Steroid withdrawal in mycophenolate mofetil-treated renal allograft recipients

BACKGROUND

Acute rejection is an inherent risk of the withdrawal of steroids in renal allograft recipients. Mycophenolate mofetil is a potent immunosuppressant that, when given with cyclosporine (CsA), reduces the incidence of acute rejection and may facilitate discontinuation of steroids without increasing the risk of rejection.

METHODS

In an open pilot study, steroids were withdrawn from 26 adult cadaveric kidney transplant recipients. Corticosteroids were discontinued between 4 and 30 (mean 17) months after transplantation, and steroid-free follow-up ranged from 7 to 18 (mean 10) months.

RESULTS

Mean CsA doses, CsA blood levels, and serum creatinine at the time of steroid withdrawal and at last patient visit after cessation of steroids were 4.2+/-1.2 mg/kg/day and 3+/-0.8 mg/kg/day (P<0.001), 170+/-53 ng/ml and 113+/-34 ng/ml (P<0.001), and 133+/-36 microM/L and 130+/-37 microM/L (NS), respectively. No rejection episodes occurred after steroid withdrawal.

CONCLUSIONS

This open study shows that corticosteroids can be safely and successfully withdrawn from renal allograft recipients receiving CsA and mycophenolate mofetil.

Early protocol renal allograft biopsies and graft outcome

To evaluate whether biopsies performed early after transplantation in stable grafts can predict graft failure due to chronic transplant nephropathy, a protocol biopsy was performed at three months in 98 patients treated with antilymphocytic antibodies, cyclosporine and prednisone. Patients were followed for 58 +/- 16 months. Histological diagnosis according to the Banff schema were: normal (N = 41), borderline changes (N = 12), chronic transplant nephropathy (CTN; N = 30), CTN associated to borderline changes (N = 11) and acute rejection (N = 4). Biopsies displaying acute rejection were not considered for statistical analysis. Since clinical characteristics of patients displaying CTN either with or without tubulitis were not different, biopsies were grouped as presence or absence of CTN. Patients displaying CTN had an increased incidence of acute rejection before performing biopsy (24.3 vs. 3.9%, P = 0.003), a higher mean cyclosporine level until biopsy (242 +/- 74 vs. 214 +/- 59 ng/ml, P = 0.049) and a lower actuarial graft survival (80.5% vs. 94.4%, P = 0.024). We conclude that early protocol biopsies are useful to detect patients at risk of losing their graft due to chronic transplant nephropathy.

Automated classification of renal interstitium and tubules by local texture analysis and a neural network

OBJECTIVE

To segment renal interstitial space in order to automatically quantify renal cortical interstitial volume fraction (Vvint/cortex) by means of image analysis techniques.

STUDY DESIGN

The study group consisted of 35 renal biopsies with different degrees of chronic interstitial damage. Biopsies were stained with Sirius red and digitized under polarized light. Two methods were employed to segment interstitial space: (1) interstitial bright particles were thresholded, and afterwards interstitial space was reconstructed with a morphologic operation, and (2) the texture of the surroundings of each pixel was quantified by means of local granulometry, and this information was employed as the input of a neural network in order to classify interstitial and tubular pixels.

RESULTS

The correlation between Vvint/cortex obtained manually and both methods was r = .92. The first method produced some deformation of tubular contours and underestimated Vvint/cortex (beta = .70) when compared to the second approach (beta = .95) (P < .05).

CONCLUSION

Two different algorithms based on image analysis techniques allow the classification of renal interstitial and tubular structures and consequently allow the automated and precise estimation of renal Vvint/cortex.

Changes in T-cell phenotype and adhesion molecules expression in psoriatic lesions after low-dose cyclosporin therapy

Cyclosporin is a very effective treatment for severe psoriasis, but its exact mechanism of action in this disease is not completely understood. It has been hypothesized that the drug could act through the inhibition of the expression of certain cell adhesion molecules on the keratinocytes prior to the reduction in the number of epidermal inflammatory cells. Several studies have focused on ICAM-1 changes on keratinocytes and endothelial cells after cyclosporin treatment in psoriatic patients but their results have been somewhat contradictory. We examined changes in T-cell markers and adhesion molecules among keratinocytes, endothelial and inflammatory cells after low-dose cyclosporin treatment for severe psoriasis. We performed a histological and immunohistochemical study on psoriatic skin among 10 patients (7 males and 3 females; mean age 37 years) treated with low-dose (2.5 mg/kg/day) cyclosporin, prior to therapy, after 1 month, and after 3 months of treatment. The mean PASI (Psoriasis Area and Severity Index) before treatment was 23 +/- 4, 13 +/- 7 after the first month of therapy, and 8 +/- 2 at the end of the third month of therapy. Pretherapy samples showed a moderate to severe inflammatory infiltrate mainly due to T-lymphocytes expressing a T-cell memory (UCHL-1) and helper/inducer (CD4) phenotype. Most of these cells also expressed HLA-DR and LFA-1 and ICAM-1 antigens. After the treatment, an overall reduction in the degree of epidermal hyperplasia was seen (p = 0.01). The severity of the infiltrate was clearly reduced (p = 0.05), but no significant changes in the phenotype profile were observed. Although slightly reduced, endothelial ICAM-1 expression persisted after cyclosporin therapy. Keratinocyte ICAM-1 expression was uniformly and significantly reduced after 1 month and 3 months of therapy (p = 0.01). These results support the hypothesis that cyclosporin interferes with the expression of keratinocyte adhesion molecules in patients with psoriasis. Servitje O, Bordas X, Serón D, Vidaller A, Moreno A, Curcó N, Sais G, Peyrí J. Changes in T-cell phenotype and adhesion molecules expression in psoriatic lesions after low-dose cyclosporin therapy.

Glomerular up-regulation of EIIIA and V120 fibronectin isoforms in proliferative immune complex nephritis

Fibronectin: (FNs) comprise a family of adhesive glycoproteins that are prominent components of mesangial extracellular matrix and accumulate during glomerular injury. By alternative splicing of an unique mRNA precursor, various FN isoforms can be originated. In rat, three regions of the molecule are involved: EIIIA, EIIIB and V. Because specific FN isoforms are expressed in embryogenesis and wound healing, conditions characterized by cell migration and adhesion, we examined the pattern of FN isoforms in the mild and severe phases of a progressive immune complex proliferative nephritis in rats. We constructed specific probes to analyze the splicing pattern of FN pre-mRNAs by ribonuclease protection assays. FN mRNAs containing EIIIA, EIIIB and V regions increased along, the progression of nephritis, though the increment of EIIIB-FN mRNA was modest. However, different regulation of all these isoforms was observed. The percentage of FN mRNA containing the EIIIA exon versus total FN increased with the severity of the disease, while the percentage of FN mRNA containing the EIIIB exon decreased. Relative V-FN mRNA expression versus total FN mRNA increased only in the severe phase. By means of specific antibodies we also studied the presence of EIIIA, EIIIB and V-FN proteins in the kidney. In the normal glomerutus, EIIIA-FN protein was barely detectable in the mesangium, increasing in the mild phase of nephritis. In the severe phase of nephritis, increased EIIIA-FN was localized in the mesangium, in Bowman's capsule and in crescents. By contrast, EIIIB-FN protein in the glomerulus was absent even in the severe phase. V120-FN protein, an isoform that mediates the attachment of leukocytes through the VLA-4 integrin, was present in the mesangium and glomerular capillary loops in control animals, and increased in the severe phase of nephritis, coinciding with a strong leukocyte infiltration. In conclusion, our results show that during immune glomerular injury there were marked changes in the pattern of FN isoforms expression. Since those isoforms, particularly V120 isoform, are important in cell adhesion and migration, their up-regulation may facilitate the recruitment of cells into the injured glomeruli. The blockade of the interaction between V120-FN and infiltrating leukocytes may represent a new approach to the treatment of nephritis.

Interferon-inducible protein-10 is highly expressed in rats with experimental nephrosis

Interferon-inducible protein (IP)-10 is a small glycoprotein member of a family of chemotactic cytokines structurally related to interleukin-8. We have recently described the induction of IP-10 mRNA in mouse mesangial cells stimulated with lipopolysacharide, interferon-gamma, and tumor necrosis factor-alpha. To further evaluate a possible role for this chemokine in renal injury, we have studied IP-10 in an experimental model of nephrosis induced in rats by adriamycin. High levels of glomerular IP-10 mRNA expression and glomerular and tubulointerstitial IP-10 protein were seen on day 21, coinciding with maximal proteinuria, glomerular tumor necrosis factor mRNA expression, and interstitial cellular infiltrates. Maintenance on a low protein diet not only delayed the appearance of proteinuria and interstitial cellular infiltrate but also decreased glomerular IP-10 mRNA expression. Isolated normal glomeruli and cultured glomerular epithelial and mesangial cells from normal rats expressed IP-10 mRNA upon stimulation with 100 U/ml interferon or 1 microgram/ml lipopolysaccharide for 3 hours. IP-10 mRNA expression was also inducible by lipopolysaccharide and cytokines in NRK 49F renal interstitial fibroblasts and, to a lesser extent, in NRK 52E tubular epithelial cells. Furthermore, IP-10 protein was inducible in murine mesangial cells. We conclude that IP-10 is highly inducible in vitro and in vivo in resident glomerular and tubulointerstitial cells. IP-10 may participate in the modulation of renal damage in experimental nephrosis.

ACE inhibition reduces proteinuria, glomerular lesions and extracellular matrix production in a normotensive rat model of immune complex nephritis

We studied the effect of the angiotensin converting enzyme (ACE) inhibitor, quinapril, on the clinical and morphological lesions of a normotensive model of immune complex nephritis. Untreated rats developed massive nephrotic syndrome, intense cell proliferation and glomerular and tubulointerstitial lesions. In the renal cortex of nephritic rats there was a significant increase in gene expression of TGF-beta 1, fibronectin and collagens, and ACE activity. Systolic blood pressure remained normal with progression of the disease. Administration of quinapril for three weeks to animals with glomerular lesions (proteinuria 20 to 50 mg/day) avoided the development of intense proteinuria (79 +/- 28 vs. 589 +/- 73 mg/day, P < 0.001) and decreased cell proliferation, glomerulosclerosis, tubulointerstitial lesions, and inflammatory infiltrates. Cortical gene expression of TGF-beta 1 and matrix proteins was also diminished. ACE activity was inhibited by 68% in renal cortex. These results show that quinapril administration to normotensive rats with immune complex nephritis decreases proteinuria and glomerular and tubulointerstitial lesions, probably modulating the local angiotensin II generation and its effects on cell growth, TGF beta and matrix protein synthesis.

Quantification of interstitial chronic renal damage by means of texture analysis

There is a relationship between chronic renal damage and renal function at the time of biopsy. Since the quantification of interstitial lesions with morphometric techniques is very time consuming, a fully automatic method to quantify chronic damage is desirable. Progression of chronic renal damage could be viewed as a texture modification of tubulointerstitial structures. The aim of the present work is to study whether chronic renal damage could be automatically measured by means of texture analysis based on mathematical morphology. Among the morphological tools the best suited for our purpose is that of granulometry. Between four and six fields from 35 renal biopsies with different degrees of renal damage were stained with Sirius red and digitized under polarized light. In each field granulometric function with a circular structuring element was obtained. Interstitial volume fraction was measured with a point counting technique. Glomerular filtration rate at the time of biopsy was available in each case. A positive relationship between granulometric function and glomerular filtration rate was observed (r2 = 0.85). The determination coefficient between interstitial volume fraction and renal function was (r2 = 0.54). In conclusion, we describe a fully automatic method that precisely quantifies interstitial chronic renal damage.

Relationship between donor renal interstitial surface and post-transplant function

Forty-three biopsies were performed between 30 and 60 min after reperfusion. Patients (22 males/21 females, mean age 41 +/- 12 years, mean donor age 32 +/- 14 years) were treated either with antilymphocytic globulin, cyclosporin, and prednisolone (24 cases), or OKT3, cyclosporin, and prednisolone (19 cases). Ten patients had delayed post-transplant renal function (DPRF), defined as haemodialysis requirements after surgery, and seven patients had acute rejection 11 +/- 16 days post-transplant. Kidneys were perfused with a hypertonic solution containing mannitol. All patients were followed up for at least 30 months. During follow-up, five patients lost their grafts due chronic rejection, two patients due to noncompliance and one due to recurrence of focal segmental glomerulosclerosis. One patient died from heart infarction. Biopsies were stained with H&E, Masson's trichrome, periodic acid-Schiff (PAS) and silver methenamine. Interstitial fibrosis, interstitial oedema, tubular vacuolization, and peritubular capillary oedema were measured using a semiquantitative scale. Five 400 x magnification micrographs of cortical interstitium from silver-methenamine-stained sections were used to measure percentage of interstitial surface with a morphometer. Interstitial surface was 18.7 +/- 6.2% (range 3.2-35.3%). A positive correlation was found between interstitial surface and donor age (r = 0.469, P = 0.0015). No relationship was found between warm and cold ischaemia times and tubular vacuolization or peritubular capillary oedema.(ABSTRACT TRUNCATED AT 250 WORDS)

Antilymphocyte globulin versus OKT3 induction therapy in cadaveric kidney transplantation: a prospective randomized study

Different induction therapies have been used in renal transplantation to avoid cyclosporine (CsA) nephrotoxicity and early acute graft rejection. This study compares the efficacy of a short course of prophylactic OKT3 to that of antilymphocyte globulin (ALG) in preventing acute renal allograft rejection when administered concomitantly with CsA and steroids. Between March 1988 and December 1990, 140 first-cadaver renal transplant recipients were randomly allocated to two immunosuppression groups--ALG group (n = 68): ALG 15 mg/kg just before transplant surgery, ALG 12 mg/kg the first day after transplant, followed by four doses of 10 mg/kg on alternate days; and OKT3 group (n = 72): OKT3 5 mg just before transplant, followed by four doses of 5 mg/d. Both groups included low-dose CsA and steroids. The incidence of rejection during the first 3 months after transplantation was 15% in the ALG group and 19% in the OKT3 group (NS). Kaplan-Meier estimates of patients free of rejection at 2 years was 85% in the ALG group and 77% in the OKT3 group (NS). The 3-year actuarial graft survival was 82% and 85% (NS), and 3-year patient survival was 97% and 98% (NS), in the ALG and OKT3 groups, respectively. These results indicate that the concomitant association of CsA and ALG or OKT3 constitutes a safe and effective therapeutic strategy that provides a low incidence of rejection and gives good results for patient and graft survival.

[Mannitol solution (M-400) vs. mannitol solution combined with allopurinol in the prevention of post-transfusion acute renal failure]

Evaluation on the incidence of Acute Renal Failure (ARF) from a total of 41 corpse renal graft receptors, 20 of which received perfusion with mannitol solution at 400 mOsm/kg (Group 1) and 21 the same mannitol solution plus allopurinol (Group 2). No significant differences were present between both groups when they were analyzed for ARF incidence (15% vs 23.8%); overall incidence was 19.5%. 24-hour initial diuresis was shown to be an excellent predictor for long-term graft functionality. We can conclude that the addition of mannitol to the perfusion solution contributes decisively to reduce post-transplantation ARF, while addition of allopurinol does not have further beneficial effects.