Development of diabetic vascular lesions in normal kidneys transplanted into patients with diabetes mellitus

A Simple Review of Small Vessel Disease Manifestation in the Brain, Retina, and Kidneys

Small blood vessels express specific phenotypical and functional characteristics throughout the body. Alterations in the microcirculation contribute to many correlated physiological and pathological events in related organs. Factors such as comorbidities and genetics contribute to the complexity of this topic. Small vessel disease primarily affects end organs that receive significant cardiac output, such as the brain, kidney, and retina. Despite the differences in location, concurrent changes are seen in the micro-vasculature of the brain, retina, and kidneys under pathological conditions due to their common histological, functional, and embryological characteristics. While the cardiovascular basis of pathology in association with the brain, retina, or kidneys has been well documented, this is a simple review that uniquely considers the relationship between all three organs and highlights the prevalence of coexisting end organ injuries in an attempt to elucidate connections between the brain, retina, and kidneys, which has the potential to transform diagnostic and therapeutic approaches.

Peritoneal Vascular Changes in Continuous Ambulatory Peritoneal Dialysis (CAPD): An in Vivo Model for the Study of Diabetic Microangiopathy

Replication of the basement membrane of the peritoneal capillaries and the mesothelium is observed in all uremic patients after a period of continuous ambulatory peritoneal dialysis (CAPD). Biopsy specimens of the parietal peritoneum were taken in diabetic and non-diabetic patients on insertion or repositioning of the CAPD catheter. The basement membrane of the capillaries and mesothelium was normal in non-diabetics on insertion of the catheter, but after 2 to 66 months of CAPD, multiple replication was found. In nearly all the diabetics there was already replication of the basement membrane of the peritoneal capillaries before CAPD was begun but the basement membrane of the mesothelium was intact. After several months of CAPD thickening of the basement membrane of the capillaries was found in 36% of diabetics, sometimes to the point of occlusion. After CAPD, replication of the basement membrane of the mesothelium has been observed in both diabetics and nondiabetics although it is initially perfectly normal in both. CAPD is proposed as an experimental model for diabetic microangiopathy in man.

Occurrence of Diabetic Nephropathy After Renal Transplantation Despite Intensive Glycemic Control: An Observational Cohort Study

OBJECTIVE

The kinetics and risk factors of diabetic nephropathy after kidney transplantation remain unclear. This study investigated the posttransplant occurrence of diabetic nephropathy and the contribution of posttransplant glycemic control.

RESEARCH DESIGN AND METHODS

We performed a single-center prospective cohort study of 953 renal allograft recipients and 3,458 protocol-specified renal allograft biopsy specimens up to 5 years after transplantation. The effects of pretransplant diabetes and glycemic control (glycated hemoglobin levels) on the posttransplant histology were studied.

RESULTS

Before transplantation, diabetes was present in 164 (17.2%) renal allograft recipients, primarily type 2 (n = 146 [89.0%]). Despite intensive glycemic control (glycated hemoglobin 7.00 ± 1.34% [53 ± 14.6 mmol/mol], 6.90 ± 1.22% [52 ± 13.3 mmol/mol], and 7.10 ± 1.13% [54 ± 12.4 mmol/mol], at 1, 2, and 5 years after transplantation), mesangial matrix expansion reached a cumulative incidence of 47.7% by 5 years in the pretransplant diabetes group versus 27.1% in patients without diabetes, corresponding to a hazard ratio of 1.55 (95% CI 1.07-2.26; P = 0.005). Mesangial matrix expansion was not specific for diabetic nephropathy and associated independently with increasing age. Pretransplant diabetes was associated with posttransplant proteinuria but not with estimated glomerular filtration rate, graft failure, or any other structural changes of the glomerular, vascular, or tubulointerstitial renal compartments. The occurrence of diabetic nephropathy was independent of posttransplant glycated hemoglobin levels.

CONCLUSIONS

Mesangial matrix expansion, an early indicator of diabetic nephropathy, can occur rapidly in patients with diabetes before transplantation, despite intensive glycemic control. Prevention of diabetic nephropathy requires more than pursuing low levels of glycated hemoglobin.

Diabetic nephropathy after kidney transplantation in patients with pretransplantation type II diabetes: A retrospective case series study from a high-volume center in the United States

BACKGROUND

Patients with type II diabetes mellitus (DM) undergoing renal transplantation are at risk of diabetic nephropathy (DN) in the transplanted kidney. The true risk of developing post-transplantation DN is unknown, and post-transplantation DN is poorly characterized in the literature.

METHODS

The biopsy database at the University of Maryland Medical Center was queried for kidney transplant biopsies which demonstrated evidence of DN. The time from transplantation to biopsy-proven DN (time to diagnosis, TTD) was calculated and analyzed in the context of demographics, serum creatinine, and onset of diabetes. By extrapolating the total number of patients who developed DN in the last 2 years, we estimated the recurrence rate of DN.

RESULTS

Sixty patients whose renal biopsies met criteria were identified. The mean age was 56.6 (±1.58) years, and the mean creatinine level at time of biopsy was 1.65 (±0.12) mg/dL. Simultaneous pathological diagnoses were frequent on kidney biopsy; rejection was present at variable rates: classes I, IIA, IIB, and III were 5.0%, 66.7%, 18.4%, and 10%, respectively. The mean TTD was 1456 (±206) days. TTD was significantly shorter for patients receiving a cadaveric vs living donor renal transplant (1118 ± 184 vs 2470 ± 547 days, P = 0.004). Older patients (r = 0.378, P = 0.003) and patients with higher serum creatinine (r = 0.282, P = 0.029) had shorter TTDs. Extrapolations showed that 74.7% of patients would be free of DN 10 years after renal transplantation.

CONCLUSIONS

Diabetic nephropathy occurs after transplantation, and this appears to be due to both donor and recipient-derived factors. Encouragingly, our estimates suggest that as many as 75% of patients may be free of DN at 10 years following kidney transplantation.

Visit-to-visit variability of blood pressure and renal function decline in patients with diabetic chronic kidney disease

The authors previously reported that the visit-to-visit variability of blood pressure is correlated with renal function decline in nondiabetic chronic kidney disease. Little is known about the association between visit-to-visit variability and renal function decline in patients with diabetic chronic kidney disease. The authors retrospectively studied 69 patients with diabetic chronic kidney disease stage 3a, 3b, or 4. The standard deviation and coefficient of variation of blood pressure in 12 consecutive visits were defined as visit-to-visit variability of blood pressure. The median observation period was 32 months. In univariate correlation, the standard deviation and coefficient of variation of blood pressure were not significantly associated with the slope of estimated glomerular filtration rate. There was no significant association between the visit-to-visit variability of blood pressure and renal function decline in patients with diabetic chronic kidney disease, in contrast with our previous study of nondiabetic patients with chronic kidney disease.

Outcomes of de novo allograft diabetic nephropathy in renal allograft recipients

OBJECTIVES

Despite increased use of diabetogenic immunosuppressive drugs and increased incidence of new-onset diabetes after transplant in renal allograft recipients, there are few case studies on the subject of de novo allograft diabetic nephropathy and interstitial fibrosis/tubular atrophy without specific glomerular changes. We sought to study the outcomes of allograft diabetic nephropathy and interstitial fibrosis/tubular atrophy without specific glomerular changes in patients with new-onset diabetes after transplant.

MATERIALS AND METHODS

We reviewed the case records of all new-onset diabetes after transplant patients who underwent graft biopsy for graft dysfunction from 1992 to 2010. We analyzed the clinical characteristics and outcomes of new-onset diabetes after transplant patients with de novo allograft diabetic nephropathy and interstitial fibrosis/tubular atrophy without specific glomerular changes.

RESULTS

Of the 1989 recipients, 421 patients developed new-onset diabetes after transplant and 26 underwent graft biopsy. Of the 26 patients, 9 had histopathologic evidence of de novo allograft diabetic nephropathy, and 17 had interstitial fibrosis/tubular atrophy without specific glomerular changes. The mean duration from transplant to developing novo allograft diabetic nephropathy was 115.2 months (range, 33-192 mo), and from developing new-onset diabetes after transplant to allograft diabetic nephropathy, was 109.66 months (range, 27-188.4 mo). Of the 9 patients with de novo allograft diabetic nephropathy, 3 died (33.3%), 2 reached end-stage renal disease (22.2%), and 4 remained stable (44.4%). Of the 17 with interstitial fibrosis/tubular atrophy, 2 died (11.7%), 5 developed end-stage renal disease (29.4%), and 10 remained stable on triple immunosuppression and insulin therapy during follow-up (58.8%).

CONCLUSIONS

De novo allograft diabetic nephropathy is a significant cause of graft and patient loss in renal allograft recipients who develop new-onset diabetes after transplant.

Temporal profile of diabetic nephropathy pathologic changes

Diabetic nephropathy, by far, is the most common cause of end stage renal disease in the US and many other countries. In type 1 diabetes, the natural history of diabetic nephropathy is tightly linked to evolution of classic lesions of the disease, namely glomerular basement membrane thickening, increased mesangial matrix, and reduced glomerular filtration surface density. These lesions progress in parallel and correlate with increased albumin excretion rate and reduced glomerular filtration rate across a wide range of renal function. In fact, the vast majority of the variances of albumin excretion and glomerular filtration rates can be explained by these glomerular lesions alone in type 1 diabetic patients. Although, classic lesions of diabetic nephropathy, indistinguishable from those of type 1 diabetes, also occur in type 2 diabetes, renal lesions are more heterogeneous in type 2 diabetic patients with some patients developing more advanced vascular or chronic tubulointerstitial lesions than diabetic glomerulopathy. More research biopsy longitudinal studies, especially in type 2 diabetic patients, are needed to better understand various pathways of renal injury in diabetic nephropathy.

Diabetic kidney disease; review of the current knowledge

Diabetes is the most common cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD) in most parts of the world. 20 to 30% of diabetic patient have diabetic nephropathy in type 1 and type 2. Hyperglycemia is the key of nephropathy creation. Hyperglycemia also by production of toxic materials, advanced glycosylated end product (AGE), increased activity of aldose reductase has some role. Some metabolites of arachidonic acid, hemodynamic derangements and genetic factors have also some role. Although diabetic nephropathy is most common cause of nephropathy in these patients, but diabetic patients are also prone to other urinary tract and renal parenchymal disease and should not be confused with renal failure due to diabetic nephropathy. The principle of treatment of diabetic nephropathy is based on tight control of hyperglycemia, tight control of blood pressure and glomerular pressure, control of dyslipidemia, restriction of protein intake and smoking withdrawal.

Morphologic features of declining renal function in type 1 diabetes

Progressive renal dysfunction is a major complication of type 1 diabetes. Studying relationships between evolution of diabetic nephropathy lesions and renal functional alterations (structural-functional relationships) helps to better understand the natural history of diabetic nephropathy. The focus of this review is our current understanding of the interplay between morphologic changes of diabetic nephropathy and glomerular filtration rate (GFR) loss. These morphologic changes often may not progress in parallel to each other or to the decline in GFR or increase in albumin excretion rate (AER). Quantitative measures of renal (mainly glomerular) structural changes can predict a substantially larger fraction of AER variability compared with that of GFR, especially using linear correlation analyses. However, nonlinear models better fit the structural-functional relationships across a wide range of GFRs and AERs. Currently, there are insufficient longitudinal data to show which structural changes predict the slope of GFR decline in type 1 diabetic patients. Based on cross-sectional studies, however, such a predictor would be about 10% more robust in patients whose GFR was 45 mL/min/1.73 m(2) or greater if comprised of a composite of glomerular, tubular, and interstitial parameters versus glomerular changes alone. For a slowly progressive disease, such as diabetic nephropathy, in which, especially in the earlier stages, it takes a long time for GFR to decline substantially, such predictors are much needed and, if sufficiently precise, could potentially serve as a surrogate of renal functional decline in clinical trials.

Early histologic lesions and risk factors for recurrence of diabetic kidney disease after kidney transplantation

BACKGROUND

Recurrence of diabetic kidney disease (DKD) after diabetic kidney transplantation has been reported. The aim of this study was to determine the early histologic lesions, focusing especially on abnormal glomerular angiogenesis, and clinical risk factors of recurrent DKD after kidney transplantation.

METHODS

The authors studied 34 renal transplant recipients with diabetes and 30 without diabetes. All patients had undergone both baseline and posttransplant follow-up biopsies. Glomerular morphometric analyses of the mesangial area, the capillary number, and the capillary area were performed with a computer-assisted image analyzer, and glomerular basement membrane (GBM) thickness was evaluated by electron microscopy. The incidence of polar vasculosis as an angiogenic phenomenon was also evaluated. Clinical data including hemoglobin (Hb)A1c, blood pressure, urinary albumin excretion, and serum lipid profiles were compared with histologic parameters.

RESULTS

Together with the increased glomerular mesangial area and GBM thickness, the glomerular capillary number and area and the incidence of polar vasculosis were significantly higher in patients with diabetes. Most of these alterations were significantly associated with the mean posttransplant HbA1c levels but not with blood pressure or lipid profiles. In the multiple regression analysis, HbA1c level remained significantly associated with these histologic parameters.

CONCLUSIONS

Similar to mesangial expansion and GBM thickening, glomerular neovascularization represented by increased capillary number and area and glomerular polar vasculosis can occur as an early diabetic lesion in recurrent DKD. Posttransplant hyperglycemia is a significant risk factor predictive of the progression of recurrent DKD in kidney allografts.

A long-term prevention of diabetic nephropathy in a patient with type 1 diabetes after simultaneous pancreas and kidney transplantation

We report a case of type 1 diabetes mellitus who was successfully treated with simultaneous pancreas and kidney (SPK) transplantation and both grafts survived for 16 yr. A 30-yr-old woman underwent SPK transplantation from a non-heart-beating donor in January 1992. She was treated with combined immunosuppressive therapy consisting of cyclosporine, azathioprine, methylprednisolone, and anti-lymphocyte globulin. Allograft kidney biopsy was performed 10 yr after transplantation to determine the cause of proteinuria, which revealed no recurrence of diabetic nephropathy, suggesting that long-term normalization of glycemic control achieved by successful pancreas transplantation can prevent recurrence of diabetic nephropathy in the kidney allograft.

Having one kidney does not accelerate the rate of development of diabetic nephropathy lesions in type 1 diabetic patients

OBJECTIVE

Reduced nephron number is hypothesized to be a risk factor for chronic kidney disease and hypertension. Whether reduced nephron number accelerates the early stages of diabetic nephropathy is unknown. This study investigated whether the rate of development of diabetic nephropathy lesions was different in type 1 diabetic patients with a single (transplanted) kidney compared with patients with two (native) kidneys.

RESEARCH DESIGN AND METHODS

Three groups of volunteers were studied: 28 type 1 diabetic kidney transplant recipients with 8-20 years of good graft function, 39 two-kidney patients with duration of type 1 diabetes matched to the time since transplant in the one-kidney group, and 30 age-matched normal control subjects. Electron microscopic morphometry was used to estimate glomerular structural parameters on 3.0 +/- 1.4 glomeruli per biopsy.

RESULTS

In the one- versus two-kidney diabetic subject groups, respectively, serum creatinine (means +/- SD 1.3 +/- 0.4 vs. 0.9 +/- 0.2 mg/dl; P < 0.001), systolic blood pressure (133 +/- 13 vs. 122 +/- 11 mmHg; P < 0.001), and albumin excretion rate (median [range] 32.1 microg/min [2-622] vs. 6.8 microg/min [2-1,495]; P = 0.006) were higher. There were no differences in the one- versus two-kidney diabetic subject groups, respectively, in glomerular basement membrane width (median [range] 511 nm [308-745] vs. 473 nm [331-814]), mesangial fractional volume (mean +/- SD 0.30 +/- 0.06 vs. 0.27 +/- 0.07), mesangial matrix fractional volume (0.16 +/- 0.05 vs. 0.16 +/- 0.06), and mesangial matrix fractional volume per total mesangium (0.61 +/- 0.07 vs. 0.64 +/- 0.09). However, these glomerular structural parameters were statistically significantly higher in both diabetic subject groups compared with normal control subjects. Results were similar when patients receiving ACE inhibitors were excluded from the analyses.

CONCLUSIONS

Reduced nephron number is not associated with accelerated development of diabetic glomerulopathy lesions in type 1 diabetic patients.

[Pancreatic transplantation: 1. Indications and results]

In the face of a rising incidence of diabetes, pancreatic transplantation seems to be the only treatment capable of normalizing glycosylated hemoglobin and stabilizing or improving the complications of diabetes. To date, more than 19,000 pancreatic transplantations have been done worldwide. Surgical indications must take into account the constraints and risks specific to the diabetic illness, the risks of a complex surgical procedure, and the absolute necessity for long term immunosuppression. Combined kidney/pancreas transplantation is the most common procedure (90% of cases) and is the most effective treatment for renal insufficiency due to diabetes. Results have improved significantly over the last ten Years due to improvements in the surgical technique and to improvement of immunosuppressive regimens. Results are at least as good and perhaps better than those achieved in the transplantation of other solid organs; patient survival, renal graft survival, and pancreatic graft survival are respectively 95%, 92%, and 85% at one Year. Results of pancreatic transplantation alone have improved and now seem equal to those of combined organ transplantation. Transplantation seems to be cost-effective in the overall care of advanced diabetes, particularly in those patients on chronic dialysis or having degenerative complications.

Recurrent and de novo diabetic nephropathy in renal allografts

BACKGROUND

Histologic findings of diabetic nephropathy (DN) are observed in allografts of patients with pretransplant (PreTx) diabetes mellitus (DM) and in patients who develop DM posttransplant (PostTx). Patients with allograft biopsies (Bx) were retrospectively studied to determine the incidence of recurrent and de novo DN and to ascertain what, if any, risk factors predispose to histologic DN in either patient population.

METHODS

From the renal transplant services at four hospitals from 1992 to 2000, the authors identified all patients with PreTxDM and PostTxDM (n=81). Those with renal biopsies performed >/=18 months PostTx were classified according to the presence or absence of histologic DN (Bx-positive, n=23; Bx-negative, n=35). Patients were then subdivided into four categories-recurrent DN (n=16), de novo DN (n=7), no recurrent DN (n=27), and no de novo DN (n=8)-for analyses.

RESULTS

Among these 58 patients, 74.1% had PreTx and 25.9% had PostTx diabetes. Of those with histologic DN, 69.6% were recurrent DN and 30.4% were de novo DN, making de novo DN at least as likely to develop as recurrent DN. After the onset of diabetes in the de novo population, the time to development of histologic DN was similar in the recurrent and the de novo patients (6.68+/-3.86 years vs. 5.90+/-3.13 years, P=0.66) and more rapid than previously reported. Apart from a more frequent family history of hypertension in patients with allograft DN compared with those without allograft DN, known risk factors for the development of native DN did not significantly differ among patients in the four cohorts. Proposed risk factors related to transplantation did not correlate with the development of recurrent or de novo DN.

CONCLUSION

Among patients with histologic DN, de novo DN occurred at least as frequently as recurrent DN, and the time to onset of histologically apparent DN was more rapid than previously reported. Neither the usual clinical predictors of DN nor clinical variables related to transplantation clearly distinguished the group with DN from the group without it, potentially implicating novel mechanisms in its pathogenesis.

The relationship between glucose control and the development and progression of diabetic nephropathy

Diabetic nephropathy is a major cause of morbidity and mortality in patients with diabetes; it occurs in about one third of such patients. The course of nephropathy is better defined and similar for both type 1 and type 2 diabetes. Patients initially develop microalbuminuria (albumin excretion rates [AERs] between 20 and 200 micrograms/min), then overt nephropathy (AER > or = 200 micrograms/min), and finally a decline in glomerular filtration rate (GFR) eventuating in end-stage renal disease. Although metabolic control has long been hypothesized as a contributor to the development of nephropathy, it is only in recent years that this hypothesis has been proven. A number of observational studies have shown correlations between glycemic control and the development of various levels of albuminuria and also declines in GFR. However, large long-term prospective, randomized, interventional studies have now definitely proven that improved metabolic control that achieves near-normoglycemia can significantly decrease the development and progression of diabetic nephropathy as well as other long-term complications of diabetes, including retinopathy and neuropathy. It is now conceivable that the achievement of near-normoglycemia, plus medications that inhibit the renin-angiotensin system if microalbuminuria develops, may greatly decrease the numbers of patients eventually requiring renal replacement therapy.

Pancreas after kidney transplants in posturemic patients with type I diabetes mellitus

Pancreas after previous kidney (PAK) transplants are an attractive option for type 1 diabetic patients because of the short waiting time and use of living kidney donors. Factors associated with the increased success rate of PAK transplants in four immunosuppressive eras were analyzed. Between July 1, 1978, and April 30, 2000, 406 PAK transplants were performed in posturemic patients. Four immunosuppressive eras were analyzed: (1) the precyclosporine era, era 1 (n = 65; 16%); (2) the cyclosporine era, era 2 (n = 109; 27%); (3) the tacrolimus era with monoclonal or polyclonal antibody induction therapy, era 3 (n = 104; 26%); and (4) the tacrolimus era with monoclonal and polyclonal antibody induction therapy, era 4 (n = 128; 31%). Patient and graft survival, rejection, and technical failure rates were calculated. Patient survival rates have remained high over time, from 91% (era 1) to 96% (era 4) at 1 yr posttransplant. Pancreas graft survival rates with primary cadaver transplants have significantly increased, from 17% (era 1) to 81% (era 4) at 1 yr. The rate of graft loss from rejection has significantly decreased, from 78% (era 1) to 9% (era 4) at 1 yr. Results were best when donors and recipients were matched for at least one antigen per HLA locus. Kidney graft survival was higher in PAK transplant recipients compared with diabetic recipients of kidney transplants alone from the time of the kidney as well as the pancreas transplants. PAK recipients now enjoy >80% graft survival at 1 yr. This improvement in outcome results from better immunosuppression, good matching, and close posttransplant monitoring for rejection.

Lessons learned from more than 1,000 pancreas transplants at a single institution

OBJECTIVE

To determine outcome in diabetic pancreas transplant recipients according to risk factors and the surgical techniques and immunosuppressive protocols that evolved during a 33-year period at a single institution.

SUMMARY BACKGROUND DATA

Insulin-dependent diabetes mellitus is associated with a high incidence of management problems and secondary complications. Clinical pancreas transplantation began at the University of Minnesota in 1966, initially with a high failure rate, but outcome improved in parallel with other organ transplants. The authors retrospectively analyzed the factors associated with the increased success rate of pancreas transplants.

METHODS

From December 16, 1966, to March 31, 2000, the authors performed 1,194 pancreas transplants (111 from living donors; 191 retransplants): 498 simultaneous pancreas-kidney (SPK) and 1 simultaneous pancreas-liver transplant; 404 pancreas after kidney (PAK) transplants; and 291 pancreas transplants alone (PTA). The analyses were divided into five eras: era 0, 1966 to 1973 (n = 14), historical; era 1, 1978 to 1986 (n = 148), transition to cyclosporine for immunosuppression, multiple duct management techniques, and only solitary (PAK and PTA) transplants; era 2, 1986 to 1994 (n = 461), all categories (SPK, PAK, and PTA), predominantly bladder drainage for graft duct management, and primarily triple therapy (cyclosporine, azathioprine, and prednisone) for maintenance immunosuppression; era 3, 1994 to 1998 (n = 286), tacrolimus and mycophenolate mofetil used; and era 4, 1998 to 2000 (n = 275), use of daclizumab for induction immunosuppression, primarily enteric drainage for SPK transplants, pretransplant immunosuppression in candidates awaiting PTA.

RESULTS

Patient and primary cadaver pancreas graft functional (insulin-independence) survival rates at 1 year by category and era were as follows: SPK, era 2 (n = 214) versus eras 3 and 4 combined (n = 212), 85% and 64% versus 92% and 79%, respectively; PAK, era 1 (n = 36) versus 2 (n = 61) versus 3 (n = 84) versus 4 (n = 92), 86% and 17%, 98% and 59%, 98% and 76%, and 98% and 81%, respectively; in PTA, era 1 (n = 36) versus 2 (n = 72) versus 3 (n = 30) versus 4 (n = 40), 77% and 31%, 99% and 50%, 90% and 67%, and 100% and 88%, respectively. In eras 3 and 4 combined for primary cadaver SPK transplants, pancreas graft survival rates were significantly higher with bladder drainage (n = 136) than enteric drainage (n = 70), 82% versus 74% at 1 year (P =.03). Increasing recipient age had an adverse effect on outcome only in SPK recipients. Vascular disease was common (in eras 3 and 4, 27% of SPK recipients had a pretransplant myocardial infarction and 40% had a coronary artery bypass); those with no vascular disease had significantly higher patient and graft survival rates in the SPK and PAK categories. Living donor segmental pancreas transplants were associated with higher technically successful graft survival rates in each era, predominately solitary (PAK and PTA) in eras 1 and 2 and SPK in eras 3 and 4. Diabetic secondary complications were ameliorated in some recipients, and quality of life studies showed significant gains after the transplant in all recipient categories.

CONCLUSIONS

Patient and graft survival rates have significantly improved over time as surgical techniques and immunosuppressive protocols have evolved. Eventually, islet transplants will replace pancreas transplants for suitable candidates, but currently pancreas transplants can be applied and should be an option at all stages of diabetes. Early transplants are preferable for labile diabetes, but even patients with advanced complications can benefit.

Diabetic nephropathy after renal transplantation. Clinical and pathologic features

The histologic diagnosis of diabetic glomerulosclerosis was made in 14 renal transplant recipients. All 14 had insulin-dependent diabetes mellitus, which was the original cause of end-stage renal disease in 12; one patient had membranoproliferative glomerulonephritis and another patient had membranous nephropathy as the cause of end-stage renal disease. Insulin-dependent diabetes mellitus was diagnosed at an average age of 18.5 years (range, 8-41 years), and the mean duration of diabetes prior to transplantation was 15 years (range, 2-25 years). All patients were recipients of first kidney transplants (six living related donors and eight cadavers). The histologic diagnosis of diabetic glomerulosclerosis was made on average, 97 months after transplantation (range 41-154 months). All 14 patients had proteinuria (mean 5.3 g/24 hr; range 1.1-12 g/24 hr) and renal dysfunction (mean serum creatinine level, 2.8 mg/dl). Patient and graft survival rates at 1 year, 5 years, and 10 years after transplantation were 100%, 92%, and 59%, and 100%, 92%, and 34%, respectively. Graft failure was due to diabetic nephropathy in seven patients, diabetic nephropathy and membranous nephropathy in one patient, and death due to a cerebrovascular accident in one patient. A total of five patients are alive with a functioning kidney. Of the eight patients who returned to dialysis, four are alive, three remain on dialysis, and 1 had a combined kidney and pancreas transplant. Histologic findings were as follows: 9/14 had moderate or severe diffuse glomerular basement membrane thickening and 2/14 had nodular glomerulosclerosis. Arteriolar lesions were prominent in all cases and was graded moderate or severe in 11 cases. The development of allograft diabetic nephropathy is associated with a high rate of allograft failure.

Recurrent diseases in the kidney transplant

Virtually all diseases affecting the native kidney recur in the kidney transplant with the exception of Alport syndrome, polycystic kidney disease, hypertension, chronic pyelonephritis, and chronic interstitial nephritis. Fortunately, in the majority of patients, recurrence of the original disease has minimal clinical impact, with only approximately 5% of all graft loss occurring as a result of recurrent disease. The primary renal diseases that commonly recur include membranoproliferative glomerulonephritis type II, IgA nephropathy, and focal and segmental glomerular sclerosis. The most common systemic disease that recurs is diabetic nephropathy. Living-related transplantation should be used with caution in patients with the hemolytic uremic syndrome, recurrent focal and segmental glomerular sclerosis, and membraneous glomerulonephritis. Fabry disease and primary hyperoxaluria type I are no longer absolute contraindications to kidney transplantation.

De novo diabetic glomerulosclerosis in a renal allograft recipient

Posttransplant diabetes mellitus is a well-recognized complication of renal transplantation. Although such patients are at risk for the development of de novo diabetic glomerulosclerosis with increasing graft survival, this has rarely been reported. We describe a patient with posttransplant diabetes mellitus who developed end-stage renal failure due to diabetic glomerulosclerosis 12 years after renal transplantation.

Expression of transforming growth factor beta is elevated in human and experimental diabetic nephropathy

Diabetes is now the most common cause of progressive kidney failure leading to dialysis or transplantation. The central pathological feature of diabetic nephropathy is accumulation of extracellular matrix within the glomeruli. The factors in the diabetic milieu responsible for extracellular matrix accumulation are not understood. Here we report that in glomeruli of rats made diabetic there is a slow, progressive increase in the expression of transforming growth factor beta (TGF-beta) mRNA and TGF-beta protein. A key action of TGF-beta is induction of extracellular matrix production, and specific matrix proteins known to be induced by TGF-beta were increased in diabetic rat glomeruli. These proteins include an alternatively spliced form of fibronectin, tenascin, and the proteoglycan biglycan. TGF-beta has not previously been implicated in the matrix accumulation that occurs in the diabetic kidney. Glomeruli from humans with diabetic nephropathy also showed a striking increase in immunoreactive TGF-beta protein and deposition of the special form of fibronectin, whereas glomeruli from normal subjects or from individuals with other glomerular diseases (where extracellular matrix accumulation is not a feature) were negative or barely positive. These results implicate TGF-beta in the pathogenesis of diabetic nephropathy.

The glomerular mesangium in diabetes mellitus

Like the renal glomerular mesangium in patients with diabetic nephropathy, glomerular mesangial cell cultures grown in 30 mM glucose accumulate increased amounts of the extracellular matrix (ECM) proteins fibronectin, laminin, and type IV collagen. This is due to increased ECM protein synthesis and mRNA levels. Similar to other cells types that are affected by the diabetic state (such as, vascular cells and peripheral nerve), mesangial cells transport glucose by an insulin-independent, facilitated diffusion transport system. Kinetic studies reveal that intracellular glucose levels may reach the ambient glucose concentrations achieved in diabetes. Growth studies reveal that glucose does not exert its effect on mesangial cell ECM accumulation by affecting cell growth, but rather it causes an increase in diacylglycerol (DAG) mass and activates protein kinase C. Agents such as phorbol myristate acetate (PMA) and the cell permeable DAG analogue, oleoyl acetyl glycerol (OAG) which activate protein kinase C also increase ECM mRNAs. These results implicate protein kinase C activation in the increased ECM accumulation observed in mesangial cell cultures grown in high glucose.

Similarity of the constituents between glomerular arteriolar and mesangial lesions in experimental diabetes

In our previous studies in experimental diabetic rats, we have observed close similarities of ultrastructure and accumulation of IgG and IgM between the mesangial expansion and arteriolar hyalinosis of the glomerulus, and have presumed that both diabetic lesions are essentially of similar nature. In the present study, we carried out a further study on the constituents of both these lesions, using the PA-TCH-SP-PD technique for neutral carbohydrates, sialic acid and glycoproteins and the IgG-gold-silver technique for type IV collagen and fibronectin. The above staining and immunolabelings proved to be comparable in both lesions of diabetic glomerulopathies. This argues for the hypothesis of the identity of the two lesions.

Ultrastructural and immunohistochemical similarities between glomerular arteriolar and mesangial lesions in experimental diabetes

It has thus far been speculated that plasma proteins have leaked and accumulated in diabetic expanded mesangium. We have previously shown that glomerular arteriolar hyalinosis has frequently occurred and has consisted of basement membrane-like extracellular matrix in alloxan diabetic rats. In the present study, the two diabetic glomerular lesions, arteriolar hyaline nodules and increased mesangial matrix, were comparatively evaluated by means of electron microscopy and immunohistochemistry. It was revealed that both of these lesions contained, in common, finely particulate extracellular matrix mingled with cytoplasmic fragments, and exhibited intense immunoreactions for IgG and IgM. It is indicated that both types of diabetic glomerular lesions are essentially of the same nature.

Global glomerular sclerosis and glomerular arteriolar hyalinosis in insulin dependent diabetes

We studied the lesions of global glomerular sclerosis and arteriolar hyalinosis in 43 (29 females) insulin-dependent diabetes mellitus (IDDM) patients whose creatinine clearance (CCr) was greater than or equal to 45 ml/min/1.73 m2 and whose renal biopsies had at least 20 glomeruli available for study. These patients, ages 17 to 55 years, had IDDM for 7 to 32 (20 +/- 6, means +/- SD) years. CCr ranged from 47 to 139 (91 +/- 25) ml/min/1.73 m2 and urinary albumin excretion (UAE) from 5 to 3386 (median = 127) mg/24 hrs. Eighteen patients were hypertensive. Thus, these patients represented a broad clinical range from normal renal function through overt diabetic nephropathy. The percent of glomeruli which were globally sclerosed was strongly correlated with CCr (r = -0.64, P less than 0.0001) and log UAE (r = +0.67, P less than 0.001). Hypertension was more common in patients with more than 10% sclerosed glomeruli (chi square = 9.5, P less than 0.002). Percent sclerosed glomeruli was highly significantly correlated with the index of severity of the arteriolar hyalinosis lesion (r = +0.66, P less than 0.0001) and mesangial volume fraction (r = +0.61, P less than 0.0001). We hypothesize that arteriolar hyalinosis could contribute to global glomerular sclerosis through severe compromise of glomerular blood flow. Alternately, global glomerular sclerosis may result from marked mesangial expansion and capillary occlusion. However, in this broad range of patients it appeared that global glomerular sclerosis and mesangial expansion were not infrequently independent diabetic renal lesions which could contribute separately to the ultimate development of overt diabetic nephropathy.

Diabetic nephropathy: changing concepts of pathogenesis and treatment

The metabolic changes which accompany hyperglycemia in a person with diabetes are thought to cause renal hyperperfusion and intraglomerular hypertension, especially in the person with a predisposition to essential hypertension. Intraglomerular hypertension causing deposition of protein in the mesangium leads to glomerulosclerosis and renal failure. Screening for microalbuminuria can predict which type I diabetic patients will develop nephropathy. The decline in renal function in established diabetic nephropathy can be slowed with aggressive treatment of hypertension. The use of ACE inhibitors may also decrease intraglomerular hypertension. Whether similar treatment in the person with preclinical diabetic nephropathy would delay or prevent the onset of diabetic nephropathy is being investigated. Restricted protein intake, anti-platelet and rheolitic drugs may have a role in the treatment of established diabetic nephropathy. In end stage renal failure, renal transplantation is the treatment of choice. When transplantation cannot be performed, chronic ambulatory peritoneal dialysis is preferable to hemodialysis.

Diabetic nephropathy without hyperglycemia

Three cases are presented in which biopsy-proven diabetic nephropathy was found in nephrotic patients with no prior history of diabetes. One patient presented with advanced retinopathy and end-stage renal disease (ESRD), another with retinopathy and mild renal insufficiency, and a third with mild renal insufficiency alone. In each case, biopsy showed diffuse and nodular glomerulosclerosis with no evidence of kappa or lambda light chains. The patients had normal fasting serum glucose values, and two had normal oral glucose tolerance tests. Twenty-three similar cases in the literature were reviewed, and in most, some evidence of diabetes or hyperglycemia was found; five cases remained in which there was no evidence of hyperglycemia at any time. The cases reviewed included a disproportionate number of men (65%) and blacks (42%). It is concluded that diabetic nephropathy may exist in the absence of detectable hyperglycemia in a small number of extraordinarily susceptible individuals. Men and blacks appear to be at increased risk.

The mental efficiency of the elderly person with type II diabetes mellitus

Cognitive function is often impaired in type I diabetes mellitus, especially when onset is in early childhood. Limited evidence suggests similar impairment in the much larger population of older persons with type II diabetes. We report here the results of 13 measures of mental efficiency in persons between 65 and 77 years of age without gross mental impairment. Nineteen persons with type II diabetes were compared with 19 controls with normal glycosylated hemoglobin values and to seven persons not previously known to have diabetes but who had elevated glycosylated hemoglobin. Significant differences (P less than .05) between the nondiabetic control and diabetic groups were noted on eight of the 13 tests. The group of subjects with elevated glycosylated hemoglobins showed levels of cognitive performance intermediate between the normal and known diabetic groups on the majority of tests. These findings confirm that mental efficiency is frequently impaired in older persons with diabetes. Given the high prevalence of diabetes in the aging population we suggest that diabetes may be another important factor contributing to premature loss of cognitive abilities in older people.

Diabetic microangiopathy, genetics, environment, and treatment

As the major cause of disability and death in insulin-dependent diabetes, microangiopathy is obviously of major concern to diabetologists. Unlike macroangiopathy, which can readily be prevented by means that are currently on hand, the origin and treatment of microangiopathy remain far more problematical. The complexity of this lesion is indicated by the findings in this laboratory that hyperglycemia induced by the rodenticide, vacor, can cause microangiopathy independent of genetic diabetes, yet significant microangiopathic lesions can be detected in genetic diabetic patients before the appearance of hyperglycemia. Further, there is now intriguing evidence based both on basement membrane measurements from our laboratory and on clinical studies showing that significant microangiopathy only rarely occurs prior to the onset of puberty. The evidence that control or even normalization of blood glucose levels does not influence the course of established microangiopathy is becoming increasingly convincing. Five prospective, randomized studies over the past five years have shown that strict regulation of glucose has no consistent benefit on, and in some studies may, at least transiently, accelerate, the retinopathy of diabetes. Moreover, the first controlled study of successful pancreatic transplantation to achieve normalization of blood glucose levels has again demonstrated that established retinopathy is neither prevented nor even delayed by normal glucose levels. This review, therefore, emphasizes that, though hyperglycemia is required for clinically significant microangiopathy to occur, clearly other factors, genetic, environmental, or both, must play major roles in determining the course of microangiopathy. It is toward these nonglycemic factors in the development of diabetic microangiopathy that future research should increasingly be directed.

The relationship between metabolic control and vascular complications of diabetes mellitus

Animal studies strongly support the notion that the microvascular complications of diabetes are a consequence of the metabolic derangements. The evidence from human studies is not nearly as persuasive, but controlled prospective clinical trials are examining this issue more incisively than has been possible previously.

Some lessons from the studies of renal biopsies in patients with insulin-dependent diabetes mellitus

The authors have studied relationships of renal structure and function in more than 100 patients with insulin-dependent diabetes mellitus (IDDM), aged 13-55 years (mean, 30 years) with diabetes for 1-30 years (mean, 19 years). The authors confirmed the unique nature of the diabetic lesions that, in constellation, occur in no other disease. It was found that increased fractional mesangial volume (Vv Mes) is strongly associated with decreased glomerular filtration rate (GFR), proteinuria, and hypertension and that all patients with overt diabetic nephropathy have Vv Mes in excess of 0.35 micron 3/micron 3. This relationship results from constriction of the capillary lumen and filtration surface as a consequence of increased Vv Mes. Global glomerulosclerosis (scarring) is common in IDDM patients and appears related to arteriolar hyalinosis. Focal segmental glomerulosclerosis is a rare lesion in these patients. Having a single kidney (transplanted IDDM patients) is not associated with accelerated lesion development. The presence or absence of microalbuminuria (MA), per se, does not predict underlying glomerular structure, which may vary from the normal range to a level of pathology bordering on that regularly associated with overt nephropathy. However, when MA is associated with hypertension, or reduced GFR or both, urine albumin excretion (UAE) generally exceeds 40 mg/24 hr, and glomerular pathology is always present. The authors concluded that diabetic nephropathy is a unique renal disorder that cannot be caused by hemodynamic factors alone. The authors further conclude that MA becomes a predictor only when other features of overt nephropathy are already present and that serious diabetic glomerular lesions can be present in patients with normal UAE.

Pathobiochemical aspects of diabetic nephropathy

Diabetic nephropathy develops in many diabetic patients as consequence of glomerulosclerosis. On the basis of a series of recent observations it is suggested that a combination of metabolic and hemodynamic changes is responsible for the pathogenesis of diabetic nephropathy. Since the glomerular filtration unit has been characterized to consist of collagen type IV and minor components like laminin, fibronectin and heparan sulfate proteoglycan, influence of diabetes on basement membrane (BM) components has been studied. Biochemical alterations of glomerular BM consist of an increased nonenzymatic glucosylation of type IV collagen leading to unphysiological crosslinking. This, in turn, may result in alteration of the size selective properties of the glomerular filtration unit. Changes in composition of glomerular BM have recently been described. An increased synthesis of type IV collagen with concomitant decrease of heparan sulfate proteoglycan may lead to alteration of the charge selective barrier and consequently to increased permeability of the glomerular BM. Permanently unbalanced synthesis of BM components finally results in obliteration of the capillary lumen. In late state nephropathy intrinsic basement membrane components are no longer produced. Instead, massive accumulation of PAS positive material occurs.

Recurrence of disease following renal transplantation

The diagnosis of recurrent renal disease after transplantation is dependent on an accurate and complete diagnosis of the initial cause of renal failure and a similar determination of the cause of graft failure. To be classified as recurrent, the disease in the renal graft must be identical to that seen in the native kidneys. Recurrence of disease accounts for less than 2% of all graft failures, but the overall incidence of recurrent disease is probably 5 to 10 times more common. The most frequent cause of recurrent disease is glomerulonephritis, which was first recognized to recur soon after renal transplantation was introduced. It was then recognized that a variety of metabolic disorders would recur, but it has taken 25 years of experience for a clear picture to emerge of recurrence in most conditions. No initial cause of renal failure poses a contraindication to at least one attempt at transplantation, although with Fabry's disease and oxalosis, a special assessment of the risks for the individual recipient is warranted. In some patients, experience has shown the need for a delay in the commitment to transplantation (eg, in those with anti-glomerular basement membrane [GBM] antibody glomerulonephritis or Henoch Schonlein purpura), the need for the choice of a particular immunosuppressive regimen (eg, in hemolytic uremic syndrome [HUS]), the need for avoidance of primary nonfunction (eg, in oxalosis), and the desirability of avoiding live kidney donation (eg, in heterozygote donors in Fabry's disease, high-risk recipients with focal glomerulosclerosis, and in recipients with HUS). Probably all types of glomerulonephritis recur, but with great variation in frequency and severity. In some forms of glomerulonephritis, recurrence may be frequent and definite on histopathological criteria but may only have a minor clinical expression (eg, dense deposit disease, anti-GBM antibody glomerulonephritis, IgA nephropathy), but in others, recurrence is less predictable yet it is clearly associated with premature graft failure (eg, focal glomerulosclerosis, membranous nephropathy). A common theme emerging is that where the initial glomerulonephritis is aggressive and causes kidney failure over a short time, recurrence is more likely, and when present, it will lead to graft failure with an increased frequency. Clinical manifestations, the frequency of recurrence, and the prognosis of the graft are now identified for most conditions. Unexpected observations have included the rarity of recurrent systemic lupus erythematosus (SLE), the immediate return of heavy proteinuria in focal glomerulosclerosis, and the predictable return of dense deposit disease.(ABSTRACT TRUNCATED AT 400 WORDS)

Renal transplantation in diabetic patients is confirmed therapy while pancreas transplantation should be performed only in an investigational setting

Kidney transplantation is now firmly established as the standard treatment for all diabetic patients with end-stage renal failure. In an analysis of all renal transplants at the University of Minnesota between June 1, 1980 and May 31, 1987, there were no differences in renal allograft functional survival rates for diabetic and nondiabetic recipients. At one year the survival rates were 84% (n = 151) and 86% (n = 260) for those treated with azathioprine, prednisone and ALG; 86% (n = 101) and 87% (n = 104) for those treated with cyclosporine-prednisone, and 92% (n = 165) and 89% (n = 191) for those treated with triple therapy (cyclosporine, azathioprine, and prednisone). Pancreas transplantation remains an investigational procedure for nonuremic diabetic patients but may be considered therapeutic in diabetic renal allograft recipients because such patients are obligated to immunosuppression and only the surgical risks of pancreas transplantation need to be considered, which are now acceptably low. Recipients of pancreas transplants performed simultaneous with the kidney have patient and pancreas graft survival rates of greater than 90% and +/- 60% at several institutions, including our own. The potential for benefit of pancreas transplantation, however, is greater in the nonuremic nonkidney transplant patient, and pancreas transplantations are being performed in such patients at a few institutions. An early beneficial effect of pancreas transplantation preexisting proliferative retinopathy has not been discerned, although long-term retinopathy has been stable in patients with functioning grafts. Preliminary studies have shown a beneficial effect on neuropathy and on microscopic lesions of diabetic nephropathy, but at the expense of cyclosporine toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of whole pancreas and pancreatic islet transplantation in controlling nephropathy and metabolic disorders of diabetes

To compare the long-term effectiveness of whole pancreas transplantation and pancreatic islet transplantation in controlling the metabolic disorders and preventing the kidney lesions of alloxan diabetes, metabolic and morphologic studies were performed in four groups of rats: (1) NC-116 nondiabetic controls; (2) DC-273 untreated alloxan-diabetic controls; (3) PDT-182 rats that received syngeneic pancreaticoduodenal transplants not long after induction of diabetes with alloxan; and (4) IT-92 rats that received an intraportal injection of at least 1500 and usually 2000 syngeneic pancreatic islets soon after induction of diabetes with alloxan. Each month for 24 months after diabetes was well established, body weight and plasma concentrations of glucose and insulin were measured, and five lesions were scored by light microscopy in 50 glomeruli and related tubules in each kidney by a "blind" protocol: glomerular basement membrane thickening, mesangial enlargement, Bowman's capsule thickening, Armanni-Ebstein lesions of the tubules, and tubular protein casts. There were progressive and highly significant increases in the incidence and severity of all five kidney lesions in the diabetic control rats compared with the nondiabetic control rats. No significant differences were found between the kidneys of Group PDT and those of Group NC, demonstrating that whole pancreas transplantation prevented all of the diabetic kidney lesions throughout the 2-year study period. In contrast, within 3-9 months after pancreatic islet transplantation and thereafter, the incidence and severity of the five diabetic kidney lesions were similar in Group IT and Group DC. Whole pancreas transplantation produced precise metabolic control of diabetes throughout the 24 months of study, whereas pancreatic islet transplantation did not accomplish complete metabolic control, particularly beyond the first several months after transplantation. The difference in the completeness of metabolic control achieved by the two types of transplants is the most likely explanation for their sharp difference in effectiveness in preventing diabetic nephropathy.

New establishment of hypertensive diabetic animal models: neonatally streptozotocin-treated spontaneously hypertensive rats

Hypertensive diabetic animal models have been developed by injecting streptozotocin (STZ) in neonatal stroke-resistant spontaneously hypertensive rats (SHRSR) and stroke-prone SHR (SHRSP) at the age of two days. After the treatment, the animals showed mild insulin deficiency and mild hyperglycemia at the age of three to four months. Diabetic nephropathy was produced particularly in STZ-treated SHRSR at the age of six months. The effect of neonatal STZ injection on hyperglycemia varied among normotensive Wistar-Kyoto rats (WKY), SHRSR, and SHRSP; SHRSR showed the highest glucose levels, SHRSP showed intermediate levels, and WKY was the lowest. All STZ-treated SHRSR showed glycosuria, while glycosuria was not observed in the treated SHRSP and WKY. Histologic study indicated that these strain differences were partly ascribed to differences in islet B-cell sensitivity to toxic effects of STZ. The development of hypertension was not accelerated in these SHRSR and SHRSP compared with respective nontreated controls. Since STZ-treated SHRSR develop mild diabetic symptom with hypertension and develop mild diabetic glomerulosclerosis, they are good models for studying vascular complications or other problems relating to the synergism between hypertension and diabetes mellitus.