Stabilisation of diabetic retinopathy following simultaneous pancreas and kidney transplant

Effects of pancreas-kidney transplantation on diabetic retinopathy

The effects of pancreas transplantation (PTx) on diabetic retinopathy (DR) are still debated. We studied the course of DR in 48 patients (age: 40 +/- 7 years; males/females 26/22, body mass index (BMI): 23.0 +/- 2.4 kg/m2, duration of diabetes: 24 +/- 8 years) bearing a successful PTx (combined with a kidney). Follow-up ranged 6-60 months (median: 17 months). Before transplantation, according to the Eurodiab Study classification, 12 patients (25%) had nonproliferative retinopathy (NPDR; mild, moderate or severe), and 36 patients (75%) had laser-treated and/or proliferative retinopathy (LT/PDR). During the follow-up, in the NPDR group improvement/deterioration was defined as regression/progression to a lower/higher retinopathy grade; in the LT/PTD group, stabilization was defined as no new neo-vessel formation or development of new lesions requiring laser-treatment. In the NPDR group, five (41.7%) patients improved of one or more lesion grading, three (25%) patients showed no change, and four (33.3%) patients progressed of one grade. In the LT/PDR group, the post-transplant data were: stabilization in 35 (97%) patients, and worsening in one (3%) patient. The number of improved/stabilized patients was significantly higher in the transplanted than in a control group of nontransplanted type 1 diabetic patients. In conclusion, despite a relatively short follow-up period, successful PTx in our cohort of patients was associated with improvement and/or stabilization of DR in the majority of recipients.

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.

C-peptide: much more than a byproduct of insulin biosynthesis

OBJECTIVES

During the past decade, numerous studies in both humans and animals have demonstrated that C-peptide, although not influencing blood sugar control, might play a role in preventing and potentially reversing some of the chronic complications of type 1 diabetes. The aim of this paper is to present an up-to-date review of C-peptide, focusing on its role in insulin biosynthesis and in the classification of diabetes mellitus, as well as its potential clinical applications.

METHODS AND RESULTS

The relevant literature cited in the MEDLINE database shows that the measurement of C-peptide production combined with screening for the presence of islet-cell and other autoantibodies seems to exert an important role in the accurate differentiation between patients with type 1 and type 2 diabetes. Also, both experimental and clinical data provide evidence suggesting that combined replacement of insulin and C-peptide has potential therapeutic value in patients with type 1 diabetes.

CONCLUSIONS

Further study in this area is warranted, but the findings that pancreas transplants promote the reversal of diabetic neuropathy and stabilization of diabetic retinopathy and that both pancreas and islet transplants lead to the reversal of diabetic nephropathy lend credence to the concept that combined replacement of insulin and C-peptide may more effectively mitigate the inexorable progression of diabetes-related complications.

Stage-dependent effect of pancreatic transplantation on diabetic ocular complications in the Spontaneously Diabetic Torii rat

BACKGROUND

In terms of the temporal relationship between pancreas transplantation (PTx) and reversal of diabetic ocular complications, it has been difficult but important to determine a "point of no return." Thus, it is of great clinical interest to evaluate the efficacy of PTx on diabetic ocular complications.

METHODS

A spontaneous type 2 diabetic model of Spontaneously Diabetic Torii (SDT; RT1) rats was used in the present study, and syngeneic PTx was performed.

RESULTS

In the control SDT rats that received no treatment, hyperglycemia (>250 mg/dL) was developed from 25.2+/-3.9 weeks of age. Lens opacity was observed in all rats at 15 weeks after the onset of diabetes. Fluorescein angiography and immunohistochemistry detected the nonperfusion area and neovascularization in the retina at 5 weeks of diabetes. Daily insulin treatment could not prevent or reverse the ocular changes in our experiment. Fluorescein filling defect of the retinal vessels was observed at 10 weeks of diabetes. However, in the PTx rats, normoglycemia was achieved at all experimental time points. Diabetic cataract and retinopathy could have been prevented and improved if PTx had been performed at 5 weeks, but not at 10 weeks after the onset of diabetes. With PTx treatment, an inhibition of angiogenesis in the retina at 5 weeks after the onset of diabetes was demonstrated by immunohistochemistry.

CONCLUSIONS

Our results indicate that the potential use of the SDT rat for diabetes study and the positive effect of PTx performed before the "point of no return" could prevent and cure diabetic ocular complications.

Systemic considerations in the management of diabetic retinopathy

PURPOSE

To highlight the systemic factors which affect onset and/or progression of diabetic retinopathy (DR) and to emphasize the role and responsibilities of ophthalmologists and other eye care providers to ensure that appropriate systemic medical evaluation of the patient with diabetes is being pursued.

DESIGN

Literature review of publications relevant to diabetic retinopathy, blood glucose control, diabetes mellitus type, hypertension, renal disease, elevated serum lipids, exercise, pregnancy, anticoagulation, thrombolysis, smoking, anemia and antioxidant ingestion.

FINDINGS

Intensive blood glucose control and control of systemic hypertension reduce the risk of new onset DR and slow the progression of existing DR. Severe DR may be an indicator of renal disease while severe renal disease and its treatment can affect the progression of DR. Elevated serum lipids are associated with macular exudate and moderate visual loss. Certain types of excessive exercise in patients with advanced stages of retinopathy may aggravate vitreous hemorrhage. During pregnancy, DR should be monitored closely as transient progression of DR can occur. Therapeutic anticoagulation and thrombolysis are not contraindicated at any stage of DR. Anemia can result in progression of DR, smoking in general should be discouraged, and the role of antioxidant therapy requires further study.

CONCLUSIONS

Blindness from diabetic retinopathy is now largely preventable with timely detection and appropriate interventional therapy. Routine, repetitive, lifelong, expert clinical retinal examination is essential for the fundamental ophthalmic care of the patient with diabetes. However, diabetes mellitus is a systemic disease and thus optimal ophthalmic care must include diligent evaluation and treatment of concomitant systemic disorders that influence the development, progression and ultimate outcome of diabetic retinopathy. Optimization of these systemic considerations through an intensive, multi-disciplinary, healthcare team-based approach will maximize the ophthalmic and general health of these patients. Ophthalmologists and other eye care providers are critical members of this team with unique responsibilities to ensure that appropriate systemic medical evaluation is being pursued.

Guidelines for the referral and management of patients eligible for solid organ transplantation

Members of the Clinical Practice Committee, American Society of Transplantation, have attempted to define referral criteria for solid organ transplantation. Work done by the Clinical Practice Committee does not represent the official position of the American Society of Transplantation. Recipients for solid organ transplantation are growing in numbers, progressively outstripping the availability of organ donors. As there may be discrepancies in referral practice and, therefore, inequity may exist in terms of access to transplantation, there needs to be uniformity about who should be referred to transplant centers so the system is fair for all patients. A review of the literature that is both generic and organ specific has been conducted so referring physicians can understand the criteria that make the patient a suitable potential transplant candidate. The psychosocial milieu that needs to be addressed is part of the transplant evaluation. Early intervention and evaluation appear to play a positive role in maximizing quality of life for the transplant recipient. There is evidence, especially in nephrology, that the majority of patients with progressive failure are referred to transplant centers at a late stage of disease. Evidence-based medicine forms the basis for medical decision-making about accepting the patient as a transplant candidate. The exact criteria for each organ are detailed. These guidelines reflect consensus opinions, synthesized by the authors after extensive literature review and reflecting the experience at their major transplant centers. These guidelines can be distributed by transplant centers to referring physicians, to aid them in understanding who is potentially an acceptable candidate for transplantation. The more familiar physicians are with the exact criteria for specific organ transplantation, the more likely they are to refer patients at an appropriate stage. Individual transplant centers will make final decisions on acceptability for transplantation based on specific patient factors. It is hoped that this overview will assist insurers/payors in reimbursing transplant centers for solid organ transplantation, based on criteria for acceptability by the transplant community. The selection and management of patients with end-stage organ failure are constantly changing, and future advances may make obsolete some of the criteria mentioned in the guidelines. Most importantly, these are intended to be guidelines, not rules.