Progression of macrovascular disease after transplantation

Immunosuppression-related neurological disorders in kidney transplantation

A large number of neurological disorders can affect renal transplant recipients, potentially leading to disabling or life-threatening complications. Prevention, early diagnosis and appropriate management of these conditions are critical to avoid irreversible lesions. A pivotal role in the pathogenesis of common post-transplant neurological disorders is played by immunosuppressive therapy. The most frequently administered regimen consists of triple immunosuppression, which comprises a calcineurin inhibitor (CNI), a purine synthesis inhibitor and glucocorticoids. Some of these immunosuppressive drugs may lead to neurological signs and symptoms through direct neurotoxic effects, and all of them may be responsible for the development of tumors or opportunistic infections. In this review, after a brief summary of neurotoxic pathogenetic mechanisms encompassing recent advances in the field, we focus on the clinical presentation of more common and severe immunosuppression-related neurological complications, classifying them by characteristics of urgency and anatomic site. Our goal is to provide a general framework that addresses such clinical issues with a multidisciplinary approach, as these conditions require.

Pancreas Transplantation: Indications, Techniques, and Outcomes

Pancreas transplantation treats insulin-dependent diabetes with or without concurrent end-stage renal disease. Pancreas transplantation increases survival versus no transplant, increases survival when performed as simultaneous pancreas-kidney versus deceased-donor kidney alone, and improves quality of life. Careful donor and recipient selection are paramount to good outcomes. Several technical variations exist for implantation: portal versus systemic vascular drainage and jejunal versus duodenal versus bladder exocrine drainage. Complications are most frequently technical in the first year and immunologic thereafter. Graft rejection is challenging to diagnose and is treated selectively. Islet cell transplantation currently has inferior outcomes to whole-organ pancreas transplantation.

Follow-up of secondary diabetic complications after pancreas transplantation

PURPOSE OF REVIEW

Successful pancreas transplantation restores physiologic glycemic and metabolic control. Its effects on overall patient survival (especially for simultaneous pancreas-kidney transplantation) are clear-cut. We herein review the available literature to define the impact of pancreas transplantation on chronic complications of diabetes mellitus.

RECENT FINDINGS

With longer-term follow-up, wider patient populations, and more accurate investigational tools (clinical and functional tests, noninvasive imaging, histology, and molecular biology), growing data show that successful pancreas transplantation may slow the progression, stabilize, and even favor the regression of secondary complications of diabetes, both microvascular and macrovascular, in a relevant proportion of recipients.

SUMMARY

Patients who are referred for pancreas transplantation usually suffer from advanced chronic complications of diabetes, which have classically been deemed irreversible. A successful pancreas transplantation is often able to slow the progression, stabilize, and even reverse many microvascular and macrovascular complications of diabetes. Growing clinical evidence shows that the expected natural history of long-term diabetic complications can be significantly modified by successful pancreas transplantation.

Pancreas transplantation

SPK transplant is the definitive treatment of type 1 diabetes combined with end-stage renal disease. Long-term graft function can lead to improvement in diabetes-related complications and, in patients younger than 50 years, can lead to improved overall survival. PAK transplant and PA transplant do not result in similar improvements in patient survival, but with appropriate patient selection, they can improve quality of life by rendering patients insulin-free. Pancreas transplant is associated with more surgical complications and higher perioperative morbidity and mortality than KTA. Therefore, careful donor and recipient selection along with meticulous surgical technique are mandatory for optimal outcomes.

Pancreas transplantation

Since the introduction of pancreas transplantation more than 40 years ago, efforts to develop more minimally invasive techniques for endocrine replacement therapy have been in progress, yet this surgical procedure still remains the treatment of choice for diabetic patients with end-stage renal failure. Many improvements have been made in the surgical techniques and immunosuppressive regimens, both of which have contributed to an increasing number of indications for pancreas transplantation. This operation can be justified on the basis that patients replace daily injections of insulin with an improved quality of life but at the expense of a major surgical procedure and lifelong immunosuppression. The various indications, categories, and outcomes of patients having a pancreas transplant are discussed, particularly with reference to the effect on long-term diabetic complications.

The impact of functioning pancreas-kidney transplantation and pancreas alone transplantation on the lipid metabolism of statin-naïve diabetic patients

OBJECTIVE

To compare the lipid profile (total cholesterol - TC, triglycerides - TG, high density lipoprotein cholesterol - HDL-c, low density lipoprotein cholesterol - LDL-c and non-HDL cholesterol - NHDL-c) of patients with functioning pancreas-kidney transplantation (PKT) or pancreas transplantation alone (PTA) after one (T1) and two yr (T2) following their pre-transplantation data (T0).

METHODS

Fifty-three type 1 diabetic patients underwent pancreas transplantation (42 PKT and 11 PTA) remaining euglycemic after transplantation were evaluated before and one and two yr after the procedures. They were using predominantly tacrolimus-mycophenolate mofetil-based immunosuppression and low glucocorticoid dose with systemic venous drainage of the pancreatic graft. None of them used hypolipidemic agents for economical reasons. Lipids were reported as means +/- standard error of the mean. Data obtained in T0 were compared with T1 and T2 using ANOVA followed by Student's t-test.

RESULTS

TC, LDL-c, NHDL-c and TG were lower in T1 and T2 when compared with T0 (p < 0.05) in PKT, while no change was observed for HDL-c (p > 0.05). PTA group showed no significant changes in lipids.

CONCLUSION

In spite of the known side effects of tacrolimus-based immunosuppression to lipids, our study with a statin-naïve sample showed improvements (PKT) or stabilization (PTA) in the serum lipid profile after pancreas transplantation.

Neuroimaging and neurologic complications after organ transplantation

Neurologic complications are common after transplantation and affect 30-60% of transplant recipients. The etiology of most of the posttransplant neurologic disorders is related to the opportunistic infections, both systemic and involving central nervous system (CNS), toxicity of immunosuppressive medications, and the metabolic insult created by the underlying primary disease and the transplant procedure. Neuroimaging studies are one of the key tools in the evaluation and enable early diagnosis of neurologic complications in transplant patients, especially posterior reversible leukoencephalopathy syndrome, central pontine myelinolysis, intracerebral hemorrhage, and fungal and bacterial abscesses. Magnetic resonance imaging (MRI) is the preferred technique, but each of the available neuroimaging techniques offers a unique insight into the pathophysiologic mechanisms underlying neurologic complications of transplantation. The role of neuroimaging in this population includes early detection of calcineurin inhibitor neurotoxicity, opportunistic infections, neoplasia, metabolic disorders, or cerebrovascular diseases. In addition, we can monitor longitudinal progression of disease and treatment response.

The long-term management of pancreas transplantation

Diabetes mellitus (DM) is a major health problem worldwide, which affects 18.2 million individuals (6.3% of the population) in the United States. Currently, the prevalence of Type 1 DM in the United States is estimated to be 1,000,000 individuals, and 30,000 new cases are diagnosed each year. In addition to end-stage renal disease (ESRD), DM is associated with blindness, accelerated atherosclerosis, dyslipidemia, cardio- and cerebrovascular disease, amputation, poor quality of life, and overall lifespan reduction. It accounts for more than 160,000 deaths per year in the United States alone. In 2002, the annual national direct and indirect costs of Types 1 and 2 DM exceeded $130 billion, which included hospital and physician care, laboratory tests, pharmaceutical products, and patient workdays lost because of disability or premature death. Hyperglycemia alone or in concert with hypertension is the primary factor influencing the development of major diabetic complications. From 1990 to 2001, the number of existing ESRD cases to DM increased by more than 300%, while the rate per million populations increased from 167% to 491%. The number is expected to grow 10-fold by 2030 to 1.3 million accounting for 60% of ESRD population. To date, DM is the leading indication for transplantation and is the cause of ESRD in more than 40% of all transplant recipients each year.

Relationship between oxidative stress parameters and atherosclerotic signs in the carotid artery of stable renal transplant patients

Reactive oxygen species (ROS) may participate in atheroma plaque formation, which may be noninvasively diagnosed by Doppler ultrasound of carotid artery. We sought to determine the relationship between the presence of carotid artery lesions and oxidative parameters to identify factors that may influence these lesions in renal transplant patients. Fifty renal transplanted patients with stable renal function and without diabetes mellitus were studied for more than 1 year posttransplantation. Echo Doppler examination of the carotid artery was performed to assess the intimal media thickness (IMT), atheroma plaques, calcification, and stenosis. Data were collected on oxidative parameters: malondialdehyde (MDA), glutathione peroxidase (GPx), catalase, superoxide dismutase (SOD), glutathione reductase (GR), and lipid profile. The serum GPx level among patients without atheroma plaques, calcification, or stenosis was higher than in those with ultrasound signs. The LDL cholesterol fraction was lower in patients with no ultrasound signs of atherosclerotic lesions; total cholesterol values showed the same behavior. In conclusion, transplanted patients with atheromatous plaques, calcification, and carotid stenosis have a greater degree of hypercholesterolemia and lower antioxidant activity (lower GPx). Recipient age was the principal risk factor for the presence of increased IMT, atheroma plaque, calcification, and/or stenosis of carotid artery in renal transplant patients.

Pancreas and islet cell transplantation

Transplantation of the pancreas or islet cells constitutes surgical treatment for patients with type 1 diabetes mellitus. Pancreas transplantation is now an established procedure for the surgical treatment of diabetes mellitus. Islet cell transplantation has the potential to be the procedure of choice once it becomes more routine because of the minimal surgery involved. Included in this chapter are the pathophysiology of diabetes, rationale for transplantation, and the surgical procedure itself.

Pancreas transplantation: indications and consequences

Pancreas transplantation continues to evolve as a strategy in the management of diabetes mellitus. The first combined pancreas-kidney transplant was reported in 1967, but pancreas transplant now represents a number of procedures, each with different indications, risks, benefits, and outcomes. This review will summarize these procedures, including their risks and outcomes in comparison to kidney transplantation alone, and how or if they affect the consequences of diabetes: hyperglycemia, hypoglycemia, and microvascular and macrovascular complications. In addition, the new risks introduced by immunosuppression will be reviewed, including infections, cancer, osteoporosis, reproductive function, and the impact of immunosuppression medications on blood pressure, lipids, and glucose tolerance. It is imperative that an endocrinologist remain involved in the care of the pancreas transplant recipient, even when glucose is normal, because of the myriad of issues encountered post transplant, including ongoing management of diabetic complications, prevention of bone loss, and screening for failure of the pancreas graft with reinstitution of treatment when indicated. Although long-term patient and graft survival have improved greatly after pancreas transplant, a multidisciplinary team is needed to maximize long-term quality, as well as quantity, of life for the pancreas transplant recipient.

Impact of kidney transplantation on glycemic control and cardiovascular risk factors in insulin-treated diabetic patients receiving cyclosporine: A longitudinal study

BACKGROUND

In insulin-treated patients with diabetes, kidney transplantation (KTP) may influence glycemic control, insulin requirements, as well as vascular risk profiles, but the data are controversial. In 10 selected insulin-treated diabetic patients with normally functioning kidney transplants, receiving cyclosporine for immunosuppression, we evaluated the fasting blood glucose, HbA1c, lipid levels, blood pressure, and insulin-requirement from 1 year before to 1 year after KTP.

RESULTS

There were no significant differences in the mean HbA1c levels 6 and 3 months before transplantation (8.3 +/- 1.7 and 8.0 +/- 1.4%, respectively) and 3 and 12 months after transplantation (8.2 +/- 1.6 and 7.9 +/- 1.5%, respectively). The mean fasting blood glucose levels increased only transiently by 7% during the first week after transplantation (not significant). The insulin requirement was approximately the same at 3 and 6 months before (42 +/- 14 and 42 +/- 13 IU/d, respectively) and at 3 and 12 months after transplantation (44 +/- 13 and 41 +/- 13 IU/mL, respectively). Only 1 week after transplantation did the insulin requirement increase transiently by 14% to 48 +/- 14 IU/d (P < .05). The mean levels of cholesterol and triglycerides as well as mean blood pressure were not significantly different before and after transplantation.

CONCLUSION

Only immediately after KTP did mean blood glucose and insulin requirement increase. At least 3 months after transplantation, glycemic control and insulin requirements as well as the vascular risk factors were approximately the same as before the procedure.

Pancreas transplantation improves vascular disease in patients with type 1 diabetes

OBJECTIVE

Pancreas transplantation (PTX) normalizes glucose and improves microvascular complications, but its impact on macrovascular disease is still debated.

RESEARCH DESIGN AND METHODS

Carotid intima-media thickness (IMT), shown to correlate with cardiovascular disease (CVD) risk and events, was determined prospectively by ultrasonography in successful pancreas transplant recipients to evaluate the effect of PTX on CVD risk. Carotid IMT and CVD risk factors of pancreas transplant recipients (n = 25) were compared with three groups: individuals with type 1 diabetes without significant nephropathy (n = 20), nondiabetic kidney transplant recipients (n = 16), and normal control subjects (n = 32). Mean age of pancreas transplant recipients at the time of transplantation was 42.4 +/- 1.2 years (mean +/- SE) and duration of diabetes was 25.9 +/- 1.4 years.

RESULTS

After PTX, HbA(1c) level (P < 0.0001) decreased to normal and, whereas creatinine level (P = 0.0002) decreased, it remained elevated compared with normal control subjects (P < 0.05). Blood pressure, BMI, fasting lipid levels, smoking frequency, and use of hypolipidemic agents were unchanged. Mean carotid IMT was increased in pancreas transplant candidates but decreased by 1.8 +/- 0.1 year after PTX (P = 0.0068), no longer different from that in normal control subjects or patients with type 1 diabetes.

CONCLUSIONS

Carotid IMT improves after successful PTX within 2 years of the procedure, with normalization of HbA(1c) and improved renal function, independent of changes in lipid levels, BMI, blood pressure, smoking, or use of hypolipidemic agents. This study suggests that CVD risk, future events, and mortality should improve after PTX in the absence of other significant, untreated CVD risk factors.

Impact of kidney transplantation on the progression of cardiovascular disease

Kidney transplantation, of all the treatment modalities for end-stage renal disease, affords the greatest potential for prolonged survival and improved quality of life. Great strides in immunosuppressant therapy have improved graft survival and forced clinicians to consider other health-care needs of kidney transplant recipients. Chief among these needs is the prevention and treatment of cardiovascular disease. Cardiovascular disease is the most common cause of death among patients with a working renal allograft. Because therapies for primary and secondary prevention are successful in the general population, transplant clinicians are increasingly focused on preventing or limiting the progression of cardiovascular disease. Initiation of aggressive management of conventional atherosclerotic risk factors and uremia-related risk factors, ideally during the early stages of chronic kidney disease (CKD) or after kidney transplantation, and efforts to delay the progression of kidney disease will hopefully reduce the cardiovascular burden in transplant recipients.

Infrainguinal revascularization after renal transplantation

BACKGROUND

Although evidence suggests that end-stage renal disease is associated with poor limb salvage and patient survival after arterial revascularization, little is known about the effect of renal transplantation. We analyzed the outcome in patients with renal transplants who underwent infrainguinal bypass procedures.

METHODS

Data prospectively entered into our vascular registry were reviewed for all patients who underwent lower extremity bypass procedures from January 1, 1990, through January 31, 2002. Sixty patients were identified who had a functioning renal allograft at infrainguinal revascularization. Kaplan-Meier survival curves were generated for limb salvage, patency, and patient survival and were compared with the Mantel-Cox log- rank test.

RESULTS

Sixty patients (40 men, 20 women; mean age, 47.1 years) underwent 76 bypass procedures in 71 limbs. Preoperative demographic data included diabetes (59 of 60 patients, 98.3%), coronary artery disease (26 of 60 patients, 43.3%), and preoperative serum creatinine concentration (SCr) greater than 2.0 mg/dL (9 of 60 patients, 11.7%). Mean follow-up was 25.1 months. Overall major complication rate was 11.8%, and 30-day mortality rate was 1.3%. Survival was 93.3% at 1 year and 66.6% at 5 years. Limb salvage was 87% at 1 year and 78% at 5 years. Primary graft patency was 78% at 1 year and 44% at 5 years. Preoperative SCr less than or equal to 2.0 mg/dL was associated with improved overall patient survival (5-year survival, 73.4% vs 37.5%; P =.01, log-rank test). Limb salvage and patency rates were not significantly affected by preoperative SCr greater than 2.0 mg/dL.

CONCLUSIONS

Lower extremity bypass can be performed safely and effectively in patients who have undergone renal transplantation. However, the importance of a well-functioning renal allograft at surgery is demonstrated by marked improvement in patient survival.

Pancreas and kidney transplantation

Kidney transplantation is preferred over dialysis for management of end-stage renal disease complicating type I or type 2 diabetes, for those who are eligible. Simultaneous pancreas-kidney (SPK) or pancreas after kidney transplantation (PAK) is an important alternative to kidney transplantation alone for type I diabetes patients if the patient is able to withstand the additional risks of these procedures, because of the benefits of glucose control on other diabetic complications. Pancreas transplantation alone (PTA) is most useful for the treatment of debilitating, frequent hypoglycemia complicating type I diabetes, if renal function is adequate. One-year pancreas graft survival is best after SPK (82%) but has significantly improved after both PAK (74%) and PTA (76%). The I-year kidney graft and patient survival rates after SPK are similar to kidney transplantation alone. Pancreas transplantation normalizes glucose beyond what can be achieved with insulin therapy and has been shown to decrease progression of or improve most, if not all, diabetic end-organ complications using current immunosuppression regimens. However, the diabetologist and endocrinologist should remain involved in the care of the pancreas or kidney transplant recipient for treatment of vascular disease risk factors such as dyslipidemia, surveillance of other diabetic complications including foot ulcers, surveillance and treatment of bone loss, and management of hyperglycemia if it recurs.

Cigarette smoking: an important renal risk factor - far beyond carcinogenesis

In recent years, it has become apparent that smoking has a negative impact on renal function, being one of the most important remediable renal risk factors. It has been clearly shown that the risk for high-normal urinary albumin excretion and microalbuminuria is increased in smoking compared to non-smoking subjects of the general population. Data from the Multiple Risk Factor Intervention Trial (MRFIT) indicate that at least in males, smoking increases the risk to reach end-stage renal failure. Smoking is particularly "nephrotoxic" in older subjects, subjects with essential hypertension and patients with preexisting renal disease. Of interest, the magnitude of the adverse renal effect of smoking seems to be independent of the underlying renal disease. Death-censored renal graft survival is decreased in smokers, indicating that smoking also damages the renal transplant. Cessation of smoking has been show to reduce the rate of progression of renal failure both in patients with renal disease or a renal transplant. The mechanisms of smoking-induced renal damage are only partly understood and comprise acute hemodynamic (e.g., increase in blood pressure and presumably intraglomerular pressure) and chronic effects (e.g., endothelial cell dysfunction). Renal failure per se leads to an increased cardiovascular risk. The latter is further aggravated by smoking. Particularly survival of smokers with diabetes mellitus on hemodialysis is abysmal. In the present review article the current state of knowledge about the renal risks of smoking is reviewed. It is the aim of the article to point out that smoking not only increases the risk of renal cell carcinoma or uroepithelial cell carcinoma, but also the risk of a faster decline of renal function. The latter is a relatively new negative aspect which has not been widely recognized.

Transplante de Pâncreas e de Ilhotas Pancreáticas: Visão de Nefrologista

Os autores, após dimensionarem o problema do diabetes mellitus e da nefropatia diabética no Brasil e no mundo, fazem uma revisão, sob a ótica do nefrologista, sobre transplante de pâncreas e de ilhotas pancreáticas, centrada nos riscos e benefícios do transplante combinado de pâncreas e rim (TCPR) para o diabético urêmico. No texto é ressaltada a importância da colaboração entre o endocrinologista e o nefrologista para melhorar a sobrevida dos diabéticos com nefropatia e para uma definição local sobre a viabilidade e validade do estabelecimento de um programa de TCPR.

Carotid intima media thickness decreases after pancreas transplantation

BACKGROUND

Pancreas transplantation (PTX) improves diabetic microvascular complications, but it is unknown whether PTX alters macrovascular disease. Carotid intima media thickness (IMT) has been shown to correlate with cardiovascular events, so this study was designed to evaluate changes in carotid IMT after PTX.

METHODS

Four groups were studied: PTX candidates (n=60); successful PTX recipients (n=89; mean time since PTX=4.0+/-0.3 years); patients with type 1 diabetes but without nephropathy (n=20); and normal controls (n=32). Mean IMT and mean of maximum carotid IMT measurements (mean-max IMT), hemoglobin A1C, serum creatinine, body mass index (BMI), blood pressure, smoking status, use of hypolipidemic medications, and fasting lipids were determined in all groups.

RESULTS

Age, gender distribution, and BMI were not different among the groups. Duration of diabetes was also equal between pre- and post-PTX groups. Mean and mean-max IMT were greatest pre-PTX and decreased after PTX (P<0.05) to a value that was not different from controls. Hemoglobin A1C and creatinine decreased, and high density lipoprotein (HDL) increased after PTX (P<0.05), but there were no significant differences in other lipids, BMI, use of lipid lowering agents, blood pressure, or smoking status.

CONCLUSIONS

Carotid IMT is lower after PTX, suggesting a reduction in overall cardiovascular risk independent of changes in use of hypolipidemic agents, smoking, blood pressure, BMI, or lipids, except HDL. Improved carotid IMT after successful PTX predicts a reduction in future vascular disease events and suggests that the macrovascular disease of type 1 diabetes is at least partially reversible with improved glucose control.

Neurologic complications of transplantation

BACKGROUND

Organ transplantation is one of the most dynamic fields in medicine and has evolved into a life-saving option for thousands of patients with previously fatal conditions. The posttransplantation clinical course is frequently associated with neurologic complications that are usually related to pretransplant morbidity, the surgical procedure of transplantation, immunosuppression, and opportunistic infection.

REVIEW SUMMARY

Neurologic complications of organ transplantation may be divided into complications common to all types of allografts and complications that are specific for a particular type of organ transplantation. The most common complications include seizures, opportunistic central nervous system (CNS) infection, metabolic encephalopathy, stroke, intracranial hemorrhage, and drug-related adverse events. Opportunistic CNS infection may have a subtle presentation and should not be overlooked, as the consequences of delayed treatment may be grave. Neurotoxicity of immunosuppressive agents is also a frequent cause of neurologic complications and may occur in the setting of normal serum drug levels. The clinical course of transplant patients is frequently complex, requiring close cooperation between the transplant team and specialty consultants. Prolonged survival of transplant patients will shift the focus of neurologic complications from acute, perioperative to chronic complications of immunosuppression.

CONCLUSIONS

Neurologic complications of organ transplantation are commonly related to opportunistic infection or neurotoxicity of immunosuppressive agents, requiring careful titration of immunosuppression. Timely diagnosis of CNS infection or other causes of neurologic dysfunction may significantly improve recovery and outcome in these patients.

Trends and perspectives in pancreas and simultaneous pancreas and kidney transplantation

Pancreas transplantation is still the best option to achieve normoglycaemia and insulin independence in patients with type I diabetes. As a result of improvements in surgical techniques, immunosuppression and patient selection, one year survival rates of 95, 83, and 88% for patient, pancreas, and kidney survival, respectively, are reported for patients with simultaneous pancreas and kidney transplantation. The main goals for the future are to reduce postoperative morbidity, to identify the relevant indications for single pancreas transplantation, to adopt the best surgical technique for individual patients' needs (bladder versus enteric drainage with or without portal venous delivery of insulin), and to develop immunosuppressive strategies with low nephrotoxic and diabetogenic potential.

Appropriateness and timing of kidney and/or pancreas transplants in type 1 and type 2 diabetes

Cure of diabetes through cell or organ transplantation remains an unattained but highly desirable goal. For now, prevention of end organ complications of diabetes is the most appropriate application of transplantation for patients with enough evidence of progressive disease to justify the substantial surgical and immunosuppression-based risks of pancreas transplantation. Uremic diabetics should, if possible, be offered renal transplantation, alone or in combination with pancreas transplantation, to obviate the excessive mortality associated with prolonged maintenance dialysis. Islet transplantation has been widely clinically unsuccessful but holds new promise as the therapy of choice for the future. This report reviews the history, state of the art, and selection process for timing and application of currently available transplantation modalities for diabetic patients.