[Micro RNA-155 expression in hemodialysis PBMC]. / Espressione del micro rna-155 nelle PBMC di pazienti in emodialisi cronica.

INTRODUCTION: MicroRNAs (miR) are fragments of non-coding RNA acting at post-transcriptional level, which modulate gene expression, and play a key role in several pathophysiological pathways. The aim of this study is to analyze the expression of miR-155 in basal Peripheral Blood Mononuclear Cells (PBMC) of chronic hemodialysis (HD) patients, before and after standard 4 -hour sessions, and after PHA stimulation compared with PBMC from healthy subjects. METHODS: miR-155 was isolated from chronic HD patients' PBMC and from PBMC derived from healthy subjects. Expression levels were quantified with Real-Time PCR; PCR reactions were performed using a specific thermocycler and cycle threshold levels were calculated using dedicated software. Blood samples were taken from HD patients after the long inter-dialytic interval. Data were expressed as MSE and statistical differences were calculated with t-test. RESULTS: Relative quantity (RQ) of pre-dialysis MiR-155 was 3.770.62 times higher than the control group (P=0,003). There was no significant difference before and after hemodialysis sessions. Pre-dialysis mir-155 RQ in PHA PBMC was 1.790.59 times higher than non stimulated PBMC (P=0.019). CONCLUSIONS: these preliminary data show a significant miR-155 up-regulation of HD PBMC when compared to PBMC from healthy individuals. An additional up-regulation was observed in HD PHA PBMC. Similar miR-155 expression was found in HD PBMC comparing pre and post-hemodialysis sessions.

Mechanisms underlying sCD40 production in hemodialysis patients.

CD40 and its ligand (CD40L) regulate several cellular functions, including T and B-cell activation. The soluble form of CD40 (sCD40) antagonizes CD40/CD40L interaction. Patients undergoing hemodialysis (HD) present elevated sCD40 serum levels, which underlying molecular mechanisms are unknown. We studied sCD40 serum and urinary levels, CD40 membrane and gene expression and membrane shedding in HD, uremic not-HD patients (UR) and healthy subjects (N). We found that in HD sCD40 serum levels were higher than UR and N, being significantly elevated in anuric patients, and that sCD40 correlated to renal function in UR subjects, who presented also a reduced sCD40 urinary excretion rate. HD and UR presented reduced CD40 membrane and gene expression. The concentration of TNF-α converting enzyme (TACE), responsible for CD40 cleavage was not different between HD and N. Therefore the reduced renal clearance is the main cause of elevated sCD40 levels in HD. This finding could have relevant clinical implications.

Pretransplant and protocol biopsies may help in defining short and mid-term kidney transplant outcome.

Although many variables may affect long-term graft survival no biomarker is available to identify donor kidney with poor quality and with inadequate short and long-term outcome. While in marginal donors pre-transplant renal biopsies are commonly performed to establish if donor kidneys are suitable for transplantation they are not performed in standard donors. In this study we assessed the relevance of pre-transplant morphological features on post-transplant renal function and evaluated the association between perioperative parameters with posttransplant histological and clinical findings. Kidney transplant recipients undergone pre-transplant and post transplant protocol biopsies at 1, 6, and 12 months were enrolled in the study. Perioperative and posttransplant clinical and biochemical parameters were recorded. Semiquantitative analysis of PAS stained kidney sections was used to determine the degree of lesions. Glomerular volume was measured by computed morphometry. A strong inverse correlation was found between donor age and renal graft function at 1, 6, and 12 months after transplantation. A prompt functional recovery was associated with a better renal function at 6 months and one year. Kidneys with higher glomerular volume demonstrated a lower serum creatinine at 1 month. Higher tubulo-interstitial grading at protocol biopsies was associated with a poor renal function at 1 month. Our findings confirm the importance of donor age in kidney transplant long-term outcome and demonstrate that pretransplant and protocol biopsies are valid options to determine graft outcome and to define therapeutic strategies and tailor immunosuppressive regimen for each patient.

Erythema nodosum in kidney transplant recipient: a rare complication of pneumonia treatment.

Erythema nodosum (EN) is a cutaneous inflammatory reaction, usually reported in young women, but it is rarely observed among transplant patients. Localization in the lower extremities is typical, mostly involving the anterior surfaces of the legs. Several viral, bacterial, mycotic, and non-infectious etiologies, such as autommune disorders, drugs, inflammatory bowel diseases, sarcoidosis, pregnancy, and malignancies, have been found. We describe the case of a young woman kidney transplant recipient developing bilateral, erythematous, warm nodules localized on the anterior surface of her legs after antibiotic treatment for pneumonia with levofloxacin. Her immunosuppression was sirolimus and mycophenolate mofetil. EN was diagnosed by skin biopsy; microscopic examination showed septal panniculitis with granulomas. As a complete remission of the lesions was obtained in our patient after interruption of levofloxacin therapy, we suspect that levofloxacin was involved in the pathogenesis of EN. In fact, the management of EN is based on the treatment of underlying or associated conditions.

Sirolimus prevents short-term renal changes induced by ischemia-reperfusion injury in rats.

BACKGROUND: Ischemia-reperfusion (I/R) is present at various degrees in kidney transplants. I/R plays a major role in early function and long-term survival of renal allograft. The purpose of our study was to determine if immunosuppressants modulate I/R in a model that separates I/R from all immune responses. METHODS: Sprague-Dawley rats with monolateral renal I/R received daily cyclosporine (A), tacrolimus (B), sirolimus (C) or saline (D). Sham-operated rats received saline (E). After 30 days, glomerular filtration rate for each kidney was measured by inulin clearance. Kidney injury was examined, and TGF-ß, fibronectin and metalloproteases were evaluated by real-time PCR, Western blot and zymography. RESULTS: Sirolimus, but not cyclosporine and tacrolimus, prevented a glomerular filtration rate decrease in I/R kidneys (403 ± 303 vs. 1,006 ± 484 µl/min, p < 0.05; 126 ± 170 vs. 567 ± 374 µl/min, p < 0.05; 633 ± 293 vs. 786 ± 255; A, B and C group, respectively, I/R vs. contralateral kidneys). Sirolimus reduced ED-1+ cell infiltrate, interstitial fibrosis and intimal thickening of small vessels observed in I/R kidneys of controls and calcineurin inhibitor-treated rats. Tacrolimus and cyclosporine increased fibronectin and TGF-ß expression and matrix deposition. Only sirolimus increased metalloprotease activity. CONCLUSIONS: Sirolimus but not calcineurin inhibitors prevented I/R-induced kidney injury.

Robotic-assisted laparoscopic donor nephrectomy with transvaginal extraction of the kidney.

Transvaginal recovery of the kidney has recently been reported, in a donor who had previously undergone a hysterectomy, as a less-invasive approach to perform laparoscopic live-donor nephrectomy. Also, robotic-assisted laparoscopic kidney donation was suggested to enhance the surgeon's skills during renal dissection and to facilitate, in a different setting, the closure of the vaginal wall after a colpotomy. We report here the technique used for the first case of robotic-assisted laparoscopic live-donor nephrectomy with transvaginal extraction of the graft in a patient with the uterus in place. The procedure was carried out by a multidisciplinary team, including a gynecologist. Total operative time was 215 min with a robotic time of 95 min. Warm ischemia time was 3 min and 15 s. The kidney was pre-entrapped in a bag and extracted transvaginally. There was no intra- or postoperative complication. No infection was seen in the donor or in the recipient. The donor did not require postoperative analgesia and was discharged from the hospital 24 h after surgery. Our initial experience with the combination of robotic surgery and transvaginal extraction of the donated kidney appears to open a new opportunity to further minimize the trauma to selected donors.

The epidemic of chronic kidney disease: looking at ageing and cardiovascular disease through kidney-shaped lenses.

In recent years, a 'silent' chronic kidney disease (CKD) epidemic has been proposed by many authors. The 'outbreak' is because of the inclusion of a large proportion of the elderly population within stage 3 CKD according to the Kidney Disease Outcomes Quality Initiative staging system. Unfortunately, this does not take into account the fact that renal function normally declines with age; in addition, the Modification of Diet in Renal Disease formula used to calculate glomerular filtration rate underestimates renal function in the elderly. Because population preventive strategies need a precise definition of the target for screening, a more accurate tool to detect CKD in the general population is required. Considerable interest in CKD has been generated by the evidence that predialysis CKD is associated with increased risk of cardiovascular disease (CVD). Such an association per se does not imply that CKD is a causal determinant of CVD. As CKD has been detected particularly in elderly individuals, it is tempting to speculate that an association may exist between age and cardiovascular outcomes in patients with CKD. Furthermore, the definition of CKD is a nosographic simplification that includes diseases with different causes and pathogenetic mechanisms. The aetiologies of renal diseases can affect cardiovascular outcomes, and the two major causes of end-stage renal disease, diabetes mellitus and hypertension, indeed do so. These findings point to a need for a better definition of CKD to optimize the allocation of healthcare resources and to clarify the nature of the association between CKD and CVD.

Mesenchymal stem cells infusion prevents acute cellular rejection in rat kidney transplantation.

Mesenchymal stem cells (MSC) are multipotent cells that differentiate into various mature cell lineages. MSC show immunomodulatory effects by inhibiting T-cell proliferation. We evaluated the effect of the infusion of MSC in rats experimental kidney transplantation. Sprague-Dawley transgenic rats (SD) able to express the green fluorescent protein (EGFP) were used as MSC donors. Syngeneic (Lewis to Lewis, n = 10) and allogeneic (Fischer to Lewis, n = 10) kidney transplantations were performed after bilateral nephrectomy. Five transplanted rats who received syngeneic grafts, were treated with 3 x 10(6) MSC (Gr B), while the other 5 did not received MSC (Gr A). Five rats with allogenic grafts received 3 x 10(6) MSC (Gr C) and another 5 did not receive MSC (Gr D). The MSC were infused directly into the renal artery of the graft. No immunosuppressive therapy was provided. The animals were killed after 7 days. Biochemical analysis for renal function, histological (Banff criteria) and immunohistological analysis (ED1+ and CD8+) were performed on treated animals. MSC improved kidney function in Gr B and D vs Gr A and C. The tubular damage appeared to be less severe among Gr B and Gr D with respect to Gr A and C (P < .01). Vasculitis was more accentuated in Gr A and C (P < .01). MSCs reduced the inflammatory infiltrate; in Gr B and D, the number of ED1+ cells was lower than in Gr A and C (P < .005), which was also observed for CD8+ cells (P < .05). Our study demonstrated that the infusion of MSC attenuated histological damage from acute rejection by reducing the cellular infiltration.

Which is the most suitable and effective route of administration for mesenchymal stem cell-based immunomodulation therapy in experimental kidney transplantation: endovenous or arterial?

Immunomodulating cell therapy represents a new perspective for the control of cellular immune responses that determine the occurrence of acute rejection (ACR) in allo-transplantation. Mesenchymal stem cells (MSC) demonstrate immunoregulatory effects by inactivating T-cell components that regulate tissue damage in transplantation models. The presumed mechanism of action is recruitment of cells by a cytokine network. The purpose of this study was to test which route of administration (intra-arterial vs intravenous) was the most effective route to achieve immunomodulating effects in experimental rat kidney transplantation. Transgenic Sprague-Dawley rats (SD) expressing the enhanced green fluorescent protein (EGFP) at the somatic level were used as MSC donors: Allogeneic Fischer to Lewis grafts (n = 4 per group) were performed in rats after bilateral nephrectomy. In Gr B, 3 x 10(6) MSCs were infused into the renal graft artery, whereas in Gr C, they were infused into the tail vein. The untreated Gr A were a control group. No immunosuppressive therapy was administered. The animals were sacrificed at day 7 postoperatively. Biochemical analysis for renal function, histological (Banff criteria) and immunohistological (anti-EGFP-Immunoglobulin) analysis were performed on the transplanted animals. In Gr B, functional recovery was more rapid (creatinine: Gr B vs Gr C, P < .05). The inflammatory infiltrate in the graft was less in Gr B vs Gr C, with preservation of tubules, arteries, and glomeruli (P < .01). Intra-arterial infusion of MSCs was more effective to control ACR.

Effects of sirolimus on human mesangial cells.

Mesangial cell (MC) proliferation and production of extracellular matrix or loss of MC are both central findings in a number of renal proteinuric diseases. However, the role of MC as components of the glomerular filtration barrier and whether MC alterations induce changes in the glomerular filtration barrier leading to proteinuria are still matters of debate. The effects of Sirolimus (SRL) in proteinuric nephropathies is controversial: some papers have indicated a reduction and others, an increase in proteinuria after sirolimus treatment. Considering the pivotal role of MC in the pathogenesis of many chronic nephropathies, we evaluated the effect of SRL on cultured human MC. We treated primary human MC cultures with SRL, or platelet-derived growth factor (PDGF) or SRL + PDGF, or dimethylsulfoxide, the SRL vehicle, as a control. PDGF was used to activate MC. After 48 hours treatment, MC showed a significant growth increase that was significantly reduced by SRL (P < .01). Apoptosis, determined by the TUNEL assay and flow cytometry, was not modified by the treatments at 24 hours. SRL treatment increased significantly the number of alpha-smooth muscle actin-positive cells compared with controls (P < .05). Cells treated with SRL and SRL + PDGF showed significant changes in morphology with increased mean cell surface, perimeter, and maximum diameter (P < .01) but not protein content. Furthermore, MC treated with SRL showed decreased migration through polycarbonate membranes. The changes induced by SRL may help to explain some of the in vivo effects observed in SRL-treated patients.

Toll-like receptor 4 expression is increased in circulating mononuclear cells of patients with immunoglobulin A nephropathy.

We investigated Toll-like receptors (TLR-3, -4 and -7) expression in circulating mononuclear cells of patients with immunoglobulin A nephropathy (IgAN), a disease with debated relationships with mucosal immunity. TLR-4 expression (detected by fluorescence activated cell sorter) and mRNA transcriptional levels (Taqman) were significantly higher in patients with IgAN than in healthy controls (P = 0.00200 and P = 0.0200). TLR-3 and TLR-7 were not modified significantly. In IgAN patients proteinuria was correlated significantly with TLR-4 expression (P = 0.0312). In a group of nephrotic syndromes, TLR-3, -4 and -7 expression was similar to healthy controls. A significant difference in TLR-4 expression and mRNA levels was found between very active IgAN patients (proteinuria > 1 g/1.73 m(2)/day in association with severe microscopic haematuria) and inactive patients (proteinuria < 0.5 g/1.73 m(2)/day, with absent or minimal haematuria). No correlation with levels of aberrantly glycosylated IgA1, age, renal biopsy features or therapy was found. This study shows for the first time an up-regulation of TLR-4 in circulating mononuclear cells of patients with IgAN, particularly in association with proteinuria and heavy microscopic haematuria.

Increased asymmetric dimethylarginine serum levels are associated with acute rejection in kidney transplant recipients.

Asymmetric dimethylarginine (ADMA) has been identified as a marker of endothelial dysfunction and an independent risk factor for cardiovascular events in uremic subjects. This study evaluated ADMA plasma levels in kidney transplant recipients. ADMA levels were serially measured during the first year posttransplantation in 41 recipients treated with cyclosporine regimen (CY), sirolimus (SIR), or low-dose cyclosporine plus everolimus (E). Homocysteine, C reactive protein (CRP), nitric oxide (NO), and standard routine laboratory analyses were determined serially. ADMA significantly increased at 6 months posttransplantation, but was significantly lower among patients on SIR or E. NO was only slightly reduced in patients with increased ADMA levels. Interestingly, ADMA was significantly increased during the first 4 days posttransplantation in patients who experienced acute rejection during the first 6 months after transplantation. The same group of patients demonstrated higher levels of CRP and systolic blood pressure before transplantation. Our results demonstrated that ADMA was increased in patients on CY at 6 months. When increased soon after transplantation ADMA may be associated with episodes of acute rejection in kidney transplant recipients. The presence of elevated systolic blood pressure, as well as CRP and ADMA levels, suggested a role for endothelial dysfunction in the development of acute rejection episodes among deceased donor kidney transplant recipients.

The improvement of ischemia/reperfusion injury by erythropoetin is not mediated through bone marrow cell recruitment in rats.

BACKGROUND: Ischemia/reperfusion (I/R) injury is a major cause of acute renal failure in kidney transplantation; however, the mechanisms of kidney damage and repair are not yet clear. So far no treatment has been effective to prevent I/R injury. In the present study we evaluated the effect of erythropoetin (EPO) in I/R injury in rats. We investigated the role of bone marrow cells (BMC) in kidney repair and the effect of EPO on BMC recruitment. MATERIALS AND METHODS: Female Sprague Dawley rats transplanted with male BMCs underwent I/R injury. In the treatment group rats received 5000 IU of EPO 30 minutes before renal ischemia. At 2 and 4 weeks after I/R, rats were humanely killed and we measured creatinine clearance (glomerular filtration rate [GFR]), proteinuria, and body weight (BW). Renal tissue was harvested for histologic and molecular analysis. Fluorescein in situ hybridization (FISH) and TUNEL were used to determined the presence of male cell chimerism and apoptosis in renal tissue. RESULTS: At 4 weeks after I/R, EPO significantly improved GFR (1.8 +/- 0.2 vs 1.2 +/- 0.14 mL/min; P < .05). No significant differences between EPO and control rats were observed in proteinuria, BW, and hemoglobin levels at 2 and 4 weeks. After death, the kidney showed only minimal tubulointerstitial changes, which were more marked in control rats. FISH analysis demonstrated a low degree of microchimerism, not significantly different between EPO and control rats. Apoptosis decreased between 2 and 4 weeks after I/R, in both EPO and control groups. CONCLUSION: EPO improved GFR and injury at 4 weeks after I/R; however, it did not enhance the recruitment of BMC.

Rapamycin reduces proteinuria and renal damage in the rat remnant kidney model.

Rapamycin is an immunosuppressive drug used to prevent acute allograft rejection in solid organ transplantation. It shows less nephrotoxicity than calcineurin inhibitors. We evaluated the effect of rapamycin in rats undergoing 5/6 nephrectomy, a model of proteinuric and progressive renal failure. Fourteen days after surgery rats were randomized either to receive rapamycin or to remain untreated (control). Rats were humanely killed on day 91; serum creatinine, creatinine clearance, and proteinuria were assessed. Renal sections were stained with periodic acid-Schiff to evaluate glomerular volume (Gv), glomerulosclerosis (GS) and tubulointerstitial damage (TIS); we evaluated GS and TIS by Sirius red staining (SR). Epithelial-to-mesenchymal transition (EMT) was assessed by immunohistochemistry. Rapamycin affected neither serum creatinine nor creatinine clearance; it reduced Gv (controls, 5.9 +/- 3.1 x 10(6); rapamycin, 1.3 +/- 0.7 x 10(6) microm(3)) and proteinuria (control, 349 +/- 146; rapamycin, 56 +/- 27 mg/24 h; P < .05); rapamycin ameliorated GS (control, 78 +/- 7; rapamycin, 36 +/- 7%; P < .05; SR: control, 13.2 +/- 3.5; rapamycin, 3.8 +/- 1.0%; P < .05), and TIS (control, 3.25 +/- 0.5; rapamycin, 1.0 +/- 0.1; P < .05; SR: control, 29 +/- 3; rapamycin, 11 +/- 3%; P < .05). Rapamycin reduced alphaSMA (control, 3.25 +/- 0.5; rapamycin, 1.0 +/- 0.1; P < .05), VIM (control, 3.5 +/- 0.6; rapamycin, 1.0 +/- 1.4; P < .05), and CD68(+) cells infiltration (control, 110 +/- 43; rapamycin, 24 +/- 1 cells; P < .05). Rapamycin slows the progression of renal damage in the rat remnant kidney and may represent a novel approach to the treatment of chronic kidney disease.

[Regulatory T cells in kidney transplant recipients]. / Cellule T-regolatorie nel trapianto di rene.

Immunosuppressive drugs are essential for the prevention of acute transplant rejection but some may not promote long-term tolerance. Tolerance to self-antigens is ensured naturally by several mechanisms; one major mechanism depends on the activity of regulatory T lymphocytes (Treg), particularly CD4+CD25+ T cells. The transcription factor forkhead box protein 3 (Foxp3) has been identified as a molecular marker for Treg cells. The direct effects of immunosuppressive drugs on CD4+CD25+ cells are uncertain. In the clinical setting, basiliximab used in the induction phase of immunosuppression effectively reduced the number of acute rejection episodes. We studied the effects of the most widely used immunosuppressive induction regimens including cyclosporine, mycophenolate mofetil, steroids, and anti-CD25 monoclonal antibody (basiliximab) on the capacity to regulate human Treg in vivo. Twenty first cadaveric kidney transplant recipients (14 men, 6 women) were enrolled in the study. Blood samples were collected before kidney transplant and after one month. Blood sampling was done immediately before the administration of immunosuppressive therapy after an overnight fast. None of the transplant recipients presented laboratory or clinical signs of infection or acute rejection. The number and percentage of CD4+CD25+ and Foxp3+ T cells were determined by fluorescence activated cell sorter (FACS) analysis. Our results showed absence of both CD4+CD25+ and CD4+CD25+ Foxp3+ T cells one month after transplant. Peripheral CD4+CD25-Foxp3+ T cells significantly decreased after transplant but did not disappear. These preliminary data suggest that immunosuppressive induction therapy with basiliximab completely suppresses CD4+CD25+ regulatory cells and significantly reduces the total number of Foxp3+ lymphocytes.