Factors That Influence Delayed Graft Function in Kidney Transplants: A Single-Center Paired Kidney Analysis.

BACKGROUND: The risk factors associated with delayed graft function (DGF) and its impact in kidney transplant (KTx) outcomes remains controversial; it is possible that donor renal characteristics influence the initial graft function in KTx. OBJECTIVE: Evaluate risk factors associated with DGF and its impact in KTx outcomes. METHODS: One hundred six mate KTx mate recipients performed in a single center were grouped according to the presence or absence of DGF. RESULTS: Donors were predominantly men (58%); 70% were standard criteria type, with a mean Kidney Donor Profile Index (KDPI) of 62% ± 28%, median age of 42 ± 15 and presenting hospitalization time of 6 ± 5 days. KTx recipients presented an overall DGF rate of 82%, lasting 12 ± 7 days. Pairs presenting DGF were older than pairs without DGF (P = .008), while cold ischemia time (CIT) was significantly shorter in the group without DGF compared to those presenting DGF (P = .003). The KDPI of the KTx pairs was significantly higher in pairs with DGF versus without DGF (P = .04). No statistically significant differences in 1 year allograft and patient survival were observed. Recipient age (odds ratio = 6.3, confidence interval = 1.5-25.8; P = .009) and CIT (odds ratio = 4.6, confidence interval = 1.2-17.7; P = .002) were significantly associated with DGF. CONCLUSION: This study suggests that recipient age, cold ischemic time, and KDPI are factors associated with DGF. In addition, DGF had no impact on 1-year renal function, allograft, and patient survival. In the transplant conditions of our country, Brazil, CIT seems to represent an important variable to be managed, and the aim should be to reduce this factor as much as possible.

Nonsurgical periodontal therapy combined with laser and photodynamic therapies for periodontal disease in immunosuppressed rats.

BACKGROUND: Periodontal disease is often associated with systemic diseases and is characterized by destruction of the tissues supporting the teeth. Patients using immunosuppressive drugs such as tacrolimus are among those who suffer from tissue destruction. OBJECTIVE: We sought to evaluate the effects of laser and photodynamic therapies (PDT; nonsurgical) as an adjunct to scaling and rootplaning (SRP) in the treatment of corona-induced periodontitis in rats immunosuppressed with tacrolimus (Prograf). MATERIALS AND METHODS: The animals were divided into 5 groups. Each groups had 6 rats. Group I, the control group, received only saline solution throughout the study period of 42 days and did not receive periodontal treatment; group II received saline solution and SRP; group III received tacrolimus (1 mg/kg per day) and was treated with SRP; group IV animals were treated identically to group III and then administered laser treatment; and in group V, the animals were treated identically to group III and then administered PDT. RESULTS: Statistical analysis indicated decreased bone loss with the progression of time (P = .035). There was no difference between the bone loss associated with the types of treatment administered to groups I, II, and III (P > .9) or groups IV and V (P > .6). The analysis also indicated that immunosuppression was not a bone loss-determining factor. CONCLUSION: Laser and PDT therapies were effective as an adjunctive treatment to SRP in reducing bone loss caused by experimental periodontitis induced in animals being treated systemically with tacrolimus.

Dissociation of the effects of MTEP [3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]piperidine] on conditioned reinstatement and reinforcement: comparison between cocaine and a conventional reinforcer.

To advance understanding of the potential of metabotropic glutamate receptor (mGluR) 5 as treatment targets for cocaine addiction, the effects of MTEP [3-[(2-methyl-1,3-thiazol-4-yl) ethynyl]piperidine] (a selective mGluR5 antagonist) on conditioned reinstatement of cocaine seeking were examined. To test whether modification of conditioned reinstatement by MTEP is selective for drug-directed behavior or reflects general actions on motivated behavior, effects of MTEP on reinstatement induced by a stimulus conditioned to palatable conventional reward, sweetened condensed milk (SCM), were also evaluated. Previous data suggest that mGluR manipulations preferentially interfere with conditioned reinstatement compared with cocaine self-administration. Therefore, the effects of MTEP on cocaine self-administration were compared with MTEP's effects on SCM-reinforced behavior using the same cocaine doses and SCM concentrations employed for establishing conditioned reinstatement. Male Wistar rats were trained to associate a discriminative stimulus (S(D)) with response-contingent availability of cocaine or SCM and subjected to reinstatement tests after extinction of cocaine or SCM-reinforced behavior. MTEP (0.3-10 mg/kg i.p.) dose-dependently attenuated the response-reinstating effects of both the cocaine S(D) and SCM S(D). MTEP also decreased cocaine self-administration without a clear graded dose-response profile and did not modify SCM-reinforced responding. The findings implicate mGluR5-regulated glutamate transmission in appetitive behavior controlled by reward-related stimuli but without selectivity for cocaine seeking. However, the data suggest a differential role for mGluR5 in the acute reinforcing effects of cocaine versus conventional reward. These observations identify mGluR5 as potential treatment targets for cocaine relapse prevention, although the profile of action of mGluR5 antagonists remains to be more closely examined for potential anhedonic effects.

Role of glutathione s-transferase polymorphisms and chronic allograft dysfunction.

Polymorphisms within genes encoding glutathione S-transferases (GSTs) may affect responses against damage induced by oxidative stress and therefore play a role to prevent chronic allograft dysfunction (CAD). In the present study, we estimated the frequencies of GSTM1- and GSTT1-null genotypes among 227 renal transplant recipients seeking to establish an association with CAD. Patients persistently displaying serum creatinine (sCr) values < or = 1.5 mg/dL, measured creatinine clearances (CLcr) > or = 50 mL/min/1.73 m(2), and 24-hour proteinuria < or = 500 mg were classified as normal graft function (NF; n = 107). In contrast, the CAD group (n = 120) presented sCr > 1.5 mg/dL, CLcr < 50 mL/min/1.73 m(2), and proteinuria > 500 mg. The GSTM1 and GSTT1 polymorphisms were evaluated by the multiplex polymerase chain reaction. The frequencies of GSTT1-null genotypes in NF and CAD cohorts were 15% and 24.2%, respectively (P = .057), while GSTM1-null genotypes in the same groups of patients were 44% and 46.7% (P = .389). A combination of null genotypes for GSTT1 and GSTM1 was observed in 9.2% of patients with CAD and in 5.6% of those with NF (P = .449). This study did not show an association of either GSTT1- and GSTM1-null genotypes with CAD. It is likely that development and progression of CAD are determined by a combination of complex genetic traits resulting from the interplay of several genes rather than a single gene.

Effect of whole bone marrow cell infusion in the progression of experimental chronic renal failure.

INTRODUCTION: The therapeutic potential of adult stem cells for the treatment of chronic diseases is becoming increasingly evident over the last few years. In the present study, we sought to assess whether the infusion of bone marrow-derived mononuclear cells (MoSCs) and mesenchymal cells (MSCs) could reduce/stabilize the rate of progression of chronic renal failure (CRF) in rats. METHODS: We used the 5/6 renal mass reduction model to induce chronic renal failure in male Wistar rats. Renal function was assessed by measurements of serum creatinine (sCr), creatinine clearance (Clcr), and 24-hour proteinuria at baseline as well as 60 and 120 days after surgery. MoSCs and MSCs obtained from bone marrow aspirates were separated by the Ficoll-Hypaque method. After a 12- to 14-day culture, 1.5 x 10(6) MSCs and the same number of MoSCs were injected into the renal parenchyma of the remanant kidney of rats with CRF on the day of surgery. RESULTS: Among the control group, at day 120, the results were sCr = 1.31 +/- 0.5 mg/dL, Clcr = 0.64 +/- 0.35 mL/min, and proteinuria = 140.0 +/- 57.7 mg/24 h. Rats treated with MoSCs at day 120 had sCr = 0.81 +/- 0.20 mg/dL, Clcr = 1.05 +/- 0.26 mL/min, and proteinuria = 61 +/- 46.5 mg/24 h, while rats injected with MSCs had sCr = 0.95 +/- 0.1 mg/dL, Clcr = 0.68 +/- 0.24 mL/min, and proteinuria = 119.2 +/- 50.0 mg/24 h. Analysis of the progression to CRF showed that the treatment significantly reduced the rate of decline in Clcr after treatment with MoSc: control: -0.0049 +/- 0.0024 mL/min/d versus MSC: - 0.0013 +/- 0.0017 mL/min/d versus MoSC: +0.0002 +/- 0.0016 mL/min/d (P = .017). Proteinuria tended to be lower among the treated groups. Histological scores of chronic damage were not different, but distinct patterns of chronic lesions were observed among treated rats. CONCLUSION: Our results showed that progression of CRF in rats could be slowed/stabilized by intrarenal parenchymal injection of MoSCs. A trend toward reduction in the progression rate of CRF was also observed with injection of MSCs.

Effect of folate, vitamin B6, and vitamin B12 intake and MTHFR C677T polymorphism on homocysteine concentrations of renal transplant recipients.

Plasma hyperhomocysteinemia (HHcy) is considered a risk factor for chronic allograft dysfunction (CAD), the main cause of functional loss in transplant recipients. Genetic polymorphisms that alter enzymes involved in homocysteine (Hcy) metabolism, such as methylenetetrahydrofolate reductase (MTHFR), and vitamin deficiency can result in HHcy. The objectives of this study were to investigate the relationship between HHcy and CAD development, and to evaluate the effect of intake of folate and vitamins B6 and B12 as well as MTHFR C677T polymorphism on Hcy concentrations. Ninety-eight renal transplant recipients including 48 showing CAD and 50 with normal renal function (NRF), were included in this cross-sectional study. Peripheral blood samples were collected for plasma Hcy quantification by liquid chromatography/sequential mass spectrometry (LC-MS/MS), and for MTHFR polymorphism analysis using polymerase chain reaction-restriction fragment length polymorphism. Dietary intake was evaluated using a nutritional questionnaire. HHcy (P=.002) and higher mean concentrations of Hcy (P=.029) were associated with CAD. An association was observed between HHcy and 677T variant allele in the CAD group (P=.0005). There was no correlation between Hcy concentration and folate, vitamin B6 or vitamin B12 intake in the CAD group. However, a negative correlation was observed between Hcy concentration and folate intake (P=.043), and also between Hcy concentration and vitamin B6 intake (P=.030) in the NRF group. According to our study, HHcy is associated with CAD development. In patients with CAD, MTHFR polymorphism seems to have a greater effect on the Hcy concentration than the vitamin intake. Increased folate and vitamin B6 intakes seem to reduce Hcy concentrations among transplant recipients with NRF, and could contribute to reducing the risk of CAD development.

Combination of angiotensin-converting enzyme and methylenetetrahydrofolate reductase gene polymorphisms as determinant risk factors for chronic allograft dysfunction.

OBJECTIVE: The aim of this study was to investigate the frequency of gene angiotensin-converting enzyme insertion/deletion (ACE I/D) and methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) variants, as well as to evaluate the plasma homocysteine concentrations in 217 patients who underwent renal transplantation at least 12 months prior to define risk factors for chronic allograft dysfunction. METHODS: The presence of the polymorphism ACE deletion was assessed by polymerase chain reaction (PCR) analysis. MTHFR polymorphisms were determined by PCR and restriction fragment length polymorphism (RFPL) techniques. The restriction enzymes were Hinf I and Mbo II for MTHFR variants C677T and A1298C, respectively. Plasma homocysteine concentrations were measured by liquid chromatography-tandem mass spectrometry (LS-MS/MS). RESULTS: Hyperhomocysteinemias were more common in patients with chronic allograft dysfunction (P = .004). No statistically significant differences were observed between the allelic and genotypic distributions of MTHFR and ACE polymorphisms. An effective risk factor was found when the polymorphisms of the ACE and MTHFR genes and hyperhomocysteinemia were associated (odds ratio 2.51; 95% confidence interval 1.19-5.28). In conclusion, our study identified that the presence of hyperhomocysteinemia in combination with unfavorable genotypes contributes to an increased risk for development of chronic allograft dysfunction.

Angiotensin-converting enzyme gene polymorphism in chronic allograft nephropathy.

Angiotensin causes an increased activity of hypertrophic and fibrotic processes, which similarly develop in the walls of small vessels of a renal graft during chronic rejection. In this context, the angiotensin-converting enzyme (ACE) gene, associated with increased angiotensin production, has been the subject of studies on renal diseases. The present study evaluated the influence of the ACE gene deletion polymorphism in chronic allograft nephropathy. We evaluated 240 renal transplant recipients including, 119 with normal renal function and 121 with chronic allograft nephropathy. The polymorphism was determined by polymerase chain reaction and genotyping performed after electrophoresis in 1.5% agarose gels stained with ethidium bromide. The frequency of the polymorphic allele was similar in both groups of patients. Furthermore, no significant effect of genotype was observed in chronic allograft nephropathy. Therefore, in this study, we observed no influence of the ACE gene polymorphism in chronic allograft nephropathy.

Hyperhomocysteinemia and MTHFR C677T and A1298C polymorphisms are associated with chronic allograft nephropathy in renal transplant recipients.

Hyperhomocysteine has been reported to be an important risk factor for the development of atherosclerosis. Identification of risk factors, such as hyperhomocysteinemia, is crucial for a better understanding of the events that lead to degenerative processes in the vascular system and for a correct understanding of the potential role of methylene-tetrahydrofolate reductase enzymes (MTHFR) to help in the treatment of vascular disease observed in chronic allograft nephropathy (CAN). In this study we analyzed the plasma homocysteine concentrations and MTHFR C677T and A1298C polymorphism frequencies among 110 renal transplant recipients (53 with CAN and 57 with normal renal function). All recipients had undergone renal transplantation at least 12 months prior to this investigation to establish a possible correlation with the posttransplant outcome. Plasma homocysteine concentrations were measured by liquid chromatography-tandem mass spectrometry and MTHFR polymorphisms were investigated by the PCR-RFLP technique. The results demonstrated that in renal transplant recipients, hyperhomocysteinemia in addition to the presence of the allelic variants for both MTHFR polymorphisms (677T/1298C) might play a role as an additional risk factor for CAN. We understand that analysis of these polymorphisms might have a role in the CAN process. Therefore, studies to evaluate their presence in renal transplant patients may be extremely useful to individualize immunosuppressive protocols to inhibit or retard the progression of CAN.

The Amazonia variant of Vibrio cholerae: molecular identification and study of virulence genes

The pathogenic O1 Amazonia variant of Vibrio cholerae has been shown previously to have a cytotoxin acting on cultured Vero and Y-1 cells, and to lack important virulence factors such as the cholera toxin (Coelho et al. 1995a). This study extends the molecular analysis of the Amazonia strains, detecting the presence to the toxR gene, with a very similar sequence to that of the El Tor and classical biotypes. The outer membrane proteins are analysed, detecting a variation among the group of Amazonia strains, with three different patterns found. As a by-product of this work a polymerase chain reation fragment was sequenced, reading part of the sequence of the Lon protease of the Amazonia strains. The gene was not previously described in V. cholerae, but its sequences is present in the TIGR database specific for this species.