Compression of the ulnar nerve in Guyon's canal by uremic tumoral calcinosis

We describe the case of a 70-year-old woman with chronic renal failure on haemodialysis presenting with an ulnar nerve compression in Guyon's canal secondary to uremic tumoral calcinosis. Excision of calcium deposits and external neurolysis of the ulnar nerve were successfully performed. Simultaneously, the hyperphosphatemia and hypercalcemia were corrected. The pathogenesis of this condition is different from primary tumoral calcinosis. Clinical and radiological features and therapy are discussed. Uremic tumoral calcinosis is an unusual etiology of ulnar nerve compression in Guyon's canal not previously reported in dialysis patients.

Sirolimus in association with mycophenolate mofetil induction for the prevention of acute graft rejection in renal allograft recipients

INTRODUCTION

A previous trial in renal transplantation comparing sirolimus (rapamycin) to cyclosporine (CsA) in a triple-drug therapy regimen with azathioprine and corticosteroids found that the incidence of acute rejection was similar (approximately 40%) with a trend for better renal function with sirolimus.

METHODS

In 14 European centers, first cadaveric renal allograft recipients were randomized to receive sirolimus (n = 40) or CsA (n = 38) in an open-label design. All patients received corticosteroids and mycophenolate mofetil 2 g/day. Sirolimus and CsA were concentration controlled; trough levels of mycophenolic acid and prednisolone were also measured.

RESULTS

At 12 months, graft survival (92.5% sirolimus vs. 89.5% CsA), patient survival (97.5% sirolimus vs. 94.7% CsA), and the incidence of biopsy-proven acute rejection (27.5% sirolimus vs. 18.4% CsA) were not statistically different. The use of antibodies to treat suspected rejection episodes was also similar (7.5% sirolimus vs. 5.3% CsA). More sirolimus patients received bolus steroid therapy (20 vs. 11, P = 0.068). From month 2 onward, the calculated glomerular filtration rate was consistently higher in sirolimus-treated patients. The adverse events reported more frequently with sirolimus were thrombocytopenia (45% vs. 8%) and diarrhea (38% vs. 11%). In the CsA group, increased creatinine (18% vs. 39%), hyperuricemia (3% vs. 18%), cytomegalovirus infection (5% vs. 21%), and tremor (5% vs. 21%) were observed significantly more often.

DISCUSSION

Patient and graft survival and the incidence of biopsy-proven acute rejection at 12 months were comparable between sirolimus and CsA, whereas safety profiles were different. These data suggest that sirolimus may be used as primary therapy for the prevention of acute rejection.

Immunosuppression in older renal transplant patients

Renal transplantation procedures in patients older than 60 years of age have clearly improved in recent years. In the cyclosporin era, graft and patient survival are good. However, older patients exhibit a higher mortality, especially from infectious and cardiovascular causes, than young patients. In this article we review the immunosuppressive treatment in older patients, analyse what drugs can be used and finally propose several immunosuppressive combinations to treat this group of patients. Currently, new immunosuppressive drugs enable more flexible immunosuppressive protocols. Nevertheless, to avoid overimmunosuppression, elderly patients should be treated with lower doses and fewer immunosuppressive drugs.

Efficacy and tolerance of interferon-alpha(2b) in the treatment of chronic hepatitis C virus infection in haemodialysis patients. Pre- and post-renal transplantation assessment

BACKGROUND

Hepatitis C virus (HCV) infection represents an important problem for the dialysis population due to its high prevalence and the long-term development of chronic liver disease, particularly following renal transplantation.

METHODS

In order to assess the efficacy and tolerance of interferon (IFN) in the treatment of chronic hepatitis C in haemodialysis (HD) patients and their clinical course following renal transplantation, a multicentre, randomized, open-label study was conducted to compare IFN therapy vs a control group.

RESULTS

Nineteen HCV RNA-positive patients received 3 x 10(6) U of IFN s.c., three times a week (post-HD), and 17 HCV RNA-positive patients were assigned to the control group. Tolerance to IFN therapy was good in nine patients, while treatment was discontinued in the other 10 due to the occurrence of side effects. HCV RNA was negative at the end of treatment in 14 out of 19 patients (74%) receiving IFN and in one patient (5%) in the control group. Six out of the 14 patients who initially responded to IFN therapy had a virological relapse (43%). Eight patients (42%) remained HCV RNA-negative, three of them until the day that renal transplantation (RT) was performed (7, 12 and 27 months, respectively), as did five patients on HD during the follow-up (27+/-5 months). Eight out of the nine patients (89%) who completed therapy were HCV RNA-negative at the end of treatment, and seven of them (78%) remained HCV RNA-negative during the follow-up on dialysis (21+/-8 months). Mean transaminase (ALT) values were significantly decreased following IFN therapy, while no changes were observed during the follow-up period in the control group. Fifteen patients (10 in the treatment group and five in the control group) underwent RT. Three patients in the treatment group were HCV RNA-negative at RT, and one of them had a virological relapse 20 months after RT, while the other two remained HCV RNA-negative at 3 months and 24 months after RT, respectively. In contrast to the control group, transaminase (ALT) remained within normal limits in all patients in the treatment group. Finally, during the post-RT follow-up, the transaminase mean values were significantly lower in treated patients vs patients in the control group (P<0.05).

CONCLUSIONS

It is concluded that the biochemical and virological response to IFN therapy is good in HD patients. In addition, IFN therapy appears to exert a beneficial effect on the course of liver disease following RT, regardless of the virological response. Despite the fact that IFN therapy was discontinued in 10 out of the 19 patients due to the occurrence of side effects, these disappeared following discontinuation of therapy. Therefore, IFN therapy is advisable for HCV-infected dialysis patients who are candidates for RT.

Losartan decreases plasma levels of TGF-beta1 in transplant patients with chronic allograft nephropathy

BACKGROUND

Chronic allograft nephropathy represents the principal cause of graft loss after the first year of transplantation. Transforming growth factor-beta1 (TGF-beta1) is a key factor in fibrogenesis and has been involved in the pathogenesis of chronic allograft nephropathy and other chronic nephropathies. Experimental studies have demonstrated that the angiotensin II receptor antagonist (losartan) could decrease the synthesis of TGF-beta1. The aim of this study was to determine the plasma levels of TGF-beta1 in transplant patients with chronic allograft nephropathy, and to evaluate the effect of losartan on TGF-beta1 plasma levels and other vasoactive peptides (angiotensin II, plasma renin activity, aldosterone, endothelin-1, and nitrites and nitrates). Angiotensin-converting enzyme genotypes were also determined in all patients.

METHODS

Fourteen transplant patients with chronic allograft nephropathy were included. Treatment with losartan (50 mg) was introduced. Consecutive determinations of TGF-beta1 and other vasoactive peptides were performed during follow-up.

RESULTS

Patients with chronic allograft nephropathy presented higher plasma levels of TGF-beta1 than the control groups. The treatment with losartan significantly decreased the plasma levels of TGF-beta1 (P < 0.05) and endothelin (P < 0.05) in all patients. The decrease of TGF-beta1 was statistically correlated with the blockade of the angiotensin II receptor (P < 0.05). No significant correlation could be demonstrated between angiotensin-converting enzyme genotypes and TGF-beta, endothelin-1, and nitrite-nitrate serum levels.

CONCLUSIONS

This study demonstrates that losartan significantly decreases the plasma levels of TGF-beta1, the most important fibrogenetic factor. These results could play a decisive role in the treatment and prevention of chronic nephropathies, not only graft nephropathy, because the intrinsic pathogenetic mechanism is very similar in all forms, with a crucial roles for the renal renin-angiotensin system and TGF-beta1.

Sirolimus (rapamycin)-based therapy in human renal transplantation: similar efficacy and different toxicity compared with cyclosporine. Sirolimus European Renal Transplant Study Group

BACKGROUND

Sirolimus (rapamycin) is a potent immunosuppressant with a mechanism of action different from cyclosporine (CsA) or tacrolimus.

METHODS

In 11 European centers, first cadaveric renal allograft recipients were randomized to CsA (n=42) or sirolimus (n=41). Dosing of these agents was concentration-controlled and open-labeled. All patients received corticosteroids and azathioprine.

RESULTS

At 12 months, graft survival (98% sirolimus vs. 90% CsA), patient survival (100% vs. 98%), and incidence of biopsy-confirmed acute rejection (41% vs. 38%) were similar. Serum creatinine was lower with sirolimus, significantly (P< or =0.05) so at 3 and 4 months, and serum uric acid and magnesium were normal. Laboratory abnormalities reported significantly more often with sirolimus included hypertriglyceridemia (51% vs. 12%), hypercholesterolemia (44% vs. 14%), thrombocytopenia (37% vs. 0%), leukopenia (39% vs. 14%), and, of lesser importance, increased liver enzymes and hypokalemia. These abnormalities improved 2 months after transplantation when the sirolimus target trough level was lowered from 30 to 15 ng/ml. Occurrence of cytomegalovirus was comparable (14% vs. 12%); incidences of herpes simplex (24% vs. 10%, P=0.08) and pneumonia (17% vs. 2%, P=0.03) were higher with sirolimus. No gingival hyperplasia was seen with sirolimus, tremor was rare, and hypertension was less frequent (17% vs. 33%). Two malignancies were observed with CsA and none with sirolimus.

CONCLUSIONS

Results at 12 months suggest that sirolimus can be used as base therapy in the prophylaxis of acute renal transplant rejection, and has a safety profile that differs from CsA.

[Compression of the sciatic nerve in uremic tumor calcinosis]

Tumoral calcinosis is an uncommon and benign condition characterized by the presence of slow-growing calcified periarticular soft tissue masses of varying size. They are usually asymptomatic and nerve compression is rare. We describe the case of a 54-year-old female patient on long-term hemodialysis for chronic renal failure presenting sciatica in the left lower limb secondary to an extensive uremic tumoral calcinosis that affected the hip and thigh. The pathogenesis of uremic tumoral calcinosis as well as the treatment and clinical outcome are analyzed. The uncommon nerve compression due to tumoral calcinosis are reviewed. In conclusion, uremic tumoral calcinosis is a not previously reported infrequent cause of sciatic nerve compression.

Uremic tumoral calcinosis in patients receiving longterm hemodialysis therapy

OBJECTIVE

To analyze a series of uremic tumoral calcinosis (UTC) in patients receiving longterm dialysis therapy.

METHODS

Twelve patients receiving longterm hemodialysis affected by tumoral calcinosis were analyzed. Clinical, radiological, and pathological features were evaluated and pathogenic factors were reviewed.

RESULTS

The most common sites for UTC were the elbow, hip, hand, and wrist. The lesions were multiple (67%, n = 8), of large size, and symptomatic with joint mobility impairment (75%, n = 9) as well as nerve compression (33%, n = 4). High serum calcium and phosphate concentrations were detected in 50% (n = 6) and 100% of the patients, respectively. An increased calcium-phosphorus product (Ca x P) was observed in all patients, either due to overt secondary hyperparathyroidism (42%, n = 5), or secondary to iatrogenic hypercalcemia and/or severe hyperphosphoremia of multifactorial etiology (i.e., prolonged and excessive administration of calcitriol and calcium carbonate, insufficient dialysis and inadequate phosphorus chelating therapy, etc.) (58%, n = 7). Several treatment strategies were followed (surgical excision, parathyroidectomy, renal transplant) in combination with aggressive medical therapy to decrease Ca x P product, achieving complete remission in 83% of the patients.

CONCLUSION

UTC lesions show clinical and pathogenic features that differ from those of idiopathic tumoral calcinosis. The most important pathogenic factor involved in UTC is an increase in Ca x P, not necessarily related to hyperparathyroidism. Combined treatment strategies allow complete remission in a high proportion of patients. A low Ca x P is necessary to prevent development of UTC.

Efficacy and safety of losartan in the treatment of hypertension in renal transplant recipients

Arterial hypertension, which represents a common problem in patients with renal transplant, contributes to the cardiovascular morbidity and mortality of these patients. The most usual immunosuppressive drugs (cyclosporine and FK-506) collaborate on the development of hypertension. Calcium channel blockers are the most habitually used antihypertensive drugs in this population, although its long-term hemodimamycs effects could be deleterious especially in transplanted patients with chronic graft nephropathy. Losartan, a specific blocker of angiotensin II (AT1) receptors, has demonstrated a potent antihypertensive effect with a good safety and tolerance profile. The glomerular effects of losartan could be useful in transplanted patients. The present open, prospective and multicenter study evaluated the efficacy and safety of losartan in the treatment of hypertension in a group of patients with a renal transplant. Seventy-six patients with systolic blood pressure > or = 140 and/or diastolic blood pressure > or = 90 mm Hg, and/or patients on therapy with one antihypertensive drug and related side effects were included. After inclusion, therapy with losartan 50 mg/24 hr was started, discontinuing the previous antihypertensive therapy and/or therapy which caused the side effects. At four weeks, if blood pressure (BP) was not controlled, hydrochlorothiazide 25 mg or furosemide 40 mg/24 hr was added. At baseline and at weeks 2, 4, 8 and 12, the following parameters were monitored: BP, creatinine, hematocrit, hemoglobin, glucose, ions, uric acid, cholesterol, triglycerides, bilirubin, SGOT, SGPT, GGT, LDH, calcium, phosphate, alkaline phosphatase, proteinuria, and both cyclosporine and FK-506 levels in whole blood. Sixty-seven patients completed the 12-week study period. Mean blood pressure decreased from 113 +/- 10 to 102 +/- 9 mm Hg at the end of the study (P < 0.0001); 38 of the 67 patients (56.7%) who completed the study had a SBP lower than 140 mm Hg and a DBP lower than 90. These blood pressures were obtained in 30 patients on monotherapy with losartan (78.9%). Proteinuria decreased significantly at week 4 and was confirmed at week 12, especially in patients with proteinuria > or = 300 mg/24 hr. Nine patients were withdrawn during the study period for different reasons. Serum creatinine showed a slight, non-clinically significant increase at week 4, remaining stable until the end of the study. Two patients developed a mild normocytic anemia, and three others presented a mild impairment of pre-existent anemia. No interactions with cyclosporine or FK-506 were described. These results indicate that losartan is effective in reducing BP in hypertensive patients with a renal transplant. It has a good tolerance profile and does not interfere with immunosuppressive therapy.

High phosphate level directly stimulates parathyroid hormone secretion and synthesis by human parathyroid tissue in vitro

Phosphate retention plays an important role in the pathogenesis of secondary hyperparathyroidism in patients with renal failure. In in vitro studies, high extracellular phosphate levels directly stimulate PTH secretion in rat and bovine parathyroid tissue. The present study evaluates the effect of high phosphate levels on the secretion of PTH and the production of prepro PTH mRNA in human hyperplastic parathyroid glands. The study includes parathyroid glands obtained from patients with primary adenomas and from hemodialysis and kidney-transplant patients with diffuse and nodular secondary hyperplasia. The experiments were performed in vitro using small pieces of parathyroid tissue. The ability of high calcium levels to decrease PTH secretion was less in adenomas than in secondary hyperplasia; among the secondary hyperplasia, nodular was less responsive to an increase in calcium than diffuse hyperplasia. In diffuse hyperplasia, PTH secretion was increased in response to 3 and 4 mM phosphate compared with 2 mM phosphate, despite a high calcium concentration in the medium; prepro PTH mRNA levels increased after incubation in 4 mM phosphate. Similar results were obtained with nodular hyperplasia, except that the elevation of PTH secretion in response to 3 mM phosphate did not attain statistical significance. In adenomas, high calcium concentrations (1.5 mM) did not result in inhibition of PTH secretion, independent of the phosphate concentration, and the prepro PTH mRNA was not significantly increased by high phosphate levels. In conclusion, first, the PTH secretory response to an increase in calcium concentration is less in nodular than diffuse hyperplasia; second, high phosphate levels directly affect PTH secretion and gene expression in patients with advanced secondary hyperparathyroidism.

Advances in transplantation and immunosuppression

This report presents highlights from four sections of the 17th Annual Meeting of the American Society of Transplant Physicians (Chicago; May 9-13, 1998): immunosuppressive drugs; immunosuppressive protocols; basic immunology; and areas of clinical interest. Studies were presented on the immunosuppressive effects of tacrolimus, mycophenolate mofetil, sirolimus and analogues, daclizumab and basiliximab, among other compounds. Regarding immunosuppressive protocols, many studies focused on the need for steroid withdrawal a short period after renal transplantation; other subjects discussed were the avoidance of nephrotoxic drugs and the avoidance of acute graft rejection. The section on basic immunology covered transforming growth factor-beta chemotaxis, adhesion molecules and co-stimulation. Hepatitis C virus continues to be an area of current clinical interest, as is the problem of chronic rejection. Finally, lipids and statins were accorded great relevance at this meeting.

Hepatitis C virus and renal transplantation

During the past 12 months additional evidence has emerged from several studies, indicating that hepatitis C virus infection is the most important liver disease after renal transplantation. A new, severe and rare entity called fibrosing cholestatic hepatitis can lead to early liver failure, although the most important complications appeared in the long-run. Encouraging results with ribavirin have been described. Although glomerular lesions and more severe infections can appear in hepatitis C virus patients, graft and patient survival rates in most series are similar to those in hepatitis-C-negative patients. Survival is also better among hepatitis-C-positive patients after renal transplantation than in hepatitis-C-positive patients on dialysis on the waiting list for transplantation. Finally, the use of kidneys from hepatitis-C-positive donors is suggested for transplant into hepatitis C RNA positive patients matching the hepatitis C genotype.

Glomerular diseases in patients with hepatitis C virus infection after renal transplantation

Currently, it is well known that hepatitis c virus (HCV) represents the major cause of chronic liver disease in renal transplant patients. On the other hand, HCV has been described in association with different types of glomerular diseases, usually type I membranoproliferative glomerulonephritis (MGPN) and less frequently membranous glomerulonephritis (MGN). After renal transplantation two glomerular entities have described in HCV positive patients: MPGN, associated or not with cryoglobulinemia, hypocomplememtemia and rheumatoid factor and another lesion was MGN. All patients had chronic HCV infection and with detectable HCV RNA in the serum, developed proteinuria, nephrotic syndrome and microhematuria. Characteristically MGN occurs without cryoglobulinemia, hypocomplememtemia and rheumatoid factor. The clinical pictures and outcomes of these pathological pictures seem to be similar to those of the novo MPGN or MGN in renal transplant patients. These entities seem to be more frequent in HCV-positive than in HCV-negative patients. Also, a possible relationship between HCV infection and transplant glomerulopathy has been described. Therefore, in renal transplant patients with proteinuria, serology for HCV infection, HCV RNA and immunological tests should be performed as part of the differential diagnosis.

Membranous glomerulonephritis associated with hepatitis C virus infection in renal transplant patients

BACKGROUND

Hepatitis C virus (HCV) infection has been described in association with various types of glomerular diseases, usually type I membranoproliferative glomerulonephritis and rarely membranous glomerulonephritis (MGN). In this article, we describe the first series of MGN exhibited in renal transplant patients and associated with HCV infection.

METHODS

From January 1980 to December 1994, 2045 kidney transplantations were performed in our renal transplant units. A retrospective analysis demonstrated an overall 20% prevalence of HCV virus-positive patients; 409 transplanted patients were HCV positive (ELISA and RIBA).

RESULTS

Fifteen patients developed an allograft MGN (3.66%) 24 months after renal transplantation. MGN appeared in the form of significant proteinuria (>1.5 g/24 h) with stable renal function. In all cases, graft biopsy demonstrated a thickening of the capillary wall, subepithelial electron-dense deposits, and IgG and C3 diffuse granular deposits along the basal membrane. Ten cases were considered de novo, two cases were considered recurrent MGN, and three cases were considered undetermined because the primary renal disease was chronic glomerulonephritis. All patients showed negative antinuclear antibodies and cryoglobulins, normal complement, and negative rheumatoid factors. During follow-up (an average of 2 years), 12 patients developed a progressive worsening of renal function, with increased serum creatinine and persistent proteinuria; 8 of the 12 patients returned to dialysis. Of the remaining three cases, two patients showed partial remission of nephrotic syndrome after high doses of steroids, and one patient persisted with stable renal function and proteinuria (<2 g/24 h.).

CONCLUSIONS

In summary, HCV is preferentially associated with MGN in renal transplant patients, rather than with membranoproliferative glomerulonephritis as in the normal adult population. MGN associated with HCV infection has a similar clinical picture and outcome to posttransplant idiopathic de novo MGN, with persistent massive proteinuria and progressive deterioration of renal function.