Mediterranean Style Diet and Kidney Function Loss in Kidney Transplant Recipients

Fueling the success of transplantation through nutrition: recent insights into nutritional interventions, their interplay with gut microbiota and cellular mechanisms

PURPOSE OF REVIEW

The role of nutrition in organ health including solid organ transplantation is broadly accepted, but robust data on nutritional regimens remains scarce calling for further investigation of specific dietary approaches at the different stages of organ transplantation. This review gives an update on the latest insights into nutritional interventions highlighting the potential of specific dietary regimens prior to transplantation aiming for organ protection and the interplay between dietary intake and gut microbiota.

RECENT FINDINGS

Nutrition holds the potential to optimize patients' health prior to and after surgery, it may enhance patients' ability to cope with the procedure-associated stress and it may accelerate their recovery from surgery. Nutrition helps to reduce morbidity and mortality in addition to preserve graft function. In the case of living organ donation, dietary preconditioning strategies promise novel approaches to limit ischemic organ damage during transplantation and to identify the underlying molecular mechanisms of diet-induced organ protection. Functioning gut microbiota are required to limit systemic inflammation and to generate protective metabolites such as short-chain fatty acids or hydrogen sulfide.

SUMMARY

Nutritional intervention is a promising therapeutic concept including the pre- and rehabilitation stage in order to improve the recipients' outcome after solid organ transplantation.

Association between oral nutrition and inflammation after intestinal transplantation

Intestinal transplantation (Itx) can be a life-saving treatment for certain patient populations, including those patients with intestinal failure (IF) who develop life-threatening complications due to the use of parenteral nutrition (PN). Most patients who have undergone Itx are eventually able to tolerate a full oral diet. However, little guidance or consensus exists regarding optimizing the specific components of an oral diet for Itx patients, including macronutrients, micronutrients and dietary patterns. While oral dietary prescriptions have moved to the forefront of primary and preventive care, this movement has yet to occur across the field of organ transplantation. Evidence to date points to the role of systemic chronic inflammation (SCI) in a wide variety of chronic diseases as well as post-transplant graft dysfunction. This review will discuss current trends in oral nutrition for Itx patients and also offer novel insights into nutritional management techniques that may help to decrease SCI and chronic disease risk as well as optimize graft function.

Role of nutritional therapy on dietary habits and glycemic control in insulin-treated kidney transplant patients with diabetes

AIMS

To evaluate the effect of nutritional therapy on glycemic compensation and key cardio-renal risk markers in patients with diabetes and kidney transplant, on insulin treatment by Multiple Daily Injection (MDI) or Continuous Subcutaneous Insulin Infusion (CSII).

METHODS

34 patients with diabetes on insulin treatment and kidney transplant recipients were enrolled;12 participated in the structured nutritional program (intervention group), 22 patients (control group) did not receive nutritional protocol. Both groups were then divided into subgroups according to the method of insulin administration (MDI and CSII).

RESULTS

Statistically significant reduction in fasting blood glucose values, glycosylated hemoglobin (HbA1c) and glycosuria were observed in both groups at the end of the study. The intervention group, significantly reduced total cholesterolemia and the glycemic index, together with reduced dietary intake of lipids, cholesterol, soluble carbohydrates and increased consumption of carbohydrates and fiber. These improvements were even more pronounced in patients treated with CSII.

CONCLUSIONS

A proper nutritional approach optimize glycometabolic outcomes and contribute significantly to the reduction of the major cardiovascular risk factors in renal transplant patients.

Metabolic acidosis in chronic kidney disease: mere consequence or also culprit?

Metabolic acidosis is a frequent complication in non-transplant chronic kidney disease (CKD) and after kidney transplantation. It occurs when net endogenous acid production exceeds net acid excretion. While nephron loss with reduced ammoniagenesis is the main cause of acid retention in non-transplant CKD patients, additional pathophysiological mechanisms are likely inflicted in kidney transplant recipients. Functional tubular damage by calcineurin inhibitors seems to play a key role causing renal tubular acidosis. Notably, experimental and clinical studies over the past decades have provided evidence that metabolic acidosis may not only be a consequence of CKD but also a driver of disease. In metabolic acidosis, activation of hormonal systems and the complement system resulting in fibrosis have been described. Further studies of changes in renal metabolism will likely contribute to a deeper understanding of the pathophysiology of metabolic acidosis in CKD. While alkali supplementation in case of reduced serum bicarbonate < 22 mmol/l has been endorsed by CKD guidelines for many years to slow renal functional decline, among other considerations, beneficial effects and thresholds for treatment have lately been under intense debate. This review article discusses this topic in light of the most recent results of trials assessing the efficacy of dietary and pharmacological interventions in CKD and kidney transplant patients.

Dietary protein intake and plant-dominant diets to mitigate risk of allograft dysfunction progression in kidney transplant recipients

PURPOSE OF REVIEW

There are limited studies on the benefits of low dietary protein intake (DPI) and plant-dominant diets to delay kidney allograft dysfunction. We evaluate evidence regarding the association or effects of the amount and type of DPI on allograft function.

RECENT FINDINGS

There is conflicting evidence regarding the benefits of low DPI and plant-dominant diet including PLADO and PLAFOND on kidney allograft function. Taking the strength of evidence including study design, sample size, and time to follow-up, the proposed amount of DPI to slow the progression of allograft dysfunction, avoid negative nitrogen balance, and skeletal muscle mass loss is 1.0-1.3 g/kg/day during an immediate posttransplant period or when high protein catabolic rate exists. The DPI may be 0.8-1.0 g/kg/day in patients with stable allograft function. Patients with chronic allograft rejection or estimated glomerular filtration rate <25 ml/min may benefit from the DPI of 0.55-0.60 g/kg/day, while those with failed allograft requiring transition to dialysis including incremental (twice-weekly) hemodialysis should consider increasing DPI to 1.0-1.2 g/kg/day.

SUMMARY

While there is a lack of strong evidence, individualized approaches based on the patient's comorbidities, net state of immunosuppression, and periods posttransplant may guide the appropriate amount and type of DPI to slow allograft dysfunction.

Vegetable Intake, but Not Fruit Intake Is Inversely Associated With Fasting Plasma Glucose in Kidney Transplant Recipients

BACKGROUND

The association between dietary intake and glycemic control has been extensively investigated in type 2 diabetes. However, little is known about this association in kidney transplant recipients (KTRs).

METHODS

We performed an observational study involving 263 adult KTRs with a functioning allograft for at least 1 year at the outpatient clinic of the Hospital from November 2020 to March 2021. Dietary intake was assessed by food frequency questionnaire. Linear regression analyses were performed to evaluate the association between fruit and vegetable intake and fasting plasma glucose.

RESULTS

The vegetable and fruit intake were 238.24 g/d (102.38-416.67) and 511.94 g/d (321.19-849.05), respectively. The fasting plasma glucose was 5.15 ± 0.95 mmol/L. The linear regressions revealed that vegetable intake, but not fruit intake was inversely associated with fasting plasma glucose in KTRs (adjusted R2 = 0.203, P < .001). The clear dose-response relation was observed. Moreover, each 100 g increase in vegetable intake was associated with 11.6% reduction of fasting plasma glucose.

CONCLUSIONS

Vegetable intake, but not fruit intake, is inversely associated with fasting plasma glucose in KTRs.

Nutrition Management for Chronic Kidney Disease: Differences and Special Needs for Children and Adults

Common goals of nutritional therapy across the spectrum of pediatric and adult chronic kidney disease (CKD) include maintaining normal body mass and composition and reducing associated morbidity and mortality. Adult nephrologists caring for children and adolescents may be challenged by the existing complexities in identifying and interpreting the nutritional status and growth in children. Pediatric nephrologists may face situations that call for a sound knowledge of assessing nutritional status and providing nutrition therapy for adolescents and young adults. One important additional nutrition goal in children is to achieve normal growth and development. Children are growing and therefore need more calories and nutrients than just maintaining their body weight and composition. Lack of weight and height gain actually is considered failure to thrive in children. Some fundamental differences in approaches to nutritional therapy in CKD are necessitated based on the etiology of CKD. A large proportion of adults with CKD are diabetics, so the approach would be a low-carbohydrate diet. Children with CKD, especially young ones, often are anorexic, so calorie supplements that could include quite a lot of carbohydrates often are prescribed. More adults with CKD have hypertension and atherosclerotic comorbidities, which result in recommendations for low-salt and low-fat diets. Children with CKD often have salt and electrolyte wasting disease states and would require normal- or even high-salt diets, and fats often are included in supplements to bolster calorie intake. Low-protein diets often are recommended in adults with predialysis CKD to slow disease progression. Children are growing and have a higher protein daily requirement. Low-protein diets have not been found to be efficacious in children with CKD, in achieving normal growth, or in slowing disease progression. Adult nephrologists caring for children and adolescents may be challenged by the existing complexities in identifying and interpreting nutritional status and growth in children. Pediatric nephrologists may face situations that call for a sound knowledge of assessing nutritional status and providing nutrition therapy for adolescents and young adults. This article discusses the differences in the assessment of nutritional status between children and adults, as well as provides a comprehensive approach to nutritional management for CKD across the age spectrum. Semin Nephrol 43:x-xx © 2023 Elsevier Inc. All rights reserved.

High Alternative Health Eating Index-Taiwan Scores Are Associated With Prevention of Graft Dysfunction in Taiwanese Renal Transplant Recipients

BACKGROUND

Various dietary quality indices demonstrate that a higher dietary quality score is associated with a reduced risk of several chronic diseases. However, creating an index tailored to the national population is crucial. The study investigated the association between the Alternative Healthy Eating Index-Taiwan (AHEI-Taiwan) and graft dysfunction in Taiwanese renal transplant recipients (RTRs).

METHODS

A prospective cohort study recruited 102 RTRs with a functioning allograft without acute rejection in the last 3 months from September 2016 to June 2018. Laboratory data were obtained from the medical records of patients. Graft dysfunction was indicated by an estimated glomerular filtration rate (eGFR) <60 mL/min per 1.73 m² in accordance with the Kidney Disease Outcomes Quality Initiative guideline. The dietary quality index AHEI-Taiwan was adapted from the AHEI based on Taiwanese dietary recommendations.

RESULTS

Mean age, renal transplant time, and eGFR were 48.9 ± 12.8 years, 8.5 ± 5.8 years, and 54.9 ± 17.8 mL/min per 1.73 m², respectively, in 102 RTRs. The RTRs with the highest quartile of AHEI-Taiwan scores were older and had a higher eGFR. Logistic regression analysis adjusted for age, sex, calories, Charlson comorbidity index, transplant time, and dialysis time showed that the highest quartile of the AHEI-Taiwan was associated with an 88% (odds ratio, 0.12; 95% CI, 0.03-0.59, P < .01) lower risk of graft dysfunction.

CONCLUSION

A high AHEI-Taiwan score was associated with a reduced risk of graft dysfunction in Taiwanese RTRs.

Cardiovascular disease risk factors and lifestyle modification strategies after pediatric kidney transplantation: what are we dealing with, and what can we target?

Kidney transplantation in pediatric patients can lead to partial improvement of some of the cardiometabolic parameters that increase the risk for cardiovascular disease (CVD) in patients with chronic kidney disease. However, even after restoration of kidney function, transplant recipients remain at risk for CVD due to the continual presence of traditional and non-traditional risk factors, including the side effects of immunosuppression and chronic inflammation. This educational review describes the prevalence of CVD risk factors in pediatric kidney transplant recipients and presents available evidence for therapeutic lifestyle changes and other non-pharmacologic strategies that can be used to improve traditional and modifiable CVD risk factors. Although trial-grade evidence for interventions that improve CVD in pediatric kidney transplant recipients is limited, potential strategies include lowering dietary sodium and saturated fat intake and increasing physical activity levels. Intensive follow-up may help patients achieve guideline-recommended goals for reducing their overall CVD risk.

Adherence to Mediterranean Diet in Individuals on Renal Replacement Therapy

Patients on renal replacement therapy are typically subject to several dietary restrictions; however, this approach has been questioned in recent years, with some suggesting that the Mediterranean diet might be beneficial. Data on the adherence to this diet and factors that influence it are scarce. We conducted a web survey among individuals on renal replacement therapy (dialysis or kidney transplant, KT) using the MEDI-LITE questionnaire to assess adherence to the Mediterranean diet and dietary habits in this population. Adherence to the Mediterranean diet was generally low, and significantly lower among participants on dialysis versus KT recipients (19.4% vs. 44.7%, p < 0.001). Being on dialysis, adopting fluid restrictions, and having a basic level of education were predictors of low adherence to the Mediterranean diet. Consumption of foods typically included in the Mediterranean diet, including fruit, legumes, fish, and vegetables, was generally low, particularly among those on dialysis. There is a need for strategies to improve both the adherence to and the quality of the diet among individuals on renal replacement therapy. This should be a shared responsibility between registered dietitians, physicians, and the patient.

Nutrition Disturbances and Metabolic Complications in Kidney Transplant Recipients: Etiology, Methods of Assessment and Prevention-A Review

Nutrition disturbances occur at all stages of chronic kidney disease and progress with the decrease of the kidney filtration rate. Kidney transplantation (KTx) as the best form of kidney replacement therapy poses various nutritional challenges. Prior to transplantation, recipients often present with mild to advanced nutrition disturbances. A functioning allograft not only relieves uremia, acidosis, and electrolyte disturbances, but also resumes other kidney functions such as erythropoietin production and vitamin D3 metabolism. KTx recipients represent a whole spectrum of undernutrition and obesity. Since following transplantation, patients are relieved of most dietary restrictions and appetite disturbances; they resume old nutrition habits that result in weight gain. The immunosuppressive regimen often predisposes them to dyslipidemia, glucose intolerance, and hypertension. Moreover, most recipients present with chronic kidney graft disease at long-term follow-ups, usually in stages G2-G3T. Therefore, the nutritional status of KTx patients requires careful monitoring. Appropriate dietary and lifestyle habits prevent nutrition disturbances and may improve kidney graft function. Despite many nutritional guidelines and recommendations targeted at chronic kidney disease, there are few targeted at KTx recipients. We aimed to provide a brief review of nutrition disturbances and known nutritional recommendations for kidney transplant recipients based on the current literature and dietary trends.

Arterial hypertension in kidney transplantation: huge importance, but few answers

Abstract Arterial hypertension (AH) after renal transplantation (RTX) is correlated with worse cardiovascular and renal outcomes, with loss of renal function, decreased graft survival and higher mortality. RTX recipients have discrepant blood pressure (BP) values when measured in the office or by systematic methodologies, such as Ambulatory Blood Pressure Monitoring (ABPM), with significant prevalence of no nocturnal dipping or nocturnal hypertension, white coat hypertension and masked hypertension. The aim of the present study was to review the issue of hypertension in RTX, addressing its multifactorial pathophysiology and demonstrating the importance of ABPM as a tool for monitoring BP in these patients. Treatment is based on lifestyle changes and antihypertensive drugs, with calcium channel blockers considered first-line treatment. The best blood pressure target and treatment with more favorable outcomes in RTX are yet to be determined, through well-conducted scientific studies, that is, in terms of AH in RTX, we currently have more questions to answer than answers to give.

Hipertensão arterial no transplante renal: grande importância, mas poucas respostas

Resumo Hipertensão arterial (HA) no póstransplante renal (TXR) se correlaciona com piores desfechos cardiovasculares e renais, com perda de função renal, diminuição da sobrevida do enxerto e maior mortalidade. Receptores de TXR apresentam valores discrepantes de pressão arterial (PA) quando ela é obtida em consultório ou por metodologias sistematizadas, como a Monitorização Ambulatorial da PA (MAPA), com prevalências significantes de ausência de descenso noturno ou hipertensão noturna, hipertensão do avental branco e hipertensão mascarada. O objetivo do presente estudo foi rever a temática da hipertensão no TXR, abordando sua fisiopatologia multifatorial e demonstrando a importância da MAPA como ferramenta de acompanhamento da PA nesses pacientes. O tratamento é baseado em mudanças no estilo de vida e em fármacos anti-hipertensivos, sendo os bloqueadores de canais de cálcio considerados de primeira linha. A melhor meta pressórica e o tratamento com desfechos mais favoráveis no TXR ainda estão por ser determinados, por meio de estudos bem conduzidos cientificamente, ou seja, em termos de HA no TXR temos atualmente mais questões a responder do que respostas a dar.

Can Mediterranean Diet Have a Positive Impact on Kidney Health? A Pending Answer to a Long-Time Question

Dietary studies conducted in chronic kidney disease (CKD) patients were focused on the quantities of single nutrients, however it is possible that the excessive attention put on the restriction of proteins, sodium, potassium and phosphorus may compromise the overall quality of the diet in terms of micronutrients and palatability. Instead, concentrating on the nutritional quality healthy dietary patterns, may provide a better approach to improve nutritional prescriptions in CKD patients. All these dietary regimens share common features as reduced content of red meat, salt and saturated fatty acids, and higher fiber content, but may differ in terms of single nutrients consumption. In particular, Mediterranean Diet (Med Diet) has been associated with reduced incidence of diabetes, cardiovascular diseases and obesity, all conditions that are also strictly related to CKD. Given its low content of animal proteins and high contents of fiber it is possible that Med Diet may exert also positive effects on CKD as well as on its metabolic complications. In this review we summarize the role of Med Diet in primary prevention of CKD and on its progression.

Donor obesity and weight gain after transplantation: two still overlooked threats to long-term graft survival

The effect of donor obesity on kidney transplantation success has long been an overlooked clinical research area. Even though there is no strict guideline in most countries prohibiting donation from obese individuals, most candidates with a body mass index >35-40 kg/m² are rejected due to concerns regarding long-term renal functional deterioration in the donor. The effects of excessive fat mass on renal function and allograft survival have been analysed by several longitudinal and follow-up studies. These studies have documented the deleterious effect on long-term graft outcomes of excessive body mass in living kidney donors and de novo obesity or pre-existing obesity worsening after transplantation on kidney outcomes. However, there is a paucity of clinical trials aimed at countering overweight and obesity in living and deceased kidney donors and in transplant patients. In this review we will briefly discuss the mechanism whereby fat excess induces adverse kidney outcomes and describe the effects on graft function and survival in living obese donors.

Dietary Risk Factors and Eating Behaviors in Peripheral Arterial Disease (PAD)

Dietary risk factors play a fundamental role in the prevention and progression of atherosclerosis and PAD (Peripheral Arterial Disease). The impact of nutrition, however, defined as the process of taking in food and using it for growth, metabolism and repair, remains undefined with regard to PAD. This article describes the interplay between nutrition and the development/progression of PAD. We reviewed 688 articles, including key articles, narrative and systematic reviews, meta-analyses and clinical studies. We analyzed the interaction between nutrition and PAD predictors, and subsequently created four descriptive tables to summarize the relationship between PAD, dietary risk factors and outcomes. We comprehensively reviewed the role of well-studied diets (Mediterranean, vegetarian/vegan, low-carbohydrate ketogenic and intermittent fasting diet) and prevalent eating behaviors (emotional and binge eating, night eating and sleeping disorders, anorexia, bulimia, skipping meals, home cooking and fast/ultra-processed food consumption) on the traditional risk factors of PAD. Moreover, we analyzed the interplay between PAD and nutritional status, nutrients, dietary patterns and eating habits. Dietary patterns and eating disorders affect the development and progression of PAD, as well as its disabling complications including major adverse cardiovascular events (MACE) and major adverse limb events (MALE). Nutrition and dietary risk factor modification are important targets to reduce the risk of PAD as well as the subsequent development of MACE and MALE.

Associations between Advanced Glycation End Products, Body Composition and Mediterranean Diet Adherence in Kidney Transplant Recipients

There is limited evidence on the associations between dietary patterns, body composition, and nonclassical predictors of worse outcomes such as advanced glycation end products (AGE) in kidney transplant recipients (KTRs). The aim of this cross-sectional study was to determine the level of AGE-determined cardiovascular (CV) risk in Dalmatian KTRs and possible associations between AGE, adherence to the Mediterranean diet (MeDi), and nutritional status. Eighty-five (85) KTRs were enrolled in this study. For each study participant, data were collected on the level of AGE, as measured by skin autofluorescence (SAF), Mediterranean Diet Serving Score (MDSS), body mass composition, anthropometric parameters, and clinical and laboratory parameters. Only 11.76% of the participants were adherent to the MeDi. Sixty-nine percent (69%) of KTRs had severe CV risk based on AGE, while 31% of KTRs had mild to moderate CV risk. The results of the LASSO regression analysis showed that age, dialysis type, dialysis vintage, presence of CV and chronic kidney disease, C- reactive protein level, urate level, percentage of muscle mass, and adherence to recommendations for nuts, meat, and sweets were identified as positive predictors of AGE. The negative predictors for AGE were calcium, phosphate, cereal adherence according to the MeDi, and trunk fat mass. These results demonstrate extremely low adherence to the MeDi and high AGE levels related CV risk in Dalmatian KTRs. Lifestyle interventions in terms of CV risk management and adherence to the MeDi of KTRs should be taken into consideration when taking care of this patient population.

Non-Immunologic Causes of Late Death-Censored Kidney Graft Failure: A Personalized Approach

Despite continuous advances in surgical and immunosuppressive protocols, the long-term survival of transplanted kidneys is still far from being satisfactory. Antibody-mediated rejection, recurrent autoimmune diseases, and death with functioning graft are the most frequent causes of late-kidney allograft failure. However, in addition to these complications, a number of other non-immunologic events may impair the function of transplanted kidneys and directly or indirectly lead to their failure. In this narrative review, we will list and discuss the most important nonimmune causes of late death-censored kidney graft failure, including quality of the donated kidney, adherence to prescriptions, drug toxicities, arterial hypertension, dyslipidemia, new onset diabetes mellitus, hyperuricemia, and lifestyle of the renal transplant recipient. For each of these risk factors, we will report the etiopathogenesis and the potential consequences on graft function, keeping in mind that in many cases, two or more risk factors may negatively interact together.

Obesity and Lifestyle Habits among Kidney Transplant Recipients

Background: Obesity may negatively impact clinical outcomes in kidney transplant (KT) recipients. Limited information is available on the prevalence of obesity in this population, and on the lifestyle habits associated with obesity. Methods: we conducted an online, anonymous survey to assess of the proportion of KT recipients with obesity, adherence to the Mediterranean diet (i.e., a dietary regimen with proven renal and cardiovascular outcomes) using the MEDI-Lite questionnaire, and level of physical activity using the International Physical Activity Questionnaire (IPAQ) short form among KT recipients. Results: 255 KT recipients participated. Median (25th−75th quartile) age was 56.0 (48.0; 62.0) years, 43.9% female, median BMI 23.9 (21.6; 26.5) kg/m2. The proportion of KT recipients with obesity was 9.8% (95% confidence interval, 6.4 to 14.1%). Adequate adherence to the Mediterranean diet (Medi-Lite score >9) was overall low (44.7%; 40.0 vs. 45.2% in those with or without obesity, respectively; p = 0.618). In participants with obesity the Medi-Lite score inversely correlated with BMI (R = −0.45; p < 0.025). Overall, 30.6% of participants had a low level of physical activity (44.0 vs. 29.1% of those with or without obesity, respectively; p = 0.125). The amount of energy expended walking was significantly lower among participants with obesity (462 (0.0; 1436) vs. 1056 (433; 2005) METs/week, p = 0.017). Conclusions: the burden of obesity among KT recipients is similar to that of the general population. Adherence to the Mediterranean diet was generally low, and nearly one-third of participants had a low level of physical activity. Building specialized multidisciplinary teams to manage obesity in KT recipients is urgently needed.

Interconnectedness between periodontitis stage, oral hygiene habits, adherence to the Mediterranean diet and nutritional status in Dalmatian kidney transplant recipients: a cross-sectional study

The aim of this cross-sectional study was to determine the associations between the Mediterranean diet (MeDi), nutritional status parameters, muscle strength, and periodontal status in Dalmatian kidney transplant recipients (KTRs). 89 KTRs were included in this analysis, 40 (45%) women, with a mean age of 61 years (IQR = 13) and a mean time since kidney transplantation of 5 years (IQR = 6.6). An OHIP-14 questionnaire and questionnaire-based periodontal history were obtained from all participants, a comprehensive periodontal examination was performed. Body composition data, anthropometric and clinical parameters were collected for each study participant. The Mediterranean Diet Serving Score (MDSS) was used to assess MeDi adherence, and handgrip strength was measured with a hand dynamometer. Our results showed low adherence to MeDi in KTRs (28%) and almost 50% of KTRs suffer from severe forms of periodontitis. We also found a low OHIP-14 score and poor oral hygiene habits. KTRs with a less severe form of periodontitis had higher muscle mass and handgrip strength. MDSS score was associated with a higher number of teeth, and everyday cereal intake was inversely associated with the periodontitis stage. Our results demonstrate the associations between nutritional status, muscle strength, dietary habits, and periodontal health in Dalmatian KTRs.

The Impact of Human Microbiotas in Hematopoietic Stem Cell and Organ Transplantation

The human microbiota heavily influences most vital aspects of human physiology including organ transplantation outcomes and transplant rejection risk. A variety of organ transplantation scenarios such as lung and heart transplantation as well as hematopoietic stem cell transplantation is heavily influenced by the human microbiotas. The human microbiota refers to a rich, diverse, and complex ecosystem of bacteria, fungi, archaea, helminths, protozoans, parasites, and viruses. Research accumulating over the past decade has established the existence of complex cross-species, cross-kingdom interactions between the residents of the various human microbiotas and the human body. Since the gut microbiota is the densest, most popular, and most studied human microbiota, the impact of other human microbiotas such as the oral, lung, urinary, and genital microbiotas is often overshadowed. However, these microbiotas also provide critical and unique insights pertaining to transplantation success, rejection risk, and overall host health, across multiple different transplantation scenarios. Organ transplantation as well as the pre-, peri-, and post-transplant pharmacological regimens patients undergo is known to adversely impact the microbiotas, thereby increasing the risk of adverse patient outcomes. Over the past decade, holistic approaches to post-transplant patient care such as the administration of clinical and dietary interventions aiming at restoring deranged microbiota community structures have been gaining momentum. Examples of these include prebiotic and probiotic administration, fecal microbial transplantation, and bacteriophage-mediated multidrug-resistant bacterial decolonization. This review will discuss these perspectives and explore the role of different human microbiotas in the context of various transplantation scenarios.

Ultra-processed foods and risk of all-cause mortality in renal transplant recipients

BACKGROUND

Renal transplant recipients (RTRs) have a 6-fold higher risk of mortality than age- and sex-matched controls. Whether high consumption of ultra-processed foods is associated with survival in RTRs is unknown.

OBJECTIVES

We aimed to study the association between high consumption of ultra-processed foods and all-cause mortality in stable RTRs.

METHODS

We conducted a prospective cohort study in adult RTRs with a stable graft. Dietary intake was assessed using a validated 177-item FFQ. Food items were categorized according to the NOVA classification system and the proportion ultra-processed foods comprised of total food weight per day was calculated.

RESULTS

We included 632 stable RTRs (mean ± SD age: 53.0 ± 12.7 y, 57% men). Mean ± SD consumption of ultra-processed foods was 721 ± 341 g/d (28% of total weight of food intake), whereas the intake of unprocessed and minimally processed foods, processed culinary ingredients, and processed foods accounted for 57%, 1%, and 14%, respectively. During median follow-up of 5.4 y [IQR: 4.9-6.0 y], 129 (20%) RTRs died. In Cox regression analyses, ultra-processed foods were associated with all-cause mortality (HR per doubling of percentage of total weight: 2.13; 95% CI: 1.46, 3.10; P < 0.001), independently of potential confounders. This association was independent from the quality of the overall dietary pattern, expressed by the Mediterranean Diet Score (MDS) or Dietary Approaches to Stop Hypertension (DASH) score. When analyzing ultra-processed foods by groups, only sugar-sweetened beverages (HR: 1.21; 95% CI: 1.05, 1.39; P = 0.007), desserts (HR: 1.24; 95% CI: 1.02, 1.49; P = 0.03), and processed meats (HR: 1.87; 95% CI: 1.22, 2.86; P = 0.004) were associated with all-cause mortality.

CONCLUSIONS

Consumption of ultra-processed foods, in particular sugar-sweetened beverages, desserts, and processed meats, is associated with a higher risk of all-cause mortality after renal transplantation, independently of low adherence to high-quality dietary patterns, such as the Mediterranean diet and the DASH diet.This trial was registered at clinicaltrials.gov as NCT02811835.

Mediterranean Diet Adherence and Nutritional Status in Dalmatian Diabetic Hypertensive Patients Regarding Presence of Chronic Kidney Disease—Is There Any Difference?

In recent years, the Mediterranean diet has emerged as one of the dietary patterns that could have positive effects on overall health as well in the treatment of non-communicable chronic diseases. The aim of this cross-sectional study was to determine differences in adherence to the Mediterranean diet (MeDi) and nutritional status in patients with type 2 diabetes mellitus (T2DM) and arterial hypertension (AH) regarding the presence of chronic kidney disease (CKD). Two hundred and forty-eight Dalmatian diabetic hypertensive patients (DDHP) were included, and 164 (66.1%) of them had CKD. Data about anthropometric parameters, clinical and laboratory parameters, as well as lifestyle questionnaire and Mediterranean Diet Serving Score (MDSS) were collected for each study participant. Furthermore, body composition was assessed using MC-780 Multi Frequency Segmental Body Mass Analyzer (Tanita). Body mass index (BMI) as well as waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) were calculated. Results showed that only 8.9% of DDHP were adherent to the MeDi without significant differences regarding the presence of CKD. Therefore, only 9.1% of participants with CKD were adherent to the MeDi. Dietary recommendations were received by 52.8% of DDHP and 49.4% with CKD, while only 12.8% of those with CKD were adherent to the given recommendations. The results showed that 88.3% of DDHP and 87.8% of the DDHP with CKD were overweight or obese. Statically significant lower frequency of nut intake suggested by the MeDi was found in those participants with CKD (p = 0.02). Therefore, the significant associations between adherence to each MeDi component as well as MDSS score with the development of CKD among all study subjects were not found. In conclusion, the results showed a low level of nutritional care in our region and low adherence to MeDi among DDHP. According to the results, there is an urgent need to improve nutritional care in our region, with a special focus on the MeDi for this especially vulnerable population of patients.

Nutritional and dietary interventions to prolong renal allograft survival after kidney transplantation

PURPOSE OF REVIEW

Diet plays an important role in slowing progression of chronic kidney disease in native and transplanted kidneys. There is limited evidence on the association on dietary intake with renal allograft function. Mechanisms of major nutrients and dietary patterns with focusing on a plant-based diet related to kidney transplant health and longevity are reviewed.

RECENT FINDINGS

High dietary protein intake may adversely affect renal allograft. Low protein plant-focused diets such as Dietary Approaches to Stop Hypertension, plant-dominant low-protein diet and Mediterranean diets appear associated with favorable outcomes in slowing renal allograft function decline. The mechanism may be related to a change in renal hemodynamic by decreasing glomerular hyperfiltration from low dietary protein intake and plant-based ingredients. Recent observational studies of association between dietary protein intake and kidney allograft outcomes are conflicting. Although strong evidence is still lacking, a low protein diet of 0.6-0.8 g/kg/day with at least 50% of the protein source from plant-based components in kidney transplant recipients with stable kidney allograft function should be considered as the dietary target.

SUMMARY

Dietary intervention with low-protein plant-focused meals may improve outcomes in kidney transplant recipients, but the evidence remains limited and further studies are warranted.

Associations between Depression, Nutritional Status and Mediterranean Diet in Dalmatian Kidney Transplant Recipients

Depression has been addressed as a predictor of worse outcomes in kidney transplant recipients (KTRs). Nutritional status plays a great role in treatment of this population. The Mediterranean diet (MeDi) has been associated with lower levels of depressive symptoms. The aim of this cross-sectional study was to determine the rate of depression and its correlations to nutritional status and dietary habits according to the MeDi in Dalmatian KTRs. We included 115 KTRs, and data about body composition and anthropometric, laboratory and clinical parameters were obtained for each study participant. The Beck Depression Inventory-II (BDI-II) questionnaire was used to assess depressive symptoms and the Mediterranean Diet Serving Score (MDSS) was used to assess adherence to the MeDi. We found the presence of depressive symptoms in 21.73% of the Dalmatian KTRs. BDI-II score was reciprocally associated with fat mass, trunk visceral fat, anthropometric parameters of obesity, triglyceride levels and olive oil consumption. Inverse associations were found between BDI-II score and skeletal muscle mass, handgrip strength, MCV, hemoglobin levels and consumption of fish and white meat, as suggested by the MeDi. Our results showed the interconnections between nutritional status, dietary habits and depression in Dalmatian KTRs.

Polyphenols and Novel Insights Into Post-kidney Transplant Complications and Cardiovascular Disease: A Narrative Review

Kidney transplantation is the preferred treatment for end-stage kidney disease. It is, however, not devoid of complications. Delayed graft function related to ischemia-reperfusion injury (IRI), calcineurin inhibitor (CNI) nephrotoxicity, diabetes, and a particularly high-rate cardiovascular disease (CVD) risk, represent important complications following kidney transplantation. Oxidative stress and chronic low-grade inflammation are mechanisms of disease incompletely abrogated in stable kidney transplant recipient (KTR), contributing to the occurrence of these complications. Polyphenols, bioactive compounds with recognized antioxidant and anti-inflammatory properties have been strongly associated with prevention of CVD in the general population and have been shown to decrease IRI and antagonize CNI nephrotoxicity in animal experimental models, therefore they may have a role in prevention of complications in KTR. This narrative review aims to summarize and discuss current evidence on different polyphenols for prevention of complications, particularly prevention of CVD in KTR, pointing toward the need of further studies with potential clinical impact.

Association of serum bicarbonate with graft survival and mortality in kidney transplant recipients

BACKGROUND

Metabolic acidosis is an independent risk factor for kidney disease progression with a high prevalence after kidney transplantation (KTx). Remarkably, it is still unclear if there is an impact of metabolic acidosis on graft function and death after KTx. Thus, we wanted to investigate if serum bicarbonate is associated with long-term graft outcome and mortality after KTx.

METHODS

We performed a single-center retrospective study including adult de novo KTx patients between 1999 and 2015. Cox proportional hazard model was used to analyze a possible association between time-dependent serum bicarbonate measurements and graft failure or death.

RESULTS

Four hundred thirty KTRs were included in the analysis with a mean age of 50.9 ± 13.4 years. Mean observation time was 4.7 ± 2.8 years. Two hundred eighty-four (66%) patients were male and 318 (74%) had received a deceased donor kidney transplant. Mean bicarbonate and eGFR levels 1 year post-transplant amounted to 22.9 ± 3.1 mEq/L and 61 ± 26 ml/min/1.73 m², respectively. Prevalence of metabolic acidosis was 31% 1 year after transplantation. Fourteen (3%) patients died and 31 (7%) suffered from graft failure. Higher bicarbonate levels were associated with significantly lower hazards for graft failure (Hazard Ratio (HR) = 0.88; 95% Confidence Interval (CI): 0.79-0.98) and mortality (HR = 0.79; 95% CI 0.66-0.93) after adjusting for potential confounders such as age, donor type and time-varying eGFR.

CONCLUSIONS

Our analysis showed that higher serum bicarbonate levels are positively associated with long-term graft and patient survival in kidney transplant recipients. Thus, serum bicarbonate may serve as a predictor and independent risk factor for graft and patient outcome after KTx as has been previously shown for patients with CKD.

A Qualitative Study of Clinician Barriers and Enablers to Implementing the Mediterranean Dietary Pattern with Kidney and Liver Transplant Recipients

INTRODUCTION

Solid organ transplant recipients experience greater cardiometabolic risk than the general population. Following a Mediterranean dietary pattern has been shown to reduce cardiometabolic risk. This study aimed to assess multidisciplinary clinician perspectives of routine nutrition care for kidney and liver transplant recipients and barriers and enablers to implementation of the Mediterranean dietary pattern.

METHODS

Semi-structured individual interviews were conducted with clinicians in a metropolitan health service at tertiary/quaternary transplant centres involved in longer-term management of kidney and liver transplants recipients. Audio-recorded interviews were transcribed verbatim and analysed using thematic content analysis.

FINDINGS

Nineteen clinicians (9 medical officers, 5 dietitians, 3 nurses and 2 other allied health professionals) were interviewed. Four themes with 11 subthemes were identified: the Mediterranean dietary pattern is not part of routine care (there are competing clinical priorities; healthy eating principles aligned with but not the full dietary pattern are recommended); variation in knowledge and acceptance of this dietary approach (variances in information sources and degree of knowledge of Mediterranean dietary pattern clinical evidence); nutrition advice is influenced by service delivery and culture (there is lack of consistent nutrition advice; limited consultation time; and reliance on existing patient education resources); and patient-centred care influences decisions on nutrition advice (clinicians do not know how to recommend this dietary pattern in a patient-centred manner).

DISCUSSION

The Mediterranean dietary pattern is not considered part of routine post-transplant nutrition care. To be implemented in these services intervention strategies which address the identified barriers and potential enablers need to be considered.

Mediterranean Diet Adherence and Nutritional Status in Dalmatian Kidney Transplant Recipients-Are They Related?

The aim of this study was to evaluate adherence to Mediterranean diet (MeDi) and possible correlation of MeDi adherence and nutritional status parameters in Dalmatian kidney transplant recipients (KTRs). One hundred and sixteen KTRs were included in this study. Data about Mediterranean Diet Serving Score (MDSS), body mass composition, anthropometric parameters, clinical and laboratory parameters were collected for each study participant. The results showed 25% adherence to the MeDi in Dalmatian KTRs. MDSS showed association with higher serum albumin and phosphorus level and higher skeletal muscle mass. Also, significant association between diabetic status and MDSS was found. Adherence to olive oil intake suggested by the MeDi showed significant association with lower level of triglycerides and adherence to nuts suggestions was associated with lower level of fat mass. Following MeDi recommendations for consumption of other foods (cereals, potato, eggs, vegetables, fruits and dairy) were also associated with body mass composition parameters and laboratory findings. In conclusion, low adherence to the MeDi in Dalmatian KTRs raises high concerns. The results showed that MeDi can have favorable effects on nutritional status in KTRs. A structured nutritional approach is needed to enhance adherence to the MeDi and prevent possible adverse effects in this patient population.

Acidosis and alkali therapy in patients with kidney transplant is associated with transcriptional changes and altered abundance of genes involved in cell metabolism and acid-base balance

BACKGROUND

Metabolic acidosis occurs frequently in patients with kidney transplant and is associated with higher risk for and accelerated loss of graft function. To date, it is not known whether alkali therapy in these patients improves kidney function and whether acidosis and its therapy is associated with altered expression of proteins involved in renal acid-base metabolism.

METHODS

We collected retrospectively kidney biopsies from 22 patients. Of these patients, 9 had no acidosis, 9 had metabolic acidosis (plasma HCO3- < 22 mmol/l), and 4 had acidosis and received alkali therapy. We performed transcriptome analysis and immunohistochemistry for proteins involved in renal acid-base handling.

RESULTS

We found the expression of 40 transcripts significantly changed between kidneys from non-acidotic and acidotic patients. These genes are mostly involved in proximal tubule amino acid and lipid metabolism and energy homeostasis. Three transcripts were fully recovered by alkali therapy: the Kir4.2 K+-channel, an important regulator of proximal tubule HCO3--metabolism and transport, ACADSB and SHMT1, genes involved in beta-oxidation and methionine metabolism. Immunohistochemistry showed reduced staining for the proximal tubule NBCe1 HCO3- transporter in kidneys from acidotic patients that recovered with alkali therapy. In addition, the HCO3-exchanger pendrin was affected by acidosis and alkali therapy.

CONCLUSIONS

Metabolic acidosis in kidney transplant recipients is associated with alterations in the renal transcriptome that are partly restored by alkali therapy. Acid-base transport proteins mostly from proximal tubule were also affected by acidosis and alkali therapy suggesting that the downregulation of critical players contributes to metabolic acidosis in these patients.

A Narrative Review of Dietary Approaches for Kidney Transplant Patients

A healthy eating pattern has proven to lower the risk of metabolic and cardiovascular diseases. However, there are sparse dietary recommendations for kidney transplant recipients, and the ones available focus only on single nutrients intake, such as sodium, potassium, and proteins, and not on the overall eating pattern. Considering that individuals do not typically consume nutrients in isolation, but as part of a complete dietary pattern, it is challenging for the average transplanted patient to understand and implement specific dietary recommendations. Also, single-nutrient interventions demonstrate largely inconclusive effects, and it seems improbable that they could have a strong enough impact on transplant outcomes. Dietary trends such as plant-based diets, intermittent fasting, low-carb diet/keto-diet, and juicing, have gained major attention from the media. Herein, we review the potential risks and benefits of these diets in kidney transplant recipients and provide an updated dietary recommendation for this population with consideration of current nutritional trends. Overall, the Mediterranean and DASH diets have demonstrated to be the most beneficial dietary patterns to the post kidney transplant population by focusing on less meat and processed foods, while increasing the intake of fresh foods and plant-based choices. We believe that to maintain a healthy lifestyle posttransplant, patients should be educated about the scientific evidence of different diets and choose a dietary pattern that is sustainable long-term.

Metabolic syndrome-related dietary pattern and risk of mortality in kidney transplant recipients

BACKGROUND AND AIMS

Presence of the metabolic syndrome (MetS) importantly contributes to excess mortality in kidney transplant recipients (KTRs). However, it is unclear which dietary factors drive the adverse role of MetS in KTRs. We aimed to define a dietary pattern that maximally explained the variation in MetS components, and to investigate the association between this MetS-related dietary pattern (MetS-DP) and all-cause mortality in KTRs.

METHODS AND RESULTS

We included 429 adult KTRs who had a functioning graft ⩾1 year. A MetS-DP was constructed using habitual dietary intake derived from a 177-item food frequency questionnaire. We used reduced rank regression (RRR), and defined the six components of MetS (waist circumference, systolic blood pressure, diastolic blood pressure, serum triglycerides, HbA1c, and HDL cholesterol) as response variables and 48 food groups as predictor variables. We evaluated the association between the MetS-DP and all-cause mortality using multivariable Cox regression analysis. The MetS-DP was characterized by high intakes of processed meat and desserts, and low intakes of vegetables, tea, rice, fruits, milk, and meat substitutes. During a mean follow-up of 5.3 ± 1.2 years, 63 KTRs (14.7%) died. Compared to the lowest tertile of the Mets-DP score, those with the greatest adherence had a more than 3-fold higher risk of all-cause mortality (hazard ratio [HR] = 3.63; 95% confidence interval [CI], 1.70-7.74, P < 0.001), independent of potential confounders.

CONCLUSIONS

We identified a MetS-related dietary pattern which was independently associated with all-cause mortality in KTRs. The association between this dietary pattern and all-cause mortality was mediated by MetS. Clinical trial reg. no. NCT02811835.

Food Literacy Is Associated With Adherence to a Mediterranean-Style Diet in Kidney Transplant Recipients

OBJECTIVES

Adherence to a Mediterranean-style diet is associated with improved health outcomes in kidney transplant recipients (KTR). However, poor dietary habits, including excessive sodium intake, are common in KTR, indicating difficulties with incorporating a healthy diet into daily life. Food literacy is identified as potential facilitator of a healthy diet, but the precise relationship between food literacy and dietary intake in KTR has not been investigated. This study examined food literacy levels in KTR and its association with adherence to a Mediterranean-style diet and sodium intake.

METHODS

This cross-sectional study is part of the TransplantLines Cohort and Biobank Study. Food literacy was measured with the Self-Perceived Food Literacy (SPFL) questionnaire. Dietary intake assessment with food frequency questionnaires was used to calculate the Mediterranean Diet Score. Sodium intake was based on the 24-hour urinary sodium excretion rate. Associations of SPFL with Mediterranean Diet Score and sodium intake were assessed with univariable and multivariable linear regression analyses.

RESULTS

In total, 148 KTR (age 56 [48-66]; 56% male) completed the SPFL questionnaire with a mean SPFL score of 3.63 ± 0.44. Higher SPFL was associated with a higher Mediterranean Diet Score in KTR (β = 1.51, 95% confidence interval 0.88-2.12, P ≤ .001). Although KTR with higher food literacy tended to have a lower sodium intake than those with lower food literacy (P = .08), the association of food literacy with sodium intake was not significant in a multivariable regression analysis (β = 0.52 per 10 mmol/24-hour increment, 95% confidence interval -1.79 to 2.83, P = .66).

CONCLUSIONS

Higher levels of food literacy are associated with better adherence to a Mediterranean-style diet in KTR. No association between food literacy and sodium intake was found. Further studies are needed to determine if interventions on improving food literacy contribute to a healthier diet and better long-term outcomes in KTR.

Nutrition-Based Management of Inflammaging in CKD and Renal Replacement Therapies

Access to renal transplantation guarantees a substantial improvement in the clinical condition and quality of life (QoL) for end-stage renal disease (ESRD) patients. In recent years, a greater number of older patients starting renal replacement therapies (RRT) have shown the long-term impact of conservative therapies for advanced CKD and the consequences of the uremic milieu, with a frail clinical condition that impacts not only their survival but also limits their access to transplantation. This process, referred to as “inflammaging,” might be reversible with a tailored approach, such as RRT accompanied by specific nutritional support. In this review, we summarize the evidence demonstrating the presence of several proinflammatory substances in the Western diet (WD) and the positive effect of unprocessed food consumption and increased fruit and vegetable intake, suggesting a new approach to reduce inflammaging with the improvement of ESRD clinical status. We conclude that the Mediterranean diet (MD), because of its modulative effects on microbiota and its anti-inflammaging properties, may be a cornerstone in a more precise nutritional support for patients on the waiting list for kidney transplantation.

Dietary Assessment and Self-Management Using Information Technology in Order to Improve Outcomes in Kidney Transplant Recipients

Big data and artificial intelligence (AI) will transform the way research in nephrology is carried out and consequently improve the performance of clinical practice in nephrology and transplantation. Managing long-term health outcomes in kidney transplant recipients (KTR) includes the improvement of modifiable factors, such as diet. Self-management using information technology (IT) aims to facilitate lifestyle changes, manage symptoms and treatment in the course of chronic kidney disease (CKD) or any chronic condition. The advantages of health mobile applications further include the capacity of data compilation and yielding responses to numerous research questions in nephrology and transplantation. However, studies investigating the employment of such applications in KTR and its impact in kidney transplant outcomes are still lacking. The specific advantages of dietary assessment and self-management using IT in order to improve outcomes in KTR are presently discussed. This Special Issue features a great set of articles regarding IT approaches to improve kidney allograft survival and posttransplant outcomes in all areas.

Plasma cadmium is associated with increased risk of long-term kidney graft failure

The kidney is one of the most sensitive organs to cadmium-induced toxicity, particularly in conditions of long-term oxidative stress. We hypothesized that, in kidney transplant recipients, nephrotoxic exposure to cadmium represents an overlooked hazard for optimal graft function. To test this, we performed a prospective cohort study and included 672 outpatient kidney transplant recipients with a functioning graft of beyond one year. The median plasma cadmium was 58 ng/L. During a median 4.9 years of follow-up, 78 kidney transplant recipients developed graft failure with a significantly different distribution across tertiles of plasma cadmium (13, 26, and 39 events, respectively). Plasma cadmium was associated with an increased risk of graft failure (hazard ratio 1.96, 95% confidence interval 1.56‒2.47 per log₂ ng/L). Similarly, a dose-response relationship was observed over increasing tertiles of plasma cadmium, after adjustments for potential confounders (donor, recipient, transplant and lifestyle characteristics), robust in both competing risk and sensitivity analyses. These findings were also consistent for kidney function decline (graft failure or doubling of serum creatinine). Thus, plasma cadmium is independently associated with an increased risk of long-term kidney graft failure and decline in kidney function. Further studies are needed to investigate whether exposure to cadmium represents an otherwise overlooked modifiable risk factor for adverse long-term graft outcomes in different populations.

Mediterranean diet and the risk of chronic kidney disease: A systematic review and meta-analysis

OBJECTIVE

Mediterranean diet has been shown to be associated with lower risk of cardiovascular disease. However, its association with chronic kidney disease (CKD) remains inconclusive as the results were not consistent among population-based studies. This study aims to assess the association between Mediterranean diet adherence and CKD prevention.

METHODS

We performed a systematic review and meta-analysis of studies describing the risk for CKD in community-dwelling subjects ≥18 years of age. Mediterranean diet adherence was assessed by standardized food frequency questionnaires. The search was conducted through MEDLINE, EMBASE and Cochrane Library.

RESULTS

Of 168 citations, a total of nine (n = 19 151) and four studies (n = 8467) were included in the systematic review and meta-analysis, respectively. Only studies adopting Mediterranean Diet Scale (MDS) were included in the analysis. The mean score was 3.8 ± 0.3 points. With the mean follow-up duration of 20.6 ± 7.0 years, the pooled odds ratio (OR) for CKD was 0.901 (95% confidence interval [CI] 0.868-0.935) for each 1-point increment of MDS. The incidence of CKD was 0.026 events per person-year (95% CI 0.008-0.045). Moreover, male sex was associated with the incidence of CKD in an adjusted meta-regression analysis. In contrast, there was no significant association between age, black race, smoking, diabetes, hypertension estimated glomerular filtration rate and total daily energy intake vs CKD incidence.

CONCLUSION

Adherence to Mediterranean diet by a 1-point increment of MDS was associated with 10% lower risk of CKD. However, there were insufficient data on patients with pre-existing CKD or dialysis.

Circulating Arsenic is Associated with Long-Term Risk of Graft Failure in Kidney Transplant Recipients: A Prospective Cohort Study

Arsenic is toxic to many organ systems, the kidney being the most sensitive target organ. We aimed to investigate whether, in kidney transplant recipients (KTRs), the nephrotoxic exposure to arsenic could represent an overlooked hazard for graft survival. We performed a prospective cohort study of 665 KTRs with a functional graft ≥1 year, recruited in a university setting (2008‒2011), in The Netherlands. Plasma arsenic was measured by ICP-MS, and dietary intake was comprehensively assessed using a validated 177-item food-frequency questionnaire. The endpoint graft failure was defined as restart of dialysis or re-transplantation. Median arsenic concentration was 1.26 (IQR, 1.04‒2.04) µg/L. In backwards linear regression analyses we found that fish consumption (std β = 0.26; p < 0.001) was the major independent determinant of plasma arsenic. During 5 years of follow-up, 72 KTRs developed graft failure. In Cox proportional-hazards regression analyses, we found that arsenic was associated with increased risk of graft failure (HR 1.80; 95% CI 1.28-2.53; p = 0.001). This association remained materially unaltered after adjustment for donor and recipient characteristics, immunosuppressive therapy, eGFR, primary renal disease, and proteinuria. In conclusion, in KTRs, plasma arsenic is independently associated with increased risk of late graft failure.