Circulating Plasma Omega-7 Monounsaturated Fatty Acids (Cis-Vaccenic Acid and Palmitoleic Acid) Are Related to All-Cause Mortality: The Lifelines Fatty Acids Cohort Study

Objectives

Determine whether plasma omega-7 cis-vaccenic acid and palmitoleic acid levels are related to all-cause mortality in a general population.

Methods

Plasma phospholipids (PL) and triglycerides (TG) fatty acids were measured by gas chromatography with polar column and detected with a flame ionization detector in the Lifelines fatty acids cohort study participants (n = 864). Associations with all-cause mortality were analyzed by Cox proportional hazards regression with adjustment for conventional risk factors.

Results

During a median follow-up of 9.3 years, 33 (3.9%) participants died. Adjusting for typical risk factors, high levels of plasma PL and TG cis-vaccenic acid, and TG palmitoleic acid were found to be associated with all-cause mortality. A 1-SD increase in PL cis-vaccenic acid, TG cis-vaccenic acid, and TG palmitoleic acid was associated with increased risk of all-cause mortality with HRs (95% CI) of 1.69 (1.17–2.46), 1.54 (1.03–1.15), and 1.44 (1.08–1.92), respectively. Compared to the lowest tertile, the HRs (95% CI, p-trend) for the highest tertile of PL cis-vaccenic acid, TG cis-vaccenic acid, and TG palmitoleic acid were 3.0 (1.05–8.56, 0.03), 2.25 (0.87–5.85), and 3.39 (1.24–9.28, 0.02), respectively.

Conclusions

Elevated levels of plasma cis-vaccenic acid and palmitoleic acid are risk factors for all-cause mortality.

Funding Sources

The data analyses from the Lifelines Cohort that were carried out in this paper were funded by Friesl and Campina. The funders had no role in study design, data collection and analysis, manuscript preparation and decision to publish.

MO589PLASMA CONCENTRATIONS OF TRIMETHYLAMINE N-OXIDE, AND ITS DIETARY DETERMINANTS ARE ASSOCIATED WITH INCREASED RISK OF GRAFT FAILURE

Background and Aims

Due to the critical shortage of kidneys for transplantation, the identification of modifiable factors related to graft failure is highly desirable. The role of trimethylamine-N-oxide (TMAO) in graft failure remains undetermined. Here we aimed to investigate the clinical utility of TMAO and its dietary determinants for graft failure prediction in renal transplant recipients (RTRs).

Method

We included 448 RTRs who participated in the TransplantLines Cohort Study. Cox proportional-hazards regression analyses were performed to study the association of plasma TMAO with graft failure. Net Benefit, a decision analysis method, was performed to evaluate the clinical utility of TMAO and dietary information in the prediction of graft failure.

Results

Among RTRs (age 52.7 ± 13.1 years; 53% males), baseline median TMAO was 5.6 (3.0–10.2) µmol/L. In multivariable regression analysis, the most important dietary determinants of TMAO were egg intake (Std. β = 0.10 [95%CI, 0.01;0.19]; P=0.03), fiber intake (Std. β = -0.13 [95%CI, -0.22, -0.05]; P =0.002), and fish and seafood intake (Std. β = 0.11 [95%CI, 0.02,0.20]; P=0.01). After a median follow-up of 5.3 (4.5–6.0) years, graft failure was observed in 58 subjects. TMAO was associated with increased risk of graft failure, independent of age, sex, BMI, blood pressure, lipids, albuminuria and eGFR (Hazard Ratio per 1-SD increase of TMAO, 1.62 (95% confidence interval (CI): 1.22; 2.14, P<0.001). A TMAO and dietary enhanced prediction model offered approximately double Net Benefit compared to a previously reported, validated prediction model for future graft failure, allowing the detection of 21 RTRs per 100 RTRs tested with no false positives versus 10 RTRs respectively.

Conclusion

A predictive model for graft failure, enriched with TMAO and its dietary determinants yielded a higher Net Benefit compared with an already validated model. This study suggests that TMAO and its dietary determinants are associated with an increased risk of graft failure and that it is clinically meaningful.

MO928EXHALED HYDROGEN AS A MARKER OF INTESTINAL FERMENTATION IS ASSOCIATED WITH DIARRHEA IN KIDNEY TRANSPLANT RECIPIENTS

Background and Aims

Diarrhea is a common gastrointestinal (GI) complaint among kidney transplant recipients (KTR). Exhaled hydrogen (H2) is a surrogate marker of small intestinal bacterial overgrowth, which has been proposed to drive GI symptoms such as diarrhea. In a large cohort of KTR, we assessed the amount of exhaled H2 to evaluate its association with diarrhea and potential clinical and dietary determinants.

Method

Clinical, laboratory and dietary data from the TransplantLines Biobank and Cohort Study (NCT03272841), comprising 424 KTR were analyzed. Exhaled H2 concentration was measured using a model DP Quintron Gas Chromatograph. Diarrhea was classified according to the Bristol Stool Form Scale (BSFS) and stool water content was measured using a freeze-drying method. Dietary intake was assessed using a validated self-administered food frequency questionnaire (FFQ). Possible determinants of exhaled H2, such as sex, age, eGFR, mycophenolate mofetil and tacrolimus use, and several other clinical, biochemical and nutritional factors, were studied using univariable linear regression. All variables with a p<0.05 were included in a multivariable linear regression model run backward to identify the determinants of exhaled H2 production.

Results

KTR (55.4±13.2 years, 60.8% male, mean eGFR 49.8±19.1 mL/min/1,73 m2) were divided into three groups according to median exhaled H2 concentration (G1, 1.0-6.9 ppm, n=151; G2, 7.0-19.9 ppm, n=139; G3, ≥20.0 ppm, n=134). Hence, signs of small intestinal bacterial overgrowth (exhaled H2 ≥20 ppm) were identified in 31.6% of KTR. Seventy-six patients (33.0%) had diarrhea according to BSFS. Exhaled H2 correlated with stool water content (r=0.24, p=0.04) and increased risk of diarrhea (OR = 6.03, 95% CI 1.6-22.1, p<0.01). In multivariable linear regression analyses, polysaccharide intake was independently associated with exhaled H2 (std. β=0.24, p=0.01), whereas the other factors were not significant.

Conclusion

These findings suggest that higher fasting exhaled H2 is associated with increased risk of diarrhea in KTR with polysaccharide intake as an independent determinant of exhaled H2. The present results suggest that diarrhea in KTR may reflect an altered small bowel gut microbial composition, at least partly under dietary influence.

FC 081ULTRA-PROCESSED FOOD CONSUMPTION AND RISK OF INCIDENT CHRONIC KIDNEY DISEASE: THE LIFELINES COHORT

Background and Aims

Ultra-processed foods (UPF), that are widespread in Western-style diet, are risk factors for the development of cardiovascular disease, diabetes, obesity, hypertension, and all-cause mortality. The role of UPF in kidney function decline, however, is still unknown. The aim of this study was to investigate the associations of UPF consumption with incident CKD and estimated glomerular filtration rate (eGFR) decline. Additionally, we considered the heterogeneity of UPF by identifying different patterns of UPF consumption.

Method

The study was performed in a prospective general population-based cohort in the Northern Netherlands. A total of 78 346 participants who were free of CKD at baseline were included in this study. The dietary information was assessed at baseline using a 110-item food frequency questionnaire. The proportion (in weight) of UPF in the total diet was calculated and UPF consumption patterns were identified by principle component analysis (PCA). Multivariable logistic regression analyses were used to evaluated the associations of the proportion of UPF consumption and UPF patterns, respectively, with risk of incident CKD and a ≥20% eGFR decline.

Results

Average UPF consumption was 37.7% of total food intake in grams. After a mean (SD) follow-up of 7.9±1.1 years, 2 072 participants developed CKD and 7 611 had a ≥20% eGFR decline. The consumption of UPF was independently associated with a higher risk of incident CKD (OR for an absolute increment of 10 % of UPF in the diet 1.07 [95% CI 1.01-1.13], P=0.026) and with a higher risk of ≥20% eGFR decline (OR10% increment 1.07 [95% CI 1.05-1.10], P<0.001). PCA revealed four habitual UPF consumption patterns. The “warm savory snack” pattern was associated with both incident CKD (OR 1.13 [1.04-1.23], P=0.003) and a ≥20% eGFR decline (OR 1.08 [1.05-1.11], P<0.001). The “sweet snack” pattern was associated with eGFR decline (OR 1.06 [1.03-1.09], P<0.001) only, whereas the “Dutch traditional” and the “cold snack” were not associated with CKD or eGFR decline.

Conclusion

A higher UPF consumption was associated with higher risks of incident CKD and eGFR decline in the general population. Different UPF consumption patterns were identified, with different impact on renal risk. The “warm savory snack” pattern and the “sweet snack” pattern were associated with kidney function decline. Our findings suggest that UPF need to be considered in designing future dietary strategies for CKD prevention.

FC 125DIURETIC USE IS ASSOCIATED WITH INCREASED RISK FOR POSTTRANSPLANTATION DIABETES MELLITUS IN RENAL TRANSPLANT RECIPIENTS

Background and Aims

Posttransplantation diabetes Mellitus (PTDM) is one of the major medical problems in renal transplant recipients (RTRs). Diuretic-induced hyperglycemia and diabetes have been described in the general population. We aimed to investigate whether diuretics also increase PTDM risk in RTRs.

Method

We included 486 stable outpatient RTRs (with a functioning graft ≥1 year) without diabetes from a prospective longitudinal study (the Transplantlines Food and Nutrition Study [NCT02811835]). Participants were classified as diuretic users and non-diuretic users based on their medication use recording at baseline. PTDM was defined according the American Diabetes Association’s diagnostic criteria for diabetes. Multivariable Cox proportional-hazards regression analyses were performed to assess the prospective association between diuretic use and the risk of PTDM development.

Results

Median time since transplantation was 5.4 (2.0-12.2) years and 168 (35%) RTRs were taking diuretics. After 5.2 (IQR, 4.0 5.9) years of follow up, 54 (11%) RTRs developed PTDM. In Kaplan-Meier (log-rank test, p<0.001) and Cox regression analyses, diuretic use was found to be associated with incident PTDM after adjustment for age, sex, fasting plasma glucose (FPG), and HbA1c (hazard ratio[HR] 3.28, 95% CI 1.84-5.83; p<0.001). The association remained independent of further adjustment for potential confounders, including lifestyle, use of other medication, kidney function, transplantation-specific parameters, BMI, lipids, and blood pressure. Exploratory analyses further indicates that, in Cox regression analyses, both thiazide (n=74) and loop diuretics (n=76) as two main types of diuretics used among RTRs appeared to be associated with the development of PTDM, independent of age, sex, FPG, and HbA1c ([HR 2.70, 95% CI 1.24-5.29; p=0.012], and [HR 5.08, 95% CI 2.49-10.34; p<0.001], respectively).

Conclusion

This study demonstrates that diuretics overall, associated with the risk of developing PTDM in RTRs, independent of established risk factors for PTDM development. The association was consistent for thiazide and loop diuretics.

P1650HIGH-DENSITY LIPOPROTEIN PARTICLES AND THEIR RELATIONSHIP TO POSTTRANSPLANTATION DIABETES IN RENAL TRANSPLANT RECIPIENTS

Background and Aims

It is established that high concentrations of High-Density Lipoprotein (HDL) are associated with low risk of type 2 diabetes and posttransplantation diabetes mellitus (PTDM). However, HDL particles vary by size, density, and biological action. The aim of our study was to determine the association between different HDL particles with the development of PTDM in renal transplant recipients (RTRs).

Method

We included 351 stable outpatient adult RTR with a functioning graft ≥1 year from the Tranplantlines Food and Nutrition Study(NCT02811835). HDL particle concentration and size were measured by 1H-NMR spectroscopy using a Vantera® NMR Clinical Analyzer (LabCorp, Raleigh, NC). HDL size was weighted averages derived from the sum of the diameter of each subclass multiplied by its relative mass percentage. Estimated ranges of HDL diameter for the HDL subclasses were as follows: large HDL particles, 9.6–13 nm; medium HDL particles, 8.1–9.5 nm; and small HDL particles, 7.4–8.0 nm. PTDM was defined according the American Diabetes Association’s diagnostic criteria for diabetes. Multivariable-adjusted Cox proportional-hazards regression analyses were performed to assess the prospective association of HDL particles with PTDM.

Results

During 5.2 (IQR, 4.1–5.8) years of follow-up, 39 (11%) RTR developed PTDM. In a multivariable Cox regression analysis, higher HDL cholesterol was associated with a lower risk of PTDM development, after adjustment for age, sex and BMI (hazard ratio[HR] 0.55, 95% CI 0.36-0.83 per 1SD mg/dL; P=0.005). Moreover, among different HDL indices; HDL size, and large HDL were inversely associated with PTDM, after adjustment for age, sex, and BMI ([ HR 0.48, 95% CI 0.31-0.76 per 1SD nm; P=0.002], and [HR 0.63, 95% CI 0.47-0.84 per 1SD µmol/L; P=0.002], respectively ). However medium HDL and small HDL were not associated with risk of developing PTDM ([ HR 0.88, 95% CI 0.64-1.23 per 1SD µmol/L; P=0.48], and [HR 1.14, 95% CI 0.85-1.52 per µmol/L; P=0.37], respectively ). In additional models, the association remained significant for HDL cholesterol, HDL size, and large HDL after adjustment for other confounders including, the lifestyle, use of medication, kidney function and transplantation-specific parameters. In the last model after adjustment for age, sex, BMI, triglycerides, systolic blood pressure, and fasting plasma glucose, association were similar for HDL cholesterol, HDL size, and large HDL ([ HR 0.61, 95% CI 0.40-0.94 per 1SD mg/dL; P=0.024], [HR 0.58, 95% CI 0.36-0.93 per 1SD nm; P=0.025], and [HR 0.68, 95% CI 0.50-0.93 per 1SD µmol/L; P=0.017].

Conclusion

In this study, we found that higher concentrations of HDL cholesterol, large HDL, and higher HDL size were associated with a lower risk of developing PTDM in RTRs, independent of established risk factors for PTDM development.

P0863TYPE OF PROTON PUMP INHIBITOR AND RISK OF IRON DEFICIENCY IN RENAL TRANSPLANT RECIPIENTS

Background and Aims

Use of proton-pump inhibitors (PPIs) is common practice in renal transplant recipients (RTRs). Emerging data suggest several adverse effects of use of PPIs, including development of iron deficiency (ID). Although the latter has been shown with respect to PPIs, specific analyses for different types of PPIs and the associated risk of ID have not been performed.

Method

We used data from the TransplantLines Biobank and Cohort study, an ongoing prospective cohort study among all types of solid organ transplant recipients. For the current study, we used data from stable RTRs with a functional graft for more than 1 year post transplantation (n=795). We excluded RTRs who used any form of iron supplementation (n=54) and EPO-stimulating agents (n=24), resulting in 728 RTRs eligible for analyses. Use of PPIs was subdivided in different types of PPIs, i.e. omeprazole, esomeprazole, pantoprazole, and rabeprazole. ID was defined as TSAT<20% and ferritin <300 µg/L. Logistic regression analysis was used to assess the associations between PPIs and ID.

Results

We included 728 RTRs (age 56±13 years, 61% males), with a mean eGFR of 53±18 ml/min/1.73m2, a median [interquartile range] ferritin level of 96 (44 – 191) µg/L and mean TSAT of 24±10%. PPIs were used by 504 (69%) of the included RTRs, of which 398 (79%), 55 (11%), 49 (10%), and 2 (0.4%) respectively used omeprazole, pantoprazole, esomeprazole, and rabeprazole. Use of PPIs was strongly associated with ID (OR, 2.20; 95%CI 1.48 – 3.28; P<0.001), independent of adjustment for age, sex, BMI, eGFR, hs-CRP, smoking, alcohol use, use of calcineurine inhibitors, prednisolone, antiplatelet drugs, and antihypertensives. When subdividing the PPIs into the different types, both omeprazole (OR, 1.98; 95%CI 1.39 – 2.83; P<0.001) and esomeprazole (OR, 2.11; 95%CI 1.09 – 4.07; P=0.03) were independently associated with iron deficiency, whereas pantoprazole was not associated (OR, 0.89; 95%CI 0.47 – 1.70; P=0.73).

Conclusion

Omeprazole and esomeprazole, but not pantoprazole, are associated with an increased risk of ID. Our results are in line with previous reports that pantoprazole has the lowest potency with least increase in intragastric pH, thereby possibly interfering less with reduction of ferric to ferrous iron, and subsequently iron absorption. Future studies are warranted to confirm our present findings.

P1634TIME-UPDATED SERUM CALCIUM AND PHOSPHATE ARE ASSOCIATED WITH GRAFT AND PATIENT OUTCOMES AFTER KIDNEY TRANSPLANTATION

Background and Aims

Disturbances in calcium-phosphate homeostasis are common after kidney transplantation. The clinical implications of changes in calcium-phosphate homeostasis after transplantation are unclear. The aim of this study was to assess the relationship between time-updated serum calcium and phosphate levels and subsequent graft and patient outcomes.

Method

Kidney transplant recipients with ≥2 serum calcium and phosphate measurements were included from a large single-center cohort; only first transplants were considered. Patients with graft failure <3 months were excluded, as were measurements obtained when eGFR was <15 mL/min/1.73m2 or during intensive care unit admission. Normocalcemia was defined as (albumin-corrected) calcium between 2.20 and 2.60 mmol/L (8.8-10.4 mg/dL), and normophosphatemia as 0.70-1.50 mmol/L (2.17-4.64 mg/dL). Time-updated multivariable Cox regression analyses and time-updated restricted cubic splines analyses were performed to assess the relationship between post-KTx serum corrected calcium and phosphate levels and mortality and death-censored graft failure (DCGF). Final models were adjusted for recipient age, sex, BMI, eGFR, proteinuria, systolic BP (all time-updated), antihypertensive drug use, recipient CMV status, donor age, sex, and status (living or post-mortal), cold and warm ischemia times, HLA mismatches, primary kidney disease, and serum phosphate (in calcium analyses) or corrected calcium (in phosphate analyses).

Results

A total of 2,769 patients with 138,496 serum corrected calcium and phosphate levels post-KTx were included (median [IQR] 43 [31-61] measurements per patient). Mean age was 47 ± 14 yrs, 42.3% was female, and 19% underwent a pre-emptive transplantation. Hypercalcemia was more common in the first year (15%) and declined to ∼5% during long-term follow-up; hypocalcemia occurred in ∼10% throughout. Hypophosphatemia (24.3%) and hyperphosphatemia (15.5%) were particularly common during the first 30 days post-transplant, and stabilized at ∼10% and ∼5% after the first year. During median follow-up of 16.3 (8.7 – 25.2) years, 477 patients (17.2%) developed DCGF and 1050 (37.9%) patients died. In multivariable regression analyses, post-transplant hypocalcaemia was associated with an increased risk of DCGF (fully adjusted hazard ratio [HR] 2.01 [95% CI 1.61-2.50], P<0.0001; Figure 1A), but not mortality (HR 1.06 [95% CI 0.88-1.27], P=0.55; Figure 1B). Post-transplant hypercalcaemia was associated with an increased risk of mortality (HR 1.77 [95% CI 1.44-2.17], P<0.0001), but not DCGF (HR 0.79 [95% CI 0.48-1.32], P=0.37). Patients with post-KTx hyperphosphatemia were at increased risk of both DCGF (HR 37.12 [95% CI 30.33-45.42], P<0.0001; Figure 1C) and mortality (HR 3.17 [95% CI 1.65-3.86], P<0.0001; Figure 1D). Patients with hypophosphataemia had a lower risk of developing DCGF (HR 0.48 [95% CI 0.28-0.81], P<0.01), but not mortality (HR 0.92 [95% CI 0.72-1.18], P=0.42). Similar results were obtained in sensitivity analyses in a subgroup with parathyroid hormone data available (N=1,412) or after exclusion of the highest and lowest 0.5% of calcium or phosphate levels.

Conclusion

Post-transplant hypocalcaemia and hyperphosphatemia are associated with an increased risk of DCGF, while hypophosphataemia was linked with a lower DCGF risk. Hypercalcaemia and hyperphosphataemia were associated with an increased mortality risk. These findings underline the relevance of keeping calcium and phosphate within normal range after kidney transplantation.

P1653METABOLIC SYNDROME-RELATED DIETARY PATTERN AND RISK FOR MORTALITY IN RENAL TRANSPLANT RECIPIENTS

Background and Aims

The metabolic syndrome (MetS) is an important risk factor for premature mortality in renal transplant recipients (RTR). Diet plays an important role in MetS development. Although an unhealthy diet may affect the long term outcome in RTR, no specific dietary patterns have been established that are linked with MetS in RTR. Reduced rank regression (RRR) has emerged as a method that identifies linear functions of predictor variables (food groups) that explain maximized variation in the response variables (biomarkers). We aim to identify a MetS-related dietary pattern (MetS-DP) in RTR, and to test its association with all-cause mortality.

Method

We included 432 adult RTR who had a functioning graft ≥1 year and were free of diabetes at baseline. The MetS-DP was constructed at baseline using dietary information derived from a 177-item food frequency questionnaire by reduced rank regression (RRR). In the RRR model, six components of MetS were used as response variable (age- and sex- adjusted waist circumference, systolic blood pressure, diastolic blood pressure, serum triglycerides, HbA1c, and HDL cholesterol), and 48 food groups were made as predictor variables. Using Cox proportional regression, we evaluated the association between the Met-DP score and all-cause mortality in RTR.

Results

The MetS-DP was characterized by a high intake of fat processed meat and desserts, and a low intake of vegetables, tea, rice, fruits, milk and vegetarian products. During a mean follow-up of 5.2 ±1.2 year, 64 RTRs (14.8%) died. Multivariate analysis showed that RTR in the highest tertile of MetS-DP score had a higher risk of all-cause mortality (hazard ratio [HR]=2.38; 95% confidence interval [CI],1.16-4.91, P=0.018) compared to the lowest tertile, independent of potential confounders.

Conclusion

The results suggest that the MetS-DP is significantly associated with all-cause mortality in RTR. Dietary measures may be useful to prevent MetS and reduce mortality in RTR.

P1673ANEMIA AND DECREASED MUSCLE MASS AND MUSCLE STRENGTH IN KIDNEY TRANSPLANT RECIPIENTS

Background and Aims

Post-transplant anemia is highly prevalent in kidney transplant recipients (KTRs). It is known that anemia impairs health-related quality of life, especially physical functioning. Although surmised, data about the latter are scarce. Hence, we aimed to investigate the association between anemia and muscle mass and muscle strength in KTRs.

Method

We used the TransplantLines Biobank and Cohort study, a prospective cohort study among all types of solid organ transplant recipients. For the current study, we used stable KTRs with a functional graft for more than 1 year post transplantation and with data available on hemoglobin levels and muscle mass (n=824). Muscle mass was assessed using 24-hour urinary creatinine excretion. Muscle strength was determined by means of hand grip strength using a dynamometer. Hand grip strength was tested three times with 30 seconds recovery time between attempts. For current analyses, the mean overall hand grip strength was calculated. Anemia was defined as hemoglobin <12 g/dL for women and <13 g/dL for men, according to WHO definitions. We used multivariable linear regression analyses to assess associations between anemia and muscle mass and strength.

Results

We included 824 KTRs (age 56±13 years, 60% males), with a mean hemoglobin of 13.5±1.8 g/dL. Anemia was present in 28% (n=277) of KTRs. Serum hemoglobin was associated with creatinine excretion, independent of age, sex, eGFR, BMI, hs-CRP, smoking status, alcohol use, and the use of RAAS-inhibitors, calcineurin inhibitors, proliferation inhibitors, or prednisolone (β=0.13, P<0.001). Similarly, the presence of anemia was independently associated with a lower creatinine excretion (β=-0.09, P=0.002). In line with creatinine excretion, hemoglobin levels (β=0.15, P<0.001) and the presence of anemia (β=-0.09, P=0.002) were also associated with handgrip strength independent of potential confounders.

Conclusion

Low hemoglobin levels and anemia are both strongly associated with lower muscle mass and muscle strength in KTRs, likely impairing physical functioning. Future research is needed to address whether correction of anemia improves physical performance in KTRs.

P1625HIGHER DIETARY ACID LOAD IS ASSOCIATED WITH INCREASED RISK FOR KIDNEY FUNCTION DECLINE AND GRAFT FAILURE IN KIDNEY TRANSPLANT RECIPIENTS

Background and Aims

Dietary acid load is associated with low grade metabolic acidosis and might accelerate kidney function decline in patients with chronic kidney disease (CKD). We investigated whether dietary acid load, estimated as net endogenous acid production (NEAP), is associated with kidney function decline in kidney transplant recipients (KTR) and to what extent this association is mediated by variation in venous bicarbonate (HCO3-).

Method

We used data from 642 KTR with a functioning graft ≥1 year after transplantation who were enrolled in the Transplantlines Food & Nutrition Cohort Study between 2008-2011. We applied the Frassetto equation (NEAP = (54.5 X protein (g/d) / potassium (mEq/d) - 10.2)) to calculate NEAPFFQ using intake reported in food frequency questionnaires and NEAPUrine from assessments of 24 hours urinary urea and potassium excretion. Patients were divided into tertiles of NEAP and differences across tertiles were analyzed by ANOVA, Kruskall-Wallis and Chi-Square tests, as appropriate. Cox regression models were used to study the associations between NEAPFFQ and NEAPUrine (both continuous variables and categories) with the composite endpoint kidney function decline, defined as doubling of serum creatinine or graft failure. Mediation analyses were performed to evaluate whether these associations were explained by venous bicarbonate.

Results

Mean age was 53±13 years, 56.1% were men, and mean eGFR was 52±20 ml/min/1.73m2. Patients within the highest tertile of NEAPFFQ were younger (P=0.04), more recently transplanted (P=0.002), consumed less fruit and vegetables (P<0.001), more fish (P=0.001), less alcohol (P=0.01), more meat (P<0.001) and had lower serum HCO3- concentration (P=0.02). During a median follow-up time of 5.3 (4.1-6.0) years, 121 (18.8%) patients developed kidney function decline. In multivariable Cox regression analysis, higher NEAPFFQ (per SD increase) was associated with increased risk of kidney function decline, independent of potential confounders, including age, sex, BMI, time after transplantation, primary kidney disease, eGFR and proteinuria (adjusted HR 1.30; 95%CI 1.10-1.53, P=0.002). Compared to patients in the lowest NEAPFFQ tertile, those in the highest tertile had a >1.5 higher risk of kidney function decline (adjusted HR 1.67; 95%CI 1.07-2.62, P=0.03). We observed similar results using NEAPUrine as the study exposure (adjusted HR 1.46 per SD increase; 95%CI 1.24-1.73, P<0.001; adjusted HR 1.99; 95%CI 1.24-3.18, P=0.004 for patients in the highest versus lowest tertile of NEAPUrine). These associations between NEAPFFQ (Figure A) and NEAPUrine (Figure B) with kidney function decline were visualized by fitting multivariable Cox regression models based on restricted cubic splines.

Mediation analyses estimated that venous HCO3- at baseline mediated 19.3% (P=0.008) of the association between NEAPFFQ and kidney function decline and 26.5% (P=0.002) of the association between NEAPUrine with kidney function decline.

Conclusion

Higher NEAP is associated with a higher risk for kidney function decline in KTR, and this association was in part mediated by venous HCO3-. We speculate that reducing dietary acid load might mitigate the risk of kidney function decline in KTR.

P1754ASSOCIATION OF GUT MICROBIAL FERMENTATION WITH DIARRHEA IN KIDNEY TRANSPLANT RECIPIENTS

Background and Aims

Diarrhea is a common complaint by kidney transplantation recipients (KTR). Metabolic abnormalities and immunosuppressive drugs may cause alterations in the gut microbiome possibly leading to diarrhea. A hydrogen (H2) breath test, reflecting nutrient fermentation, can detect changes in the composition of gut microbiota. In the present study, we studied the association of exhaled H2 with diarrhea in KTR, and investigated its determinants.

Method

All data were collected from the TransplantLines Biobank Cohort Study (NCT03272841). Living kidney donors were used as healthy controls. Breath H2 concentrations were analysed using solid state-sensor gas-chromatography. The stool water content was measured by faecal dry matter analysis and diarrhea was classified as >80% of water content in stools. Age, sex, body mass index (BMI), diabetes mellitus, eGFR and immunosuppressive medication were tested as potential determinants for H2 using linear multivariable regression.

Results

We included 424 KTR (mean age 55.4 ± 13.2 years, 39,1% female, transplant vintage 5.5 ± 9.5 years) and 164 healthy controls in this study. Immunosuppressive drugs included tacrolimus (78.5%), mycophenolate mofetil (MMF, 73.3%), cyclosporine (9.0%), and everolimus (2.4%) in various combinations. The median concentration of H2 in exhaled breath was significantly higher among KTR versus healthy controls (11.0 ppm [5.0 - 25.0] vs 9.0 ppm [4.0-22.5] p=0.005). The exhaled H2 was correlated with stool water content (r=0.24, p=0.04), as shown in figure 1. Serum tacrolimus trough levels were associated with exhaled H2 (standardized β=0.14, p=0.01), independent of age, sex, BMI, diabetes mellitus, eGFR and other immunosuppressive medication. In contrast, MMF trough levels were not independently associated with H2 (standardized β=0.07, p=0.21).

Conclusion

Exhaled H2, a marker of gut fermentation, is higher in KTR compared to healthy controls, and is associated with stool water content. Present results suggest that altered gut microbial fermentation contributes to the occurrence of diarrhea in KTR. Tacrolimus trough level was an independent determinant of H2. These data encourage further studies to validate the association of immunosuppressive drugs, gut microbiota and post-transplant diarrhea.

Methylglyoxal down-regulates the expression of cell cycle associated genes and activates the p53 pathway in human umbilical vein endothelial cells

Although methylglyoxal (MGO) has emerged as key mediator of diabetic microvascular complications, the influence of MGO on the vascular transcriptome has not thoroughly been assessed. Since diabetes is associated with low grade inflammation causing sustained nuclear factor-kappa B (NF-κB) activation, the current study addressed 1) to what extent MGO changes the transcriptome of human umbilical vein endothelial cells (HUVECs) exposed to an inflammatory milieu, 2) what are the dominant pathways by which these changes occur and 3) to what extent is this affected by carnosine, a putative scavenger of MGO. Microarray analysis revealed that exposure of HUVECs to high MGO concentrations significantly changes gene expression, characterized by prominent down-regulation of cell cycle associated genes and up-regulation of heme oxygenase-1 (HO-1). KEGG-based pathway analysis identified six significantly enriched pathways of which the p53 pathway was the most affected. No significant enrichment of inflammatory pathways was found, yet, MGO did inhibit VCAM-1 expression in Western blot analysis. Carnosine significantly counteracted MGO-mediated changes in a subset of differentially expressed genes. Collectively, our results suggest that MGO initiates distinct transcriptional changes in cell cycle/apoptosis genes, which may explain MGO toxicity at high concentrations. MGO did not augment TNF-α induced inflammation.

Lower Renal Function Is Associated With Derangement of 11-β Hydroxysteroid Dehydrogenase in Type 2 Diabetes

Context

Derangement of 11-β hydroxysteroid dehydrogenase type 1 and type 2 (11β-HSD1 and 11β-HSD2), which regulate intracellular cortisol production, has been suggested in both type 2 diabetes (T2D) and chronic kidney disease (CKD). However, activity of 11β-HSD enzymes in patients with T2D and CKD has never been assessed.

Objectives

To compare 11β-HSD activities between patients with T2D and healthy controls, and assess whether in T2D, renal function is associated with 11β-HSD activities.

Design

Cross-sectional analysis in the Diabetes and Lifestyle Cohort Twente (DIALECT-1).

Setting

Referral center for T2D.

Patients

Patient with T2D [n = 373, age 64 ± 9 years, 58% men, 26% of patients estimated glomerular filtration rate (eGFR) <60 mL/min·1.73 m²] and healthy controls (n = 275, age 53 ± 11 years, 48% men).

Mean Outcome Measure

We measured cortisol, cortisone, and metabolites [tetrahydrocortisol (THF), allo-THF (aTHF), and tetrahydrocortisone (THE)] in 24-hour urine samples. Whole body 11β-HSD and 11β-HSD2 activities were calculated as the urinary (THF + aTHF)/THE and cortisol/cortisone ratios, respectively.

Results

Patients with T2D had a higher (THF + aTHF)/THE ratio [1.02 (0.84 to 1.27) vs 0.94 (0.79 to 1.0), P < 0.001] and cortisol/cortisone ratio [0.70 (0.58 to 0.83) vs 0.63 (0.54 to 0.74), P < 0.001] than healthy controls. In T2D, lower eGFR was associated with a higher (THF + aTHF)/THE ratio (β = −0.35, P < 0.001), and a higher cortisol/cortisone ratio (β = −0.16, P = 0.001).

Conclusions

In this real-life secondary care setting of patients with T2D, 11β-HSD enzymes activities were shifted to higher intracellular cortisol production in T2D, which was further aggravated in patients with CKD. Prospective analyses are warranted to investigate causality of these associations.

Monoclonal Antibody RYSK173 Recognizes the Dinuclear Zn Center of Serum Carnosinase 1 (CN-1): Possible Consequences of Zn Binding for CN-1 Recognition by RYSK173

BACKGROUND AND AIMS

The proportion of serum carnosinase (CN-1) recognized by RYSK173 monoclonal antibody negatively correlates with CN-1 activity. We thus hypothesized that the epitope recognized by RYSK173 is accessible only in a catalytically incompetent conformation of the zinc dependent enzyme and we mapped its position in the CN-1 structure. Since patients with kidney failure are often deficient in zinc and other trace elements we also assessed the RYSK173 CN-1 proportion in serum of these patients and studied the influence of hemodialysis hereon in relation to Zn2+ and Cu2+ concentration during hemodialysis.

METHODS AND RESULTS

Epitope mapping using myc-tagged CN-1 fragments and overlapping peptides revealed that the RYSK173 epitope directly contributes to the formation of the dinuclear Zn center in the catalytic domain of homodimeric CN-1. Binding of RYSK173 to CN-1 was however not influenced by addition of Zn2+ or Cu2+ to serum. In serum of healthy controls the proportion of CN-1 recognized by RYSK173 was significantly lower compared to end-stage renal disease (ESRD) patients (1.12 ± 0.17 vs. 1.56 ± 0.40% of total CN-1; p<0.001). During hemodialysis the relative proportion of RYSK173 CN-1 decreased in parallel with increased serum Zn2+ and Cu2+ concentrations after dialysis.

CONCLUSIONS

Our study clearly indicates that RYSK173 recognizes a sequence within the transition metal binding site of CN-1, thus supporting our hypothesis that metal binding to CN-1 masks the epitope. The CN-1 RYSK173 proportion appears overall increased in ESRD patients, yet it decreases during hemodialysis possibly as a consequence of a relative increase in transition metal bound enzyme.

Critical weight loss is a major prognostic indicator for disease-specific survival in patients with head and neck cancer receiving radiotherapy

BACKGROUND

Pre-treatment weight loss (WL) is a prognostic indicator for overall survival (OS) in head and neck cancer (HNC) patients. This study investigates the association between WL before or during radiotherapy and disease-specific survival (DSS) in HNC patients.

METHODS

In 1340 newly diagnosed HNC patients, weight change was collected before and during (adjuvant) radiotherapy with curative intent. Critical WL during radiotherapy was defined as >5% WL during radiotherapy or >7.5% WL until week 12. Differences in 5-year OS and DSS between WL groups were analysed by Cox's regression with adjustments for important socio-demographic and tumour-related confounders.

RESULTS

Before radiotherapy, 70% of patients had no WL, 16% had ≤5% WL, 9% had >5-10% WL, and 5% had >10% WL. Five-year OS and DSS rates for these groups were 71%, 59%, 47%, and 42% (P<0.001), and 86%, 86%, 81%, and 71%, respectively (P<0.001). After adjustment for potential confounders, >10% WL before radiotherapy remained significantly associated with a worse OS (HR 1.7; 95% CI 1.2-2.5; P=0.002) and DSS (HR 2.1; 95% CI 1.2-3.5; P=0.007).The 5-year OS and DSS rates for patients with critical WL during radiotherapy were 62% and 82%, compared with 70% and 89% for patients without critical WL (P=0.01; P=0.001). After adjustment, critical WL during radiotherapy remained significantly associated with a worse DSS (HR 1.7; 95% CI 1.2-2.4; P=0.004).

CONCLUSION

Weight loss both before and during radiotherapy are important prognostic indicators for 5-year DSS in HNC patients. Randomised studies into the prognostic effect of nutritional intervention are needed.

The involvement of GSK3beta in bipolar disorder: integrating evidence from multiple types of genetic studies

We aimed to get a comprehensive insight into the genetic evidence supporting the role of GSK3beta in bipolar disorder (BD). Using broad searches in NCBI's PubMed and the Genetic Association Database we looked for association, whole-genome linkage, genome-wide association, gene expression, pharmocogenomic, epigenetic, cytogenetic, and mouse model studies performed for BD until July 2009. Per gene, we rated the degree of converging evidence across these types of genetic studies. The genes most consistently associated with BD in the genetic studies we reviewed were GSK3beta , GRK3, 5-HTTLPR, GRIN3, COMT, and GLUR3. GSK3beta stood out as it was implicated in at least five types of genetic studies. Although our results are limited by design differences of included studies and possibly by publication bias, GSK3beta is a plausible candidate gene for BD from a pharmacological and a genetic perspective. Future studies investigating the effects of GSK3beta manipulation in BD seem warranted.

Biomechanics of cranial dynamics during daily living activities

Motion tracking capabilities of a head-mounted accelerometer apparatus were investigated in conjunction with three-dimensional motion analysis techniques during activities of daily living. In this report, measures between systems are compared for jogging, toe-touching, and start-from-rest tasks. Good fidelity was found for most measures between systems; some phase shifts and amplitude discrepancies were observed, and attributed to transducer orientation and system asynchrony. This preliminary work demonstrates the potential benefits of hybrid motion analysis systems.

Global distribution of TEM-1 and ROB-1 beta-lactamases in Haemophilus influenzae

OBJECTIVES

To determine the global distribution of TEM-1 and ROB-1 beta-lactamases in Haemophilus influenzae isolated from patients with community-acquired respiratory tract infection during the first 4 years of the PROTEKT study (1999-2003). To investigate the activities of commonly used antibiotics against these isolates.

METHODS

For 14 870 H. influenzae, MIC testing was performed using NCCLS broth microdilution methodology. For 2225 beta-lactamase-positive (BLP) H. influenzae, TEM-1 and ROB-1 genes were detected using a Taqman PCR method.

RESULTS

beta-Lactamase positivity was 15.0% overall but varied greatly by country (<5% in several countries to 67.9% in Taiwan). Prevalences of TEM-1 and ROB-1 BLP H. influenzae were 93.7% and 4.6%, respectively, however almost all ROB-1 isolates were found in Canada, the USA and Mexico. ROB-1 isolates (n = 102) were less susceptible against cefaclor (29.4% versus 87.6%) and cefprozil (42.2% versus 91.9%) than TEM-1 (n = 2085) isolates. Differences in susceptibility rates for chloramphenicol, co-trimoxazole and tetracycline were also found between the two groups.

CONCLUSIONS

The ROB-1 beta-lactamase was found almost exclusively in North America and was more active against cefaclor and cefprozil than the TEM-1 beta-lactamase.

Syndromes of disordered chromatin remodeling

Syndromes of disordered 'chromatin remodeling' are unique in medicine because they arise from a general deregulation of DNA transcription caused by mutations in genes encoding enzymes which mediate changes in chromatin structure. Chromatin is the packaged form of DNA in the eukaryotic cell. It consists almost entirely of repeating units, called nucleosomes, in which short segments of DNA are wrapped tightly around a disk-like structure comprising two subunits of each of the histone proteins H2A, H2B, H3 and H4. Histone proteins are covalently modified by a number of different adducts (i.e. acetylation and phosphorylation) that regulate the tightness of the DNA-histone interactions. Mutations in genes encoding enzymes that mediate chromatin structure can result in a loss of proper regulation of chromatin structure, which in turn can result in deregulation of gene transcription and inappropriate protein expression. In this review we present examples of representative genetic diseases that arise as a consequence of disordered chromatin remodeling. These include: alpha-thalassemia/mental retardation syndrome, X-linked (ATR-X); Rett syndrome (RS); immunodeficiency-centromeric instability-facial anomalies syndrome (ICF); Rubinstein-Taybi syndrome (RSTS); and Coffin-Lowry syndrome (CLS).

Macrolide resistance by ribosomal mutation in clinical isolates of Streptococcus pneumoniae from the PROTEKT 1999-2000 study

Sixteen (1.5%) of the 1,043 clinical macrolide-resistant Streptococcus pneumoniae isolates collected and analyzed in the 1999-2000 PROTEKT (Prospective Resistant Organism Tracking and Epidemiology for the Ketolide Telithromycin) study have resistance mechanisms other than rRNA methylation or efflux. We have determined the macrolide resistance mechanisms in all 16 isolates by sequencing the L4 and L22 riboprotein genes, plus relevant segments of the four genes for 23S rRNA, and the expression of mutant rRNAs was analyzed by primer extension. Isolates from Canada (n = 4), Japan (n = 3), and Australia (n = 1) were found to have an A2059G mutation in all four 23S rRNA alleles. The Japanese isolates additionally had a G95D mutation in riboprotein L22; all of these originated from the same collection center and were clonal. Three of the Canadian isolates were also clonal; the rest were not genetically related. Four German isolates had A2059G in one, two, and three 23S rRNA alleles and A2058G in two 23S rRNA alleles, respectively. An isolate from the United States had C2611G in three 23S rRNA alleles, one isolate from Poland had A2058G in three 23S rRNA alleles, one isolate from Turkey had A2058G in four 23S rRNA alleles, and one isolate from Canada had A2059G in two 23S rRNA alleles. Erythromycin and clindamycin resistance gradually increased with the number of A2059G alleles, whereas going from one to two mutant alleles caused sharp rises in the azithromycin, roxithromycin, and rokitamycin MICs. Comparisons of mutation dosage with rRNA expression indicates that not all alleles are equally expressed. Despite their high levels of macrolide resistance, all 16 isolates remained susceptible to the ketolide telithromycin (MICs, 0.015 to 0.25 microg/ml).

Molecular characterization of macrolide resistance mechanisms among Streptococcus pneumoniae and Streptococcus pyogenes isolated from the PROTEKT 1999-2000 study

In this study, the distribution of macrolide resistance mechanisms was determined for isolates of Streptococcus pneumoniae and Streptococcus pyogenes obtained from the PROTEKT 1999-2000 study (a global, longitudinal study of the antibacterial susceptibility of bacterial pathogens associated with community-acquired lower respiratory tract infections). The global macrolide resistance mechanism distribution results for 1043 macrolide-resistant S. pneumoniae isolates collected from 25 countries were as follows: 35.3% mef(A), 56.2% erm(B), 6.8% both mef(A) and erm(B), 0.2% erm(A) subclass erm(TR) and 1.5% negative for mechanisms tested. Mechanisms of macrolide resistance were found to vary widely between countries and different geographical regions with mef(A) predominating in North America and erm(B) in Europe. Approximation of genotype from macrolide MIC without molecular determination of the mechanism of resistance resulted in an error of 10.2% (106 isolates). Overall, for 143 macrolide-resistant S. pyogenes isolates, 46.1% of the isolates tested were mef(A), 30.8% were erm(B), 23.1% were erm(A) subclass erm(TR) and no isolates were negative for all the genetic markers tested. Again, the distribution varied widely between countries and geographical regions. This study provides valuable baseline data for the continued monitoring of the evolution of macrolide resistance development in these important respiratory tract pathogens. The ketolide telithromycin retained excellent anti-pneumococcal activity irrespective of macrolide resistance mechanism, having a MIC(90) of 0.25, 0.5 and 0.5 mg/L against mef(A), erm(B) and mef(A)+erm(B) macrolide-resistant S. pneumoniae, respectively. It also exhibited potent activity against S. pyogenes that had become resistant to macrolides via either mef(A), (MIC(90 )0.5 mg/L) or erm(TR), (MIC(90) 0.03 mg/L).

Serial passage of Chlamydia spp. in sub-inhibitory fluoroquinolone concentrations

We investigated the in vitro development of fluoroquinolone resistance in Chlamydia trachomatis and Chlamydia (Chlamydophila) pneumoniae grown in McCoy cell monolayers in supplemented Eagle's minimum essential medium. With C. trachomatis, initial passages at sub-inhibitory fluoroquinolone concentrations did not affect fluoroquinolone susceptibility. However, after an initial lag of 10-24 passages (depending upon the fluoroquinolone used), fluoroquinolone resistance developed rapidly. The final fluoroquinolone MIC after a total of 30 passages was >256 times the MIC of the original wild-type strain with ofloxacin or ciprofloxacin passage. Analysis of the quinolone-resistance determining regions of two quinolone-resistant C. trachomatis mutants obtained after 30 passages showed that both isolates had a single serine to isoleucine substitution at amino acid position 83 in GyrA. In stark contrast, with C. pneumoniae no reduced fluoroquinolone susceptibility could be sustained, even after 30 passages with moxifloxacin or ofloxacin. With sparfloxacin passage, some indication of resistance was observed but no viable organisms could be isolated for further investigation. It is possible that fluoroquinolone-resistant C. pneumoniae are less able to survive than wild type, which may explain why resistance does not develop readily.

Detection of macrolide resistance mechanisms in Streptococcus pneumoniae and Streptococcus pyogenes using a multiplex rapid cycle PCR with microwell-format probe hybridization

In this study, a multiplex rapid cycle PCR with microwell-format probe hybridization method was developed to perform high-volume screening for macrolide resistance determinants in isolates of Streptococcus pneumoniae and Streptococcus pyogenes. The method was then utilized to determine the distribution of macrolide resistance mechanisms in recent isolates of S. pneumoniae and S. pyogenes from Great Britain and Ireland. For 83 strains of macrolide resistant S. pneumoniae tested, 51 (61.4%) were positive for mef(A), 29 (34.9%) erm(B), two (2.4%) double mechanisms mef(A) + erm(B), and one (1.2%) negative for all mechanisms tested. For 56 strains of macrolide-resistant S. pyogenes tested, 33 (58.9%) were positive for erm(A) subclass erm(TR), 18 (32.1%) mef(A) and five (8.9%) erm(B).

[Automation of medical literature--and information services]

It is important for clinical practice to be able to find (or retrieve) relevant literature and to keep informed of the state of medical science. The fact that the contents of articles in journals are now accessible via computers is the result of integration of bibliographic techniques, medical knowledge and computer technology. Articles published in some 5000 medical journals can nowadays be retrieved electronically via Medline and Embase together (but medical literature in Dutch is underrepresented). Computerised insertion of publications into Internet dose not make information traceable or accessible, let alone reliable and readable. It cannot be predicted if electronic versions of scientific periodicals will replace the printed editions completely. However, valuable, reliable information will always have its price, even on Internet. It is unlikely that electronic information published privately (internet) will replace scientific publishers soon, for readers will still want selection and monitoring of contents and language. Good layout, professional typography and suitable illustrations to enhance reading comfort and cognitive processes, will even become more important. The problems arising from the immensity of scientific knowledge are not (any longer) of a technological nature-what is needed is a cultural about-turn of the information infrastructure in medical-scientific associations, organizations and institutions.

Pregnancy following miscarriage: course of grief and some determining factors

This prospective study aimed to investigate the impact of both (the speediness of) a subsequent pregnancy and the birth of a viable child on grief arising from a previous pregnancy loss. Data were collected from a series of written questionnaires. Of the 2140 pregnant women who participated in the study, 227 lost a baby by miscarriage (85%) or perinatal death (15%). In 221 women, the loss concerned a singleton. At each of four post-loss assessments, these women completed the Perinatal Grief Scale. They also indicated whether they had conceived again and, if they had, related how they felt about that. Data were analyzed by means of hierarchical multiple regression. Both conceiving again and the birth of a living child lessened grief. A speedy new pregnancy was only rarely found to be detrimental. It is suggested that parents, at least following miscarriage, no longer be advised to wait a specific time before conceiving again. Preferably their individual situation should be discussed with them in order to help them make their own informed decision concerning the subsequent pregnancy.