Spontaneous low-protein intake in older CKD patients: one diet may not fit all

Background

Protein restriction has been extended to stage 3 chronic kidney disease (CKD) regardless of age in the latest K-DOQI guidelines for the dietary management of patients with CKD. However, in elderly CKD patients there is a tendency to a spontaneous reduction in protein and energy intake that may impair the overall nutritional status. The aim of our study is to assess whether there are differences in malnutrition, exercise capacity and inflammatory status in elderly CKD patients with spontaneously low protein intake (sLPI) compared with patients with normal protein intake (NPI).

Methods

We performed a cross-sectional analysis of 123 incident patients. Malnutrition was assessed using Malnutrition Inflammation Score (MIS) and serum markers; As for physical performance, we used Short Physical Performance Battery (SPPB) and handgrip strength.

Results

We found that in older patients with advanced CKD, as many as 68% had low spontaneous protein intake, and they were more malnourished evaluated with MIS (25% vs. 10%, p = 0.033), protein-energy wasting (PEW) (43% vs. 14%, p = 0.002) and nPCR (0.63[0.51–0.69] vs. 0.95[0.87–1.1], p < 0.0001). They also had worse body composition, in terms of lower mid-arm muscular circumference (MAMC), fat tissue index (FTI) and higher overhydration (OH). sLPI patients also had higher levels of IL6 (4.6[2.9–8.9] vs. 2.8[0.8–5.1], p = 0.002). Moreover, sLPI patients were frailer (33% vs. 24%, p = 0.037) and had poorer physical performance especially when assessed with (SPPB) (7[5–9] vs. 9[7–10], p = 0.004) and gait test time (6.08 + 2 vs. 7.22 + 2.7, p = 0.04). sLPI was associated with lower physical performance [SPPB OR, 0.79 (0.46–0.97), p = 0.046] and malnutrition [MIS 1.6 (1.05–3.5), p = 0.041] independently from patients’ age and eGFR.

Conclusion

We found that in older patients with advanced CKD, up to 68% had low spontaneous protein intake and were frailer, more malnourished and with lower physical performance. These findings emphasize the importance of assessing patients’ needs, and personalized approaches with individual risk–benefit assessments should be sought. To achieve the best possible outcomes, targeted interventions should use all available tools.

Poor Nutritional Status Is Associated with Death in a Population of Dialyzed Older Persons

BACKGROUND

Older patients in hemodialysis have high prevalence of malnutrition that is often associated with rapid weight loss till cachexia.

OBJECTIVES

We aimed to investigate whether in older patients undergoing hemodialysis the association between poor nutritional status and mortality may be independent of comorbidities and other risk factors.

DESIGN

Retrospective longitudinal study.

SETTING

Unit of Nephrology, Dialysis and Kidney Transplantation of the Policlinic Hospital of Milan, Milan, Italy.

PARTICIPANTS

A total of 107 prevalent patients undergoing hemodialysis for at least three months.

MEASUREMENTS

Sociodemographic, clinical, and biological data were recorded. Unintentional weight loss (UWL) was defined as loss of body weight > 5% in 3 months or > 10% in 6 months. We computed a 21-item Frailty Index that included clinical conditions associated with malnutrition and mortality in this population. Unadjusted and adjusted Cox proportional hazard models were performed to test the association of UWL, albumin and transferrin levels with death. Survival analyses based on Kaplan-Meier estimates were performed.

RESULTS

Patients' age was 79 (±7.7) years; 38 (35%) were women. Thirty-one patients (29%) died during follow-up. Eighteen (16.8%) patients experienced UWL during the follow-up period. UWL was positively associated with death in the unadjusted model and even after the progressive inclusion of potential confounders. Low albumin levels were positively associated with death only in the unadjusted and partially adjusted models while low transferrin levels were not associated with death in none of the models. Mortality was significantly higher in those patients experiencing both UWL and albumin levels below 3.5 mg/dL.

CONCLUSIONS

In older patients undergoing chronic hemodialysis UWL is associated with mortality independently of comorbidities and other risk factors. Patients presenting both UWL and low albumin levels were those experiencing the worst outcomes in terms of mortality.

Nutritional Strategies to Prevent Muscle Loss and Sarcopenia in Chronic Kidney Disease: What Do We Currently Know?

Loss of muscle mass is an extremely frequent complication in patients with chronic kidney disease (CKD). The etiology of muscle loss in CKD is multifactorial and may depend on kidney disease itself, dialysis, the typical chronic low-grade inflammation present in patients with chronic kidney disease, but also metabolic acidosis, insulin resistance, vitamin D deficiency, hormonal imbalances, amino acid loss during dialysis, and reduced dietary intake. All these conditions together increase protein degradation, decrease protein synthesis, and lead to negative protein balance. Aging further exacerbates sarcopenia in CKD patients. Nutritional therapy, such as protein restriction, aims to manage uremic toxins and slow down the progression of CKD. Low-protein diets (LPDs) and very low-protein diets (VLPDs) supplemented with amino acids or ketoacids are commonly prescribed. Energy intake is crucial, with a higher intake associated with maintaining a neutral or positive nitrogen balance. Adequate nutritional and dietary support are fundamental in preventing nutritional inadequacies and, consequently, muscle wasting, which can occur in CKD patients. This review explores the causes of muscle loss in CKD and how it can be influenced by nutritional strategies aimed at improving muscle mass and muscle strength.

Accelerated AGEing: The Impact of Advanced Glycation End Products on the Prognosis of Chronic Kidney Disease

Advanced glycation end products (AGEs) are aging products. In chronic kidney disease (CKD), AGEs accumulate due to the increased production, reduced excretion, and the imbalance between oxidant/antioxidant capacities. CKD is therefore a model of aging. The aim of this review is to summarize the present knowledge of AGEs in CKD onset and progression, also focusing on CKD-related disorders (cardiovascular diseases, sarcopenia, and nutritional imbalance) and CKD mortality. The role of AGEs as etiopathogenetic molecules, as well as potential markers of disease progression and/or therapeutic targets, will be discussed.

MCP1 Could Mediate FGF23 and Omega 6/Omega 3 Correlation Inversion in CKD

Fibroblast growth factor 23 (FGF23) concentrations rise after the early stages of chronic kidney disease (CKD). FGF23 is involved in inflammatory reactions closely associated with an incremented risk of cardiovascular disease (CVD). There is growing evidence that omega-6 (n-6) and n-3 polyunsaturated fatty acids (PUFA) can modulate inflammation through several mediators producing an opposite effect on cardiovascular (CV) risks. In this study, we explore whether there is any correlation between PUFA, FGF23, and inflammation in CKD patients. We evaluated, cross-sectionally, 56 patients at different stages of CKD. Monocyte chemoattractant protein 1 (MCP1), and intact and c-terminal FGF23 (iFGF23, cFGF23) were quantified by the ELISA, and the fatty acids (FA) profile was analyzed by gas chromatography. Concurrently with an eGFR decrease (p < 0.01) and an MCP1 increase (p = 0.031), we observed an inversion of the correlation between FGF23 and the n-6/n-3 ratio. This last correlation was inversed in CKD stage 3 (r2 (−) 0.502 p = 0.029) and direct in stage 5 (r2 0.657 p = 0.020). The increase in MCP1 seems to trigger events in the inversion of the correlation between FGF23 and the n-6/n-3 PUFA ratio. This result strongly encourages future studies on basal pathways, on possible pharmacological interventions, and on managing kidney transplant patients treated with immunosuppressive therapy.

Frailty in kidney transplantation: a review on its evaluation, variation and long-term impact

The problem of frailty in kidney transplantation is an increasingly discussed topic in the transplant field, partially also generated by the multiple comorbidities by which these patients are affected. The criteria currently used to establish the presence and degree of frailty can be rapidly assessed in clinical practice, even in patients with chronic kidney disease (CKD). The main objectives of this work are: (i) to describe the method of evaluation and the impact that frailty has in patients affected by CKD, (ii) to explore how frailty should be studied in the pre-transplant evaluation, (iii) how frailty changes after a transplant and (iv) the impact frailty has over the long term on the survival of renal transplant patients.

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.

In Patients with Chronic Kidney Disease Advanced Glycation End-Products Receptors Isoforms (sRAGE and esRAGE) Are Associated with Malnutrition

Background: in patients with chronic kidney disease (CKD), the inflammatory and pro-oxidant milieu may contribute to malnutrition development. In this study, we investigated the relationship between inflammation, advanced glycation end-products (AGEs), and their receptors (RAGEs) with malnutrition in CKD patients. Methods: we evaluated 117 patients. AGEs were quantified by fluorescence intensity using a fluorescence spectrophotometer, soluble RAGEs isoforms, and inflammatory interleukins by ELISA. Malnutrition was assessed by a malnutrition inflammation score. Results: mean age was 80 ± +11 years, eGFR was 25 ± +11 mL/min/1.73 m2 and BMI was 28 ± 5 Kg/m2. Malnourished individuals were older, had lower estimated protein intake (nPCR 0.65 ± 0.2 vs. 0.8 ± 0.2 vs. 0.8 ± 0.3, p = 0.01), higher C reactive protein (CRP 0.6 ± 1 vs. 0.6 ± 0.7 vs. 0.17 ± 0.13, p = 0.02) and tumor necrosis factor α (TNF α 14.7 ± 8.7 vs. 15.6 ± 8 vs. 11.8 ± 5.8, p = 0.029). Malnourished patients had higher sRAGE (2813 ± 1477 vs. 2158 ± 1236 vs. 2314 ± 1115, p = 0.035) and esRAGE (648 [408–1049] vs. 476 [355–680] vs. 545 [380–730] p = 0.033). In the multivariate analysis, only sRAGE maintained its association with malnutrition (p = 0.02) independently of aging and inflammation. Conclusions: in CKD patients, RAGEs isoforms, but not AGEs, are associated with malnutrition, irrespective of systemic inflammation, aging, and renal function.

Association between Advanced Glycation End-Products and Sarcopenia in Patients with Chronic Kidney Disease

Background: In patients with chronic kidney disease (CKD), there is an overproduction and accumulation of advanced glycation end-products (AGEs). Since AGEs may have detrimental effects on muscular trophism and performance, we evaluated whether they may contribute to the onset of sarcopenia in CKD patients. Methods: We enrolled 117 patients. The AGEs were quantified by fluorescence intensity using a fluorescence spectrophotometer and soluble receptor for AGE (sRAGE) isoforms by ELISA. As for the sarcopenia definition, we used the European Working Group on Sarcopenia in Older People (EWGSOP2) criteria. Results: The average age was 80 ± 11 years, 70% were males, and the mean eGFR was 25 + 11 mL/min/1.73 m². Sarcopenia was diagnosed in 26 patients (with a prevalence of 22%). The sarcopenic patients had higher levels of circulating AGEs (3405 ± 951 vs. 2912 ± 722 A.U., p = 0.005). AGEs were higher in subjects with a lower midarm muscle circumference (MAMC) (3322 ± 919 vs. 2883 ± 700 A.U., respectively; p = 0.005) and were directly correlated with the gait test time (r = 0.180, p = 0.049). The total sRAGE and its different isoforms (esRAGE and cRAGE) did not differ in patients with or without sarcopenia. Conclusions: In older CKD patients, AGEs, but not sRAGE, are associated with the presence of sarcopenia. Therefore, AGEs may contribute to the complex pathophysiology leading to the development of sarcopenia in CKD patients.

MO575: Possible Benefits of a Low Protein Diet in Older CKD Patients at Risk of Malnutrition: A Pilot Randomized Controlled Trial

BACKGROUND AND AIMS

Current guidelines do not clarify whether older patients with advanced chronic kidney disease may benefit of low protein diet if they are at risk of malnutrition. We compared the effects of normo-calorie/normo-protein (NP) and normo-calorie/low protein diet (LP) on nutritional status and metabolic complications related to the progression of kidney damage in these patients.

METHOD

This pilot study had an open label randomized-controlled design (ClinicalTrials.gov Id: NCT05015647). Thirty-five patients were treated for six months with two different diets (LP = 17) and (NP = 18). Malnutrition was assessed by Malnutrition Inflammation Score and International Society of Renal Nutrition and Metabolism criteria. Renal function was assessed by creatinine and cystatin C based eGFR.

RESULTS

At the end of the study, Malnutrition Inflammation Score was improved in both LP and NP groups (respectively: 3 ± 3 versus 6 ± 1.5, P = 0.020 and 3 ± 2.5 versus 6 ± 2, P = 0.012), and prevalence of protein energy wasting syndrome decreased only in LP. LP group had higher eGFRcys-C (17 ± 6 versus 12 ± 4 mL/min/1.73 m2; P &lt; 0.05), lower serum urea (105 ± 65 versus 138 ± 30 mg/dL; P &lt; 0.05) and lower PTH (68 ± 10 versus 99 ± 61 ng/L; P &lt; 0.05) than NP. Serum and urinary phosphorous did not change while FGF23-intact and FGF23 c-terminal increased in both groups (FGF23-intact in LP: 70[48;98] versus 126[90;410] pg/mL, P &lt; 0.01 and in NP: 86[57;194] versus 143[119;186] pg/mL, P &lt; 0.01; FGF23 c-terminal in LP: 77[30.3;112] versus 111[63;384] RU/mL, P &lt; 0.01 and in NP: 142[56.6;175] versus 157[76.7;281] RU/mL, P &lt; 0.01).

CONCLUSION

LP diet has a favorable impact on nutritional status as much as NP diet with possible greater benefits on the progression of kidney disease and some of its metabolic complications.

Possible Benefits of a Low Protein Diet in Older Patients With CKD at Risk of Malnutrition: A Pilot Randomized Controlled Trial

Background

Current guidelines do not clarify whether older patients with advanced chronic kidney disease (CKD) may benefit of low protein (LP) diet if they are at risk of malnutrition. We compared the effects of normocalorie/normoprotein (NP) and normocalorie/LP diet on nutritional status and metabolic complications related to the progression of kidney damage in these patients.

Methods

This pilot study had an open-label randomized-controlled design (ClinicalTrials.gov Id: NCT05015647). Thirty-five patients were treated for 6 months with two different diets (LP = 17) and (NP = 18). Malnutrition was assessed by the Malnutrition Inflammation Score and International Society of Renal Nutrition and Metabolism criteria. Renal function was assessed by creatinine and cystatin-C-based estimated glomerular filtration rate (eGFR).

Results

At the end of the study, Malnutrition Inflammation Score was improved in both LP and NP groups (respectively: 3 ± 3 vs. 6 ± 1.5, p = 0.020 and 3 ± 2.5 vs. 6 ± 2, p = 0.012), prevalence of protein energy wasting syndrome decreased only in LP. LP group had higher eGFRcys-C (17 ± 6 vs. 12 ± 4 ml/min/1.73 m2; p &lt; 0.05), lower serum urea (105 ± 65 vs. 138 ± 30 mg/dl; p &lt; 0.05) and lower parathormone (68 ± 10 vs. 99 ± 61 ng/L; p &lt; 0.05) than NP. Serum and urinary phosphorous did not change while fibroblast growth factor 23 (FGF23)-intact and FGF23 c-terminal increased in both groups [FGF23-intact in LP: 70 (48; 98) vs. 126 (90; 410) pg/ml, p &lt; 0.01 and in NP: 86 (57; 194) vs. 143 (119; 186) pg/ml, p &lt; 0.01; FGF23 c-terminal in LP: 77 (30.3; 112) vs. 111 (63; 384) RU/ml, p &lt; 0.01 and in NP: 142 (56.6; 175) vs. 157 (76.7; 281) RU/ml, p &lt; 0.01].

Conclusions

LP diet has a favorable impact on nutritional status as much as NP diet with possible greater benefits on the progression of kidney disease and some of its metabolic complications.

Clinical Trial Registration

https://clinicaltrials.gov/ct2/show/NCT05015647, identifier: NCT05015647.

AGEs and sRAGE Variations at Different Timepoints in Patients with Chronic Kidney Disease

Patients with chronic kidney disease (CKD) are affected by enhanced oxidative stress and chronic inflammation, and these factors may contribute to increase advanced glycation end-products (AGEs). In this study we quantified AGEs and soluble receptors for AGE (sRAGE) isoforms and evaluated the association between their variations and eGFR at baseline and after 12 months. We evaluated 64 patients. AGEs were quantified by fluorescence intensity using a fluorescence spectrophotometer, and sRAGE by ELISA. Median age was 81 years, male patients accounted for 70%, 63% were diabetic, and eGFR was 27 ± 10 mL/min/1.73 m². At follow up, sRAGE isoforms underwent a significant decrement (1679 [1393;2038] vs. 1442 [1117;2102], p < 0.0001), while AGEs/sRAGE ratios were increased (1.77 ± 0.92 vs. 2.24 ± 1.34, p = 0.004). Although AGEs and AGEs/sRAGE ratios were inversely related with eGFR, their basal values as well their variations did not show a significant association with eGFR changes. In a cohort of patients with a stable clinical condition at 1 year follow-up, AGEs/sRAGE was associated with renal function. The lack of association with eGFR suggests that other factors can influence its increase. In conclusion, AGEs/sRAGE can be an additional risk factor for CKD progression over a longer time, but its role as a prognostic tool needs further investigation.

Association of Sarcopenia and Gut Microbiota Composition in Older Patients with Advanced Chronic Kidney Disease, Investigation of the Interactions with Uremic Toxins, Inflammation and Oxidative Stress

Sarcopenia is a prevalent condition in chronic kidney disease (CKD). We determined gut microbiota (gMB) composition in CKD patients with or without sarcopenia. Furthermore, we investigated whether in these patients, there was any association between gMB, uremic toxins, inflammation and oxidative stress. We analyzed gMB composition, uremic toxins (indoxyl sulphate and p-cresyl sulphate), inflammatory cytokines (interleukin 10, tumor necrosis factor α, interleukin 6, interleukin 17, interleukin 12 p70, monocyte chemoattractant protein-1 and fetuin-A) and oxidative stress (malondialdehyde) of 64 elderly CKD patients (10 < eGFR < 45 mL/min/1.73 m², not on dialysis) categorized as sarcopenic and not-sarcopenic. Sarcopenia was defined according to European Working Group on Sarcopenia in Older People 2 criteria. Sarcopenic patients had a greater abundance of the Micrococcaceae and Verrucomicrobiaceae families and of Megasphaera, Rothia, Veillonella, Akkermansia and Coprobacillus genera. They had a lower abundance of the Gemellaceae and Veillonellaceae families and of Acidaminococcus and Gemella genera. GMB was associated with uremic toxins, inflammatory cytokines and MDA. However, uremic toxins, inflammatory cytokines and MDA were not different in sarcopenic compared with not-sarcopenic individuals, except for interleukin 10, which was higher in not-sarcopenic patients. In older CKD patients, gMB was different in sarcopenic than in not-sarcopenic ones. Several bacterial families and genera were associated with uremic toxins and inflammatory cytokines, although none of these latter substantially different in sarcopenic versus not-sarcopenic patients.

Associations Between Cholesterol and Fatty Acid Profile on the Severity of Depression in Older Persons With Nondialysis Chronic Kidney Disease

Depressive symptoms worsen the outcomes of patients affected by chronic kidney disease (CKD). The purpose of the present article is to study the association between serum lipid profile and the severity of depression in patients with CKD. We evaluated 132 older subjects with advanced CKD (stage 3-5, not receiving dialysis) in regular follow-up in a nephrology clinic. Blood samples were collected after an overnight fast. All patients were evaluated with the Geriatric Depression Scale which is comprised of 30 items that assess the severity of depressive symptoms. A backward multivariate regression analysis was performed to study the association between lipid profile and severity of depression. Low-density lipoprotein levels (β = 2.77, P = .008) and arachidonic acid/linoleic acid ratio (β = 2.51, P = .015) were found to be significantly associated with severity of depressive symptoms. Change in dietary habits or the use of hypocholesterolemic drugs could potentially prevent depressive symptoms and ameliorate outcome of patients affected by CKD. Data from prospective studies are needed to confirm these preliminary results.

Frailty phenotype and multi-domain impairments in older patients with chronic kidney disease

BACKGROUND

Older subjects with chronic kidney disease (CKD) are often affected by multiple geriatric impairments that may benefit from a comprehensive geriatric assessment (CGA). However, ordinary execution of CGA in all these individuals would be unaffordable. We evaluated if Frailty Phenotype (FP) could identify older CKD-patients that may benefit the most from a CGA.

METHODS

We evaluated 112 CKD patients not yet on dialysis (age ≥ 65 years, eGFR < 45 ml/min). FP was defined according to the criteria proposed by Fried and co-authors. CGA evaluated four domains (nutrition, physical performance, cognition and depression). Malnutrition was defined in accordance to Malnutrition-Inflammation Score (MIS) and/or by the presence of Protein Energy Wasting syndrome (PEW). Physical performance was evaluated using Short Physical Performance Battery (SPPB) and handgrip strength. Cognitive status was assessed by using Mini Mental State Examination (MMSE) and Clock Drawing Test. Mood was investigated with Geriatric Depression Scale (GDS).

RESULTS

Average age of our cohort was 80 ± 6 years and mean eGFR 24 ± 11 ml/min/1.73 m2. Prevalence of frailty was 45%. Frail patients (F-CKD) had higher prevalence of malnutrition (58 vs 29%, p = 0.0005), physical impairment (100% vs 78%; p < 0.0001), cognitive dysfunction (83% vs 37%; p < 0.0001) and depression (50% vs 21%; p < 0.001) compared to robust ones (NF-CKD). Moreover, F-CKD patients had higher probability to have > 2 impaired domains (83% sensitivity and 76% specificity) respect to NF-CKD individuals.

CONCLUSIONS

FP is a reliable screening tool to identify older CKD-patients that may benefit from a CGA.

MO025ADVANCED GLYCATION END PRODUCTS (AGES) AND SOLUBLE RECEPTOR FOR AGES (SRAGE): ASSOCIATION WITH RISK OF MORTALITY IN CHRONIC KIDNEY DISEASE PATIENTS

Background and Aims

In chronic kidney disease patients (CKD), excessive oxidative stress, uremia and chronic inflammation may increase the production of advanced glycation end-products (AGEs) which in turn promote CKD-related morbidities and mortality. Much attention has recently been paid to the soluble receptor for AGEs (sRAGE), as a marker of inflammation, oxidative stress, atherosclerosis and heart failure. sRAGE is a decoy receptor that prevents AGEs binding to RAGE, the cell membrane form of the receptor, and RAGE-related detrimental effects.

Both AGEs and sRAGE accumulate in CKD due to the increased production and reduced kidney filtration. Recently, we reported an association between higher levels of sRAGE and mortality in hemodialysis and peritoneal dialysis patients. Whether AGEs, sRAGE and its different isoforms, namely the membrane-cleaved receptor cRAGE and the endogenous secretory form esRAGE, may also work as prognostic factors for mortality in non-dialysis CKD patients is not known.

Method

We quantified plasma sRAGE and esRAGE levels in 111 CKD patients (mean±SD age: 77.71±10.24 years, eGFR: 24.86±11.06 ml/min, male gender: 74.86%) by ELISA. Florescent AGEs and glycated albumin (GA) were quantified by AGEs-specific fluorescence (excitation: 365 nm, emission: 414-445 nm) and the quantILab assay (Werfen, Italy), respectively. The cRAGE form was estimated by subtracting esRAGE from sRAGE and the ratio cRAGE/esRAGE was calculated. AGEs were normalized against total proteins. Patients were screened for malnutrition and malnutrition-inflammation score (MIS) was calculated (4-8: risk of malnutrition, &gt;8: malnutrition). The Cox proportional-hazards model was used for investigating the association between variables and survival time. Median follow-up time was 40 months.

Results

Mean levels of sRAGE, esRAGE and cRAGE were 2317±1224 pg/ml, 648±453 pg/ml and 1669±901 pg/ml, respectively. The mean value of cRAGE/esRAGE ratio was 2.82±0.96. AGEs/total protein content was 433.2 A.U., GA was 21.3±7.5 % and MIS 5.98 ±4.67. During the follow up, 28 patients died. Univariate Cox regression indicated a prognostic role for mortality for age (HR: 1.100, 95%CI: 1.041-1.163, p &lt; 0.001), AGEs/total protein (HR: 1.004, 95%CI: 1.000-1.007, p &lt; 0.05), esRAGE (HR: 1.001, 95%CI: 1.041-1.001, p &lt; 0.01), cRAGE/esRAGE (HR: 0.5390, 95%CI: 0.331-0.888, p &lt; 0.05) and MIS (HR: 1.079, 95%CI: 1.025-1.137, p &lt; 0.01). After adjusting for age and MIS, the associations were still significant for esRAGE (HR: 1.001, 95%CI: 1.0002-1.001, p &lt; 0.01) and cRAGE/esRAGE ratio (HR: 0.572, 95%CI: 0.347-0.943, p &lt; 0.05), with AGEs/total protein at the margin of statistical significance (HR: 1.004, 95%CI: 0.9997-1.007, p = 0.0726).

Conclusion

In CKD higher levels of esRAGE and lower cRAGE/esRAGE ratio may have a prognostic role for mortality. Since esRAGE acts as a decoy receptor for AGEs and thus has a cytoprotective effect, from a pathological point of view the observed association with esRAGE but not cRAGE was quite surprisingly. One potential explanation is that AGEs increases all sRAGE isoforms, but esRAGE accumulation was greater than that of cRAGE due to a different synthesis/catabolism that needs further investigations.

In conclusion, in CKD patients esRAGE and cRAGE/esRAGE seem to be useful supportive tools to identify high risk patients.

Gut microbiota composition and frailty in elderly patients with Chronic Kidney Disease

Background

Frailty is common in older patients affected by chronic kidney disease (CKD). Since gut microbiota (gMB) may contribute to frailty, we explored possible associations between gMB and frailty in CKD.

Methods

We studied 64 CKD patients (stage 3b-4), categorized as frail (F, 38) and not frail (NF, 26) according to Fried criteria, and 15 controls (C), all older than 65 years. In CKD we assessed serum C-reactive protein, blood neutrophil/lymphocyte ratio, Malnutrition-inflammation Score (MIS); gMB was studied by denaturing gel gradient electrophoresis (DGGE), high-throughput sequencing (16S r-RNA gene), and quantitative real-time PCR (RT-PCR).

Results

No differences in alpha diversity between CKD and C and between F and NF patients emerged, but high-throughput sequencing showed significantly higher abundance of potentially noxious bacteria (Citrobacter, Coprobacillus, etc) and lower abundance of saccharolytic and butyrate-producing bacteria (Prevotella spp., Faecalibacterium prausnitzii, Roseburia spp.), in CKD respect to C. Mogibacteriaceae family and Oscillospira genus abundance was positively related to inflammatory indices in the whole CKD cohort, while that of Akkermansia, Ruminococcus and Eubacterium genera was negatively related. Compared with NF, in F there was a higher abundance of some bacteria (Mogibacteriacee, Coriobacteriacee, Eggerthella, etc), many of which have been described as more abundant in other diseases.

Conclusions

These results suggest that inflammation and frailty could be associated to gMB modifications in CKD.

Malnutrition and inflammation are associated with severity of depressive and cognitive symptoms of old patients affected by chronic kidney disease

OBJECTIVE

Chronic kidney disease (CKD) is a disabling condition associated with different medical comorbidities including depression and cognitive impairment. We investigated the association between malnutrition, inflammation and depressive/cognitive symptoms in elderly subjects with advanced CKD.

METHODS

We evaluated cross-sectionally 132 elderly subjects (age ≥65 years) with advanced CKD (stage 4-5, non-dialytic-ND) in regular follow up at the outpatient clinic of nephrology. Blood and urinary samples were collected after an overnight fast. All patients were evaluated by Geriatric Depression Scale (GDS)-30 items for severity of depressive symptoms, Mini Mental State Examination (MMSE) and the Clock Drawing Test (CDT) for cognition. Nutritional status was assessed by Malnutrition Inflammation Score (MIS). Different linear regression models were performed to study the association between clinical variables, diet and inflammatory parameters with the above mentioned rating scale scores. A final linear regression model with only previous statistically significant variables was performed for GDS scores.

RESULTS

Our cohort consisted of 95 males and 37 females with a mean age of 78 ± 7. Female gender (B = 3.20, p < .01), higher MIS (B = 0.29, p = .02) and higher IL-12p70 serum levels (pg/mL) (B = 0.37, p = .03) were associated with severity of depressive symptoms. MIS was associated with the severity of cognitive impairment as assessed by MMSE (B = -0.19, p < .01) and CDT (B = 0.10, p = .03).

CONCLUSION

In elderly subjects affected by CKD the severity of depressive symptoms and cognitive impairment is associated with specific inflammatory and nutritional parameters. These results have to be considered as preliminary and need replication by further studies.

Patients with Hypertensive Nephropathy and Chronic Kidney Disease Might Not Benefit from Strict Blood Pressure Control

BACKGROUND/AIMS

In patients with chronic kidney disease (CKD) strict blood pressure (BP) control is reno-protective. However, renal benefits from BP control might depend also on the etiology of CKD. We investigated if maintenance of BP at target is equally effective in subjects with hypertensive nephropathy (HN+) and in those with other nephropathies (HN-).

METHODS

We evaluated 148 patients with CKD (stages 3-5) in two visits at least 12 months apart. BP was measured both as office BP and 24h ambulatory blood pressure (ABP). Glomerular filtration rate (eGFR) was estimated with CKD-EPI formula. The slope of eGFR variation (ΔeGFR) was calculated as: (eGFR1-eGFR0)/months of follow up.

RESULTS

Cohort characteristics were: HN-(n=82) and HN+ (n=66), age (71±9 vs 74±9 years; p=0.09); prevalence of diabetes (57 vs 43%; p=0.19); average follow up (19±7 vs 21±9 months; p=0.3). HN- and HN+ did not differ regarding both baseline eGFR (34±18 vs 35±14 ml/min; p=0.97) and ΔeGFR (0.00±0.53 vs -0.06±0.35 ml/min/month, p=0.52). The proportion of patients with BP at target at both visits was similar in HN- and HN+ (office BP: HN- 18% and HN+ 27%; p=0.21; ABP: HN- 42% and HN+ 43; p=0.96). In patients with office BP at target at both visits HN- showed a significant improvement of ΔeGFR respect to HN+ (HN-: 0.240 ± 0.395 and HN+: -0.140±0.313 ml/min/ month; p=0.026). In patients with office BP not at target HN- and HN+ did not show any difference in ΔeGFR (HN- 0.00±0.47; HN+ -0.030±0.420 ml/min/month; p=0.66). ABP was not associated with differences in ΔeGFR either if it was at target (HN- 0.104±0.383 and HN+ 0.00±0.476 ml/min/month; p=0.42) or not (HN- -0.057±0.503 and HN+ -0.092±0.325 ml/ min/month; p=0.87).

CONCLUSION

In patients with CKD and HN+ maintenance of BP targets recommended by current guidelines is less reno-protective than it is in HN-.