C-Terminal Fragment of Agrin (CAF): A Novel Marker for Progression of Kidney Disease in Type 2 Diabetics

New Markers of Early Kidney Damage in Children and Adolescents with Simple Obesity

The impact of obesity on kidney injury and the development of chronic kidney disease (CKD) is well documented. Unfortunately, the early stages of CKD are asymptomatic, leading to a delayed diagnosis and a worse prognosis. There is a need for more sensitive indicators of kidney damage than those currently used. We aimed to assess the usefulness of serum t-CAF, urinary netrin-1, α-GST, π-GST, calbindin, and calprotectin as biomarkers of early kidney damage in obese children and to investigate the relationship between these indicators and the degree of obesity. A total of 125 simple obese, normoalbuminuric children and 33 non-obese children as controls were selected. Patients were divided into 2 subgroups according to SDS BMI (I: 2 ≤ 4, II: >4). Serum t-CAF was significantly higher in the obese group compared to the controls, as were urinary α-GST, netrin-1, π-GST, and calprotectin. No difference was found between the two obese groups. In normoalbuminuric obese children and adolescents without significant metabolic disorders, serum t-CAF may be a new biomarker for the early detection of renal dysfunction, and urinary netrin-1, α-GST, π-GST, and calprotectin may be better indicators for the detection of early tubular damage, independent of the severity of obesity.

Association between the 110-kDa C-terminal agrin fragment and skeletal muscle decline among community-dwelling older women

BACKGROUND

C-terminal agrin fragment (CAF) is a biomarker for neuromuscular junction degradation. This study aimed to investigate whether 110-kDa CAF (CAF110) was associated with the presence and incidence of low muscle mass and strength.

METHODS

This cross-sectional retrospective cohort study comprised women aged ≥65 years. We measured muscle mass using a dual-energy X-ray absorptiometry scanner, hand-grip strength, and blood sampling between 2011 and 2012. A follow-up study with the same measurements was conducted between 2015 and 2017. Low muscle mass and strength were defined as an appendicular skeletal muscle mass index <5.4 kg/m2 and hand-grip strength <18 kg, respectively. The CAF110 level was measured using enzyme-linked immunosorbent assay kits.

RESULTS

In total, 515 women (74.3 ± 6.3 years) were included in this cross-sectional analysis. Of these, 101 (19.6%) and 128 (24.9%) women presented with low muscle mass and strength, respectively. For low muscle mass, the odds ratios (ORs) of the middle and highest CAF110 tertile groups, compared with the lowest group, were 1.93 (95% confidence interval: 1.09-3.43; P = 0.024) and 2.15 (1.22-3.80; P = 0.008), respectively. After adjusting for age, the ORs remained significant: 1.98 (1.11-3.52; P = 0.020) and 2.27 (1.28-4.03; P = 0.005), respectively. Low muscle strength ORs of all the CAF110 tertile groups were not significant. In the longitudinal analysis, 292 and 289 women were assessed for incidents of low muscle mass and strength, respectively. Of those, 34 (11.6%) and 20 (6.9%) women exhibited low muscle mass and strength, respectively. For incident low muscle mass, the crude OR of the CAF110 ≥ the median value group was marginally higher than that of the CAF110 < median value group (median [interquartile range]: 1.98 [0.94-4.17] (P = 0.072). After adjusting for age and baseline muscle mass, the OR was 2.22 [0.97-5.06] (P = 0.058). All low muscle strength ORs of the median categories of CAF110 were not significant.

CONCLUSIONS

CAF110 was not associated with low muscle strength. However, CAF110 may be a potential marker for the incidence of low muscle mass.

Embryonic Ethanol but Not Cannabinoid Exposure Affects Zebrafish Cardiac Development via Agrin and Sonic Hedgehog Interaction

Recent studies demonstrate the adverse effects of cannabinoids on development, including via pathways shared with ethanol exposure. Our laboratory has shown that both the nervous system and cardiac development are dependent on agrin modulation of sonic hedgehog (shh) and fibroblast growth factor (Fgf) signaling pathways. As both ethanol and cannabinoids impact these signaling molecules, we examined their role on zebrafish heart development. Zebrafish embryos were exposed to a range of ethanol and/or cannabinoid receptor 1 and 2 agonist concentrations in the absence or presence of morpholino oligonucleotides that disrupt agrin or shh expression. In situ hybridization was employed to analyze cardiac marker gene expression. Exposure to cannabinoid receptor agonists disrupted midbrain-hindbrain boundary development, but had no effect on heart development, as assessed by the presence of cardiac edema or the altered expression of cardiac marker genes. In contrast, exposure to 1.5% ethanol induced cardiac edema and the altered expression of cardiac marker genes. Combined exposure to agrin or shh morpholino and 0.5% ethanol disrupted the cmlc2 gene expression pattern, with the restoration of the normal expression following shh mRNA overexpression. These studies provide evidence that signaling pathways critical to heart development are sensitive to ethanol exposure, but not cannabinoids, during early zebrafish embryogenesis.

C-terminal agrin fragment as a biomarker of muscle wasting and weakness: a narrative review

Ageing is accompanied by an inexorable loss of muscle mass and functionality and represents a major risk factor for numerous diseases such as cancer, diabetes and cardiovascular and pulmonary diseases. This progressive loss of muscle mass and function may also result in the insurgence of a clinical syndrome termed sarcopenia, exacerbated by inactivity and disease. Sarcopenia and muscle weakness yield the risk of falls and injuries, heavily impacting on health and social costs. Thus, screening, monitoring and prevention of conditions inducing muscle wasting and weakness are essential to improve life quality in the ageing modern society. To this aim, the reliability of easily accessible and non-invasive blood-derived biomarkers is being evaluated. C-terminal agrin fragment (CAF) has been widely investigated as a neuromuscular junction (NMJ)-related biomarker of muscle dysfunction. This narrative review summarizes and critically discusses, for the first time, the studies measuring CAF concentration in young and older, healthy and diseased individuals, cross-sectionally and in response to inactivity and physical exercise, providing possible explanations behind the discrepancies observed in the literature. To identify the studies investigating CAF in the above-mentioned conditions, all the publications found in PubMed, written in English and measuring this biomarker in blood from 2013 (when CAF was firstly measured in human serum) to 2022 were included in this review. CAF increases with age and in sarcopenic individuals when compared with age-matched, non-sarcopenic peers. In addition, CAF was found to be higher than controls in other muscle wasting conditions, such as diabetes, COPD, chronic heart failure and stroke, and in pancreatic and colorectal cancer cachectic patients. As agrin is also expressed in kidney glomeruli, chronic kidney disease and transplantation were shown to have a profound impact on CAF independently from muscle wasting. CAF concentration raises following inactivity and seems to be lowered or maintained by exercise training. Finally, CAF was reported to be cross-sectionally correlated to appendicular lean mass, handgrip and gait speed; whether longitudinal changes in CAF are associated with those in muscle mass or performance following physical exercise is still controversial. CAF seems a reliable marker to assess muscle wasting in ageing and disease, also correlating with measurements of appendicular lean mass and muscle function. Future research should aim at enlarging sample size and accurately reporting the medical history of each patient, to normalize for any condition, including chronic kidney disease, that may influence the circulating concentration of this biomarker.

Effect of targeted intervention on C-terminal agrin fragment and its association with the components of sarcopenia: a scoping review

BACKGROUND

C-terminal Agrin Fragment (CAF) has emerged as a potent biomarker for identifying sarcopenia. However, the effect of interventions on CAF concentration and the association of CAF with sarcopenia components are unclear.

OBJECTIVE

To review the association between CAF concentration and muscle mass, muscle strength, and physical performance among individuals with primary and secondary sarcopenia and to synthesize the effect of interventions on the change in the level of CAF concentration.

METHODS

A systematic literature search was conducted in six electronic databases, and studies were included if they met the selection criteria decided a priori. The data extraction sheet was prepared, validated, and extracted relevant data.

RESULTS

A total of 5,158 records were found, of which 16 were included. Among studies conducted on individuals with primary sarcopenia, muscle mass was significantly associated with CAF levels, followed by hand grip strength (HGS) and physical performance, with more consistent findings in males. While in secondary sarcopenics, the strongest association was found for HGS and CAF levels, followed by physical performance and muscle mass. CAF concentration was reduced in trials that used functional, dual task, and power training, whereas resistance training and physical activity raised CAF levels. Hormonal therapy did not affect serum CAF concentration.

CONCLUSION(S)

The association between CAF and sarcopenic assessment parameters varies in primary and secondary sarcopenics. The findings would help practitioners and researchers choose the best training mode/parameters/exercises to reduce CAF levels and, eventually, manage sarcopenia.

Review of potential biomarkers of inflammation and kidney injury in diabetic kidney disease

Diabetic kidney disease is expected to increase rapidly over the coming decades with rising prevalence of diabetes worldwide. Current measures of kidney function based on albuminuria and estimated glomerular filtration rate do not accurately stratify and predict individuals at risk of declining kidney function in diabetes. As a result, recent attention has turned towards identifying and assessing the utility of biomarkers in diabetic kidney disease. This review explores the current literature on biomarkers of inflammation and kidney injury focussing on studies of single or multiple biomarkers between January 2014 and February 2020. Multiple serum and urine biomarkers of inflammation and kidney injury have demonstrated significant association with the development and progression of diabetic kidney disease. Of the inflammatory biomarkers, tumour necrosis factor receptor-1 and -2 were frequently studied and appear to hold most promise as markers of diabetic kidney disease. With regards to kidney injury biomarkers, studies have largely targeted markers of tubular injury of which kidney injury molecule-1, beta-2-microglobulin and neutrophil gelatinase-associated lipocalin emerged as potential candidates. Finally, the use of a small panel of selective biomarkers appears to perform just as well as a panel of multiple biomarkers for predicting kidney function decline.

Circulating C-Terminal Agrin Fragment: A Potential Marker for Sarcopenia Among Type 2 Diabetes

BACKGROUND

Undetected onset of sarcopenia among individuals with chronic diseases especially Type 2 Diabetes Mellitus (T2D) makes it important to be evaluated. The feasibility of diagnosing sarcopenia in a clinical setup might be a difficult task. Circulating markers including C-terminal agrin fragment (CAF) are emerging as an alternative. Hence, the objectives of the study were to compare circulating CAF levels between T2D, prediabetes (PD) and healthy controls and to study its association with sarcopenic index, muscle mass, strength and quality.

METHODS

Ninety-nine participants (n = 42, T2D; n = 33, PD; n = 24, healthy controls) aged 18 to 60 yrs were recruited. HOMA (homeostatic model assessment) indices were derived using plasma glucose and insulin. All participants underwent lipid profiling, muscle strength including quality (isokinetic dynamometer), body composition (Dual energy X-ray Absorptiometry (DXA)) and sarcopenic index (appendicular skeletal muscle mass/body weight) assessment. Serum samples were used to estimate CAF levelsusing enzyme-linked immunosorbent assay (ELISA).

RESULTS

Median CAF level was significantly higher among T2D group compared to PD and control groups (P < 0.0001). Circulating CAF levels correlated positively with age and glycated haemoglobin (HbA1c) (both, P < 0.001) and negatively with HOMA-B and muscle quality (both, P < 0.001), and sarcopenic index (P = 0.07). Multivariable analysis demonstrated that the odds of being in the highest tertile category was 7.67, 95% C.I. (2.10, 29.3) among T2D.

CONCLUSION

Circulating CAF levels were significantly higher among T2D compared to PD and control study groups along with reduced skeletal muscle quality. This suggests that the circulating CAF level has the potential to be considered as a clinical marker to evaluate sarcopenia among T2D.

The basement membrane in the cross-roads between the lung and kidney

The basement membrane (BM) is a specialized layer of extracellular matrix components that plays a central role in maintaining lung and kidney functions. Although the composition of the BM is usually tissue specific, the lung and the kidney preferentially use similar BM components. Unsurprisingly, diseases with BM defects often have severe pulmonary or renal manifestations, sometimes both. Excessive remodeling of the BM, which is a hallmark of both inflammatory and fibrosing diseases in the lung and the kidney, can lead to the release of BM-derived matrikines, proteolytic fragments with distinct biological functions. These matrikines can then influence disease activity at the site of liberation. However, they are also released to the circulation, where they can directly affect the vascular endothelium or target other organs, leading to extrapulmonary or extrarenal manifestations. In this review, we will summarize the current knowledge of the composition and function of the BM and its matrikines in health and disease, both in the lung and in the kidney. By comparison, we will highlight, why the BM and its matrikines may be central in establishing a renal-pulmonary interaction axis.

Does diabetes modify the effect of heparin on plasma proteins? - A proteomic search for plasma protein biomarkers for diabetes-related endothelial dysfunction

AIM

Heparin administration affects the concentrations of many plasma proteins through their displacement from the endothelial glycocalyx. A differentiated protein response in diabetes will therefore, at least partly, reflect glycocalyx changes. This study aims at identifying biomarkers of endothelial dysfunction in diabetes by statistical exploration of plasma proteome data for interactions between diabetes status and heparin treatment.

METHODS

Diabetes-by-heparin interactions in relation to protein levels were inspected by regression modelling in plasma proteome data from 497 patients admitted for acute angiography. Analyses were conducted separately for all 273 proteins and as set-based analyses of 44 heparin-relevant proteins identified by gene ontology analysis and 42 heparin-influenced proteins previously reported.

RESULTS

Seventy-five patients had diabetes and 361 received heparin before hospitalization. The proteome-wide analysis displayed no proteins with diabetes-heparin interaction to pass correction for multiple testing. The overall set-based analyses revealed significant association for both protein sets (p-values<2*10^-4), while constraining on opposite directions of effect in diabetics and none-diabetics was insignificant (p-values = 0.11 and 0.17).

CONCLUSIONS

Our plasma proteome-wide interaction approach supports that diabetes influences heparin effects on protein levels, however the direction of effects and individual proteins could not be definitively pinpointed, likely reflecting a complex protein-basis for glycocalyx dysfunction in diabetes.

Plasma C-terminal agrin fragment and rapid kidney function decline in chronic kidney disease patients

C-terminal agrin fragment (tCAF) is a promising biomarker for glomerular filtration. Data regarding biomarkers that have the ability to predict rapid progression of chronic kidney disease (CKD) are sparse but necessary in order to identify patients at high risk for rapid progression. This study addresses the value of tCAF as a predictor of rapid kidney function decline in CKD patients.We measured plasma tCAF in a retrospective observational cohort study of 277 prevalent CKD patients stage I-V. Using multivariable Cox proportional hazards regression analysis, we evaluated the association of tCAF with end-stage-renal-disease (ESRD), ≥30%-decline of estimated glomerular filtration rate (eGFR) and the composite endpoint of both, adjusting for eGFR, age, systolic blood pressure, proteinuria and diabetes.The median age was 58 [interquartile range 47, 71] years, 36% were female. Median tCAF level was 822 [594, 1232] pM, eGFR was 32 [19, 48] ml/min/1.73 m. tCAF was correlated to eGFR and proteinuria (r = -0.76 and r = 0.49, P < .001 resp.). During a follow-up of 57.1 [42.9, 71.9] weeks, 36 (13%) patients developed ESRD and 13 (5%) had an eGFR decline of ≥30% (composite endpoint: 49 (18%)). In multivariable analysis, each 100 pM higher tCAF was independently associated with ESRD (hazard ratio (HR) 1.05 (95%-CI 1.02-1.08)), ≥30% eGFR decline (HR 1.10 (1.03-1.18)) and the composite endpoint (HR 1.07 (1.04-1.1)).Plasma tCAF may identify CKD patients at risk for rapid kidney function decline independent of eGFR and other risk factors for eGFR loss such as proteinuria.

Blood and urine biomarkers in chronic kidney disease: An update

INTRODUCTION

Chronic kidney disease (CKD) is a silent disease. Most CKD patients are unaware of their condition during the early stages of the disease which poses a challenge for healthcare professionals to institute treatment or start prevention. The trouble with the diagnosis of CKD is that in most parts of the world, it is still diagnosed based on measurements of serum creatinine and corresponding calculations of eGFR. There are controversies with the current staging system, especially in the methodology to diagnose and prognosticate CKD.

OBJECTIVE

The aim of this review is to examine studies that focused on the different types of samples which may serve as a good and promising biomarker for early diagnosis of CKD or to detect rapidly declining renal function among CKD patient.

METHOD

The review of international literature was made on paper and electronic databases Nature, PubMed, Springer Link and Science Direct. The Scopus index was used to verify the scientific relevance of the papers. Publications were selected based on the inclusion and exclusion criteria.

RESULT

63 publications were found to be compatible with the study objectives. Several biomarkers of interest with different sample types were taken for comparison.

CONCLUSION

Biomarkers from urine samples yield more significant outcome as compare to biomarkers from blood samples. But, validation and confirmation with a different type of study designed on a larger population is needed. More comparison studies on different types of samples are needed to further illuminate which biomarker is the better tool for the diagnosis and prognosis of CKD.

Interaction studies of a protein and carbohydrate system using an integrated approach: a case study of the miniagrin-heparin system

The major challenges in biophysical characterization of human protein-carbohydrate interactions are obtaining monodispersed preparations of human proteins that are often post-translationally modified and lack of detection of carbohydrates by traditional detection systems. Light scattering (dynamic and static) techniques offer detection of biomolecules and their complexes based on their size and shape, and do not rely on chromophore groups (such as aromatic amino acid sidechains). In this study, we utilized dynamic light scattering, analytical ultracentrifugation and small-angle X-ray scattering techniques to investigate the solution properties of a complex resulting from the interaction between a 15 kDa heparin preparation and miniagrin, a miniaturized version of agrin. Results from dynamic light scattering, sedimentation equilibrium, and sedimentation velocity experiments signify the formation of a monodisperse complex with 1:1 stoichiometry, and low-resolution structures derived from the small-angle X-ray scattering measurements implicate an extended conformation for a side-by-side miniagrin‒heparin complex.

Molecular characterization of the transition from acute to chronic kidney injury following ischemia/reperfusion

Though an acute kidney injury (AKI) episode is associated with an increased risk of chronic kidney disease (CKD), the mechanisms determining the transition from acute to irreversible chronic injury are not well understood. To extend our understanding of renal repair, and its limits, we performed a detailed molecular characterization of a murine ischemia/reperfusion injury (IRI) model for 12 months after injury. Together, the data comprising RNA-sequencing (RNA-seq) analysis at multiple time points, histological studies, and molecular and cellular characterization of targeted gene activity provide a comprehensive profile of injury, repair, and long-term maladaptive responses following IRI. Tubular atrophy, interstitial fibrosis, inflammation, and development of multiple renal cysts were major long-term outcomes of IRI. Progressive proximal tubular injury tracks with de novo activation of multiple Krt genes, including Krt20, a biomarker of renal tubule injury. RNA-seq analysis highlights a cascade of temporal-specific gene expression patterns related to tubular injury/repair, fibrosis, and innate and adaptive immunity. Intersection of these data with human kidney transplant expression profiles identified overlapping gene expression signatures correlating with different stages of the murine IRI response. The comprehensive characterization of incomplete recovery after ischemic AKI provides a valuable resource for determining the underlying pathophysiology of human CKD.

C-terminal fragment of agrin (CAF) levels predict acute kidney injury after acute myocardial infarction

Background

Patients with acute myocardial infarction are at high risk for acute kidney injury. Novel biomarkers that can predict acute kidney injury in AMI may allow timely interventions. C-terminal fragment of agrin (CAF), a proteoglycan of the glomerular and tubular basement membrane, have been recently associated with rapid renal function deterioration and proximal tubular dysfunction. It is unknown whether elevated CAF levels may serve as a novel AKI biomarker in patients presenting with AMI.

Methods

In 436 persons enrolled in a multicenter prospective observational cohort study of patients with acute myocardial infarction, we measured plasma and urine levels of several kidney injury biomarkers including CAF, neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18) and cystatin-C.The relationship between biomarker levels at baseline and the development of AKI and long-term mortality were analyzed after adjustment for demographic and clinical variables.

Results

AKI incidence was up to 15% during hospitalization. The predictive accuracy for AKI of urinary CAF was similar to NGAL and superior to other tested kidney injury biomarkers. In a multivariate model that included all possible confounding variables only urinary CAF continued to be an independent marker for AKI (OR 1.35 95%CI 1.05 -1.74). During the 2 years follow-up, only plasma CAF levels remained a significant independent predictor of mortality (OR 2.5 95%CI 1.02-6.2; P = 0.04).

Conclusions

Elevated CAF levels are associated with AKI in patients with acute myocardial infarction. Our study provides preliminary evidence that CAF levels may predict AKI and mortality after AMI in low risk patients with relative preserved kidney function at baseline.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0611-9) contains supplementary material, which is available to authorized users.

The Reference Intervals for Serum C-Terminal Agrin Fragment in Healthy Individuals and as a Biomarker for Renal Function in Kidney Transplant Recipients

BACKGROUND

C-terminal agrin fragment (CAF) has been shown to be a promising new biomarker for kidney function. The aim of this study was to verify the reference intervals for CAF in Chinese healthy adults and to assess the efficiency of CAF for monitoring renal function after transplantation.

METHODS

Serum samples were collected from 200 healthy adult subjects and 60 living donor kidney recipients before and on day 1, day 2 and at 6 months after transplantation. We measured serum CAF, creatinine, cystatin C and NGAL concentrations at each time. Estimated glomerular filtration rate (eGFR) was evaluated by Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Reference intervals for CAF were determined at 2.5th and 97.5th percentiles.

RESULTS

Serum CAF concentrations were observed to be higher in females of old age groups while no significant differences were discovered in males between age groups. There were significant gender-related differences in CAF in old age groups (50-64 and ≥65 years). Serum CAF correlated positively with serum creatinine, cystatin C and negatively with eGFR on day 1, day 2 and at 6 months after kidney transplantation. CAF and NGAL fell rapidly into the normal range on the second postoperative day, prior to creatinine and cystatin C.

CONCLUSIONS

This study verified the reference intervals for serum CAF. CAF could be a potential new biomarker for kidney function monitoring.

The C-Terminal Fragment of Agrin (CAF), a Novel Marker of Renal Function, Is Filtered by the Kidney and Reabsorbed by the Proximal Tubule

Agrin, a multidomain proteoglycan and neurotrypsin, a neuronal serine protease, are important for forming (neuromuscular) synapses. Proteolytical activity of neurotrypsin produces a C-terminal fragment of agrin, termed CAF, of approximately 22 kDA molecular size which also circulates in blood. The presence of CAF in urine suggests either glomerular filtration or secretion into urine. Blood levels of CAF have been identified as a potential novel marker of kidney function. Here we describe that several nephron segments in the mouse kidney express agrin and neutrotrypsin in addition to the localization of both protein in the glomerulum. Agrin mRNA and protein was detected in almost all nephron segments and mRNA abundance was highest in the inner medullary collecting duct. Neurotrypsin mRNA was mostly detected in the thick ascending limb of the loop of Henle, the distal convoluted tubule, and the inner medullary collecting duct. Moreover, we show that the proximal tubule absorbs injected recombinant CAF by a process shared with receptor-mediated and fluid phase endocytosis. Co-injection of CAF with recombinant human transferrin, a substrate of the receptor-mediated endocytic pathway as well as with FITC-labelled dextran (10 kDa), a marker of fluid phase endocytosis, showed partial colocalization of CAF with both markers. Further colocalization of CAF with the lysosomal marker cathepsin B suggested degradation of CAF by the lysosome in the proximal tubule. Thus, the murine kidney expresses agrin and neurotrypsin in nephron segments beyond the glomerulum. CAF is filtered by the glomerulum and is reabsorbed by endocytosis by the proximal tubule. Thus, impaired kidney function could impair glomerular clearance of CAF and thereby increase circulating CAF levels.

Serum levels of C-terminal agrin fragment (CAF) are associated with sarcopenia in older multimorbid community-dwellers: Results from the ilSIRENTE study

BACKGROUND

The C-terminal agrin fragment (CAF), a circulating byproduct of neuromuscular junction disassembly, has been proposed as a possible biomarker for sarcopenia. However, its validity in "real-world", multimorbid older persons is currently unknown. The present study was undertaken to verify if serum CAF levels were associated with sarcopenia in a population of old and very old persons living in the community.

METHODS

Data were from the ilSIRENTE Aging and Longevity Study, a prospective cohort study conducted in all persons aged 80years and older residing in the Sirente geographic area (Italy; n=332). The identification of sarcopenia was based on the criteria elaborated by the European Working Group on Sarcopenia in Older People (EWGSOP). Serum levels of CAF were determined using a commercial ELISA kit.

RESULTS

Sarcopenia was identified in 101 participants (30.8%). Serum levels of CAF were significantly higher in older adults with sarcopenia compared with non-sarcopenic participants (96.99±5.40pmol/L vs. 76.54±2.15pmol/L; p<0.001). The association remained significant in both genders after adjustment for several possible confounding factors, including age, cognition, disability status, body mass index, congestive heart failure, lung diseases, diabetes, renal failure, and plasma levels of C-reactive protein and interleukin 6.

CONCLUSIONS

Our results obtained from a fairly large sample of old and very old, multimorbid community-dwellers show that elevated serum CAF levels are associated with sarcopenia, independent of age, gender and several clinical, functional, anthropometric, and biochemical variables. The determination of serum CAF concentration may therefore be proposed as a simple screening test for sarcopenia in the community.