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.

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.

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.

[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.

Influence of methylprednisolone on plasma homocysteine levels in cadaveric renal transplant recipients.

The aim of the present study was to investigate plasma homocysteine levels in renal transplant recipients in the course of steroid-based or steroid-free immunosuppression. Data from 32 patients were retrospectively analyzed according to the steroid immunosuppressive regimen. The 20 recipients on methylprednisolone (MP) plus cyclosporine (CyA) or tacrolimus (TRL) (n = 20) showed similar creatinine levels when compared with those on calcineurin inhibitors plus mycophenolate mofetil (MMF; n = 12), (1.6 +/- 1.5 vs 1.6 +/- 0.4 mg/dL; P = NS) but significantly higher total plasma homocysteine (tHcy) levels (28.5 +/- 12.5 vs 16.3 +/- 5.5 micromol/L; P < .05). No differences of tHcy levels have been observed when patients were analyzed according to CyA- or TRL-based immunosuppression regardless of MP or MMF associations. Our data suggest that recipients, particularly those on steroid-based immunosuppression, should receive homocysteine-lowering treatment early after transplantation.

[Hepatocyte growth factor and kidney]. / Hepatocyte Growth Factor (HGF): ruolo nella embriogenesi e nella fibrosi renale.

HGF is a multifunctional polypeptide with mitogenic, motogenic and morphogenic effects. These effects are mediated by c-met, a specific receptor of HGF and a member of the receptor tyrosine kinase superfamily, virtually expressed in every type of kidney cell. HGF has a central role during embryogenesis since it stimulates epithelial differentiation of metanephric mesenchymal cells and induces branching tubules, as experiments in epithelial cells cultures demonstrated. Several studies have shown also that HGF accelerates the recovery from toxic-ischemic acute renal failure. This effect seems to be mediated by the inhibition of programmed cell death and an increased cell survival. HGF inhibits apoptosis by upregulating the protooncogene Bcl-2 and downregulating Bax. Since HGF can modulate extracellular matrix turnover, authors suggest its beneficial role in tissue remodelling and particularly in chronic renal diseases. Several studies reported a key role for HGF in reducing interstitial fibrosis and glomerular sclerosis, both in in vivo and in vitro models. This protective effect is secondary to HGF antagonizing the profibrotic action of TGF-beta. HGF modulates the balance between synthesis and degradation of extracellular matrix, increasing the expression of metalloproteases and reducing the production of their specific inhibitors TIMPs. Furthermore HGF suppresses the effect of TGF-beta by blocking the axis TGF-beta/Smad. Last, the antifibrotic effect of HGF might be modulated by the proliferative status of target cells. To sum up, the supplementation of exogenous HGF or the induction of endogenous HGF expression may provide an effective therapeutic strategy for combating chronic renal diseases.

A randomized trial of steroid avoidance in renal transplant patients treated with everolimus and cyclosporine.

In this randomized trial renal transplant recipients were treated with basiliximab, everolimus 3 mg/day, low-dose CsA. At transplantation, patients were randomized to stop steroids at the seventh day (group A) or to continue oral steroids in low doses (group B). Of the 113 patients enrolled, 65 were randomized to group A and 68 to group B. All patients were followed for 2 years. During the study 28 (43%) group A patients required reintroduced corticosteroids. One patient died, in group B. The Graft survival rate was 97% in group A and 90% in group B. There were more biopsy-proven rejections in group A (32% vs 16%; P = .044). The mean creatinine clearance was 54 +/- 21 mL/min in group A vs 56 +/- 22 mL/min in group B. Mean levels of serum cholesterol tended to be lower in group A, but the difference was of borderline significance (191 +/- 91 vs 251 +/- 188 mg/dL; P = .07). Vascular thrombosis (0 vs 5) and pneumonia requiring hospitalization (2 vs 7) tended to be more frequent in group B. Only three cases of CMV infection (1 vs 2) occurred. An immunosuppressive therapy with everolimus and low-dose CsA allows one to obtain excellent renal graft survival and stable graft function at 2 years. Early interruption of steroids in patients treated with this regimen may increase the risk of acute rejection, but neither affects graft survival nor graft function, while possibly reducing the risk of hyperlipemia and vascular thrombosis. About 60% of patients given everolimus and low-dose CsA can definitively stop steroids after 1 week.

Polyuric prerenal failure after reduction from high to normal dietary intake of sodium.

In a patient with renal amyloidosis secondary to chronic urinary tract infection with nephrotic syndrome, polyuric acute renal failure developed after reduction from a high to a normal dietary intake of sodium and was reversed by salt replacement therapy. As documented by functional and morphological studies, the patient had a marked defect of tubular sodium reabsorption at the proximal site and along the ascending limb of Henle's loop, a distal tubular unresponsiveness to aldosterone, and severe tubulointerstitial damage in the medulla. We propose that the sodium dietary reduction in conjunction with severe tubular dysfunction and hypovolemia due to nephrotic syndrome is responsible for this unused form of polyuric acute prerenal failure.

Polarization of T-helper lymphocytes toward the Th2 phenotype in uremic patients.

T-helper (Th) lymphocytes consist of Th1 and Th2 subsets. Th1 cells are effectors of cell-mediated immunity and secrete interferon-gamma (IFN-gamma), which recruits new Th1 cells in cooperation with interleukin-12 (IL-12; produced by monocytes) and inhibits Th2 differentiation. Th2 cells produce IL-4 and IL-10, which inhibit IFN-gamma secretion and cell immunity. We investigated whether the impaired immune response in uremia is associated with an altered balance of Th1/Th2. Peripheral-blood mononuclear cells (PBMCs) were collected from patients with chronic renal failure (CRF) on conservative treatment (CRF patients), patients with end-stage renal disease (ESRD) on regular hemodialysis therapy (ESRD-HD patients), and healthy controls (CON). CD4(+) cells were isolated from PBMCs by negative selection using a magnetic labeling system. PBMCs and purified CD4(+) cells were cultured in Iscove's medium and Iscove's medium plus mitogens (phytohemagglutinin and lipopolysaccharide). IFN-gamma, IL-12, IL-4, and IL-10 were measured in supernatant. The constitutive release of IL-4 and IL-10 by PBMCs and CD4(+) cells of CRF and ESRD-HD patients was increased by five to eight times in comparison with CON (P < 0.001). Constitutive IFN-gamma release by PBMCs of ESRD-HD patients was undetectable, although they secreted an increased amount of IL-12. Mitogen-stimulated release of IFN-gamma by PBMCs and CD4(+) cells of CRF and ESRD-HD patients was blunted (average PBMCs: CON, 115.8 pg/2 x10(6) cells; CRF, 81.8 pg/2 x10(6) cells; ESRD-HD, 9.3 pg/2 x10(6) cells; CD4(+) cells: CON, 358.0 pg/5 x 10(5) cells; CRF, 165.4 pg/5 x 10(5) cells; ESRD-HD, 43.5 pg/5 x 10(5) cells). The ability of PBMCs of ESRD-HD patients to secrete IFN-gamma was recovered after IL-4 and IL-10 neutralization. Uremia is associated with a prevalence of Th1 over Th2 cells and a configuration of cytokine network that depresses cell-mediated immunity.

Henoch-Schönlein purpura in a chronic hemodialysis patient.

We describe a patient on maintenance hemodialysis who developed purpura, abdominal pain with bloody stool, and gross hematuria. A skin biopsy revealed leukocytoclastic vasculitis with IgA deposits. This is the first report of Henoch-Schönlein purpura in a hemodialysis patient.

Hyperkalemia-induced ECG abnormalities in patients with reduced renal function.

Hyperkalemia is a potentially lethal condition to be aware of in the presence of ECG abnormalities especially in patients with reduced renal function. However, ECG abnormalities are not always dependent on the degree ofhyperkalemia but may be aggravated by the rapidity of the development of hyperkalemia and by associated electrolyte disorders. We describe 3 patients with renal failure and different ECG changes induced by hyperkalemia. More severe changes were observed when hyperkalemia developed rapidly, but not in presence of electrolyte disorders. Even minor ECG abnormalities must alarm physicians in patients with renal failure since severe hyperkalemia is not always associated with critical ECG changes.

Scleroembolization for treatment of hypertension caused by intrarenal arterial fibrodysplasia.

This paper reports a 13-year-old girl with severe hypertension due to fibrodysplasia of intrarenal arterial branches in the upper pole of the left kidney. Scleroembolization of the abnormal vascular region was carried out by injecting, via a transcutaneous catheter, an 80% solution of sodium iothalamate in ethanol, followed by a suspension of Gore-Tex particles in the same solution, which resulted in complete and persistent normalization of blood pressure.

Mechanism of impaired urinary concentrating ability in normokalemic primary aldosteronism.

Renal clearance studies were performed during anti-diuresis (before and after hypertonic saline infusion) and during water diuresis in three hypertensive patients with normokalemic primary aldosteronism (NPA) and in matched patients with normoreninemic essential hypertension (EH). The NPA patients showed an impaired ability to concentrate urine. By progressively increasing Cosm with saline loading, TcH2O plateaued both in NPA and in EH patients; in the former, however, the plateau occurred earlier and was lower than in the latter. In water diuresis, absolute values of CH2O were higher in NPA due to increased distal delivery secondary to impairment in proximal tubular reabsorption. Fractional CH2O (i.e. the ratio between CH2O and distal sodium delivery), however, was lower in NPA than in EH patients. Both in antidiuresis (after saline loading) and in water diuresis the NPA patients exhibited an enhanced fractional excretion of sodium. In one of NPA patients, clearance studies were repeated after adrenalectomy. In this patient, normalization of BP and reduction of body weight were associated with a rise in Uosm and a reduction in Cosm in antidiuresis; Uosm and Cosm were restored to pre-surgical values by expanding extracellular fluid volume (ECV) with saline loading. In summary our results suggest that ECV expansion is the mechanism by which urine concentration is impaired in patients with NPA.

Effect of calcineurin inhibitors on extracellular matrix turnover in isolated human glomeruli.

INTRODUCTION: Although chronic cyclosporine toxicity is mainly characterized by tubular atrophy and interstitial fibrosis, glomerular injury with expansion of mesangial matrix and sclerosis is not uncommon. Tacrolimus is a newer calcineurin inhibitor that has been used in renal transplant recipients as primary or rescue therapy. Clinical trials suggest an improved long-term graft survival among patients treated with tacrolimus. Recently we have shown that tacrolimus and cyclosporine have similar effects on extracellular matrix turnover in cultured cells. The present study was performed to investigate the effects of the calcineurin inhibitors on whole glomeruli extracellular matrix turnover. METHODS: Human glomeruli isolated from kidney biopsies just before transplantation were incubated with culture media containing either cyclosporine (200 ng/mL) or tacrolimus (10 ng/mL) for 24 hours. Glomeruli incubated only with culture medium were used as control. RESULTS: The expressions of (alpha2)IV collagen, metalloprotease 9 (MMP9), tissue inhibitors of metalloproteases 2 (TIMP-2), and TGFbeta were evaluated by in situ reverse transcription and polymerase chain reactions (RT-PCR). beta-actin was used as a control gene. Cyclosporine (but not tacrolimus) increased the expression of (alpha2)IV collagen and TIMP2 in isolated glomeruli. TGF-beta was markedly increased by cyclosporine. MMP9 expression was not affected by the calcineurin inhibitors. By light microscopy kidney biopsies did not show pathologic changes. CONCLUSION: Cyclosporine treatment modulates extracellular matrix turnover in isolated human glomeruli, inducing an imbalance between synthesis and degradation. This effect, not observed in tacrolimus-treated human glomeruli, may induce the extracellular matrix deposition and sclerosis characteristic of chronic cyclosporine toxicity.

Platelet-Independent defect in hemostasis associated with sirolimus use.

Sirolimus is currently used to prevent rejection of solid organ transplant, and sirolimus-eluting stents have shown promise for the prevention of coronary artery restenosis. Thrombocytopenia is a well-known adverse effect of sirolimus limiting its use. Herein we report on a patient in whom sirolimus caused a platelet-independent hemostasis defect. The patient was a 52-year-old woman who underwent renal transplant with consequent normal kidney function. The immunosuppressive regimen included basiliximab, steroids, and cyclosporine induction later shifted to sirolimus and mycophenolate due to biopsy findings of tubular necrosis on day 6 posttransplantation. At discharge the serum creatinine was 0.7 mg/dL. Four months after transplantation the patient was admitted to our hospital because of fever (37.5 degrees C to 38 degrees C), anorexia, and asthenia. Blood analysis showed: creatinine 1.7 mg/dL, Hb 9.6 g/dL, WBC 6 x 10(3)/microL, PLT 123 x 10(3)/microL, liver function tests normal, LDH 720 mU/mL, fibrinogen 628 mg/dL, d-dimer 0.42 ng/mL, FDP > 40 ng/mL, INR 1.10, PT 87%, aPTT 40 seconds. Cultures and tests for infection were negative. Serum sirolimus level was 25.9 ng/mL. The following day the serum creatinine rose to 2.3 mg/dL and diuresis fell to 20 mL/h. Multiple bleeding times (Ivy test) performed before the renal biopsy were repeatedly over 30 minutes (normal 3 to 5 minutes), despite normal platelet count and platelet function studies. There was no spontaneous aggregation and in vitro aggregation was normal (collagen, ADP, adrenalin, and ristocetin induced). Coagulation studies showed a defect in fibrin formation and a reduction of fibrinolysis. Suspension of sirolimus treatment was followed by remission of fever, improvement of renal function (serum creatinine 1.2 mg/dL), and normalization of bleeding time.