Increase in endogenous glucose production with SGLT2 inhibition is attenuated in individuals who underwent kidney transplantation and bilateral native nephrectomy

AIMS/HYPOTHESIS

The glucosuria induced by sodium-glucose cotransporter 2 (SGLT2) inhibition stimulates endogenous (hepatic) glucose production (EGP), blunting the decline in HbA_1c. We hypothesised that, in response to glucosuria, a renal signal is generated and stimulates EGP. To examine the effect of acute administration of SGLT2 inhibitors on EGP, we studied non-diabetic individuals who had undergone renal transplant with and without removal of native kidneys.

METHODS

This was a parallel, randomised, double-blind, placebo-controlled, single-centre study, designed to evaluate the effect of a single dose of dapagliflozin or placebo on EGP determined by stable-tracer technique. We recruited non-diabetic individuals who were 30-65 years old, with a BMI of 25-35 kg/m² and stable body weight (±2 kg) over the preceding 3 months, and HbA_1c <42 mmol/mol (6.0%). Participants had undergone renal transplant with and without removal of native kidneys and were on a stable dose of immunosuppressive medications. Participants received a single dose of dapagliflozin 10 mg or placebo on two separate days, at a 5- to 14-day interval, according to randomisation performed by our hospital pharmacy, which provided dapagliflozin and matching placebo, packaged in bulk bottles that were sequentially numbered. Both participants and investigators were blinded to group assignment.

RESULTS

Twenty non-diabetic renal transplant patients (ten with residual native kidneys, ten with bilateral nephrectomy) participated in the study. Dapagliflozin induced greater glucosuria in individuals with residual native kidneys vs nephrectomised individuals (8.6 ± 1.1 vs 5.5 ± 0.5 g/6 h; p = 0.02; data not shown). During the 6 h study period, plasma glucose decreased only slightly and similarly in both groups, with no difference compared with placebo (data not shown). Following administration of placebo, there was a progressive time-related decline in EGP that was similar in both nephrectomised individuals and individuals with residual native kidneys. Following dapagliflozin administration, EGP declined in both groups, but the differences between the decrement in EGP with dapagliflozin and placebo in the group with bilateral nephrectomy (Δ = 1.11 ± 0.72 μmol min^-1 kg^-1) was significantly lower (p = 0.03) than in the residual native kidney group (Δ = 2.56 ± 0.33 μmol min^-1 kg^-1). In the population treated with dapagliflozin, urinary glucose excretion was correlated with EGP (r = 0.34, p < 0.05). Plasma insulin, C-peptide, glucagon, prehepatic insulin:glucagon ratio, lactate, alanine and pyruvate concentrations were similar following placebo and dapagliflozin treatment. β-Hydroxybutyrate increased with dapagliflozin treatment in the residual native kidney group, while a small increase was observed only at 360 min in the nephrectomy group. Plasma adrenaline (epinephrine) did not change after dapagliflozin and placebo treatment in either group. Following dapagliflozin administration, plasma noradrenaline (norepinephrine) increased slightly in the residual native kidney group and decreased in the nephrectomy group.

CONCLUSIONS/INTERPRETATION

In nephrectomised individuals, the hepatic compensatory response to acute SGLT2 inhibitor-induced glucosuria was attenuated, as compared with individuals with residual native kidneys, suggesting that SGLT2 inhibitor-mediated stimulation of hepatic glucose production via efferent renal nerves occurs in an attempt to compensate for the urinary glucose loss (i.e. a renal-hepatic axis).

TRIAL REGISTRATION

ClinicalTrials.gov NCT03168295 FUNDING: This protocol was supported by Qatar National Research Fund (QNRF) Award No. NPRP 8-311-3-062 and NIH grant DK024092-38. Graphical abstract.

[Living donor kidney transplant: the crossover modality]

Living donor kidney transplantation (LKD) has to be considered the best transplant choice for ESRD patients in terms of organ quality and survival. ABO incompatibility and positive cross-match frequently impede LKD. Recently, options based on stronger immunosuppression, apheresis techniques and Ig administration have been proposed to overcome the biological barriers. International guidelines on LKD advise paired exchange as the preferable transplant option to avoid the hazard of blood type or cross-match incompatibility. Since 1986 many paired exchange LKD programs have been started in the world including the USA, Japan, South Korea and, in Europe, the Netherlands, Switzerland, Romania, Germany and Italy. The first Italian paired exchange LKD was performed at the Pisa Transplant Center in November 2005 between three couples of spouses. One year later a National Program was established by the Italian National Transplant Center. The second experience in Italy was again in Pisa in December 2007 between two couples of spouses. International reports have shown that paired exchange LKD offers good clinical results comparable to direct LKD. In our experience paired exchange LKD is to be considered a quality choice for uremic patients, in that it allows them to obtain the benefit of an LKD that would otherwise not be practicable.

Kidney dimensions at sonography are correlated with glomerular filtration rate in renal transplant recipients and in kidney donors

The gold standard to assess renal function is the measurement of glomerular filtration rate (GFR). For practical reasons, renal function is often evaluated from serum creatinine (S Cr) or cystatin C (S Cys), and GFR is predicted from SCr. Ultrasound scanning of the kidneys is used only to evaluate renal morphology. The aim of this study was to evaluate the relationship between sonographic renal dimensions and GFR in renal transplant recipients and in kidney donors. GFR (urinary clearance of (99m)Tc-DTPA), S Cr, and S Cys were measured in 33 donors (28 females [F], 5 males [M]; SCr, 0.81-1.90 mg/dL) and 30 recipients (8 F, 22 M; SCr, 0.96-2.42 mg/dL). GFR was also predicted using the Cockcroft and Gault (CG) formula and with the simplified Modification of Diet in Renal Disease (MDRD) formula. Length, width, and depth of kidneys and renal sinus were measured using renal sonography. Among sonographic measurements, kidney length showed the best correlation with GFR. A closer correlation with GFR was found in donors (r = 0.639; P < .00007) than in recipients (r = 0.511; P < .005). In either case, the correlation of kidney length with GFR was greater than that of S Cr or S Cys, and similar to that of CG or MDRD GFR. Accuracy of kidney length as an indicator of GFR impairment was not statistically different from laboratory tests. Only in donors did CG show better accuracy. In conclusion, renal dimensions at sonography closely correlated with GFR. Thus, renal sonography can give information also on the function of the renal graft and of the remaining kidney of living donors.

Neoral versus prograf in simultaneous pancreas-kidney transplantation with portal venous drainage: three-year results of a single-center, open-label, prospective, randomized pilot study

BACKGROUND

The preferential use of tacrolimus (Prograf) over cyclosporine microemulsion (Neoral) in simultaneous pancreas-kidney transplantation (SPKTx) is mainly based on historical, retrospective studies. We herein report the 3-year results of a single-center, prospective, randomized comparison of the two calcineurin inhibitors in the setting of mycophenolate mofetil (MMF)-based immunosuppression and portal drainage of pancreas allografts.

METHODS

Between May 2001 and August 2004, 47 SPKTx recipients who were stratified by recipient sex, were alternatively assigned to treatment with Neoral (n = 22) or Prograf (n = 25). Concurrent immunosuppression included induction treatment with basiliximab and maintenance with MMF and steroids.

RESULTS

After a median follow-up of 24.0 months, all patients remained in the study arm into which they were initially enrolled. No pancreas rejection episode was observed. One acute kidney rejection was recorded in the Neoral arm (4.5%) as compared with 7 (28.0%) including one steroid-resistant episode, in the Prograf arm (P = .03). The cumulative incidence of adverse events was 31.8% (n = 7) in the Neoral arm compared with 92.0% (n = 23) in the Prograf arm (P < .0001). One patient died in each study arm. Patient, pancreas, and kidney survivals overlapped at 1- and 3-years posttransplant, namely all 95.4% for the Neoral arm compared with 95.8%, 91.8%, and 95.8%, respectively, for the Prograf arm (P > .05).

CONCLUSIONS

We conclude that in MMF-based immunosuppression there is no convincing evidence that Prograf should be preferred to Neoral in SPKTx.

A technique for retroperitoneal pancreas transplantation with portal-enteric drainage

BACKGROUND

Pancreas transplantation (PTx) with portal-enteric drainage (PED) has been associated with difficulties in respect to arterial anastomosis and graft accessibility for percutaneous biopsy. We describe a new technique that circumvents these difficulties.

METHODS

Between April 2001 and April 2004, a total of 113 recipients were scheduled for PTx with PED. The superior mesenteric vein was approached from the right retroperitoneal aspect instead of from the anterior transmesenteric route. The pancreas graft was eventually placed in the right retroperitoneal space, being covered by the ascending colon and its mesentery.

RESULTS

One hundred ten (97.3%) PTx were performed as planned. Systemic venous effluent was preferred in three patients because of incidental diagnosis of liver cirrhosis during surgery (n=1) and severe obesity (body mass index>35 kg/m2) (n=2). The Y iliac artery graft was kept as short as possible, and arterial anastomosis was always performed with ease. After a mean follow-up period of 21.2+/-19.9 months, the relaparotomy rate was 13.6%. No patient died after repeat surgery, and none required multiple relaparotomies. Overall, 10 grafts were lost because of acute rejection (n=3), chronic rejection (n=2), venous thrombosis (n=2), recipient death (n=2), and late (6-month) arterial thrombosis (n=1). One-year patient and graft survival were 98.1% and 90.7%, respectively.

CONCLUSIONS

Our data confirm that PTx with PED is not associated with an increased risk. The technique described has distinctive technical advantages and should be included in the repertoire of PTx.

Kidney Transplantation From Donors Aged 65 Years or More as Single or Dual Grafts

AIM

The organ shortage and aging donor population force transplant centers to accept donors previously considered unusable for kidney transplantation. We report the experience of two Italian transplant centers with single (SKTx) and dual (DKTx) kidney transplantation from donors aged 65 years or more.

METHODS

The study population comprised 75 SKTx (mean donor age 70.5 years) and 28 DKTx (mean donor age 75.0 years). Kidneys from donors with a calculated admission creatinine clearance <50 mL/min, a Karpinski's score on kidney biopsy between 5 and 7, or both were allocated to DKTx. Grafts with better function or lower biopsy scores were employed for SKTx.

RESULTS

Delayed graft function occurred in 45.3% of SKTx and in 39.3% of DKTx. After a mean follow-up period of 30.0 +/- 19.5 months, the acute rejection rate was 24.0% in SKTx and 7.1% in DKTx. Mean serum creatinine was 1.8 +/- 0.9 and 1.8 +/- 1.3 mg/dL in SKTx, and 1.8 +/- 1.6 mg/dL and 1.3 +/- 0.2 mg/dL in DKTx at 1 and 5 years, respectively. Patient survival was 93.3% and 91.2% in SKTx, and 92.9% and 92.9% in DKTx at 1 and 5 years, respectively. Graft survival was 92.0% and 88.3% in SKTx, and 89.3% and 89.3% in DKTx at the same time intervals. Keeping preservation time below 16 hours and avoiding calcineurin inhibitors were both associated with improved graft survival and function.

CONCLUSION

Careful donor selection, short preservation time, and tailored immunosuppression allow safe and efficient use of elderly donor kidneys.

Outcome of pregnancy after organ transplantation: a retrospective survey in Italy

The number of women who decide to have a child after organ transplantation has increased. We determined the outcomes of 67 pregnancies of women who had undergone kidney, liver or heart transplantation. All recipients had been maintained on immunosuppressive therapy before and during pregnancy. Pregnancy complications at term were observed in 17 out of 67 women (25%), hypertension being the most frequent complication (16.17%). Two transplant rejections were reported. Sixty-eight infants were delivered (including one pair of twins); five women had two pregnancies at term. Twenty-eight miscarriages (29.2%) were recorded. Of these 68 babies (including the pair of twins), 40 (58.8%) were born at term and 28 (41.2%) before term. The babies were followed-up for 2 months to 13 years. According to our previous experience, our study shows that patients who have undergone organ transplantation can give birth to healthy infants as long as they are monitored accurately during pregnancy.

Solitary pancreas transplantation: preliminary findings about early reduction of proteinuria in incipient or evident diabetic type I nephropathy

OBJECTIVE

Our work was aimed to evaluate the precocious reduction of proteinuria in patients suffering from diabetes mellitus type 1 with incipient and evident nephropathy after isolated pancreas transplantation (PTA).

MATERIALS AND METHODS

From December 2000 to March 2003, we followed 24 PTA grafts in 24 patients with diabetes mellitus type 1 (mean age 37.8 years; mean duration of diabetes 24.8 years). The pancreas was transplanted with portal-enteric drainage in 23 patients and systemic-enteric in 1 patient. The immunosuppressive therapy used basilixmab induction and tacrolimus, mycophenolate mophetil (MMF), and low dose steroid maintenance therapy. The renal function, proteinuria, and the glucose metabolic parameters were evaluated before and during the following months after transplant.

RESULTS

All patients are alive and twenty-one have a well-functioning pancreas with three grafts lost. All patients had persistence of normal renal function. Before transplantation 12 patients displayed proteinuria that was clearly reduced in 11 and gone in three patients, all of whom were insulin-independent.

CONCLUSIONS

TPA seems to reduce, and in some cases to regress, the proteinuria associated with early diabetic nephropathy.

Kidney transplantation from donors aged more than 65 years

BACKGROUND

There are no agreed criteria to predict the outcome of elderly donor kidneys or to decide between single (SKG) or dual (DKG) kidney graft transplantation.

METHODS

Between January 1999 and January 2003, 46 SKG and 14 DKG were performed from elderly donors (mean donor age 71.6 years; range: 66 to 87). Kidney biopsies were scored according to Karpinski. A calculated admission creatinine clearance <50 mL/min and/or a biopsy score of 5 or 6 were used to select kidneys for DKG. Grafts with better function or lower biopsy scores were employed for SKG.

RESULTS

Mean cold ischemia time (CIT) was 16.8 hours (range 8.1 to 28.6) in SKG, and 16.3 hours (range 4.6 to 24.3) for the first kidney and 17.4 hours (range 5.1 to 25.9) for the second graft in DKG. Delayed graft function (DGF) occurred in 34.1% SKG and in 28.5% DKG. Acute rejection rates were 9.1% for SKG and 0% for DKG. Three-year actuarial patient survival rates were 97.7% for SKG and 92.9% for DKG; for kidneys, 95.4% and 92.9%. One-year mean serum creatinine levels were 1.8 mg/dL (range 1.1 to 4.0) for SKG and 1.2 mg/dL (range 1.0 to 1.8) for DKG (P =.01). CIT longer than 16 hours was related to increased rates of DGF for both SKG (45.4% vs 22.7%) or DKG (42.9% vs 14.3%) and reduced 3-year graft survival rates (SKG: 90.9% vs 100%; DKG: 85.7% vs 100%).

CONCLUSIONS

With stringent selection criteria and short CIT (<16 hours), elderly donor kidneys may show good results, thus meaningfully expanding the donor pool.

Dissociation between carotid artery lesions and lipid parameters in recipients of successful kidney graft

BACKGROUND

The relationships between lipid levels and atherosclerotic lesions of carotid arteries in kidney graft recipients are still unclear.

METHODS

We evaluated carotid morphology in 53 recipients of functioning renal transplantation, and studied the relationship of carotid artery wall lesions with relevant clinical and laboratory risk factors for cardiovascular disease. The patients were on stable, cyclosporine-based immunosuppressive therapy.

RESULTS

The main clinical characteristics of patients were: age, 46.5 +/- 10.1 years; males/females, 40/13; body mass index, 25.8 +/- 4.4 kg/m2; duration of transplantation, 43 +/- 52 months. Ultrasonographic scanning of carotid arteries showed the presence of lesions (intimal-media thickness and/or plaque) in 28 patients (52.8%). These recipients differed from patients without carotid lesions in terms of age (50.4 +/- 9.0 vs 42.2 +/- 9.7 years, p < 0.01) and duration of pre-transplant dialysis (4.6 +/- 3.4 vs 2.3 +/- 1.9 years, p < 0.01), whereas no statistically significant difference was observed as for total cholesterol (230 +/- 44 vs 235 +/- 35 mg/dl), LDL-cholesterol (142 +/- 32 vs 143 +/- 30 mg/dl), HDL-cholesterol (52 +/- 12 vs 58 +/- 20 mg/dl) and triglycerides (178 +/- 94 vs 167 +/- 89 mg/dl). The percentage of post-transplant diabetes was 3-fold higher in patients with carotid lesions (25 vs 8%). No difference was observed as for the following parameters: body mass index, duration of transplantation, fibrinogen levels, DDimer concentrations, reactive C-protein values, prevalence of hypertension, percentage of smokers vs non-smokers.

CONCLUSIONS

The present study supports the view that carotid artery lesions in kidney graft recipients on stable, cyclosporine-based immunosuppressive therapy may not be related to circulating lipid values.

Pregnancy after renal transplantation in Italian patients: focus on fetal outcome

BACKGROUND

In the last few years advances in surgical techniques and immunosuppression have improved not only survival, but also quality of life in organ transplanted patients. Hence, the number of women of child-bearing age who decide to have a child--which means resuming a normal life--has increased. This multicenter retrospective study describes pregnancies after kidney transplantation and is the first such survey in Italy.

METHODS

We analyzed the outcomes from 56 pregnancies in 42 kidney transplant recipients from data collected in questionnaires, hospital records, and phone interviews. All recipients were maintained on cyclosporine (CsA), azathioprine (AZA), corticosteroids or tacrolimus (FK506) before and during pregnancy.

RESULTS

The average time from transplantation to childbirth was 62 months (range 12 to 180). Complications arose during pregnancy in 16 out of 36 term pregnancies (44.4%). Four transplant rejections (11.8%) were documented, two of them irreversible. Thirty-six infants were born, and 20 abortions reported (35.7%). Of these 36 babies, 16 (44.4%) were born at term, and 20 (55.6%) before term. Thirty-three Cesarean sections were performed (91.7%). Among the 20 pre-term babies, 11 can be grouped as follows: 5 low-birth-weight (LBW) (13.9%), 4 very low-birthweight (VLBW) (8.3%) and 2 extremely very low-birth-weight (EVLBW) (5.6%). The children were followed up for periods ranging from 2 months to 13 years.

CONCLUSIONS

In kidney transplant recipients who became pregnant the incidence of spontaneous abortion and preterm delivery was increased. Newborns delivered to these patients had low birth weight, but no congenital defects were noted and their development was normal.

Erythrocytic glutathione peroxidase: its relationship to plasma selenium in man

Erythrocytic glutathione-peroxidase (GSH-Px) activity and plasma selenium concentrations were measured in 14 patients: 7 with iron deficiency and 7 with raised serum iron levels. The decreased enzymatic activity in iron deficiency was confirmed. Plasma selenium was significantly lower in patients with lower serum iron; furthermore there is a significant correlation between serum iron and plasma selenium concentrations. Another correlation even more significant was found between plasma selenium and enzyme activity in all the cases we studied. These data suggests that the importance of iron for GSH-Px activity may be merely due to its relationship with selenium and that plasma selenium concentration may be of critical importance for enzyme activity.