859 resultados para Transplanted kidney
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Reactive oxygen species are generated during ischaemia-reperfusion of tissue. Oxidation of thymidine by hydroxyl radicals (HO) leads to the formation of 5,6-dihydroxy-5,6-dihydrothymidine (thymidine glycol). Thymidine glycol is excreted in urine and can be used as biomarker of oxidative DNA damage. Time dependent changes in urinary excretion rates of thymidine glycol were determined in six patients after kidney transplantation and in six healthy controls. A new analytical method was developed involving affinity chromatography and subsequent reverse-phase high-performance liquid chromatography (RP-HPLC) with a post-column chemical reaction detector and endpoint fluorescence detection. The detection limit of this fluorimetric assay was 1.6 ng thymidine glycol per ml urine, which corresponds to about half of the physiological excretion level in healthy control persons. After kidney transplantation the urinary excretion rate of thymidine glycol increased gradually reaching a maximum around 48 h. The excretion rate remained elevated until the end of the observation period of 10 days. Severe proteinuria with an excretion rate of up to 7.2 g of total protein per mmol creatinine was also observed immediately after transplantation and declined within the first 24 h of allograft function (0.35 + 0.26 g/mmol creatinine). The protein excretion pattern, based on separation of urinary proteins on sodium dodecyl sulphate-polyacrylamide gel electrophorosis (SDS-PAGE), as well as excretion of individual biomarker proteins, indicated nonselective glomerular and tubular damage. The increased excretion of thymidine glycol after kidney transplantation may be explained by ischaemia-reperfusion induced oxidative DNA damage of the transplanted kidney.
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Purpose To determine whether diffusion-weighted (DW) magnetic resonance (MR) imaging in living renal allograft donation allows monitoring of potential changes in the nontransplanted remaining kidney of the donor because of unilateral nephrectomy and changes in the transplanted kidney before and after transplantation in donor and recipient, respectively, and whether DW MR parameters are correlated in the same kidney before and after transplantation. Materials and Methods The study protocol was approved by the local ethics committee; written informed consent was obtained. Thirteen healthy kidney donors and their corresponding recipients prospectively underwent DW MR imaging (multiple b values) in donors before donation and in donors and recipients at day 8 and months 3 and 12 after donation. Total apparent diffusion coefficient (ADCT) values were determined; contribution of microcirculation was quantified in perfusion fraction (FP). Longitudinal changes of diffusion parameters were compared (repeated-measures one-way analysis of variance with post hoc pairwise comparisons). Correlations were tested (linear regression). Results ADCT values in nontransplanted kidney of donors increased from a preexplantation value of (188 ± 9 [standard deviation]) to (202 ± 11) × 10(-5) mm(2)/sec in medulla and from (199 ± 11) to (210 ± 13) × 10(-5) mm(2)/sec in cortex 1 week after donation (P < .004). Medullary, but not cortical, ADCT values stayed increased up to 1 year. ADCT values in allografts in recipients were stable. Compared with values obtained before transplantation in donors, the corticomedullary difference was reduced in allografts (P < .03). Cortical ADCT values correlated with estimated glomerular filtration rate in recipients (R = 0.56, P < .001) but not donors. Cortical ADCT values in the same kidney before transplantation in donors correlated with those in recipients on day 8 after transplantation (R = 0.77, P = .006). FP did not show significant changes. Conclusion DW MR imaging depicts early adaptations in the remaining nontransplanted kidney of donors after nephrectomy. All diffusion parameters remained constant in allograft recipients after transplantation. This method has potential monitoring utility, although assessment of clinical relevance is needed. © RSNA, 2013 Online supplemental material is available for this article.
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Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal
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Despite Candida species are often human commensals isolated from various oral sites such as: tongue, cheek and palatal mucosa plus subgingival region, there are some properties linked to the organism commonly known as virulence factors which confer them the ability to produce disease. Oral candidiasis is one of the main oral manifestations reported in literature related to kidney transplant patients. The objectives of the present study were to identify and investigate virulence factors of yeasts isolated from the oral cavity of kidney transplant recipients admitted at the Hospital Universitário Onofre Lopes, in Natal RN. Seventy Candida species isolated from 111 kidney transplant recipients were investigated in this study. Identification of the isolates was performed by using the evidence of germ tube formation, hypertonic broth, tolerance to grow at 42°C, micromorphology and biochemical profiles. We observed a high rate of isolation of yeasts from the oral cavity of kidney transplant recipients (63.1%) being C. albicans was the most prevalent species. Oral candidiasis was diagnosed in 14.4% of transplant recipients. We evaluated virulence properties of the isolates regarding to: biofilm formation on polystyrene microplates as well as XTT reduction, adherence to acrylic resin and human buccal epithelial cells and proteinase activity. Most isolates were able to form biofilm by the method of adhesion to polystyrene. All isolates of Candida spp. remained viable during biofilm formation when analyzed by the method of XTT reduction. The number of CFU attached to the acrylic resin suggested high adherence for C. parapsilosis. C. albicans isolates showed higher median adherence to human buccal epithelial cells than non-C. albicans Candida isolates. Nevertheless, this difference was not statistically significant. C. dubliniensis showed low ability to adhere to plastic and epithelial cells and biofilm formation. Proteolytic activity was observed for all the isolates investigated, including the unique isolate of C. dubliniensis. There was a statistically significant association between proteinase production and the presence of oral candidiasis. Studies related to oral candidiasis in renal transplant recipients are limited to clinical and epidemiological data, but investigations concerning Candida spp. virulence factor for this group of individuals are still scarce. We emphasize the importance of studies related to virulence factors of yeasts isolated from this population to contribute to the knowledge of microbiological aspects of oral candidiasis
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PURPOSE: Chronic renal insufficiency (CRI) is the last stage of a chronic renal condition in which the kidney loses its filtration and endocrine functions. Chronic endocrine hypofunction causes generalized damage to the body known as Uremic Syndrome, which affects the central nervous system as well as the cardiovascular, hematologic, dermatologic, ophthalmic, endocrine, respiratory, gastrointestinal and skeletal systems. The present study reports the case of a female patient with CRI who presented facial osteodystrophy of the osteitis fibrosa type, and highlights the main features of this condition. CASE DESCRIPTION: A 24-year old, female, Caucasian patient presented chronic glomerulonephritis recurrence and lost the transplanted kidney five years before, undergoing arteriovenous fistula hemodialysis three times a week. She presented swelling of the left masseter area with a hard consistency on palpation, covered by intact skin, swelling at the bottom of the left atrium, with a hard consistency on palpation, a mucosa-like color and absence of inflammation signs, suggesting expansive bone lesions on the face. These features were compatible with hyperparathyroidism brown tumor and/or osteodystrophy. The CT scan showed expansive bone lesions of heterogeneous appearance on the left jaw, maxilla/nasal floor, and right frontotemporal suture areas. The clinical and histopathological characteristics of the lesion, in association with PHT hormone high serum levels led to renal osteodystrophy diagnosis. The patient was referred to the nephrology services. CONCLUSION: Osteodystrophic bone alterations have a high prevalence in renal disease patients, and the dentist must take these alterations into consideration in bone lesion diagnosis for this specific group of patients.
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Kidney transplantation is the best treatment option for the restoration of excretory and endocrine kidney function in patients with end-stage renal disease. The success of the transplant is linked to the genetic compatibility between donor and recipient, and upon progress in surgery and immunosuppressive therapy. Numerous studies have established the importance of innate immunity in transplantation tolerance, in particular natural killer (NK) cells represent a population of cells involved in defense against infectious agents and tumor cells. NK cells express on their surface the Killer-cell Immunoglobulin-like Receptors (KIR) which, by recognizing and binding to MHC class I antigens, prevent the killing of autologous cells. In solid organ transplantation context, and in particular the kidney, recent studies show some correlation between the incompatibility KIR / HLA and outcome of transplantation so as to represent an interesting perspective, especially as regards setting of immunosuppressive therapy. The purpose of this study was therefore to assess whether the incompatibility between recipient KIR receptors and HLA class I ligands of the donor could be a useful predictor in order to improve the survival of the transplanted kidney and also to select patients who might benefit of a reduced regimen. One hundred and thirteen renal transplant patients from 1999 to 2005 were enrolled. Genomic DNA was extracted for each of them and their donors and genotyping of HLA A, B, C and 14 KIR genes was carried out. Data analysis was conducted on two case-control studies: one aimed at assessing the outcome of acute rejection and the other to assess the long term transplant outcome. The results showed that two genes, KIR2DS1 and KIR3DS1, are associated with the development of acute rejection (p = 0.02 and p = 0.05, respectively). The presence of the KIR2DS3 gene is associated with a better performance of serum creatinine and glomerular filtration rate (MDRD) over time (4 and 5 years after transplantation, p <0.05), while in the presence of ligand, the serum creatinine and MDRD trend seems to get worse in the long term. The analysis performed on the population, according to whether there was deterioration of renal function or not in the long term, showed that the absence of the KIR2DL1 gene is strongly associated with an increase of 20% of the creatinine value at 5 years, with a relative risk to having a greater creatinine level than the median 5-year equal to 2.7 95% (95% CI: 1.7788 - 2.6631). Finally, the presence of a kidney resulting negative for HLA-A3 / A11, compared to a positive result, in patients with KIR3DL2, showed a relative risk of having a serum creatinine above the median at 5 years after transplantation of 0.6609 (95% CI: 0.4529 -0.9643), suggesting a protective effect given to the absence of this ligand.
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Simkania negevensis is a bacterium belonging to the order Chlamydiales but with certain biological characteristics different from those of chlamydia, according to which it was classified in the family Simkaniaceae. It is widespread in the environment, due to its ability to survive in amoebae also in phase cystic, for which it was hypothesized a possible transmission after contact with water in which they are present amoebae. So far it is known its role in diseases of the lower respiratory tract, such as childhood bronchiolitis and pneumonia in adults of the community, following its transmission through infected aerosols. A recent American study showed, by PCR, a high prevalence of S. negevensis in patients with lung transplant than other transplant recipients, assuming an association between the presence of the bacterium in these patients, and transplant rejection, were more frequent in lung transplant recipients infected compared to uninfected. There are no data so far analyzed in Italy relative to the population of dialysis and kidney transplant recipients relative to simkania negevensis why this study was undertaken in order to start a specific location and evaluate the scientific implications. Because its ability to assume persistent forms of infection, which may lead to a prolonged inflammatory response, Simkania negevensis, similar to other persistent bacteria or viruses, may be ivolved in pathologic complication. Sn may be a factor in graft rejection in mmunesuppressed lung transplant recipients, and further studies are planned to explore the posible association of Sn infections with various in vivo pathologies.
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BACKGROUND: Simultaneous pancreas/kidney transplantation (SPK) should be the procedure of choice for (pre)uremic patients with type 1 diabetes. All standard immunosuppressive protocols for SPK include a calcineurin-inhibitor. Both calcineurin inhibitors, cyclosporine (CyA) and probably tacrolimus (FK506) too, are associated with the occurrence of cholelithiasis due to their metabolic side effects. PATIENTS AND METHODS: We evaluated the prevalence of cholelithiasis in 83 kidney/pancreas transplanted type I-diabetic patients (46 males, 37 females, mean age 42.8 +/- 7.5 years) by conventional B-mode ultrasound 5 years after transplantation. 56 patients received CyA (group 1) and 27 received tacrolimus (group 2) as first-line-immunosuppressive drug. Additional immunosuppression consisted of steroids, azathioprine or mycophenolate mofetil. Additionally, laboratory analyses of cholestasis parameters (gamma-GT and alcalic phosphatasis) were performed. RESULTS: In total, 23 patients (28%) revealed gallstones and 52 patients (62%) revealed a completely normal gallbladder. In eight patients (10%) a cholecystectomy was performed before or during transplantation because of already known gallstones. No concrements in the biliary ducts (choledocholithiasis) could be detected. In group 2 the number of patients with gallstones was slightly lower (22%) compared with group 1 patients (30%), but without statistical significance. - Cholestasis parameters were not increased and HbA1c values were normal in both groups of patients. CONCLUSION: The prevalence of biliary disease in kidney/pancreas transplanted type I-diabetic patients with 28% is increased in comparison to the general population (10-15%). Lithogenicity under tacrolimus seems to be lower as under cyclosporine based immunosuppressive drug treatment. We recommend regular sonographical examinations to detect an acute or chronic cholecystis as early as possible, which may develop occultly in these patients.
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Caveolae are plasma membrane structures formed from a complex of the proteins caveolin-1 and caveolin-2. Caveolae interact with pro-inflammatory cytokines and are dysregulated in fibrotic disease. Although caveolae are present infrequently in healthy kidneys, they are abundant during kidney injury. An association has been identified between a CAV1 gene variant and long term kidney transplant survival. Chronic, gradual decline in transplant function is a persistent problem in kidney transplantation. The aetiology of this is diverse but fibrosis within the transplanted organ is the common end point. This study is the first to investigate the association of CAV2 gene variants with kidney transplant outcomes. Genomic DNA from donors and recipients of 575 kidney transplants performed in Belfast was investigated for common variation in CAV2 using a tag SNP approach. The CAV2 SNP rs13221869 was nominally significant for kidney transplant failure. Validation was sought in an independent group of kidney transplant donors and recipients from Dublin, Ireland using a second genotyping technology. Due to the unexpected absence of rs13221869 from this cohort, the CAV2 gene was resequenced. One novel SNP and a novel insertion/deletion in CAV2 were identified; rs13221869 is located in a repetitive region and was not a true variant in resequenced populations. CAV2 is a plausible candidate gene for association with kidney transplant outcomes given its proximity to CAV1 and its role in attenuating fibrosis. This study does not support an association between CAV2 variation and kidney transplant survival. Further analysis of CAV2 should be undertaken with an awareness of the sequence complexities and genetic variants highlighted by this study.
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Kidney transplantation is one of the most common transplantation operations in the world, accounting for up to 50 % of all transplantation surgeries. To curtail the damage to transplanted organs that is caused by ischemia-reperfusion injury and the recipient's immune system, small interfering RNA (siRNA) technology is being explored. Importantly, the kidney as a whole is a preferential site for non-specific systemic delivery of siRNA. To date, most attempts at siRNA-based therapy for transplantation-related conditions have remained at the in vitro stage, with only a few of them being advanced into animal models. Hydrodynamic intravenous injection of naked or carrier-bound siRNAs is currently the most common route for delivery of therapeutic constructs. To our knowledge, no systematic screens for siRNA targets most relevant for kidney transplantation have been attempted so far. A majority of researchers have arrived at one or another target of interest by analyzing current literature that dissects pathological processes taking place in transplanted organs. A majority of the genes that make up the list of 53 siRNA targets that have been tested in transplantation-related models so far belong to either apoptosis- or immune rejection-centered networks. There is an opportunity for therapeutic siRNA combinations that may be delivered within the same delivery vector or injected at the same time and, by targeting more than one pathway, or by hitting the same pathways within two different key points, will augment the effects of each other.
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Introduction: This study prospectively accessed the immune response to the inactivated influenza vaccine in renal transplant recipients receiving either azathioprine or mycophenolate mofetil (MMF). Side effects were investigated. Methods: Sixty-nine patients received one dose of inactivated trivalent influenza vaccine. Antihemagglutinin (HI) antibody response against each strain was measured before and one to six months after vaccination. Results: Geometric mean HI antibody titers for H1N1 and H3N2 strains increased from 2.57 and 2.44 to 13.45 (p = 0.001) and 7.20 (p < 0.001), respectively. Pre- and post-vaccination protection rates for H1N1 and H3N2 increased from 8.7% to 49.3% (p < 0.001); and 36.3% (p < 0.001) and seroconversion rates were 36% and 25.3%, respectively. There was no response to influenza B. The use of MMF reduced the H1N1 and H3N2 protection rates and the seroconversion rate for the H1N1 strain when compared with the use of azathioprine, and subjects transplanted less than 87 months also had inferior antibody response. Adverse events were mild and there were no change on renal function post-vaccination. Conclusion: Renal transplant patients vaccinated against influenza responded with antibody production for in. uenza A virus strains, but not for in. uenza B. Use of MMF and shorter time from transplantation decreased the immune response to the vaccine.
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HLA-G is a non-classic Human Leukocyte Antigen (HLA-G) Class I of low polymorphism and restricted tissue distribution that displays tolerogenic functions. In heart transplantation and in combined liver/renal allograft transplantation, the expression of HLA-G has been associated with a lower incidence of acute graft rejection episodes and absence of chronic dysfunction. Since the expression of HLA-G in renal biopsies has been investigated only in few patients who received a combined kidney and liver transplant, in this study we performed a cross-sectional study, systematically comparing the expression of HLA-G in post-transplanted renal grafts, stratifying patients according to the presence or absence of rejection.Patients and Methods: Seventy-three renal specimens (10 with acute rejection and 13 with chronic allograft nephropathy, and 50 with no signs of rejection) were immunohistochemically evaluated for HLA-G expression.Results: In the group as a whole, HLA-G molecules were detected in 40 cases (54.8%). Among specimens that presented HLA-G expression, 2 out of 40 (5%) exhibited acute rejection, 2 (5%) exhibited chronic allograft nephropathy, and the remaining 36 (90%) exhibited no signs of rejection. The comparison between patients with rejection and those without rejection showed that the expression of HLA-G was significantly increased in specimens exhibiting no signs of rejection (p<0.0001). Considering only patients with acute rejection, 8 out of 10 patients showed no HLA-G expression in their kidney biopsies when compared to patients exhibiting no signs of rejection and absence of HLA-G was observed in 14 out of 50 (p=0.0032). Similarly, considering only patients with chronic allograft nephropathy, absence of HLA-G expression was observed in I I out of 13 specimens, whereas in patients without rejection absence of HLA-G was observed in 14 out of 50 (p=0.003). Therapy with tacrolimus was significantly associated with the expression of HLA-G and a better graft prognosis. Conclusions: Our results suggest that HLA-G expression in the kidney allograft and the use of tacrolimus are associated with a lower frequency of acute renal rejection and chronic allograft nephropathy. (c) 2007 Elsevier B.V. All rights reserved.
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Background. Renal transplantation remains the optimal treatment of patients with end-stage renal disease. Urinary lithiasis represents an unusual urologic complication in renal transplantation, with an incidence of <1%. Today, recipients of kidneys from deceased donors are more likely to receive grafts with undiagnosed lithiasis, which does not occur in patients from living donors, owing to screening with computerized tomography. Objective. The aim of this study was to evaluate the incidence, diagnosis, and therapeutic management of renal lithiasis in transplanted kidneys at a single institution. Methods. We reviewed the medical records for 1,313 patients who underwent kidney transplantation from February 1968 to February 2011. Results. Among the grafts, 17 patients (1.29%) had nephrolithiasis: 9 women and 8 men. Ages ranged from 32 to 63 years (mean = 45.6 years). Fifteen patients received kidneys from cadaveric and only 2 from living related donors. Two stones, both located inside the ureter, were identified during transplant surgery (11.7%). Three instances of lithiasis were incidentally diagnosed by ultrasound during graft evaluation, within 7 days after surgery (17.6%); all 3 were in the calyces. The 12 remaining patients had the stones diagnosed later (70.58%): 6 in the calyces, 3 in the renal pelvis, and 3 inside the ureter. Conclusions. Urinary lithiasis is a rare complication in renal transplantation. In most patients the condition occurs without pain. The diagnosis and treatment options for graft urolithiasis are similar to those patients with nephrofithiasis in the general population. Extracorporeal shock wave lithotripsy (ESWL) was the most common treatment method.
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Applications of diffusion-weighted (DW) magnetic resonance (MR) imaging outside the brain have gained increasing importance in recent years. Owing to technical improvements in MR imaging units and faster sequences, the need for noninvasive imaging without contrast medium administration, mainly in patients with renal insufficiency, can be met successfully by applying this technique. DW MR imaging is quantified by the apparent diffusion coefficient (ADC), which provides information on diffusion and perfusion simultaneously. By using a biexponential fitting process of the DW MR imaging data, these two entities can be separated, because this type of fitting process can serve as an estimate of both the perfusion fraction and the true diffusion coefficient. DW MR imaging can be applied for functional evaluation of the kidneys in patients with acute or chronic renal failure. Impairment of renal function is accompanied by a decreased ADC. Acute ureteral obstruction leads to perfusion and diffusion changes in the affected kidney, and renal artery stenosis results in a decreased ADC. In patients with pyelonephritis, diffuse or focal changes in signal intensity are seen on the high-b-value images, with increased signal intensity corresponding to low signal intensity on the ADC map. The feasibility and reproducibility of DW MR imaging in patients with transplanted kidneys have already been demonstrated, and initial results seem to be promising for the assessment of allograft deterioration. Overall, performance of renal DW MR imaging, presuming that measurements are of high quality, will further boost this modality, particularly for early detection of diffuse renal conditions, as well as more accurate characterization of focal renal lesions.