The influence of dairy on the gut microbiome has not been studied extensively. We performed a randomized cross-over study to analyze the effect of high dairy intake on the gut microbiome. Subjects were randomly assigned to a high-dairy diet (HDD) (5–6 dairy portions per day) and a low-dairy diet (LDD) (≤1 dairy portion per day) for 6 weeks with a washout period of 4 weeks in between both diets. The gut microbiome was assessed using 16S rRNA gene sequencing. Compositionality and functionality of the gut microbiome was assessed using Quantitative Insights Into Microbial Ecology (QIIME) and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). Stool consistency was evaluated using the Bristol stool chart. In total, 46 healthy overweight subjects (BMI range 25–30 kg/m²) completed both intervention periods. During the HDD, there was a significantly higher abundance of the genera Streptococcus, Leuconostoc, and Lactococcus, and the species Streptococcus thermophilus, Erysipelatoclostridium ramosum and Leuconostoc mesenteroides (p_FDR < 0.10). Furthermore, during the HDD, there was a significantly lower abundance of the genera Faecalibacterium and Bilophila, and the species Faecalibacterium prausnitzii, Clostridium aldenense, Acetivibrio ethanolgignens, Bilophila wadsworthia and Lactococcus lactis (p_FDR < 0.10). There were eight subjects who became constipated during the HDD and these subjects all had a lower abundance of F. prausnitzii. This is the first cross-over study in which the effect of an HDD compared to an LDD on the gut microbiome has been studied. An HDD led to a significantly different composition of the gut microbiome, with a particularly lower abundance of F. prausnitzii and a higher abundance of S. thermophilus. Constipation was observed in several subjects during the HDD. Predicted metabolic pathways were not significantly altered due to an HDD.

Background Little is known about optimal protein intake after transplantation. The aim of this study was to prospectively investigate associations of urinary urea excretion, a marker for protein intake, with graft failure and mortality in renal transplant recipients (RTR) and potential effect modification by body mass index (BMI) and estimated glomerular filtration rate (eGFR). Methods Urinary urea excretion was measured in repeated 24-hr urine collections between 6 and 18 months after transplantation. Results In total, 940 RTR were included. During 4.4 (2.3–7.8) years of follow-up for graft failure and 4.8 (2.5–8.3) years for all-cause mortality, 78 RTR developed graft failure and 158 RTR died. Urinary urea excretion was not associated with graft failure in the overall population, but was inversely associated with graft failure in RTR with BMI less than 25 kg/m² (hazard ratio [HR], 0.64 [0.28–1.50] and 0.27 [0.09–0.83] for the second and third tertiles, respectively, P < 0.001), and in RTR with eGFR of 45 mL per min per 1.73 m² or higher (HR, 0.34 [0.15–0.79], P = 0.015 and HR, 0.31 [0.11–0.86], P = 0.025 for the second and third tertiles, respectively), both independent of potential confounders. Compared to the first tertile, RTR in the second and third tertiles of urinary urea excretion were at a lower risk of all-cause mortality (HR, 0.47 [0.32–0.69]; P < 0.001 and HR, 0.42 [0.26–0.68]; P < 0.001, respectively), independent of potential confounders. Body mass index and eGFR did not influence this association. Conclusion Urinary urea excretion, a marker for protein intake, was inversely related to graft failure in RTR with BMI less than 25 kg/m² and in RTR with an eGFR of 45 mL per min per 1.73 m² or higher. In addition, urinary urea excretion was inversely related to mortality.

Cardiovascular disease (CVD) is the leading cause of death in renal transplant recipients (RTR). Elevated plasma asymmetric dimethylarginine (pADMA), an endogenous nitric oxide synthase inhibitor produced from the turnover of methylated arginine moieties in proteins, is a risk factor for CVD and mortality. It is unknown how urinary ADMA excretion (uADMA), one of the main ADMA elimination routes, is associated with long-term survival. Furthermore, the association of pADMA and uADMA with markers for turnover of arginine-methylated proteins is unknown. We analyzed ADMA using a validated GC–MS/MS method in plasma and 24-h urine samples of 685 RTR, included ≥ 1 year after transplantation. We also analyzed urine symmetric dimethylarginine (uSDMA) using the same method. Urinary creatinine and urea excretions were used as markers for turnover of muscle protein and amino acids, respectively. We applied Cox regression analyses to study associations of pADMA, uADMA, and uSDMA with all-cause and CVD mortality. Mean pADMA was 0.61 ± 0.12 µM, uADMA was 31 ± 13 µmol/24 h, and uSDMA was 52 ± 19 µmol/24 h. Over median follow-up of 5.4 [4.9–6.1] years, 147 RTR died, of which 58 (39%) from CVD. High pADMA was associated with high all-cause mortality (HR per SD [95% CI]: 1.45 [1.26–1.67], P < 0.001), while high uADMA was associated with low all-cause and CVD mortality (HR per SD [95% CI]: 0.57 [0.47–0.69], P < 0.001, and 0.55 [0.40–0.74], P < 0.001, respectively). The associations were independent of adjustment for potential confounders. Creatinine excretion was associated with both pADMA (st. β:− 0.21, P = 0.003) and uADMA (st. β: 0.49, P < 0.001), and urea excretion was associated with uADMA (st. β: 0.56, P < 0.001). Associations of uSDMA with outcomes and with creatinine excretion and urea excretion were comparable to those of uADMA. The associations of pADMA, uADMA and uSDMA with mortality were strongly affected by adjustment for creatinine excretion and urea excretion. We found for the first time that high uADMA and high uSDMA are associated with less risk of all-cause and CVD mortality. The links of uADMA and uSDMA with markers of muscle protein and amino acid turnover may serve to further understand ADMA and SDMA homeostasis and their clinical implications.

Long‐term data on cardiovascular (CV) outcome of renal transplant recipients (RTR) on mTOR‐i (mammalian Target Of Rapamycin‐inhibitors) are scarce. In a sub‐study of the MECANO trial we investigated changes in intima media thickness (IMT), CV risk profile, Major Adverse CV Events (MACE) and survival in RTR on a mTORi versus CNI based regimen. Patients (enrolled 361) were treated with (basiliximab) and triple IS (CsA‐Cyclosporine A‐(C), MPS (M), prednisolone (P)). At M6 patients were randomized (n = 224) to the CsA group (C, P, N = 89), MPS group (M, P, N = 39) EVL group (Everolimus, P, N = 96). At week 2, M6 and M 24, IMT measurements of the Common Carotid Artery were performed. Cardiovascular risk factors were assessed at baseline, 6 and 24 months of follow‐up. Seven years survival and MACE‐free survival probability were calculated by the Cardiovascular Risk Calculator for RTR. After 7 years of follow‐up, incidence of cardiovascular events and patient survival were assessed. Mean IMT at baseline (N = 192), was 0.64 ± 0.14 mm. At M6 (N = 158), 0.66 ± 0.15, M24 IMT was 0.68 ± 0.15 (N = 95). No significant differences between groups concerning IMT, true CV events and mortality, CV risk profile, predicted MACE/Mortality were found between mTORi and CNI‐based regimen after 7 years of follow‐up.