Effects of combined pancreatic and renal transplantation on diabetic neuropathy: a two-year follow-up study

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.

Autonomic dysfunction as a mechanism of intradialytic blood pressure instability

The autonomic nervous system (ANS) is the principal endogenous defense mechanism that maintains blood pressure in the setting of hypotension. Disruption of the ANS impairs this ability and can contribute to blood pressure instability, including hypotension and hypertension. In this narrative review, we provide an overview of the ANS and the consequences of its dysfunction in patients with end-stage kidney disease treated with dialysis. We also discuss possible mechanisms of this autonomic dysfunction that may need future investigation.

Microvascular damage in type 1 diabetic patients is reversed in the first year after simultaneous pancreas-kidney transplantation

Simultaneous pancreas-kidney transplantation (SPK) is an advanced treatment option for type 1 diabetes mellitus (DM) patients with microvascular disease including nephropathy. Sidestreamdarkfield (SDF) imaging has emerged as a noninvasive tool to visualize the human microcirculation. This study assessed the effect of SPK in diabetic nephropathy (DN) patients on microvascular alterations using SDF and correlated this with markers for endothelial dysfunction. Microvascular morphology was visualized using SDF of the oral mucosa in DN (n = 26) and SPK patients (n = 38), healthy controls (n = 20), DM1 patients (n = 15, DM ≥ 40 mL/min) and DN patients with a kidney transplant (KTx, n = 15). Furthermore, 21 DN patients were studied longitudinally up to 12 months after SPK. Circulating levels of angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2) and soluble thrombomodulin (sTM) were measured using ELISA. Capillary tortuosity in the DN (1.83 ± 0.42) and DM ≥ 40 mL/min (1.55 ± 0.1) group was increased and showed reversal after SPK (1.31 ± 0.3, p < 0.001), but not after KTx (1.64 ± 0.1). sTM levels were increased in DN patients and reduced in SPK and KTx recipients (p < 0.05), while the Ang-2/Ang-1 ratio was normalized after SPK and not after KTx alone (from 0.16 ± 0.04 to 0.08 ± 0.02, p < 0.05). Interestingly, in the longitudinal study, reversal of capillary tortuosity and decrease in Ang-2/Ang-1 ratio and sTM was observed within 12 months after SPK. SPK is effective in reversing the systemic microvascular structural abnormalities in DN patients in the first year after transplantation.

Regenerative therapies for diabetic microangiopathy

Hyperglycaemia occurring in diabetes is responsible for accelerated arterial remodeling and atherosclerosis, affecting the macro- and the microcirculatory system. Vessel injury is mainly related to deregulation of glucose homeostasis and insulin/insulin-precursors production, generation of advanced glycation end-products, reduction in nitric oxide synthesis, and oxidative and reductive stress. It occurs both at extracellular level with increased calcium and matrix proteins deposition and at intracellular level, with abnormalities of intracellular pathways and increased cell death. Peripheral arterial disease, coronary heart disease, and ischemic stroke are the main causes of morbidity/mortality in diabetic patients representing a major clinical and economic issue. Pharmacological therapies, administration of growth factors, and stem cellular strategies are the most effective approaches and will be discussed in depth in this comprehensive review covering the regenerative therapies of diabetic microangiopathy.

Neurological complications of chronic kidney disease

Chronic kidney disease (CKD) is a critical and rapidly growing global health problem. Neurological complications occur in almost all patients with severe CKD, potentially affecting all levels of the nervous system, from the CNS through to the PNS. Cognitive impairment, manifesting typically as a vascular dementia, develops in a considerable proportion of patients on dialysis, and improves with renal transplantation. Patients on dialysis are generally weaker, less active and have reduced exercise capacity compared with healthy individuals. Peripheral neuropathy manifests in almost all such patients, leading to weakness and disability. Better dialysis strategies and dietary modification could improve outcomes of transplantation if implemented before surgery. For patients with autonomic neuropathy, specific treatments, including sildenafil for impotence and midodrine for intradialytic hypotension, are effective and well tolerated. Exercise training programs and carnitine supplementation might be beneficial for neuromuscular complications, and restless legs syndrome in CKD responds to dopaminergic agonists and levodopa treatment. The present Review dissects the pathophysiology of neurological complications related to CKD and highlights the spectrum of therapies currently available.

Blood flow in the skin of type 1 diabetic patients before and after combined pancreas/kidney transplantation

BACKGROUND

To analyze effects of long-term glucose normalization after pancreas transplantation, different parameters of skin microcirculation were assessed by laser Doppler fluxmetry.

METHODS

Forty-two type 1 diabetic patients after successful simultaneous pancreas/kidney transplantation (Group A, median 32.3 months posttransplant), 28 patients with functioning kidney grafts, but insulin therapy (Group B, median 64.9 months posttransplant) and 13 diabetic pretransplant patients (Group C, median 14.2 months on dialysis) were compared with 33 healthy subjects (Group D). Resting blood flow, postocclusive hyperemia, venoarteriolar response on the right foot and decrease in blood flow during cold pressure test on the left finger was assessed.

RESULTS

Postocclusive hyperemia, decrease in blood flow during cold pressure test and venoarteriolar response were higher in Group D than in all patient groups. Resting blood flow in Group A was significantly lower than in Groups B and C (following values as median): 3.6 perfusion units (PU) versus 7.4 PU in Group B, p < 0.01 and 12.1 PU in Group C, p < 0.001, respectively, and was not significantly different to controls (Group D, 5.2 PU). Postocclusive hyperemia was higher in Group A than in Groups B and C (266.7% vs 160.0%, p < 0.05 and 79.4% n.s., respectively), but significantly less than in Group D (563.5%). The microangiopathy index-high values reflecting less or no microangiopathy-was significantly higher in Group A than in Groups B and C (11.0 vs 4.3, p < 0.001 and 4.7, p < 0.05, respectively), and was very much comparable to the values in healthy controls (Group D, 10,3). The decrease in blood flow during cold pressure test was higher in Group A compared to Groups B and C (25.2% vs 21.1% and 13.8%, n.s., respectively), but much less than in Group D (65,7%).

CONCLUSION

These data suggest an improvement without complete normalization of skin microcirculation by long-term blood glucose normalization achieved by pancreas transplantation.

Is there a relationship between somatic and autonomic neuropathies in chronic alcoholics?

We investigated the relationship between somatic and autonomic neuropathy in 40 chronic alcoholics. Electromyographic and neurographic studies of upper and lower limbs and a battery of six cardiovascular reflex tests were carried out. A score for somatic or autonomic neuropathy was calculated. All parameters were investigated for possible relationship with total life dose (TLD) of alcohol intake. Somatic neuropathy was detected in 25 patients (62.5%) and autonomic neuropathy in 13 patients (32.5%). Nineteen patients (47.5%) presented only a somatic neuropathy, six patients (15%) had only an autonomic neuropathy, and seven (17.5%) had a combined somatic and autonomic neuropathy. TLD was significantly higher in the group of patients with combined neuropathy than in the group with isolated somatic neuropathy. There was no significant correlation between laboratory parameters of somatic and autonomic neuropathy. Our findings do not support the existence of a parallel involvement of peripheral somatic and autonomic cardiovascular nerve fibers in chronic alcoholism.

[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.

Cardiovascular autonomic dysfunction in uremia

Cardiovascular morbidity and mortality is common in chronic renal failure patients, and may be explained in part by abnormalities in cardiovascular autonomic regulation. This review discusses the results of cardiovascular autonomic function studies in chronic renal failure patients. While covering most methods of assessing autonomic function, we focus particularly on power spectral analysis methods. These newer techniques are non-invasive, reproducible, and allow the rapid assessment of the integrity of cardiovascular autonomic reflexes at the bedside. The abnormalities of parasympathetic, sympathetic and cardiac baroreceptor function seen in dialysis-dependent patients are highlighted, and their significance in intra-dialytic hypotension and cardiovascular mortality as well as the effects of dialysis and transplantation on these parameters examined. Importantly, studies of cardiovascular autonomic dysfunction in pre-dialysis chronic renal failure patients, when abnormalities may be amenable to intervention to prevent progression and premature cardiovascular morbidity and mortality, are reviewed.

Impact of simultaneous pancreas and kidney transplantation on progression of coronary atherosclerosis in patients with end-stage renal failure due to type 1 diabetes

OBJECTIVE

Mortality in type 1 diabetic patients with end-stage renal failure is high and dominated by coronary atherosclerotic events. With regard to prognosis, simultaneous transplantation of pancreas and kidney (SPK) may be superior to kidney transplantation alone (KTA) in type 1 diabetic patients, because normalization of blood glucose levels may reduce progression of coronary atherosclerosis and because it is well known that progression of coronary atherosclerosis is one of the major factors that determines clinical prognosis. However, no data are available on progression of coronary atherosclerosis after SPK.

RESEARCH DESIGN AND METHODS

We performed an observational angiographic study comparing progression of coronary atherosclerosis, analyzed with quantitative coronary angiography, in patients with (n = 26) and those without (n = 6) a functioning pancreas graft after SPK, to test the hypothesis that normalization of blood glucose levels by SPK may indeed reduce progression of coronary atherosclerosis in type 1 diabetic patients and thereby improve prognosis.

RESULTS

Mean follow-up was 3.9 years. Average glucose control was significantly worse for the patients without a pancreas graft than for patients with a functioning pancreas graft: 11.3 (SD 3.5) vs. 5.9 mmol/l (SD 1.1) (P = 0.03). Mean segment diameter loss (progression of diffuse coronary atherosclerosis) was 0.024 mm/year (SD 0.067) in patients with a functioning pancreas graft, compared with 0.044 mm/year (SD 0.038) in patients in whom the pancreas graft was lost. Minimum obstruction diameter loss (progression of focal coronary atherosclerosis) was 0.037 mm/year (SD 0.086) in patients with a functioning pancreas graft compared with 0.061 mm/year (SD 0.038) in patients in whom the pancreas graft was lost. Regression of atherosclerosis occurred in 38% of patients with a functioning pancreas graft compared with 0% of patients of whom the pancreas graft was lost (P = 0.035).

CONCLUSIONS

Our study provides, for the first time, evidence that in patients who have undergone SPK, progression of coronary atherosclerosis in patients with a functioning pancreas graft is reduced compared with patients with pancreas graft failure. Our observation is an important part of the explanation for the observed improved mortality rates reported in type 1 diabetic patients with end-stage renal failure after SPK compared with KTA. In light of these findings described above, SPK must to be carefully considered for all diabetic transplant candidates.

Autonomic dysfunction in uremia

Autonomic nervous system dysfunction is a common feature in uremia and may have a number of clinical sequelae. Simple cardiovascular reflex screening can be performed in patients during conservative treatment, on periodic dialysis therapy, or after kidney transplantation to diagnose and follow up autonomic function impairment. Other approaches, such as heart-rate variability studies in the frequency domain by power spectral analysis, can provide a more accurate investigation of the disease.

Management of diabetic neuropathy

The only strategy shown to be consistently beneficial in the treatment of diabetic neuropathy is meticulous control of blood glucose. The largest study of the effects of glycemic control on progression of neuropathy was the Diabetes Control and Complications Trial, which enrolled 1,500 patients. Meticulous control of blood glucose by multiple injections or continuous subcutaneous infusion both delayed the onset of neuropathy and slowed its progression. A weakness of this and other studies of the effect of glycemic control is that they used surrogate measures of improvement (or slowing of progression) of neurologic function. Most used sensory and motor nerve conduction studies and some used vibration perception thresholds. Whether such measures correlate reliably with neuropathy symptom scores, neurologic examination, quality-of-life measures, neuropathic complications (foot ulcers and amputation), and mortality remains controversial. Also, most studies of tight glycemic control do not address the complications of more intensive therapy, among them severe hypoglycemia. Severe hypoglycemia can precipitate acute painful neuropathy, and it markedly increases axonal degeneration in experimental diabetic neuropathy. Finally, all studies have been confined to patients with mild neuropathy; some patients had no clinical evidence of neuropathy. Whether benefit can accrue to patients with more advanced neuropathy is not known. The most physiologic means of achieving glycemic control is through pancreas transplantation; this can result in significant improvement in clinical and electrophysiologic measures of motor and sensory function and slightly improve autonomic function. Strategies to reduce the metabolic consequences of hyperglycemia on nerves and to enhance axonal regeneration are needed to supplement careful glycemic control. Aldose reductase inhibitors hold promise for reducing metabolic nerve injury, but further study is needed.

The effect of immunosuppressive agents (FK-506, rapamycin) on renal P450 systems in rat models

It is well known that cyclosporin, rapamycin and FK-506 (tacrolimus) are metabolized by the liver microsomal cytochrome P450 enzyme system. Although there have been reports of interaction between these drugs and the renal P450 enzyme system, differences among these immunosuppressants has not been comprehensively demonstrated. We have studied the individual capacities of these immunosuppressants to induce renal microsomal P450 enzymes similar to CYP2B4 and CYP4A2 by examining renal function in treated rats, and have correlated the results by means of biochemical, immunological and immunohistochemical assays of renal P450 enzymes. Cyclosporin caused impairment of renal function with an increase in renal-specific P450 content, but FK-506 and rapamycin did not. Laurate omega- and (omega-1)-hydroxylase activity increased in rats treated with rapamycin but decreased in those treated with FK-506. Prostaglandin A1 (PGA1) omega-hydroxylase activity increased in rats treated with FK-506 but was reduced by treatment with cyclosporin. Aminopyrine N-demethylase activity increased in rats treated with cyclosporin or FK-506, but not in those treated with rapamycin. Western-blot analysis revealed significant induction of P450, (similar to CYP2B4 of the rabbit P450 isozyme) in kidneys from rats treated with cyclosporin but not in those from rats receiving FK-506 or rapamycin. Histochemical studies clearly demonstrated a form of P450 such as CYP4A2 in the proximal tubules of rats treated with cyclosporin, but not in those of rats treated with FK-506 or rapamycin. These results show that although cyclosporin has a strong effect on renal P450 systems and induces such a system in kidney cortex (microsomal P450), FK-506 and rapamycin have no substantial effect on the induction of renal P450. These findings might clarify the nephrotoxicity induced by these immunosuppressive drugs.

Uremic autonomic neuropathy studied by spectral analysis of heart rate

BACKGROUND

There is good evidence that power spectral analysis (PSA) of heart rate variability may provide an insight into the understanding of autonomic disorders.

METHODS

We investigated 30 chronic uremic patients who were on periodic bicarbonate hemodialysis by a battery of six cardiovascular autonomic tests (beat-to-beat variations during quiet breathing and deep breathing, heart rate responses to the Valsalva maneuver and standing, blood pressure responses to standing and sustained handgrip) and PSA of heart rate variations.

RESULTS

Eleven patients (37%) had an abnormal response to only one parasympathetic test. Twelve patients (40%) had a definite parasympathetic damage, as indicated by at least two abnormal heart rate tests, whereas four (13%) had combined parasympathetic and sympathetic damage. Multivariate analysis of the cardiovascular tests revealed that 19 patients (63%) had moderate-to-severe autonomic neuropathy (AN), and 11 patients exhibited normal autonomic function. Among the symptoms suggestive of autonomic dysfunction, only impotence in males was significantly associated with test-proven AN. The PSA of the heart rate variability demonstrated a good discrimination of low-frequency (LF) and high-frequency (HF) bands (LF, 0.03 to 0.15 Hz; HF, 0.15 to 0.33 Hz) among controls, uremic patients without test-proven AN, and uremic patients with test-proven AN. A significant reduction of the LF value on supine uremic patients without AN suggests that an early sympathetic involvement exists that traditional autonomic tests were unable to detect.

CONCLUSIONS

Our study indicates that the current opinion of a major parasympathetic damage in chronic uremic patients on hemodialysis has to be modified in favor of a more widespread autonomic dysfunction involving both the sympathetic and parasympathetic pathways.

Regression and progression of cardiac sympathetic dysinnervation complicating diabetes: an assessment by C-11 hydroxyephedrine and positron emission tomography

Cardiovascular denervation complicating diabetes has been implicated in sudden cardiac death potentially by altering myocardial electrical stability and impairing myocardial blood flow. Scintigraphic evaluation of cardiac sympathetic integrity has frequently demonstrated deficits in distal left ventricular (LV) sympathetic innervation in asymptomatic diabetic subjects without abnormalities on cardiovascular reflex testing. However, the clinical significance and subsequent fate of these small regional defects is unknown. This study reports the results of a prospective observational study in which positron emission tomography (PET) with (-)-[11C]-meta-hydroxyephedrine ([11C]-HED) was used to evaluate the effects of glycemic control on the progression of small regional LV [11C]-HED retention deficits in 11 insulin-dependent diabetic subjects over a period of 3 years. The subjects were divided into two groups based on attained glycemic control during this period: group A contained six subjects with good glycemic control (individual mean HbA1c <8%), and group B contained five subjects with poor glycemic control (individual mean HbAlc > or =8%). Changes in regional [11C]-HED retention were compared with reference values obtained from 10 healthy aged-matched nondiabetic subjects. At baseline, abnormalities of [11C]-HED retention affected 7.3%+/-1.4% and 9.9%+/-6.6% of the LV in group A and B subjects, respectively, with maximal deficits of LV [ C]-HED retention involving the distal myocardial segments. At the final assessment in group A, the extent of the deficits in [11C]-HED retention decreased to involve only 1.7%+/-0.7% of LV (P<.05 v. baseline scan), with significant increases in [11C]-HED retention occurring in both the distal and proximal myocardial segments. In contrast, in group B with poor glycemic control, the extent of [11C]-HED deficits increased to involve 34%+/-3.5% of the LV (P<.01 v. baseline), with retention of [11C]-HED significantly decreasing in the distal segments ([11C]-HED retention index, 0.066+/-0.003 v. 0.057+/-0.002, P<.05, at baseline and final assessment, respectively). Poor glycemic control was associated with increased heterogeneity of LV [11C]-HED retention, since three of five group B subjects developed abnormally increased [11C]-HED retention in the proximal myocardial segments. In conclusion, defects in LV sympathetic innervation can regress or progress in diabetic subjects achieving good or poor glycemic control, respectively. In diabetic subjects with early cardiovascular denervation, institution of good glycemic control may prevent the development of myocardial sympathetic dysinnervation and enhanced cardiac risk.

Does peripheral neuropathy invariably accompany nephropathy in type 1 diabetes mellitus?

In patients with Type 1 diabetes mellitus complicated by diabetic nephropathy and retinopathy, it is usually believed that significant neuropathy is almost universal, but few studies have directly addressed this. This study assessed neuropathy in 91 such subjects, using vibration perception thresholds (VPT) and the neuropathy disability score (NDS). A total of 34% of subjects had no neuropathy on age adjusted VPT (z score) and 26% had no neuropathy on NDS. The severity of neuropathy as measured by VPT z score was related to increasing glycated haemoglobin (P = 0.02) and male sex (P = 0.03), and NDS was independently associated with age (P < 0.0001) and HbA1c (P = 0.003). These factors together accounted for only 12 and 31% of the total variance in VPT z score and NDS, respectively. In conclusion, the study has shown that a significant proportion of patients with diabetic nephropathy are free of neuropathy, but the full explanation for their protection from neuropathy is unclear.

Long-term effects of pancreatic transplantation on diabetic neuropathy

Restoration of a long-lasting euglycemic state by a functioning pancreatic transplantation (PTx) is the most logical treatment for insulin-dependent diabetes mellitus and for amelioration of secondary complications, including neuropathy. We evaluated neurological function by clinical examination, nerve conduction studies, and autonomic function tests in 115 patients with a functioning PTx and in 92 control patients treated with insulin, at baseline and 1, 2, 3.5, 5, 7, and 10 years later. In control patients, neuropathy progressively worsened during follow-up. The clinical examination score and composite indices of abnormality of motor and sensory nerve conduction decreased significantly at all intervals tested. Autonomic function indices also decreased, but significantly only after 1 year. In patients who received a successful PTx the neuropathy improved. The motor and sensory nerve conduction indices increased significantly at all intervals after transplantation, whereas the clinical examination and autonomic tests improved only slightly. Patients who received either a PTx alone, a PTx after a kidney graft, or simultaneous pancreatic and kidney transplantations improved similarly over the follow-up. These results indicate that a functioning PTx halts the progression and improves the signs of diabetic polyneuropathy by restoration of a normoglycemic state.

Neuropathy and mortality in diabetes: influence of pancreas transplantation

We collected information on patient status and cause of death for 545 insulin-dependent diabetic subjects who had cardiorespiratory reflex and nerve conduction tests performed to determine if presence and severity of autonomic and somatic neuropathy is associated with mortality and if a functioning pancreas transplantation (PTx) influences mortality. Follow-up was 12-138 months. Abnormal cardiorespiratory reflexes were present in 417 patients and there was abnormal nerve conduction in 392 patients. Mortality rates for patients with abnormal tests were higher (P < 0.0001) than for patients with normal tests. A total neuropathy score that included cardiorespiratory and nerve conduction test scores predicted survival better than separate scores. Patients with moderate neuropathy, but not those with severe neuropathy, who retained a functioning PTx, had longer survival times than patients whose PTx failed in the first 3 months. Considering only patients transplanted after 1985, those with moderate neuropathy who retained a functioning PTx had even longer survival times than nontransplanted patients.

Pancreas transplantation

Vascularized pancreas transplantation has assumed an increasing role in the treatment of diabetes mellitus. Through 1994, over 6000 pancreas transplants had been performed worldwide, with over 80% being combined pancreas-kidney transplants. Overall 1-year patient survival exceeds 90% and graft survival (complete insulin independence) exceeds 70%. Although successful pancreas transplantation achieves euglycemia and complete insulin independence, this occurs at the expense of hyperinsulinemia and chronic immunosuppression. The net effect of these changes on diabetic complications in the long term remains to be determined. In the short term, improvement in the quality of life and possible prevention of further morbidity associated with diabetes makes pancreas transplantation an important therapeutic option, particularly when combined with a kidney transplant, in appropriately selected diabetic patients.

Pancreas transplantation for diabetes mellitus

Vascularized pancreas transplantation has assumed an increasing role in the treatment of diabetes mellitus. Through 1993, over 5500 pancreas transplants have been performed worldwide, with over 80% being combined pancreas-kidney transplants. Overall one-year patient survival exceeds 90% and graft survival (complete insulin independence) exceeds 70%. Although successful pancreas transplantation achieves euglycemia and complete insulin independence, this occurs at the expense of hyperinsulinemia and chronic immunosuppression. The net result of these changes on diabetic complications in the long term remains to be determined. In the short term, improvement in the quality of life and possible prevention of further morbidity associated with diabetes makes pancreas transplantation an important therapeutic option, particularly when combined with a kidney transplant, in appropriately selected diabetic patients.

Effect of pancreas and kidney transplantation on the neuropathic profile in insulin-dependent diabetics with end-stage nephropathy

From a series of 26 diabetics selected for combined pancreas and kidney transplantations 9 died before surgery was scheduled, one died after surgery and 4 rejected the transplants. The effect of pancreas or kidney transplantation or both on vibratory perception and thermal thresholds, various motor and sensory conduction parameters were studied in 9 of the remaining 12 patients. In 6 both the pancreatic and renal grafts were functioning, in 2 the pancreas was rejected, and in 1 the kidney. At an average follow-up of 41 months after surgery, the mean total score of clinical and electrophysiological improvement in 6 patients with successful combined transplantation was 5.5 +/- 1.6 compared with -4.3 +/- 2.5 in 3 patients with one surviving transplant (P < 0.001). Similarly, the average increase in nerve conduction velocity was 5.8 +/- 1.1 m/s in patients with two functioning grafts whereas it decreased 2.9 +/- 0.7 m/s in those with only one (P < 0.001). The quality of life was considered improved in patients with successful outcome of the two organ transplantations in contrast to the statements of those with only one.

Pancreas and kidney/pancreas transplants: experimental medicine or real improvement?

Although 4000 pancreas transplants have now been done, alone or in combination with a kidney transplant, the risk/benefit profile of the procedure has not been established by controlled studies. A solo pancreas transplant abolishes the need for daily insulin but requires chronic immunosuppression, has high failure rates, and is not proved to lessen the chronic complications of diabetes. Thus, it is probably justified only in those diabetic patients with incapacitating disease. For uraemic diabetic patients, combined pancreas and kidney transplantation often removes dependence on both insulin and dialysis, and has lower rejection rates than pancreas transplant alone. However, it needs more immunosuppression than kidney transplant alone, has no proven benefit on chronic complications of diabetes, and carries an increased risk of rejection, infection, and cancer. Living-related-donor kidney transplantation followed by cadaver pancreas transplantation is a possible alternative. Transplantation of pancreatic islets could offer the advantages of strict metabolic control without the drawbacks of immunosuppressive therapy. Thus, research efforts should concentrate on immune-protected islet transplantation. An alternative approach to avoiding long-term immunosuppression is the promotion of allograft tolerance.

Are nerve conduction studies useful for monitoring the adequacy of renal dialysis?

When hemodialysis was first used clinically, a peripheral neuropathy frequently emerged. The discovery that sufficient dialysis time would prevent the emergence of symptomatic neuropathy led to the routine use of nerve conduction studies (NCS) to monitor the "adequacy" of dialysis. Modern dialysis practice has evolved since then, and the patient population is markedly different. This report addresses the question of whether there is evidence to indicate that routine use of NCS is helpful to monitor the adequacy of present-day dialysis. A critical review of the available literature reveals that there is insufficient evidence to allow one to answer the question.

High incidence of carpal tunnel syndrome in diabetic patients after combined pancreas and kidney transplantation

Fifty-eight patients with long-standing type 1 (insulin-dependent) diabetes were studied prospectively after combined pancreas and kidney transplantation for a mean observation period of 47.9 months (range 17-116 months). Thirty-three per cent of these patients (19/58) developed carpal tunnel syndrome after a mean interval of 1.7 years (range 3 months-5 years). This rate is about twice that in type 1 diabetic patients. The manifestation of carpal tunnel syndrome was not significantly associated with worsening of diabetic polyneuropathy or with deterioration of kidney or pancreas function. In all but one patient symptoms improved without surgical intervention. This study suggests that patients after combined pancreas and kidney transplantation have an increased risk of carpal tunnel syndrome for which the etiology and pathophysiology are unknown. In most patients no surgical intervention is necessary.

Effect of metabolic control on autonomic function in obese patients with newly diagnosed type 2 diabetes

To evaluate the effect of diet therapy and physical exercise on autonomic nervous function in newly diagnosed Type 2 diabetes, we followed 83 middle-aged obese patients (48 men, 35 women) for a 15-month period. After a 3-month basic education programme the patients were randomized to one of two groups for comparison of standard treatment given by community health centres (conventionally treated group) and intensive dietary and exercise education (intervention group). Autonomic function was assessed by heart rate variability during deep breathing (expiration/inspiration ratio, E/I), and by systolic blood pressure response to standing up. The intensively treated women (n = 18) had the best blood glucose throughout the study, and this was the only group to show an improvement in E/I ratio (1.19 +/- 0.03 vs 1.30 +/- 0.05, mean +/- SEM, p < 0.05). None of the groups showed any significant change in systolic blood pressure response to standing up. For further analyses, the original groups were combined and thereafter divided into those with declining fasting blood glucose during the intervention phase (n = 39) and into those with no change or increase in blood glucose level (n = 44). The group with improving blood glucose level showed an increase in E/I ratio (1.22 +/- 0.02 vs 1.28 +/- 0.03, p < 0.01) while in the other group E/I ratio remained unchanged (1.21 +/- 0.02 vs 1.20 +/- 0.02). The difference in E/I ratio between these two groups was significant at 15 months (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Patient selection for pancreas transplantation

Pancreas transplantation is the only currently available potential cure for type I diabetes. Because of the complications of the procedure and the toxicity of immunosuppression, patients must be carefully selected. The procedure can be justified in patients who already require immunosuppression for a renal allograft. The benefits of improved quality of life and protection from the development of nephropathy in the kidney allograft are significant. Pancreas transplantation alone is harder to justify; the risks of immunosuppression would seem to outweigh the known benefits of normalization of blood glucose. Before pancreas transplantation gains wide acceptance, the graft survival rates must improve. Currently, pancreas graft survival rates are greater than 80% at 1 year, but less than 50% 5 years after the transplantation. Improvement in these rates may occur with the development of more effective and less toxic immunosuppressive agents. Continued improvement in surgical technique should also contribute to overall pancreas transplantation success. Until then, however, pancreas transplantation should be viewed as a therapy for only selected patients in whom the benefits clearly outweigh the risks.

Metabolic control and progression of complications in insulin-dependent diabetic patients after kidney transplantation

Patient survival and progression of complications were monitored for 3 years after kidney transplantation in 29 type-1 diabetic patients. Ten age-matched, non-diabetic kidney-transplanted patients served as controls. Five diabetic patients died during follow-up (three cardiovascular events, two infections), three diabetic patients had a non-fatal myocardial infarction and four developed cerebrovascular complications after transplantation. Of the diabetic patients, 69% suffered from proliferative retinopathy before transplantation; 20% of them improved, 65% remained unchanged and 15% deteriorated after transplantation. Motor but not sensory conduction velocity measured from the nervus medianus improved after transplantation. Autonomic neuropathy was observed in 50% of the patients and was unaffected by transplantation. Glycaemic control did not improve significantly during follow-up (HbA1, 10.6 +/- 0.5% before and 9.5 +/- 0.6% 3 years after transplantation). Body weight increased in both diabetic and non-diabetic patients within 3 years after transplantation (from 68 +/- 2 to 77 +/- 6 kg in diabetics, P less than 0.01; from 167 +/- 4 to 77 +/- 6 kg in non-diabetics, P less than 0.01). Subcutaneous fat thickness measured from computer tomography scans of the calf increased in diabetic patients from 5.0 +/- 0.6 to 6.1 +/- 0.9 mm (P less than 0.05). However, the cross-sectional areas of triceps and calf muscles did not increase, suggesting that the increase in body weight was solely due to an increase in fat. It is clear that diabetes-related complications continue to progress and are not influenced by a successful kidney transplant.

Differential effects of near-normoglycaemia for 4 years on somatic nerve dysfunction and heart rate variation in type 1 diabetic patients

To evaluate the long-term effects of near-normoglycaemia on somatosensory and autonomic nerve dysfunction, 55 poorly controlled Type 1 diabetic patients were allocated to intensified insulin treatment using continuous subcutaneous insulin infusion or multiple insulin injections and were studied prospectively for 48 months. They were divided into three groups according to their mean HbA1 levels during the study. Group 1 (n = 19) had mean HbA1 during months 3-48 in the normal range of less than 7.8% (near-normoglycaemic control), Group 2 (n = 18) showed moderately elevated mean HbA1 between 7.8 and 8.5% (satisfactory control), and Group 3 (n = 18) had clearly elevated mean HbA1 of greater than or equal to 8.6% (poor control). In the three groups studied, the changes in nerve conduction over baseline in the median and peroneal motor nerves as well as median and ulnar sensory nerves after 4 years were inversely related to the mean HbA1 levels of months 3-48 (all p less than 0.05). No significant associations with mean HbA1 were noted for the ulnar motor and sural sensory nerve conduction, vibration perception threshold, and heart rate variation. The percentages of patients with neuropathic symptoms decreased from 32 to 14% in Group 1, remained fairly constant in Group 2, and increased from 41 to 73% in Group 3 after 48 months when compared to baseline (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical observations and experiments in diabetic neuropathy

Diabetic neuropathies form a group of diverse conditions, which can be distinguished between those which recover (acute painful neuropathies, radiculopathies, mononeuropathies) and those which progress (sensory and autonomic neuropathies). These two main groups can be distinguished in several ways: sensory and autonomic neuropathies are classic diabetic complications progressing gradually in patients with long-standing diabetes who often have other specific complications, while the reversible neuropathies do not have these features. The latter are characterised by their occurrence at any stage of diabetes, often at diagnosis, they may be precipitated on starting insulin treatment, and they are more common in men; they can occur at any age, though more often in older patients, and are unrelated to other diabetic complications. The two groups of neuropathies also show differences in nerve structural abnormalities and with regard to distinctive blood flow responses. The underlying mechanisms responsible for these very different forms of neuropathy remain speculative, but evidence for an immunological basis for the development of severe symptomatic autonomic neuropathy is presented.

The effect of pancreatic islet transplantation on experimental diabetic neuropathy

Quantitative light and electronmicroscopical morphometric techniques were used to determine the effect of pancreatic islet transplantation on experimental diabetic neuropathy. Groups of STZ-diabetic rats were given islet transplants at 3 weeks after diabetes onset (prevention) and at 6 months after diabetes onset (reversal). Comparisons were made with onset controls, age-matched non-diabetic controls and untreated diabetic controls 6 months later (n = 8 for all groups). Euglycaemia and normal levels of glycosylated haemoglobin were achieved in both groups of diabetics after islet transplantation. Loss of body weight in diabetic animals was prevented by early islet transplantation, but was only partially reversed following delayed islet transplantation. Normal growth of myelinated fibres and axons during development was retarded in untreated diabetics, but was normal in rats given islet transplants soon after the onset of diabetes (cross-sectional perimeter and area). Diabetics transplanted with islets after a delay had myelinated fibres and axons with diminished calibre. Teased fibre preparations of nerves from diabetics which had received islet transplants showed no excess of abnormalities. This study has shown that the development of certain structural abnormalities of peripheral nerve fibres is prevented in diabetic rats which receive transplants of islets of Langerhans soon after the onset of diabetes. However, once established abnormal fibre morphology can not be completely ameliorated merely by achieving and sustaining euglycaemia through delayed islet transplantation.

The Stockholm experience with pancreatic transplantation using enteric exocrine diversion

Between April 1974 and June 1990, 128 pancreatic transplantations were performed. Of these 117 were with pancreatico-enterostomy. In four consecutive series of combined transplantations in uraemic diabetic patients the 1-year graft survival rate have successively improved (27%, 65%, 68% and 73%). In three similar series of single pancreatic transplantations the results also improved but still remained inferior (0%, 33% and 33%). In a series of combined transplantations performed in preuraemic diabetic patients the 1-year actuarial graft survival rate was only 25%. The results with pancreatic transplantation with pancreatico-enterostomy are now satisfactory. However, immunological loss graft function still constitute a major problem in the non- or pre-uraemic recipients. The metabolic control in patients with functioning grafts is normal or near-normal in the majority of patients followed for at least 1 year.

Follow-up study of sensory-motor polyneuropathy in type 1 (insulin-dependent) diabetic subjects after simultaneous pancreas and kidney transplantation and after graft rejection

The influence of successful simultaneous pancreas and kidney transplantation on peripheral polyneuropathy was investigated in 53 patients for a mean observation period of 40.3 months. Seventeen patients were followed-up for more than 3 years. Symptoms and signs were assessed every 6 months using a standard questionnaire, neurological examination and measurement of sensory and motor nerve conduction velocities. While symptoms of polyneuropathy improved (pain, paraesthesia, cramps, restless-legs) and nerve conduction velocity increased, there was no change of clinical signs (sensation, muscle-force, tendon-reflexes). Following kidney-graft-rejection there was a slight decrease of nerve conduction velocity during the first year, which was not statistically significant. Following pancreas-graft rejection there was no change of nerve conduction velocity during the first year. Comparing the maximum nerve conduction velocity of the patients with pancreas-graft-rejection to the nerve conduction velocities of these patients at the end of the study, there was a statistically significant decrease of 6.5 m/s. In conclusion, we believe that strict normalization of glucose metabolism alters the progressive course of diabetic polyneuropathy. It may be stabilized or partly reversed after successful grafting even in long-term diabetic patients.

Does pancreas transplantation influence the course of diabetic retinopathy?

Between March 1983 and December 1989 a total of 57 pancreas transplants were performed in 54 patients, of whom 49 also received a kidney for end-stage diabetic nephropathy. Of the surviving 44 patients, 39 had regular pre-operative and post-operative ophthalmological examinations. Diabetic retinopathy was classified according to the original "Early treatment diabetic retinopathy study" (ETDRS) protocol. At the time of this analysis a total of 25 patients had a functioning pancreas transplant and 23 of them also a functioning renal allograft after a mean observation time of 43.2 months (Group 1). They were all free of exogenous insulin, HbA1c being 6.2% (5.1-6.9%; normal value 4.2-5.9%). Fourteen patients in Group 2 lost their pancreas transplant during the first four years. Six of them still have a functioning renal allograft, four patients regularly undergo hemodialysis. Mean HbA1c is 7.5% (5.7-9.2%). Before transplantation, grade of retinopathy according the ETDRS protocol was 6.7 (2-10) in group 1 patients and 7.9 (3-10) in group 2. In group 1 patients stabilisation of retinopathy was observed in 33 eyes (73.3%) and clear improvement achieved in 4 eyes (8.8%). Detoriation occurred in 8 eyes (17.7%) only. In group 2, 14 eyes (54%) remained stable, whereas progression of the disease continued in 12 eyes (46%). From these results it is concluded that the course of diabetic retinopathy is positively influenced by successful pancreas transplantation.

Neurophysiological study of the effect of combined kidney and pancreas transplantation on diabetic neuropathy: a 2-year follow-up evaluation

Previous study have reported a significant improvement of peripheral neuropathy following combined pancreas and kidney transplantation attributed to improvement of blood glucose control by some authors and to elimination of uraemia by others. To asses the specific role of uraemia and hyperglycaemia in neuropathy, 16 diabetic uraemic patients with combined pancreas and kidney transplantation were compared to 9 diabetic patients with a renal graft only. Neurophysiological studies of peripheral neuropathy included ulnar and deep peroneal nerve motor conduction velocity, median and sural nerve sensory conduction velocity were performed at baseline and 1 and 2 years after transplantation. One year after transplantation mean nerve conduction velocity significantly improved in both groups. However, changes were statistically significant in the kidney-pancreas group only. At the 2 year follow-up nerve conduction velocity had increased further in the pancreas-kidney group only. These data suggest that improvement of nerve conduction velocity following pancreas and kidney transplantation is predominantly due to the long-term euglycaemic state.

Sequential electrodiagnostic evaluation of diabetic neuropathy after combined pancreatic and renal transplantation

To assess the long-term evolution of diabetic polyneuropathy after a combined kidney-pancreas transplant, an electrophysiological study was performed in 20 diabetic patients before transplant, and 1 (n = 18), 2 (n = 16), 3 (n = 10) and 4 years (n = 5) at a later date. Motor and sensory scores were calculated for conduction velocity and amplitude to determine the physiopathological process. During evolution the scores were not found to be decreasing. Motor and sensory velocity scores were significantly improved (p less than 0.05) 1 and 2 years after the graft, when score values tended to stabilize. Motor and sensory amplitude scores, which are more sensitive for axonal loss assessment were slightly but not significantly improved.

Autonomic neuropathy and survival in diabetes mellitus: effects of pancreas transplantation

Cardiorespiratory reflexes were studied during slow breathing and a Valsalva maneuver in 232 Type 1 (insulin-dependent) diabetic subjects. At 1 to 7 years follow-up, death occurred in 23.4% of 175 patients with abnormal reflexes and in 3.5% of 57 patients with normal reflexes. The mortality rates of diabetic subjects with abnormal reflexes were 17% at 2.5 years, 33% at 5 years and 40% at 7 years, significantly higher than for patients with normal reflexes (4.6%, 4.6% and 13.8%). Among patients with abnormal reflexes, patients with a functioning pancreas transplantation had better survival rates than patients with a failed transplantation, and in long-term follow-up better than patients without transplantation. A functioning transplantation prevented the progressive decline of cardiorespiratory reflex function that occurred over time in control patients.

Effect of pancreatic and/or renal transplantation on diabetic autonomic neuropathy

Thirty-nine Type 1 (insulin-dependent) diabetic patients were studied prospectively after simultaneous pancreas and kidney (n = 26) and kidney grafting alone (n = 13) by measuring heart rate variation during various maneuvers and answering a standardized questionnaire every 6 to 12 months post-transplant. While age, duration of diabetes, and serum creatinine (168.1 +/- 35.4 vs 132.7 +/- 17.7 mumol/l) were comparable, haemoglobin A1 levels were significantly lower (6.6 +/- 0.2 vs 8.5 +/- 0.3%; p less than 0.01) and the mean observation time longer (35 +/- 2 vs 25 +/- 3 months; p less than 0.05) in the pancreas recipients when compared with kidney transplanted patients. Heart rate variation during deep breathing, lying/standing and Valsalva manoeuver were very similar in both groups initially and did not improve during follow-up. However, there was a significant reduction in heart rate in the pancreas recipient group. Autonomic symptoms of the gastrointestinal and thermoregulatory system improved more in the pancreas grafted subjects, while hypoglycaemia unawareness deteriorated in the kidney recipients. This study suggests that long-term normoglycaemia by successful pancreatic grafting is able to halt the progression of autonomic dysfunction.

Improvement in diabetic neuropathy 4 years after successful pancreatic and renal transplantation

We have studied the fate of diabetic neuropathy and autonomic function in 13 patients with long standing Type 1 (insulin-dependent) diabetes mellitus following combined pancreas and kidney transplantation. Fifteen diabetic patients with a kidney graft only served as controls. After initial improvement of the neuropathy in both groups, probably caused by the elimination of uraemia, a continuous improvement during the 48 months study was seen in the euglycaemic pancreas graft recipients only. Autonomic (parasympathetic) function improved only slightly and to a similar extent in both groups.

Effect of pancreas transplantation on life expectancy, kidney function and quality of life in uraemic type 1 (insulin-dependent) diabetic patients

The aim of our study was to evaluate the effects of haemodialysis, kidney transplantation and simultaneous kidney and pancreas transplantation on survival of diabetic subjects and on kidney function. 40 Type 1 (insulin-dependent) diabetic patients received a kidney transplantation: in 31 cases the kidney was transplanted simultaneously to a pancreas graft from the same donor (KP group), while in 9 cases the pancreas was not available (K group). 44 uraemic Type 1 (insulin-dependent) diabetic patients on dialysis and in waiting list for kidney transplantation, constituted the control group (HD group). Patient survival rate 1, 3 and 5 years following transplantation was better in KP group (93%, 89%, 89%, respectively) and in K group (88%, 88%, 73%, respectively) and in HD group (88%, 62%, 51%, respectively). Kidney graft survival at 1, 3 and 5 years post-transplant was better in KP group (93%, 72%, 72%, respectively) than in K group (76%, 61%, 31%, respectively). 1 year after transplantation, patients of the KP group who had lost the pancreas for technical reasons (thrombosis) were included in the K group so as to evaluate the effect of the transplanted pancreas on long-term patient and kidney survival. Patient survival rate in the KP group (17 patients) at 2 and 4 years was 100%, while at the same intervals it was 78% in the K group (13 patients). Kidney graft function rate at 2 and 4 years was 93% in the KP group (17 grafts) and 54% and 27% respectively in the K group (14 grafts).(ABSTRACT TRUNCATED AT 250 WORDS)

Update of pancreatic transplantation

Pancreatic transplantation for the treatment of diabetes mellitus in man has proved increasingly successful. Between December 1966 and August 1990 2735 pancreas transplants from 141 institutions were reported to the International Pancreas Transplant Registry. For the period 1986 to 1989 the one year graft survival rate in 1,200 patients was almost 70%, a significant improvement over the preceding five years. The commonest techniques for the diversion of pancreatic secretions are bladder drainage, intestinal drainage and duct occlusion with synthetic polymers. The survival rate of pancreas grafts is significantly higher in recipients of simultaneous pancreas and kidney transplants than in recipients of pancreas transplants after kidney transplants and transplants of the pancreas alone. For this reason pancreas transplantation is mainly indicated as an adjunct to kidney transplantation, when the patient must be given immunosuppressive treatment in any case. A steady decline in the rate of technical failures and of serious adverse reactions as a result of immunosuppressive treatment will undoubtedly widen the present indications. In most recipients of a pancreas graft the blood glucose and hemoglobin A1c levels become normal or near normal. No convincing evidence of an ameliorating effect on microangiopathic and neuropathic complications has been obtained so far. On the other hand, it is established that pancreas transplantation may prevent the development of glomerular lesions in a simultaneously grafted kidney. Previously, transplantation of pancreas islets in man has not been successful. In 1990, however, in several insulin-dependent, diabetic subjects the intraportal transplantation of islets isolated from cadaver pancreas resulted in significant insulin production, and, in a few patients, it was possible to stop insulin treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Does combined kidney and pancreas transplantation reverse functional diabetic microangiopathy?

Using videophotometric capillaroscopy and laser Doppler fluxmetry, we have investigated skin microvascular reactivity in the fingers of 14 diabetic patients with severe, late complications 20 months after combined kidney and pancreas transplantation. The results were compared with those obtained in 20 diabetic patients awaiting pancreas transplantation and in 19 healthy subjects. The capillary blood cell velocity at rest (P less than 0.01) and during postocclusive reactive hyperemia (P less than 0.05) was significantly lower in both patient groups than in the healthy controls. However, the time to peak capillary blood cell velocity during hyperemia was normal in the post-transplantation group (NS) but significantly prolonged in the pretransplantation group (P less than 0.01). The ability to decrease flow during venous stasis-the so called venoarte-riolar reflex--was strongly impaired in the pretransplantation group (P less than 0.001) but less so in the post-transplantation group (P less than 0.05) as compared to healthy controls. It may be concluded that diabetic patients, after combined kidney and pancreas transplantation, show a tendency towards better microvascular reactivity than those awaiting transplantation.

A neuropathic deficit, decreased sweating, is prevented and ameliorated by euglycemia in streptozocin diabetes in rats

Decreased sweating, especially of feet and legs, occurs in human diabetic neuropathy. It might be studied in experimental diabetes to characterize it, elucidate its mechanisms, and determine whether it can be prevented or treated. The pilocarpine-induced sweat responses (SR) in the hind foot pads of groups of control and streptozocin diabetic rats, in good (GC) and in poor (PC) glycemic control and with a crossover design after 20 wk of diabetes, were evaluated with the silicone mold sweat test to determine the number of sweat droplets per group of foot pads. The SR was dose dependent and reproducible. The SR disappeared with denervation and reappeared with reinnervation; denervation hypersensitivity did not develop. In the GC group, euglycemia was achieved by regulating the caloric intake and using multiple daily injections of Ultralente insulin. The SR was not different from that of the control group for up to 136 d. In the PC group, the SR became abnormal (P less than 0.005) at 16 d and progressively worsened: 40% of baseline values at 14 wk (P less than 0.001). After restoring euglycemia in the PC group, a normal SR occurred at 12 d. These results show that one human neuropathic deficit, failure of sweating, can be prevented or ameliorated by good glycemic control.