Association between vascular calcification scores on plain radiographs and fatty acid contents of erythrocyte membrane in hemodialysis patients

Food to Prevent Vascular Calcification in Chronic Kidney Disease

Vascular calcification (VC) is a consequence of chronic kidney disease (CKD) which is of paramount importance regarding the survival of CKD patients. VC is far from being controlled with actual medication; as a result, in recent years, diet modulation has become more compelling. The concept of medical nutritional therapy points out the idea that food may prevent or treat diseases. The aim of this review was to evaluate the influence of food habits and nutritional intervention in the occurrence and progression of VC in CKD. Evidence reports the harmfulness of ultra-processed food, food additives, and animal-based proteins due to the increased intake of high absorbable phosphorus, the scarcity of fibers, and the increased production of uremic toxins. Available data are more supportive of a plant-dominant diet, especially for the impact on gut microbiota composition, which varies significantly depending on VC presence. Magnesium has been shown to prevent VC but only in experimental and small clinical studies. Vitamin K has drawn considerable attention due to its activation of VC inhibitors. There are positive studies; unfortunately, recent trials failed to prove its efficacy in preventing VC. Future research is needed and should aim to transform food into a medical intervention to eliminate VC danger in CKD.

Circulating fatty acid profiles are associated with protein energy wasting in maintenance hemodialysis patients: a cross-sectional study

The metabolic impact of circulating fatty acids (FAs) in patients requiring hemodialysis (HD) is unknown. We investigated the associations between plasma triglyceride (TG) FAs and markers of inflammation, insulin resistance, nutritional status and body composition. Plasma TG-FAs were measured using gas chromatography in 341 patients on HD (age = 55.2 ± 14.0 years and 54.3% males). Cross-sectional associations of TG-FAs with 13 markers were examined using multivariate linear regression adjusted for potential confounders. Higher levels of TG saturated fatty acids were associated with greater body mass index (BMI, r = 0.230), waist circumference (r = 0.203), triceps skinfold (r = 0.197), fat tissue index (r = 0.150), serum insulin (r = 0.280), and homeostatic model assessment of insulin resistance (r = 0.276), but lower malnutrition inflammation score (MIS, r =  − 0.160). Greater TG monounsaturated fatty acid levels were associated with lower lean tissue index (r =  − 0.197) and serum albumin (r =  − 0.188), but higher MIS (r = 0.176). Higher levels of TG n-3 polyunsaturated fatty acids (PUFAs) were associated with lower MIS (r =  − 0.168) and interleukin-6 concentrations (r =  − 0.115). Higher levels of TG n-6 PUFAs were associated with lower BMI (r =  − 0.149) but greater serum albumin (r = 0.112). In conclusion, TG monounsaturated fatty acids were associated with poor nutritional status, while TG n-3 PUFAs were associated with good nutritional status. On the other hand, TG saturated fatty acids and TG n-6 PUFAs had both favorable and unfavorable associations with nutritional parameters.

Omega-3 fatty acids in pathological calcification and bone health

Omega-3 fatty acids (ω-3FAs) such as Docosahexaenoic acid (DHA) and Eicosapentanoic acid (EPA), are active ingredient of fish oil, which have larger health benefits against various diseases including cardiovascular, neurodegenerative, cancers and bone diseases. Substantial studies documented a preventive role of omega-3 fatty acids in pathological calcification like vascular calcification and microcalcification in cancer tissues. In parallel, these fatty acids improve bone quality probably by preventing bone decay and augmenting bone mineralization. This study also addresses that the functions of ω-3FAs not only depend on tissue types, but also work through different molecular mechanisms for preventing pathological calcification in various tissues and improving bone health. PRACTICAL APPLICATIONS: Practical applications of the current study are to improve the knowledge about the supplementation of omega-3 fatty acids. This study infers that supplementation of omega-3 fatty acids aids in bone preservation in elder females at the risk of osteoporosis and also, on the contrary, omega-3 fatty acids interfere with pathological calcification of vascular cells and cancer cells. Omega-3 supplementation should be given to the cardiac patients because of its cardio protective role. In line with this, omega-3 supplementation should be included with chemotherapy for cancer patients as it can prevent osteoblastic potential of breast cancer patients, responsible for pathological mineralization, and blocks off target toxicities. Administration of omega-3 fatty acid with chemotherapy will not only improve survival of cancer patients, but also improve the bone quality. Thus, this study allows a better understanding on omega-3 fatty acids in combating pathological complications such as osteoporosis, vascular calcification, and breast microcalcification.

Supplementary nutrients for prevention of vascular calcification in patients with chronic kidney disease

Vascular calcification (VC) and malnutrition associated with cardiovascular disease are common in patients with chronic kidney disease (CKD) treated with dialysis. VC, which reflects vascular aging, and malnutrition are also encountered in the non-CKD elderly population. This similarity of clinical findings suggests that the progression of CKD is related to aging and the existence of a causal relationship between VC and malnutrition. To retard renal progression, a low- or very-low-protein diet is usually recommended for CKD patients. Dietary education may induce malnutrition and deficiency of important nutrients, such as vitamins K and D. Menaquinone-7, a type of vitamin K2, is under investigation for inhibiting VC in elderly patients without CKD, as well as for prevention of VC in patients with CKD. Nutritional vitamin D, such as cholecalciferol, may be considered to decrease the required dose of active vitamin D, which increases the risk of VC due to increased calcium and phosphate loads. Omega-3 fatty acids are important nutrients and their ability to inhibit VC needs to be evaluated in clinical trials. This review focuses on the ability of supplementary nutrients to prevent VC in patients with CKD, in whom dietary restriction is essential.

Dietary fatty acid intake in hemodialysis patients and associations with circulating fatty acid profiles: A cross-sectional study

OBJECTIVES

The aims of this study were threefold: first, to assess the dietary fatty acid (FA) intake and blood FA status in Malaysian patients on hemodialysis (HD); second, to examine the association between dietary FA intakes and blood FA profiles in patients on HD; and third, to determine whether blood FAs could serve as a biomarker of dietary fat intake quality in these patients.

METHODS

Using 3 d of dietary records, FA intakes of 333 recruited patients were calculated using a food database built from laboratory analyses of commonly consumed Malaysian foods. Plasma triacylglycerol (TG) and erythrocyte FAs were determined by gas chromatography.

RESULTS

High dietary saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) consumption trends were observed. Patients on HD also reported low dietary ω-3 and ω-6 polyunsaturated fatty acid (PUFA) consumptions and low levels of TG and erythrocyte FAs. TG and dietary FAs were significantly associated respective to total PUFA, total ω-6 PUFA, 18:2 ω-6, total ω-3 PUFA, 18:3 ω-3, 22:6 ω-3, and trans 18:2 isomers (P < 0.05). Contrarily, only dietary total ω-3 PUFA and 22:6 ω-3 were significantly associated with erythrocyte FAs (P < 0.01). The highest tertile of fish and shellfish consumption reflected a significantly higher proportion of TG 22:6 ω-3. Dietary SFAs were directly associated with TG and erythrocyte MUFA, whereas dietary PUFAs were not.

CONCLUSION

TG and erythrocyte FAs serve as biomarkers of dietary PUFA intake in patients on HD. Elevation of circulating MUFA may be attributed to inadequate intake of PUFAs.

Impact of Blood or Erythrocyte Membrane Fatty Acids for Disease Risk Prediction: Focusing on Cardiovascular Disease and Chronic Kidney Disease

Fatty acids (FAs) are essential nutrients and main constituents of cell membranes that are involved in the signaling pathway and associated with health conditions. We investigated if blood or erythrocyte membrane FAs can predict the risk of cardiovascular disease (CVD), chronic kidney disease (CKD), and related complications. Omega-3 (n-3) FAs are important predictors for metabolic syndrome, diabetes, CVD, and CKD risks, and the n-3 index is also a good biomarker for sudden cardiac death in coronary artery disease. Linoleic acid, which is one of the major n-6 FAs reflecting recent dietary FA intake, may predict CVD risk and mortality in the general population and patients with CKD. Monounsaturated FAs (MUFAs) are also related to diabetes or diabetic nephropathy. Oleic acid, a major MUFA, is an emerging marker that is related to acute coronary syndrome, low glomerular filtration rate, and vascular calcification in patients with CKD, and can be modified by n-3 FA supplementation. Saturated FAs, trans-FAs, and FA desaturation/elongation are associated with CVD risk; however, few studies have been conducted on patients with CKD. In summary, blood or erythrocyte membrane FA measurements are important for CVD and CKD risk prediction and management. Further studies are needed to elucidate the FAs for their risk predictions.

Blood Fatty Acid Status and Clinical Outcomes in Dialysis Patients: A Systematic Review

Blood fatty acids (FAs) are derived from endogenous and dietary routes. Metabolic abnormalities from kidney dysfunction, as well as cross-cultural dietary habits, may alter the FA profile of dialysis patients (DP), leading to detrimental clinical outcomes. Therefore, we aimed to (i) summarize FA status of DP from different countries, (ii) compare blood FA composition between healthy controls and DP, and (iii) evaluate FA profile and clinical endpoints in DP. Fifty-three articles from 1980 onwards, reporting FA profile in hemodialysis and peritoneal DP, were identified from PubMed, Embase, and the Cochrane library. Studies on pediatric, predialysis chronic kidney disease, acute kidney injury, and transplant patients were excluded. Moderate to high levels of n-3 polyunsaturated fatty acids (PUFA) were reported in Japan, Korea, Denmark, and Sweden. Compared to healthy adults, DP had lower proportions of n-3 and n-6 PUFA, but higher proportion of monounsaturated fatty acids. Two studies reported inverse associations between n-3 PUFAs and risks of sudden cardiac death, while one reported eicosapentaenoic acid + docosahexaenoic acid)/arachidonic acid ratio was inversely associated with cardiovascular events. The relationship between all-cause mortality and blood FA composition in DP remained inconclusive. The current evidence highlights a critical role for essential FA in nutritional management of DP.

A review of the effect of diet on cardiovascular calcification

Cardiovascular (CV) calcification is known as sub-clinical atherosclerosis and is recognised as a predictor of CV events and mortality. As yet there is no treatment for CV calcification and conventional CV risk factors are not consistently correlated, leaving clinicians uncertain as to optimum management for these patients. For this reason, a review of studies investigating diet and serum levels of macro- and micronutrients was carried out. Although there were few human studies of macronutrients, nevertheless transfats and simple sugars should be avoided, while long chain ω-3 fats from oily fish may be protective. Among the micronutrients, an intake of 800 μg/day calcium was beneficial in those without renal disease or hyperparathyroidism, while inorganic phosphorus from food preservatives and colas may induce calcification. A high intake of magnesium (≥380 mg/day) and phylloquinone (500 μg/day) proved protective, as did a serum 25(OH)D concentration of ≥75 nmol/L. Although oxidative damage appears to be a cause of CV calcification, the antioxidant vitamins proved to be largely ineffective, while supplementation of α-tocopherol may induce calcification. Nevertheless other antioxidant compounds (epigallocatechin gallate from green tea and resveratrol from red wine) were protective. Finally, a homocysteine concentration >12 µmol/L was predictive of CV calcification, although a plasma folate concentration of >39.4 nmol/L could both lower homocysteine and protect against calcification. In terms of a dietary programme, these recommendations indicate avoiding sugar and the transfats and preservatives found in processed foods and drinks and adopting a diet high in oily fish and vegetables. The micronutrients magnesium and vitamin K may be worthy of further investigation as a treatment option for CV calcification.

Omega-3 index and cardiovascular health

Recent large trials with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the cardiovascular field did not demonstrate a beneficial effect in terms of reductions of clinical endpoints like total mortality, sudden cardiac arrest or other major adverse cardiac events. Pertinent guidelines do not uniformly recommend EPA + DHA for cardiac patients. In contrast, in epidemiologic findings, higher blood levels of EPA + DHA were consistently associated with a lower risk for the endpoints mentioned. Because of low biological and analytical variability, a standardized analytical procedure, a large database and for other reasons, blood levels of EPA + DHA are frequently assessed in erythrocytes, using the HS-Omega-3 Index® methodology. A low Omega-3 Index fulfills the current criteria for a novel cardiovascular risk factor. Neutral results of intervention trials can be explained by issues of bioavailability and trial design that surfaced after the trials were initiated. In the future, incorporating the Omega-3 Index into trial designs by recruiting participants with a low Omega-3 Index and treating them within a pre-specified target range (e.g., 8%-11%), will make more efficient trials possible and provide clearer answers to the questions asked than previously possible.

Inverse association between docosahexaenoic acid and mortality in patients on hemodialysis during over 10 years

We have previously conducted a cohort study to investigate n-3 polyunsaturated fatty acids (PUFAs) in red blood cells (RBCs) and risk of all-cause mortality in hemodialysis (HD) patients over 5 years and found that n-3 PUFAs, especially docosahexaenoic acid (DHA), might be an independent predictor of all-cause mortality. In the present study, we extended the study for another 5 years to determine whether DHA levels in RBCs still predict the mortality of HD patients during a 10-year study period. The study cohort consisted of 176 patients (64.1 ± 12.0 [mean ± standard deviation] years of age, 96 men and 80 women) under HD treatment. The fatty acid composition of patients' RBCs was analyzed by gas chromatography. During the study period of 10 years, 97 deaths occurred. After adjustment for 10 confounding factors, the hazard ratio of all-cause mortality of the HD patients in the highest DHA tertile (>8.1%) was 0.52 (95% confidence interval 0.30-0.91) compared with those in the lowest DHA tertile (<7.2%). However, other n-3 PUFAs such as eicosapentaenoic acid and docosapentaenoic acid (n-3) did not reveal any significant correlations. The level of DHA in RBCs could be an independent predictor of all-cause mortality in HD patients even during a long period of follow-up.

Cardioprotective effects of ω -3 PUFAs in chronic kidney disease

The prevalence rate of chronic kidney disease (CKD) is increasing worldwide, and cardiovascular disease (CVD) is a main cause of death in patients with CKD. The high incidence of CVD in CKD patients is related to chronic inflammation, dyslipidemia, malnutrition, atherosclerosis, and vascular calcification. Omega-3 polyunsaturated fatty acids ( ω -3 PUFAs) have been shown to reduce the risk of CVD. In this paper, we review the beneficial effects of ω -3 PUFAs on CVD and the possible cardioprotective mechanisms of ω -3 PUFAs in CKD patients by determining the effect of ω -3 PUFAs in the general population. ω -3 PUFAs have several cardioprotective benefits, such as reducing inflammation, decreasing oxidative stress, inhibiting platelet activity, exerting antiarrhythmic effects, and improving triglyceride levels, in the general population and patients with CKD. Modifications of erythrocyte membrane fatty acid content, including an increased ω -3 index and decreased oleic acid, after ω -3 PUFAs supplementation are important changes related to CVD risk reduction in the general population and patients with CKD. Further basic and clinical studies are essential to confirm the effects of ω -3 PUFAs on vitamin D activation, vascular calcification prevention, cardiovascular events, and mortality in CKD patients.

Comparison of erythrocyte membrane fatty acid contents in renal transplant recipients and dialysis patients

BACKGROUND

Alterations of erythrocyte membrane fatty acid (FA) composition play important roles in cellular function because they change the membrane microenvironment, including transmembrane receptors. The erythrocyte membrane oleic acid content is higher among patients with acute coronary syndrome and also in dialysis patients. However, available data are limited concerning erythrocyte membrane FA content in kidney transplant recipients (KTP). We sought to test the hypothesis that erythrocyte membrane FA content among KTP were different from those in dialysis patients.

METHODS

In this cross-sectional study, we recruited 35 hemodialysis, 33 peritoneal dialysis 49 KTP, and 33 normal control subjects (CTL). Their erythrocyte membrane FA content were measured by gas chromatography.

RESULTS

The mean ages of the enrolled dialysis patients, KTP, and CTL were 56.4 ± 10.1, 48.9 ± 10.4, and 49.5 ± 8.3 years, respectively. Mean kidney transplant duration was 89.8 ± 64.8 months and mean dialysis duration, 49.0 ± 32.6 months. The intakes of vegetable lipid and vegetable protein including total calories were significantly increased among KTP versus dialysis patients. Total cholesterol (P < .001) and high density lipoprotein cholesterol (HDL; P < .001) levels were significantly higher and C-reactive protein was significantly lower among KTP compared with dialysis patients. The erythrocyte membrane content of palmitoleic acid (P < .001) was significantly higher but oleic acid (P < .001) significantly lower in KTP compared with dialysis patients. The erythrocyte membrane contents of arachidonic acid and docosahexaenoic acid were significantly higher, and linoleic acid and the omega-6 FA to omega-3 FA ratio (P < .001) significantly lower in KTP compared with dialysis patients. The erythrocyte membrane content of oleic acid was independently associated with monounsaturated fatty acid (beta = 0.771, P < .001), eicosapentaeonic acid (beta = -0.244, P = .010), and HDL (beta = -0.139, P = .049) in KTP.

CONCLUSIONS

FA contents of erythrocyte membranes were significantly different in KTP compared with dialysis patients. These differences may have been associated with improved dietary intake and immunosuppression after kidney transplantation.