The Association of Nutritional Factors and Skin Autofluorescence in Persons Receiving Hemodialysis

Prospective Study of Change in Skin Autofluorescence Over Time and Mortality in People Receiving Hemodialysis

Introduction

Elevated skin autofluorescence (SAF), a measure of tissue accumulation of advanced glycation end products (AGEs), is a strong predictor of all-cause and cardiovascular mortality in the hemodialysis population. However, prospective studies investigating the association between changes in SAF over time and mortality are scarce. We therefore aimed to investigate the prognostic value of SAF trend for predicting mortality in a hemodialysis population.

Methods

We enrolled 120 patients on hemodialysis in a 5-year observational, prospective study. SAF was measured at baseline, 3, 6, 9, 12, and 24 months. Rate of change in SAF (i.e., SAF trend) was calculated using linear regression. Time to event was the number of days from baseline to death, kidney transplantation, or March 31, 2022.

Results

Mean age, mean baseline SAF, and median SAF trend were 65 ± 14 years, 3.4 ± 0.9 arbitrary units (AU), and an increase of 0.1 (-0.1 to 0.4) AU/yr, respectively. Median observation time was 42 months, during which 59 participants (49%) died. Univariable analysis identified age, history of smoking, lower serum albumin, higher baseline SAF, and increase in SAF as significant predictors of higher mortality. In multivariable analysis, higher baseline SAF (hazard ratio: 1.45; 95% confidence interval: 1.08-1.94; P = 0.01) and increasing SAF trend (2.37 [1.43-3.93]; P < 0.001) were independent predictors of increased mortality.

Conclusion

An increasing SAF trend and higher baseline SAF were independent predictors of all-cause mortality in this hemodialysis population, suggesting that monitoring of SAF may have clinical utility. Strategies to improve outcomes by reducing or preventing the increase in SAF should now be investigated in prospective studies.

Role of skin autofluorescence in managing renal and cardiac diseases in outpatient dermatology

INTRODUCTION

The accumulation of tissue-advanced glycation end products in skin results from complex and consecutive reactions and can be measured by skin autofluorescence (SAF) reader devices. This overview discusses studies evaluating the utilization of SAF in screening renal and cardiac disease.

MATERIALS AND METHODS

Literature search was performed using Google Scholar, PubMed, Springer, Ovid, and ScienceDirect.

RESULTS

SAF was an independent predictor of progression of chronic kidney disease (CKD) and was elevated in subjects on hemodialysis and peritoneal dialysis. Furthermore, SAF was significantly associated with cardiovascular events, cardiovascular mortality, and all-cause mortality in CKD patients. Other studies revealed a correlation between SAF and arterial stiffness, vascular damage, and subclinical atherosclerosis. A vegetarian diet was associated with lower SAF levels, whereas malnutrition was correlated with higher levels and increased mortality.

CONCLUSIONS

SAF measurement may be useful in managing renal and cardiac disease. Future studies are needed to clarify the specific role of SAF in the management of CKD and its noninvasive office utilization to identify comorbidities in inflammatory diseases, such as psoriasis.

Impact of malnutrition on health-related quality of life in persons receiving dialysis: a prospective study

Health-related quality of life (HRQoL) is severely impaired in persons receiving dialysis. Malnutrition has been associated with some measures of poor HRQoL in cross-sectional analyses in dialysis populations, but no studies have assessed the impact of malnutrition and dietary intake on change in multiple measures of HRQoL over time. We investigated the most important determinants of poor HRQoL and the predictors of change in HRQoL over time using several measures of HRQoL. We enrolled 119 haemodialysis and thirty-one peritoneal dialysis patients in this prospective study. Nutritional assessments (Subjective Global Assessment (SGA), anthropometry and 24-h dietary recalls) and HRQoL questionnaires (Short Form-36 (SF-36) mental (MCS) and physical component scores (PCS) and European QoL-5 Dimensions (EQ5D) health state (HSS) and visual analogue scores (VAS)) were performed at baseline, 6 and 12 months. Mean age was 64 (14) years. Malnutrition was present in 37 % of the population. At baseline, malnutrition assessed by SGA was the only factor independently (and negatively) associated with all four measures of HRQoL. No single factor was independently associated with decrease in all measures of HRQoL over 1 year. However, prevalence/development of malnutrition over 1 year was an independent predictor of 1-year decrease in EQ5D HSS, and 1-year decrease in fat intake independently predicted the 1-year decline in SF-36 MCS and PCS, and EQ5D VAS. These findings strengthen the importance of monitoring for malnutrition and providing nutritional advice to all persons on dialysis. Future studies are needed to evaluate the impact of nutritional interventions on HRQoL and other long-term outcomes.

Pilot study to investigate differences in middle molecules, oxidative stress and markers of peripheral vascular disease in patients treated by high flux haemodialysis and haemodiafiltration

Background

Dialysis patients have an increased risk of mortality. Recently treatment with haemodiafiltration (HDF) has been reported to reduce mortality, particularly cardiovascular mortality, compared to standard high-flux haemodialysis (HD). However, why HDF may offer a survival advantage remains to be determined. So, we conducted a pilot study to explore differences in middle-molecules, inflammation and markers of vascular disease in patients treated by HD and HDF.

Methods

Observational cross-sectional study measuring serum β2-microglobulin (β2M), Advanced Glycosylation End Products (AGEs) by skin autofluorescence (SAF), oxidative stress with ischaemia modified albumin ratio (IMAR) and peripheral vascular disease assessment using Ankle-Brachial Index (ABI), and arterial stiffness using Cardio-Ankle Vascular Index (CAVI).

Results

We studied 196 patients, mean age 69.1 ± 12.4 years, 172 (87.8%) treated by HD and 24 (12.2%) by HDF. Age, body mass index, co-morbidity and dialysis vintage were not different between HD and HDF groups. Middle molecules; β₂M (31±9.9 vs 31.2±10 ug/mL) and SAF (2.99±0.72 vs 3.0±0.84 AU), ABI (1.06±0.05 vs 1.07±0.10) and CAVI (9.34±1.55 vs 9.35±1.23) were not different, but IMAR was higher in the HD patients (38.4±14.8 vs 31.3 ± 17.4, P = 0.035)

Conclusions

In this pilot observational study, we found patients treated by HDF had lower oxidative stress as measured by IMAR, with no differences in middle molecules. Lower oxidative stress would be expected to have diverse protective effects on the cardiovascular system Although we found no differences in ABI and CAVI, future studies are required to determine whether reduced oxidative stress translates into clinically relevant differences over time.

AGE/RAGE in diabetic kidney disease and ageing kidney

Diabetic kidney disease (DKD) is the primary cause of chronic kidney disease that inevitably progress to end-stage kidney disease. Intervention strategies such as blood glucose control is effective for preventing DKD, but many patients with DKD still reach end-stage kidney disease. Although comprehensive mechanisms shed light on the progression of DKD, the most compelling evidence has highlighted that hyperglycemia-related advanced glycation end products (AGEs) formation plays a central role in the pathogenesis of DKD. Pathologically, accumulation of AGEs-mediated receptor for AGEs (RAGE) triggers oxidative stress and inflammation, which is the major deleterious effect of AGEs in host and intestinal microenvironment of diabetic and ageing conditions. The activation of AGEs-mediated RAGE could evoke nicotinamide adenine dinucleotide phosphate oxidase-induced reactive oxygen and nitrogen species production and subsequently give rise to oxidative stress in DKD and ageing kidney. Therefore, targeting RAGE with its ligands mediated oxidative stress and chronic inflammation is considered as an additional intervention strategy for DKD and ageing kidney. In this review, we summarize AGEs/RAGE-mediated oxidative stress and inflammation signaling pathways in DKD and ageing kidney, discussing opportunities and challenges of targeting at AGEs/RAGE-induced oxidative stress that could hold the promising potential approach for improving DKD and ageing kidney.

A Systematic Review of Handgrip Strength Measurement in Clinical and Epidemiological Studies of Kidney Disease: Toward a Standardized Approach

In chronic kidney disease (CKD), handgrip strength (HGS) is recommended as a surrogate measure of protein-energy status and functional status. However, it is not routinely used because of inconsistencies such as the optimal timing of the HGS measurement and unclear guidance regarding technique. We aimed to determine the extent of variation in the protocols and methods of HGS assessment. We aimed to identify clinical and epidemiological studies conducted on CKD that reported on the use of HGS as an outcome. A systematic literature search identified n = 129 studies with a total participant population of n = 35,192. We identified large variations in all aspects of the methodology including body and arm position, repetitions, rest time, timing, familiarization, and how scores were calculated. The heterogeneous methodologies used reinforce the need to standardize HGS measurement. After reviewing previously employed methodology in the literature, we propose a comprehensive HGS assessment protocol for use in CKD.

Understanding Development of Malnutrition in Hemodialysis Patients: A Narrative Review

Hemodialysis (HD) majorly represents the global treatment option for patients with chronic kidney disease stage 5, and, despite advances in dialysis technology, these patients face a high risk of morbidity and mortality from malnutrition. We aimed to provide a novel view that malnutrition susceptibility in the global HD community is either or both of iatrogenic and of non-iatrogenic origins. This categorization of malnutrition origin clearly describes the role of each factor in contributing to malnutrition. Low dialysis adequacy resulting in uremia and metabolic acidosis and dialysis membranes and techniques, which incur greater amino-acid losses, are identified modifiable iatrogenic factors of malnutrition. Dietary inadequacy as per suboptimal energy and protein intakes due to poor appetite status, low diet quality, high diet monotony index, and/or psychosocial and financial barriers are modifiable non-iatrogenic factors implicated in malnutrition in these patients. These factors should be included in a comprehensive nutritional assessment for malnutrition risk. Leveraging the point of origin of malnutrition in dialysis patients is crucial for healthcare practitioners to enable personalized patient care, as well as determine country-specific malnutrition treatment strategies.

The association of non-invasive skin autofluorescence measurements with cardiovascular and all-cause mortality in hemodialysis patients: a meta-analysis

BACKGROUND

This systematic review and meta-analysis were aimed to study the association of tissue accumulation of advanced glycation end products (AGEs) measured as skin autofluorescence (SAF) with cardiovascular disease (CVD), cardiovascular mortality (CVM) and all-cause mortality (ACM) in hemodialysis (HD) patients.

METHODS

All major databases were searched for relevant studies reporting SAF in dialysis patients. Data for meta-analyses were extracted in the form of odds ratios (OR) and/or hazard ratios (HR) and the pooled overall outcomes were computed for the association of SAF with CVD, CVM, ACM in HD patients using either fixed or random effects meta-analysis based on the between-study heterogeneity. The sensitivity and meta-regression analyses were performed.

RESULTS

We included nine studies in this meta-analysis. The SAF levels were associated with higher risk for cardiovascular morbidity (pooled OR = 2.59, Z = 2.30, P = 0.02), cardiovascular (pooled HR = 3.03, Z = 3.13, P = 0.002) and overall mortalities (pooled HR = 2.23, Z = 6.30, P < 0.001) in HD patients.

CONCLUSION

In HD patients, the novel and non-invasive measurement of tissue AGEs as SAF levels could be useful for risk estimating the cardiovascular and all-cause mortalities.

Higher skin autofluorescence detection using AGE-Reader™ technology as a measure of increased tissue accumulation of advanced glycation end products in dialysis patients with diabetes: a meta-analysis

This meta-analysis was conducted to compare skin autofluorescence (SAF) levels as a measure of advanced glycation end products (AGEs) accumulation between diabetic and non-diabetic dialysis patients. Relevant studies were identified primarily by searching PubMed/MEDLINE and other online databases and manual searching of cross-references. Random-effects model was used to obtain standardized mean differences (SMD) as a summary statistic. Heterogeneity was tested with meta-regression and sub-group analyses. Publication bias and robustness of this meta-analysis were tested using funnel plot and sensitivity analyses. A total of 11 reports comparing SAF between diabetic and non-diabetic dialysis patients were finally included in this meta-analysis. Dialysis patients with diabetes showed significantly higher circulatory SAF levels than their non-diabetic counterparts (SMD = 0.39; P < 0.0001). The difference was more evident in hemodialysis modality (SMD = 0.40; P < 0.0001). A one-study leave-out sensitivity analysis validated the robustness of this meta-analysis. The presence of diabetes in dialysis patients is associated with increased AGEs accumulation reflected through SAF measurements using a novel and non-invasive AGE-Reader™ technology. Our findings are in support of considering anti-AGE therapeutic strategies in addition to standard glycemic management in dialysis patients with diabetes.

Factors Associated With Change in Skin Autofluorescence, a Measure of Advanced Glycation End Products, in Persons Receiving Dialysis

Introduction

An increase over time in skin autofluorescence (SAF), a measure of accumulation of advanced glycation end products (AGE), predicts higher mortality on hemodialysis (HD). However, evidence is lacking regarding factors that contribute to changes in SAF over time in populations on dialysis. We investigated the rate of change in SAF over 1 year and the factors associated with these changes.

Methods

We enrolled 109 patients on HD and 28 on peritoneal dialysis in a prospective study. SAF was measured at baseline, 3, 6, 9, and 12 months. Rate of change in SAF was calculated using the SLOPE function in Microsoft Excel (Microsoft, Redmond, WA). Participants were then grouped into those with stable SAF or increasing SAF. Dietary AGE intake and nutritional assessments were performed at baseline, 6, and 12 months.

Results

The mean SAF trend observed was an increase of 0.30 ± 0.63 arbitrary units (AU) per year, but this varied from a decrease of 0.15 ± 0.44 to an increase of 0.76 ± 0.42 AU per year in stable and increasing SAF groups, respectively. Increasing SAF was more common in participants who developed malnutrition during the observation period, whereas those who became well-nourished were more likely to have stable SAF (8 [80%] vs. 14 [42%]; P = 0.02). Development/prevalence of malnutrition over 1 year, HD as first dialysis modality, and current smoking were independent predictors of increasing SAF.

Conclusion

SAF increases over time in most persons on dialysis. Independent determinants of increasing SAF were development/prevalence of malnutrition, HD as first dialysis modality, and current smoking. Strategies to reduce/prevent the rise in SAF, including prevention/correction of malnutrition, should be investigated in prospective studies.

Relations of advanced glycation endproducts and dicarbonyls with endothelial dysfunction and low-grade inflammation in individuals with end-stage renal disease in the transition to renal replacement therapy: A cross-sectional observational study

Background

Cardiovascular disease (CVD) related mortality and morbidity are high in end-stage renal disease (ESRD). The pathophysiology of CVD in ESRD may involve non-traditional CVD risk factors, such as accumulation of advanced glycation endproducts (AGEs), dicarbonyls, endothelial dysfunction (ED) and low-grade inflammation (LGI). However, detailed data on the relation of AGEs and dicarbonyls with ED and LGI in ESRD are limited.

Methods

We examined cross-sectional Spearman’s rank correlations of AGEs and dicarbonyls with serum biomarkers of ED and LGI in 43 individuals with chronic kidney disease (CKD) stage 5 not on dialysis (CKD5-ND). Free and protein-bound serum AGEs (N^∈-(carboxymethyl)lysine (CML), N^∈-(carboxyethyl)lysine (CEL), N_δ-(5-hydro-5-methyl-4-imidazolon-2-yl)ornithine (MG-H1)) and serum dicarbonyls (glyoxal, methylglyoxal, 3-deoxyglucosone) were analyzed with tandem mass spectrometry, and tissue AGE accumulation was estimated by skin autofluorescence (SAF). Further, serum biomarkers of ED and LGI included sVCAM-1, sE-selectin, sP-selectin, sThrombomodulin, sICAM-1, sICAM-3, hs-CRP, SAA, IL-6, IL-8 and TNF-α.

Results

After adjustment for age, sex and diabetes status, protein-bound CML was positively correlated with sVCAM-1; free CEL with sVCAM-1 and sThrombomodulin; glyoxal with sThrombomodulin; and methylglyoxal with sVCAM-1 (correlation coefficients ranged from 0.36 to 0.44). In addition, free CML was positively correlated with SAA; protein-bound CML with IL-6; free CEL with hs-CRP, SAA and IL-6; free MG-H1 with SAA; protein-bound MG-H1 with IL-6; and MGO with hs-CRP and IL-6 (correlation coefficients ranged from 0.33 to 0.38). Additional adjustment for eGFR attenuated partial correlations of serum AGEs and serum dicarbonyls with biomarkers of ED and LGI.

Conclusions

In individuals with CKD5-ND, higher levels of serum AGEs and serum dicarbonyls were related to biomarkers of ED and LGI after adjustment for age, sex and diabetes mellitus. Correlations were attenuated by eGFR, suggesting that eGFR confounds and/or mediates the relation of serum AGEs and dicarbonyls with ED and LGI.

Peritoneal dialysis has optimal intradialytic hemodynamics and preserves residual renal function: Why isn't it better than hemodialysis?

Rates of cardiovascular mortality are disproportionately high in patients with end stage kidney disease receiving dialysis. However, it is now generally accepted that patient survival is broadly equivalent between the two most frequently used forms of dialysis, in-center hemodialysis (HD) and peritoneal dialysis (PD). This equivalent patient survival is notable when considering how specific aspects of HD have been shown to contribute to morbidity and mortality. These include more rapid loss of residual renal function (RRF), HD-induced myocardial and cerebral ischemia, and risk factors associated with the intermittent delivery of HD. Potential mechanisms specific to PD that may drive cardiovascular disease include the metabolic consequences of excessive absorption of glucose and glucose degradation products (GDPs), inadequate volume control, and high rates of hypokalemia. The aim of this review is to compare and contrast the different drivers of adverse outcomes between the dialysis modalities, as greater understanding of this may help in patient-centered decision-making when considering options for renal replacement therapy.