In patients with type 1 diabetes simultaneous pancreas and kidney transplantation preserves long-term kidney graft ultrastructure and function better than transplantation of kidney alone

AIMS/HYPOTHESIS

In patients with type 1 diabetes and end-stage renal disease (ESRD) we aimed to determine whether long-term normoglycaemia, as achieved by successful simultaneous pancreas and kidney (SPK) transplantation, would preserve kidney graft structure and function better than live donor kidney (LDK) transplantation alone.

METHODS

Estimated GFR (eGFR) was calculated in SPK (n = 25) and LDK (n = 17) recipients in a stable phase 3 months after transplantation and annually during follow-up. Kidney graft biopsies were obtained at follow-up for measurement of glomerular volume (light microscopy), glomerular basement membrane (GBM) and podocyte foot process widths and mesangial volume fraction (electron microscopy).

RESULTS

SPK and LDK recipients were similar in age and diabetes duration at engraftment. Donor age was higher in the LDK group. Median follow-up time was 10.1 years. Mean HbA1c levels during follow-up were 5.5 ± 0.4% (37 ± 5 mmol/mol) and 8.3 ± 1.5% (68 ± 16 mmol/mol) in the SPK and LDK group, respectively (p < 0.001). Compared with SPK recipients, LDK recipients had wider GBM (369 ± 109 nm vs 281 ± 57 nm; p = 0.008) and increased mesangial volume fraction (median 0.23 [range 0.13-0.59] vs 0.16 [0.10-0.41]; p = 0.007) at follow-up. Absolute eGFR change from baseline was -11 ± 21 and -23 ± 15 ml min(-1) 1.73 m(-2) (p = 0.060), whereas eGFR slope was -1.1 (95% CI -1.7, -0.5) and -2.6 (95% CI -3.1, -2.1) ml min(-1) 1.73 m(-2) per year in the SPK and LDK group, respectively (p = 0.001).

CONCLUSIONS/INTERPRETATION

In patients with type 1 diabetes and long-term normoglycaemia after successful SPK transplantation, kidney graft ultrastructure and function were better preserved compared with LDK transplantation alone.

Long-term outcomes after organ transplantation in diabetic end-stage renal disease

Patients with type 1 diabetic end-stage renal disease (ESRD) may be offered single kidney transplantation from a live donor (LDK) or a deceased donor (DDK) to replace the lost kidney function. In the latter setting the patient may also receive a simultaneous pancreas together with a kidney from the same donor (SPK). Also in some cases a pancreas after kidney may be offered to those who have previously received a kidney alone (PAK). The obvious benefit of a successful SPK transplantation is that the patients not only recover from uremia but also obtain normal blood glucose control without use of insulin or other hypoglycemic agents. Accordingly, this combined procedure has become an established treatment for type 1 diabetic patients with ESRD. Adequate long-term blood glucose control may theoretically lead to reduced progression or even reversal of microvascular complications. Another potential beneficial effect may be improvement of patient and kidney graft survival. Development of diabetic complications usually takes a decade to develop and accordingly any potential benefits of a pancreas transplant will not easily be disclosed during the first decade after transplantation. The purpose of the review is to assess the present literature of outcomes after kidney transplantation in patients with diabetic ESRD, with our without a concomitant pancreas transplantation. The points of interest given in this review are microvascular complications, graft outcomes, cardiovascular outcomes and mortality.

Reversibility of established diabetic glomerulopathy by anti-TGF-beta antibodies in db/db mice

Treatment with a neutralizing anti-transforming growth factor-beta (TGF-beta) antibody can prevent the development of diabetic nephropathy in the db/db mouse, a model of type 2 diabetes. However, it is unknown whether anti-TGF-beta therapy can reverse the histological lesions of diabetic glomerulopathy once they are established. Diabetic db/db mice and their non-diabetic db/m littermates were allowed to grow until 16 weeks of age, by which time the db/db mice had developed glomerular basement membrane (GBM) thickening and mesangial matrix expansion. The mice were then treated with an irrelevant control IgG or a panselective, neutralizing anti-TGF-beta antibody for eight more weeks. Compared with control db/m mice, the db/db mice treated with IgG had developed increased GBM width (16.64+/-0.80 nm vs. 21.55+/-0.78 nm, P<0.05) and increased mesangial matrix fraction (4.01+/-0.81% of total glomerular area vs. 9.55+/-1.04%, P<0.05). However, the db/db mice treated with anti-TGF-beta antibody showed amelioration of GBM thickening (18.40+/-0.72 nm, P<0.05 vs. db/db-IgG) and mesangial matrix accumulation (6.32+/-1.79%, P<0.05 vs. db/db-IgG). Our results demonstrate that inhibiting renal TGF-beta activity can partially reverse the GBM thickening and mesangial matrix expansion in this mouse model of type 2 diabetes. Anti-TGF-beta regimens would be useful in the treatment of diabetic nephropathy.