, differentiation index, and epigenetics mechanisms. The significance was assumed when P < 0.05. Results: Skeletal muscle regeneration, assessed by cross-sectional area of tibialis anterior muscle, was higher in I-But than I-Sal group (P < 0.05). Histogram analysis also showed higher frequency of smaller fibers in I-Sal than I-But group (P < 0.05). In vitro analyses showed a reduction in the myoblasts proliferation when treated with butyrate (P < 0.05). Also, butyrate treatment downregulated genes related to cell cycle activation (cdk1, cdk2, cdk4), and up-regulated genes related to cell cycle repression (p57) (P < 0.05). The myotubes differentiation, assessed by fusion index, were higher in myoblasts treated with butyrate (P < 0.05), which was followed by an upregulation of the myogenic marker of differentiation, myogenin (P < 0.05). Moreover, butyrate was able to decrease histone deacetylase (P < 0.05) and increase histone acetyltransferase enzymatic activities (P < 0.05). Conclusion and discussion: Butyrate increased skeletal muscle regeneration in mice by accelerating the myotubes differentiation through induction of cell cycle arrest in myoblasts. Preliminary data suggested that this improvement was epigenetically mediated

Microbial-Based Therapies in the Treatment of Inflammatory Bowel Disease – An Overview of Human Studies

Inflammatory bowel disease (IBD) is a group of multifactorial and inflammatory infirmities comprised of two main entities: Ulcerative colitis (UC) and Crohn’s disease (CD). Classic strategies to treat IBD are focused on decreasing inflammation besides inducing and extending disease remission. However, these approaches have several limitations such as low responsiveness, excessive immunosuppression, and refractoriness. Despite the multifactorial causality of IBD, immune disturbances and intestinal dysbiosis have been suggested as the central players in disease pathogenesis. Hence, therapies aiming at modulating intestinal microbial composition may represent a promising strategy in IBD control. Fecal microbiota transplantation (FMT) and probiotics have been explored as promising candidates to reestablish microbial balance in several immune-mediated diseases such as IBD. These microbial-based therapies have demonstrated the ability to reduce both the dysbiotic environment and production of inflammatory mediators, thus inducing remission, especially in UC. Despite these promising results, there is still no consensus on the relevance of such treatments in IBD as a potential clinical strategy. Thus, this review aims to critically review and describe the use of FMT and probiotics to treat patients with IBD

Iohexol Clearance for Determination of Glomerular Filtration Rate in Rats Induced to Acute Renal Failure

IntroductionThe glomerular filtration rate (GFR) is considered an especially important tool for the measurement of renal function. Inulin clearance (InCl) is the classic reference method for this purpose, although it is associated with a number of disadvantages; thus, other markers have been proposed, including iohexol. Determination of iohexol clearance (IoCl) has been established for clinical use; however, its application as a GFR marker in experimental rat models has not been reported.ObjectivesThis study aims to standardize a methodology for the measurement of iohexol clearance and to evaluate its applicability as a marker of GFR in rats with induced toxic acute renal failure (ARF), using InCl as the gold standard.Materials and MethodsTwenty-six Wistar male rats (200-300 g) were divided into the following two groups: a control group (n=7) and an ARF group (n=19). ARF was induced by the subcutaneous administration of cisplatin (5 mg/kg); IoCl and InCl were determined simultaneously, and plasma creatinine (pCreat) dosage was measured colorimetrically.ResultsThe pCreat, InCl and IoCl levels were consistent with the expected values for the renal function ranges of the evaluated animals, and the IoCl and InCl levels were significantly correlated (r=0.792). An inverse moderate linear correlation between the IoCl and pCreat measurements (r=-0.587) and between the InCl and pCreat measurements (r=-0.722) were observed.ConclusionThese results confirm a correlation between IoCl and the gold standard of GFR, InCl measurement. IoCl offers a relevant advantage over InCl because determination of the former allows the animal to live after the procedure.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo, Dept Med, Div Nephrol, São Paulo, SP, BrazilUniv São Paulo, Inst Biomed Sci, Dept Immunol, São Paulo, SP, BrazilUniv São Paulo, Sch Med, Dept Nephrol, São Paulo, SP, BrazilUniversidade Federal de São Paulo, Dept Med, Div Nephrol, São Paulo, SP, BrazilWeb of Scienc

Synergistic effect of mycophenolate mofetil and angiotensin-converting enzyme inhibitor in patients with chronic allograft nephropathy

Experimental data and few clinical non-randomized studies have shown that inhibition of the renin-angiotensin system by angiotensin-converting enzyme (ACE) associated or not with the use of mycophenolate mofetil (MMF) could delay or even halt the progression of chronic allograft nephropathy (CAN). In this retrospective historical study, we investigated whether ACE inhibition (ACEI) associated or not with the use of MMF has the same effect in humans as in experimental studies and what factors are associated with a clinical response. A total of 160 transplant patients with biopsy-proven CAN were enrolled. Eighty-one of them were on ACE therapy (G1) and 80 on ACEI_free therapy (G2). Patients were further stratified for the use of MMF. G1 patients showed a marked decrease in proteinuria and stabilized serum creatinine with time. Five-year graft survival after CAN diagnosis was more frequent in G1 (86.9 vs 67.7%; P < 0.05). In patients on ACEI-free therapy, the use of MMF was associated with better graft survival. The use of ACEI therapy protected 79% of the patients against graft loss (OR = 0.079, 95%CI = 0.015-0.426; P = 0.003). ACEI and MMF or the use of MMF alone after CAN diagnosis conferred protection against graft loss. This finding is well correlated with experimental studies in which ACEI and MMF interrupt the progression of chronic allograft dysfunction and injury. The use of ACEI alone or in combination with MMF significantly reduced proteinuria and stabilized serum creatinine, consequently improving renal allograft survival.Universidade Federal de São Paulo (UNIFESP) Hospital do Rim e Hipertensão Disciplina de NefrologiaUniversidade Federal de São Paulo (UNIFESP) Departamento de PatologiaUniversidade de São Paulo Instituto de Ciências Biomédicas IV Departamento de ImunologiaUNIFESP, Hospital do Rim e Hipertensão Disciplina de NefrologiaUNIFESP, Depto. de PatologiaSciEL

A relação entre duas síndromes pró-inflamatórias da atualidade: sepse e obesidade

Several studies shows that patients with obesity have more chance to develop sepsis, moreover they possess a higher risk of mortality. Sepsis, which is a systemic infection, that culminates in modulation of cell activation and secretion of pro-inflammatory cytokines. In addition, obesity, now acknowledged as a metabolic syndrome, described as pro-inflammatory as well. This review aims to clarify and point out the relations between two disturbing syndromes of modern times.Estudos mostram que pacientes obesos têm maior chance de serem acometidos pela sepse, além de possuírem maiores riscos de mortalidade. A sepse, sendo uma infecção sistêmica que culmina na modulação da ativação de células e secreção de citocinas pró-inflamatórias e a obesidade, reconhecida como síndrome metabólica caracterizada, também, como pró-inflamatória. Esta revisão tem o objetivo de esclarecer e apontar relações entre duas síndromes dos tempos modernos

In search of mechanisms associated with mesenchymal stem cell-based therapies for acute kidney injury

Acute kidney injury (AKI) is classically described as a rapid loss of kidney function. AKI affects more than 15% of all hospital admissions and is associated with elevated mortality rates. Although many advances have occurred, intermittent or continuous renal replacement therapies are still considered the best options for reversing mild and severe AKI syndrome. For this reason, it is essential that innovative and effective therapies, without side effects and complications, be developed to treat AKI and the end-stages of renal disease. Mesenchymal stem cell (MSC) based therapies have numerous advantages in helping to repair inflamed and damaged tissues and are being considered as a new alternative for treating kidney injuries. Numerous experimental models have shown that MSCs can act via differentiation-independent mechanisms to help renal recovery. Essentially, MSCs can secrete a pool of cytokines, growth factors and chemokines, express enzymes, interact via cell-to-cell contacts and release bioagents such as microvesicles to orchestrate renal protection. In this review, we propose seven distinct properties of MSCs which explain how renoprotection may be conferred: 1) anti-inflammatory; 2) pro-angiogenic; 3) stimulation of endogenous progenitor cells; 4) anti-apoptotic; 5) anti-fibrotic; 6) anti-oxidant; and 7) promotion of cellular reprogramming. In this context, these mechanisms, either individually or synergically, could induce renal protection and functional recovery. This review summarises the most important effects and benefits associated with MSC-based therapies in experimental renal disease models and attempts to clarify the mechanisms behind the MSC-related renoprotection. MSCs may prove to be an effective, innovative and affordable treatment for moderate and severe AKI. However, more studies need to be performed to provide a more comprehensive global understanding of MSC-related therapies and to ensure their safety for future clinical applications

Glomerular damage as a predictor of renal allograft loss

Interstitial fibrosis and tubular atrophy (IF/TA) are the most common cause of renal graft failure. Chronic transplant glomerulopathy (CTG) is present in approximately 1.5-3.0% of all renal grafts. We retrospectively studied the contribution of CTG and recurrent post-transplant glomerulopathies (RGN) to graft loss. We analyzed 123 patients with chronic renal allograft dysfunction and divided them into three groups: CTG (N = 37), RGN (N = 21), and IF/TA (N = 65). Demographic data were analyzed and the variables related to graft function identified by statistical methods. CTG had a significantly lower allograft survival than IF/TA. In a multivariate analysis, protective factors for allograft outcomes were: use of angiotensin-converting enzyme inhibitor (ACEI; hazard ratio (HR) = 0.12, P = 0.001), mycophenolate mofetil (MMF; HR = 0.17, P = 0.026), hepatitis C virus (HR = 7.29, P = 0.003), delayed graft function (HR = 5.32, P = 0.016), serum creatinine ≥1.5 mg/dL at the 1st year post-transplant (HR = 0.20, P = 0.011), and proteinuria ≥0.5 g/24 h at the 1st year post-transplant (HR = 0.14, P = 0.004). The presence of glomerular damage is a risk factor for allograft loss (HR = 4.55, P = 0.015). The presence of some degree of chronic glomerular damage in addition to the diagnosis of IF/TA was the most important risk factor associated with allograft loss since it could indicate chronic active antibody-mediated rejection. ACEI and MMF were associated with better outcomes, indicating that they might improve graft survival.Universidade Federal de São Paulo (UNIFESP) Departamento de Medicina Disciplina de NefrologiaHospital Universitario Central de Asturias Servicio de NefrologíaFundación Renal Iñigo Alvarez de Toledo Y Fundación Carolina-BBVAUniversidade de São Paulo Instituto de Ciências Biomédicas IV Departamento de ImunologiaUniversidade Federal de São Paulo (UNIFESP) Departamento de PatologiaUNIFESP, Depto. de Medicina Disciplina de NefrologiaUNIFESP, Depto. de PatologiaSciEL