Association of fibroblast growth factor-23 with arterial stiffness in the Multi-Ethnic Study of Atherosclerosis

Serum Fibroblast Growth Factor 23 Levels are Associated with Vascular Smooth Muscle Dysfunction in Type 2 Diabetes

AIM

Increased level of serum fibroblast growth factor 23 (FGF23) is a hallmark of abnormal phosphate metabolism in patients with chronic kidney disease (CKD) and is recently shown to be associated with the risk of cardiovascular disease even in those without CKD. This study investigated the association between serum FGF23 levels and vascular function in patients with type 2 diabetes.

METHODS

This was a cross-sectional study involving 283 Japanese patients with type 2 diabetes. Flow-mediated dilatation (FMD) and nitroglycerin-mediated dilatation (NMD) of the brachial artery were measured via ultrasonography to evaluate vascular endothelial and smooth muscle functions, respectively. Serum intact FGF23 levels were determined via a sandwich enzyme-linked immunosorbent assay.

RESULTS

The median values of FMD, NMD, and serum FGF23 were 6.0%, 14.0%, and 27.3 pg/mL, respectively. The serum FGF23 levels were inversely associated with NMD but not with FMD, and the association was independent of atherosclerotic risk factors, estimated glomerular filtration rate (eGFR), and serum phosphate levels. Furthermore, the relationship between serum FGF23 levels and NMD was modified by kidney function, which was pronounced in subjects with normal kidney function (eGFR ≥ 60 mL/min/1.73 m2).

CONCLUSION

Serum FGF23 levels are independently and inversely associated with NMD in patients with type 2 diabetes, particularly in those with normal kidney function. Our results indicate that FGF23 is involved in vascular smooth muscle dysfunction and that increased serum levels of FGF23 may serve as a novel biomarker for vascular smooth muscle dysfunction in patients with type 2 diabetes.

Collagen type IV as the link between arterial stiffness and dementia

Arterial stiffness has been linked to impaired cognitive function and dementia but the reason for the association is uncertain. This review proposes that collagen type IV is a critical factor linking arterial stiffness and dementia. Several genome wide association studies have related arterial stiffness to Collagen type IVα. Proteomic studies of arteries, demonstrated higher levels of collagen IVα1 in persons with high arterial stiffness. Collagen type IV defects are associated genetic causes of dementia as well as dementia of a variety of other causes. There are plausible causal roles for collagen type IV in dementia. Disorders of Collagen type IV can produce (I) fibro-hyalinosis and elastosis of small arterioles leading to cerebral ischemia and infarction; (II) dysfunction of the blood brain barrier leading to cerebral hemorrhage; (III) carotid artery stiffness with increase pulse pressure induces cerebral blood vessel damage leading to cerebral atrophy. The mechanisms by which Collagen type IV can lead to vascular stiffness include its degradation by matrix metalloprotease type 2 that (a) stimulates vascular smooth muscle cells to produce more extracellular matrix or (b) liberates peptides that damage the subendothelial space. Factors, such as TGF-β1, and LDL cholesterol especially oxidized LDL can increase collagen type IV and produce vascular stiffness and dementia. Fibroblast growth factor 23, and abnormal NO signaling have been linked to collagen type IV or increased vascular stiffness and an increased risk of dementia. Recognition of the central role of collagen type IV in arterial stiffness and dementia will inspire new research focused on determining whether its modification can benefit arterial and brain health.

Reversal Of Arterial Disease by modulating Magnesium and Phosphate (ROADMAP-study): rationale and design of a randomized controlled trial assessing the effects of magnesium citrate supplementation and phosphate-binding therapy on arterial stiffness in moderate chronic kidney disease

Background

Arterial stiffness and calcification propensity are associated with high cardiovascular risk and increased mortality in chronic kidney disease (CKD). Both magnesium and phosphate are recognized as modulators of vascular calcification and chronic inflammation, both features of CKD that contribute to arterial stiffness. In this paper, we outline the rationale and design of a randomized controlled trial (RCT) investigating whether 24 weeks of oral magnesium supplementation with or without additional phosphate-binding therapy can improve arterial stiffness and calcification propensity in patients with stage 3–4 CKD.

Methods

In this multi-center, placebo-controlled RCT, a total of 180 participants with an estimated glomerular filtration rate of 15 to 50 ml/min/1.73 m2 without phosphate binder therapy will be recruited. During the 24 weeks intervention, participants will be randomized to one of four intervention groups to receive either magnesium citrate (350 mg elemental magnesium/day) or placebo, with or without the addition of the phosphate binder sucroferric oxyhydroxide (1000 mg/day). Primary outcome of the study is the change of arterial stiffness measured by the carotid-femoral pulse wave velocity over 24 weeks. Secondary outcomes include markers of calcification and inflammation, among others calcification propensity (T50) and high-sensitivity C-reactive protein. As explorative endpoints, repeated 18F-FDG and 18F-NaF PET-scans will be performed in a subset of participants (n = 40). Measurements of primary and secondary endpoints are performed at baseline, 12 and 24 weeks.

Discussion

The combined intervention of magnesium citrate supplementation and phosphate-lowering therapy with sucroferric oxyhydroxide, in stage 3–4 CKD patients without overt hyperphosphatemia, aims to modulate the complex and deregulated mineral metabolism leading to vascular calcification and arterial stiffness and to establish to what extent this is mediated by T50 changes. The results of this combined intervention may contribute to future early interventions for CKD patients to reduce the risk of CVD and mortality.

Trial registration

Netherlands Trial Register, NL8252 (registered December 2019), EU clinical Trial Register 2019-001306-23 (registered November 2019).

Fibroblast growth factor-23 as a biomarker of adverse outcomes in patients with coronary artery disease: A meta-analysis

BACKGROUND

Fibroblast growth factor-23 (FGF-23) level has been linked the adverse outcomes in patients with coronary artery disease (CAD). The purpose of this meta-analysis was to assess the predictive value of blood FGF-23 level in CAD patients.

METHODS

Two authors comprehensively searched PubMed and Embase until August 20, 2021 to identify studies investigating the association of FGF-23 level with adverse outcomes in CAD patients. Outcomes of interest were major adverse cardiovascular events (MACEs), cardiovascular or all-cause mortality.

RESULTS

Eight studies with 16,702 patients with CAD were identified. Pooled results showed that elevated FGF-23 level was associated with higher risk of MACEs (risk ratio [RR] 1.56; 95% confidence intervals [CI] 1.32-1.84), cardiovascular mortality (RR 1.99; 95% CI 1.38-2.86) and all-cause mortality (RR 1.95; 95% CI 1.67-2.27) after adjusted confounding factors. In addition, per doubling increase in FGD-23 level was associated with 24% higher risk of MACEs. Each standard deviation increases in FGD-23 level conferred a 36% higher risk of cardiovascular mortality.

CONCLUSIONS

Elevated blood FGF-23 level is associated with higher risk of MACEs, cardiovascular or all-cause mortality in patients with CAD, even after adjustment for renal function. Blood FGF-23 level may provide important predictive information in CAD patients.

Systematic Review and Meta-Analyses of the Effects of Phosphate-Lowering Agents in Nondialysis CKD

BACKGROUND

Benefits of phosphate-lowering interventions on clinical outcomes in patients with CKD are unclear; systematic reviews have predominantly involved patients on dialysis. This study aimed to summarize evidence from randomized controlled trials (RCTs) concerning benefits and risks of noncalcium-based phosphate-lowering treatment in nondialysis CKD.

METHODS

We conducted a systematic review and meta-analyses of RCTs involving noncalcium-based phosphate-lowering therapy compared with placebo, calcium-based binders, or no study medication, in adults with CKD not on dialysis or post-transplant. RCTs had ≥3 months follow-up and outcomes included biomarkers of mineral metabolism, cardiovascular parameters, and adverse events. Outcomes were meta-analyzed using the Sidik-Jonkman method for random effects. Unstandardized mean differences were used as effect sizes for continuous outcomes with common measurement units and Hedge's g standardized mean differences (SMD) otherwise. Odds ratios were used for binary outcomes. Cochrane risk of bias and GRADE assessment determined the certainty of evidence.

RESULTS

In total, 20 trials involving 2498 participants (median sample size 120, median follow-up 9 months) were eligible for inclusion. Overall, risk of bias was low. Compared with placebo, noncalcium-based phosphate binders reduced serum phosphate (12 trials, weighted mean difference -0.37; 95% CI, -0.58 to -0.15 mg/dl, low certainty evidence) and urinary phosphate excretion (eight trials, SMD -0.61; 95% CI, -0.90 to -0.31, low certainty evidence), but resulted in increased constipation (nine trials, log odds ratio [OR] 0.93; 95% CI, 0.02 to 1.83, low certainty evidence) and greater vascular calcification score (three trials, SMD, 0.47; 95% CI, 0.17 to 0.77, very low certainty evidence). Data for effects of phosphate-lowering therapy on cardiovascular events (log OR, 0.51; 95% CI, -0.51 to 1.17) and death were scant.

CONCLUSIONS

Noncalcium-based phosphate-lowering therapy reduced serum phosphate and urinary phosphate excretion, but there was an unclear effect on clinical outcomes and intermediate cardiovascular end points. Adequately powered RCTs are required to evaluate benefits and risks of phosphate-lowering therapy on patient-centered outcomes.

New Insights into the Role of FGF-23 and Klotho in Cardiovascular Disease in Chronic Kidney Disease Patients

Alterations of fibroblast growth factor 23 (FGF-23) and Klotho levels are considered to be the earliest biochemical abnormality of chronic kidney disease - mineral and bone disease (CKDMBD) syndrome. Moreover, emerging data suggests that the dysregulated FGF-23 and Klotho axis has many effects on the cardiovascular (CV) system and contributes significantly to the increased CV morbidity and mortality rates of CKD patients. This review examines recent evidence on the role of FGF-23 and Klotho in the development and progression of CV complications of uremia namely cardiac hypertrophy, uremic cardiomyopathy, and atherosclerotic and arteriosclerotic vascular lesions. Moreover, the available evidence on their associations with adverse clinical outcomes are summarized. Undoubtedly, more studies are needed to further elucidate the effects of FGF-23 and Klotho on the heart and vessels and to gain insights into their prognostic value as CV risk factors. Finally, large prospective studies are required to test the hypothesis that modification of their levels would have a favourable impact on the unacceptably high mortality rates of these patient populations.

High Cardiovascular Risk in Older Men With Severe Peripheral Artery Calcification on High-Resolution Peripheral QCT Scans: The STRAMBO Study

[Figure: see text].

A Randomized Trial on the Effect of Phosphate Reduction on Vascular End Points in CKD (IMPROVE-CKD)

BACKGROUND

Hyperphosphatemia is associated with increased fibroblast growth factor 23 (FGF23), arterial calcification, and cardiovascular mortality. Effects of phosphate-lowering medication on vascular calcification and arterial stiffness in CKD remain uncertain.

METHODS

To assess the effects of non-calcium-based phosphate binders on intermediate cardiovascular markers, we conducted a multicenter, double-blind trial, randomizing 278 participants with stage 3b or 4 CKD and serum phosphate >1.00 mmol/L (3.10 mg/dl) to 500 mg lanthanum carbonate or matched placebo thrice daily for 96 weeks. We analyzed the primary outcome, carotid-femoral pulse wave velocity, using a linear mixed effects model for repeated measures. Secondary outcomes included abdominal aortic calcification and serum and urine markers of mineral metabolism.

RESULTS

A total of 138 participants received lanthanum and 140 received placebo (mean age 63.1 years; 69% male, 64% White). Mean eGFR was 26.6 ml/min per 1.73 m2; 45% of participants had diabetes and 32% had cardiovascular disease. Mean serum phosphate was 1.25 mmol/L (3.87 mg/dl), mean pulse wave velocity was 10.8 m/s, and 81.3% had abdominal aortic calcification at baseline. At 96 weeks, pulse wave velocity did not differ significantly between groups, nor did abdominal aortic calcification, serum phosphate, parathyroid hormone, FGF23, and 24-hour urinary phosphate. Serious adverse events occurred in 63 (46%) participants prescribed lanthanum and 66 (47%) prescribed placebo. Although recruitment to target was not achieved, additional analysis suggested this was unlikely to have significantly affected the principle findings.

CONCLUSIONS

In patients with stage 3b/4 CKD, treatment with lanthanum over 96 weeks did not affect arterial stiffness or aortic calcification compared with placebo. These findings do not support the role of intestinal phosphate binders to reduce cardiovascular risk in patients with CKD who have normophosphatemia.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Australian Clinical Trials Registry, ACTRN12610000650099.

Fibroblast Growth Factor 23 and Adverse Clinical Outcomes in Type 2 Diabetes: a Bitter-Sweet Symphony

PURPOSE OF REVIEW

Fibroblast growth factor 23 (FGF23) is a key phosphate-regulating hormone that has been associated with adverse outcomes in patients with chronic kidney disease (CKD). Emerging data suggest that FGF23 plays a specific role in type 2 diabetes, partly independent of kidney function. We aimed to summarize current literature on the associations between FGF23 and outcomes in patients with type 2 diabetes with or without CKD.

RECENT FINDINGS

Several cohort studies have shown strong associations between plasma FGF23 and cardiovascular outcomes in diabetic CKD. Moreover, recent data suggest that FGF23 are elevated and may also be a risk factor for cardiovascular disease and mortality in type 2 diabetes patients without CKD, although the magnitude of the association is smaller than in CKD patients. Diabetes-related factors may influence plasma FGF23 levels, and a higher FGF23 levels seem to contribute to a higher cardiovascular and mortality risk in patients with type 2 diabetes. Although this risk may be relevant in diabetic individuals with preserved kidney function, it is strongly accentuated in diabetic nephropathy. Future studies should clarify if FGF23 is merely a disease severity marker or a contributor to adverse outcomes in type 2 diabetes and establish if antidiabetic medication can modify FGF23 levels.

Positive correlation of serum fibroblast growth factor 23 with peripheral arterial stiffness in kidney transplantation patients

BACKGROUND

Fibroblast growth factor 23 (FGF-23) has a role in arterial stiffness (AS) apart from regulating mineral metabolism. We investigated the association between FGF-23 concentration and peripheral AS in renal transplantation (RT) recipients.

METHODS

The fasting blood samples of RT recipients (n = 66) were collected and analyzed.

RESULTS

A total of 29 (43.9%) RT recipients were classified under the peripheral AS group. The RT recipients in this group had a higher prevalence of diabetes (P < 0.001), hypertension (P = 0.001), and metabolic syndrome (P = 0.023); longer post-RT duration (P = 0.006); higher systolic blood pressure (P < 0.001) and diastolic blood pressure (P = 0.024); and higher fasting glucose (P = 0.002), total cholesterol (P = 0.049), blood urea nitrogen (P = 0.027), phosphorus (P = 0.047), and FGF-23 concentrations (P = 0.003) and FGF-23/α-klotho ratio (P < 0.001) but lower klotho concentrations (P = 0.025) than those in the control group. Moreover, FGF-23 concentration (adjusted odds ratio: 1.057, 95% confidence interval: 1.011-1.105, P = 0.015) was found to be an independent predictor of peripheral AS in RT recipients.

CONCLUSIONS

Serum FGF-23 concentration was a significant predictor of peripheral AS in RT recipients.

FGF23 Concentration and APOL1 Genotype Are Novel Predictors of Mortality in African Americans With Type 2 Diabetes

OBJECTIVE

Cardiovascular and renal complications contribute to higher mortality in patients with diabetes. We assessed novel and conventional predictors of mortality in African American-Diabetes Heart Study (AA-DHS) participants.

RESEARCH DESIGN AND METHODS

Associations between mortality and subclinical atherosclerosis, urine albumin-to-creatinine ratio (UACR), estimated glomerular filtration rate (eGFR), plasma fibroblast growth factor 23 (FGF23) concentration, African ancestry proportion, and apolipoprotein L1 genotypes (APOL1) were assessed in 513 African Americans with type 2 diabetes; analyses were performed using Cox proportional hazards models.

RESULTS

At baseline, participants were 55.6% female with median (25th, 75th percentile) age 55 years (49.0, 62.0), diabetes duration 8 years (5.0, 13.0), glycosylated hemoglobin 60.7 mmol/mol (48.6, 76.0), eGFR 91.3 mL/min/1.73 m² (76.4, 111.3), UACR 12.5 mg/mmol (4.2, 51.2), and coronary artery calcium 28.5 mg Ca²⁺ (1.0, 348.6); 11.5% had two APOL1 renal-risk variants. After 6.6-year follow-up (5.8, 7.5), 54 deaths were recorded. Higher levels of coronary artery calcified plaque, carotid artery calcified plaque, albuminuria, and FGF23 were associated with higher mortality after adjustment for age, sex, and African ancestry proportion. A penalized Cox regression that included all covariates and predictors associated with mortality identified male sex (hazard ratio [HR] 4.17 [95% CI 1.96-9.09]), higher FGF23 (HR 2.10 [95% CI 1.59-2.78]), and absence of APOL1 renal-risk genotypes (HR 0.07 [95% CI 0.01-0.69]) as the strongest predictors of mortality.

CONCLUSIONS

Accounting for conventional risk factors, higher FGF23 concentrations and APOL1 non-renal-risk genotypes associated with higher mortality in African Americans with diabetes. These data add to growing evidence supporting FGF23 association with mortality; mechanisms whereby these novel predictors impact survival remain to be determined.

FGF23 Level and Intima-Media Thickness Are Elevated From Early Stages of Chronic Kidney Disease

Considering high cardiovascular (CV) risk in chronic kidney disease (CKD), the aim of this cross-sectional study was to assess the association between carotid intima-media thickness (IMT) and fibroblast growth factor (FGF) 23 as important players in CV pathophysiology. Eighty-seven patients with mean estimated glomerular filtration rate 40.1 mL/min per 1.73 m² were involved. FGF23 and IMT were elevated from early stages of CKD. Mean IMT value was 1.10 ± 0.20 mm, being significantly elevated starting from early CKD, showing no correlation with FGF23 (r = -0.01, P = -0.91). Unlike the FGF23 level that followed worsening of kidney function, IMT was increasing only in the initial CKD stages, with no further increase from CKD stage 3 on. Although we found no direct association between current use of vitamin D and statin therapy, this may be associated with the sustained reference values of lipid and vitamin D status under treatment that further preclude worsening of IMT in patients with advanced CKD.

Fibroblast Growth Factor-23: A Novel Biomarker for Cardiovascular Disease in Chronic Kidney Disease Patients

Fibroblast Growth Factor (FGF)-23 increase is considered one of the earliest biochemical abnormalities in chronic kidney disease-mineral bone disorder (CKD-MBD). Furthermore, accumulating data have provided evidence of a link between increased FGF-23 levels and cardiovascular morbidity and mortality in CKD patients as well as in several other populations including cardiology patients and general population. The cellular and molecular mechanisms underlying the deleterious effect of FGF-23 on the cardiovascular system are not yet completely defined and are the focus of intense research. However, animal and human studies have demonstrated important actions of FGF-23 in the heart and vessels through which could promote the development of cardiovascular complications in uremia. Moreover, significant interactions have been reported between FGF-23 and other well recognized cardiovascular risk factors such as renin-angiotensin system and inflammation which could account, at least in part, for the observed associations between FGF-23 and adverse clinical outcomes. Further studies are needed to clarify the mechanisms responsible for the pleiotropic actions of FGF-23 and moreover to identify whether it is a modifiable risk factor and a potential target of therapeutic interventions which could probably help to reduce the unacceptably high cardiovascular morbidity and mortality of CKD patients.

FGF23 and Nutritional Metabolism

The discovery of fibroblast growth factor 23 (FGF23) has provided a more complete understanding of the regulation of phosphate and mineral homeostasis in health and in chronic kidney disease. It has also offered new insights into stratification of risk of cardiovascular events and death among patients with chronic kidney disease and the general population. In this review, we provide an overview of FGF23 biology and physiology, summarize clinical outcomes that have been associated with FGF23, discuss potential mechanisms for these observations and their public health implications, and explore clinical and population health interventions that aim to reduce FGF23 levels and improve public health.

Fibroblast growth factor 23 as novel biomarker for early risk stratification after ST-elevation myocardial infarction

OBJECTIVE

Adverse left ventricular (LV) remodelling is the major determinant of heart failure and mortality in survivors of ST-elevation myocardial infarction (STEMI). The role of fibroblast growth factor 23 (FGF-23) for LV remodelling prediction after STEMI is unknown. We therefore aimed to investigate the relation between circulating FGF-23 and LV remodelling following revascularised STEMI.

METHODS

In this prospective observational study, we included 88 consecutive patients with STEMI treated by primary percutaneous coronary intervention. FGF-23 concentrations were measured 2 (IQR: 2-2) days after symptom onset. Cardiac magnetic resonance was performed 2 (IQR: 1-3) days as well as 4 (IQR: 4-5) months after infarction to evaluate LV remodelling, defined as ≥20% increase in LV end-diastolic volume.

RESULTS

Levels of FGF-23 were significantly higher in patients who developed LV remodelling (n=11, 13%) as compared with those without LV remodelling (152.6 (102.5-241.3) vs 75.8 (58.6-105.4) relative units per millilitre, p=0.002). The association between FGF-23 and LV remodelling remained significant (OR: 14.1, 95% CI 2.8 to 70.9; p=0.001) after adjustment for biomarkers reflecting myocardial necrosis (high-sensitivity cardiac troponin T (hs-cTnT)), myocardial stress (N-terminal pro B-type natriuretic peptide (NT-proBNP)) and inflammatory state (high-sensitivity C reactive protein (hs-CRP)). Moreover, a multimarker approach adding FGF-23 to the established LV remodelling-predictive biomarkers (hs-cTnT, NT-proBNP and hs-CRP) led to a net reclassification improvement of 0.92 (95% CI 0.44 to 1.41, p<0.001) and to an integrated discrimination improvement of 0.16 (95% CI 0.08 to 0.24, p<0.001).

CONCLUSIONS

Circulating FGF-23 is independently associated with LV remodelling after reperfused STEMI. A comprehensive multimarker strategy that includes FGF-23 provides incremental prognostic value for prediction of LV remodelling.

Prognostic value of FGF23 among patients with end-stage renal disease: a systematic review and meta-analysis

Aims: Prognostic value of FGF23 in end-stage renal disease (ESRD) patients is controversial. A systematic review was conducted to quantify the association between elevated FGF23 and overall mortality among ESRD patients. Methods: MEDLINE, EMBASE, PubMed and reference lists were searched. Quality of the included studies was evaluated using Newcastle–Ottawa Scale checklist. Pooled effects were calculated as hazard ratio using fixed-effect models, and chi-square test was used for heterogeneity testing. Results: Seven studies (1406 patients) were included. Patients were at mean age of 62.3. Mean follow-up was 29.4 months. From the pooled analysis, elevated FGF23 was significantly associated with increased all-cause mortality (hazard ratio: 1.53; 95% CI: 1.05–2.25). p-value for heterogeneity was 0.10, I2 = 48%. Conclusions: ESRD patients with elevated FGF23 concentration have higher risk of death.

Epidemiologic insights on the role of fibroblast growth factor 23 in cardiovascular disease

PURPOSE OF REVIEW

Fibroblast growth factor 23 (FGF23) regulates phosphate and vitamin D homeostasis and rises as kidney function declines. Animal studies have demonstrated direct and indirect effects of FGF23 that may promote heart disease. Herein, we review the recent epidemiologic literature evaluating the relationship between FGF23 and cardiovascular disease.

RECENT FINDINGS

In observational prospective studies, higher FGF23 associates with a greater risk of incident cardiovascular disease including ischemic heart disease, stroke, heart failure, and atrial fibrillation. These studies establish a temporal sequence of events over long-term follow-up that suggest a possible role of FGF23 in cardiovascular disease pathogenesis. In most studies, risk is generally graded; however, in the largest study to date, higher FGF23 within the low-normal range was not associated with higher risk. In several recent studies higher FGF23 associated more strongly with the risk of congestive heart failure compared with atherosclerotic events, a finding consistent with surrogate endpoints and animal experiments. Currently, the utility of FGF23 as a predictive biomarker of cardiovascular risk is not established, and interventions to reduce FGF23 need to be studied to confirm its possible pathophysiologic role.

SUMMARY

Higher FGF23 is associated with the subsequent development of cardiovascular disease, and perhaps most notably heart failure, in a growing number of studies. These findings bolster ongoing efforts to lower FGF23 using strategies to reduce phosphate intake and absorption.

Plasma FGF23 and Calcified Atherosclerotic Plaque in African Americans with Type 2 Diabetes Mellitus

BACKGROUND

Fibroblast growth factor 23 (FGF23) is a phosphaturic hormone implicated in disorders of serum phosphorus concentration and vitamin D. The role of FGF23 in vascular calcification remains controversial.

METHODS

Relationships between FGF23 and coronary artery calcified atherosclerotic plaque (CAC), aortoiliac calcified plaque (CP), carotid artery CP, volumetric bone mineral density (vBMD), albuminuria, and estimated glomerular filtration rate (eGFR) were determined in 545 African Americans with type 2 diabetes (T2D) and preserved kidney function in African American-Diabetes Heart Study participants. Generalized linear models were fitted to test associations between FGF23 and cardiovascular, bone, and renal phenotypes, and change in measurements over time, adjusting for age, gender, African ancestry proportion, body mass index, diabetes duration, hemoglobin A1c, blood pressure, renin-angiotensin-system inhibitors, statins, calcium supplements, serum calcium, and serum phosphate.

RESULTS

The sample was 56.7% female with a mean (SD) age of 55.6 (9.6) years, diabetes duration of 10.3 (8.2) years, eGFR 90.9 (22.1) ml/min/1.73 m2, urine albumin:creatinine ratio (UACR) 151 (588) (median 13) mg/g, plasma FGF23 161 (157) RU/ml, and CAC 637 (1,179) mg. In fully adjusted models, FGF23 was negatively associated with eGFR (p < 0.0001) and positively associated with UACR (p < 0.0001) and CAC (p = 0.0006), but not with carotid CP or aortic CP. Baseline FGF23 concentration did not associate with changes in vBMD or CAC after a mean of 5.1 years follow-up.

CONCLUSIONS

Plasma FGF23 concentrations were independently associated with subclinical coronary artery disease, albuminuria, and kidney function in the understudied African American population with T2D. Findings support relationships between FGF23 and vascular calcification, but not between FGF23 and bone mineral density, in African Americans lacking advanced nephropathy.

[Fibroblast growth factor 23 and a novel high-sensitivity troponin I: Early markers and alternative ways of damaging the heart in chronic kidney disease]

AIM

To establish possible pathogenetic relationships between the marker of bone mineral metabolism fibroblast growth factor 23 (FGF-23) and the markers of cardiovascular diseases characterizing the state of cardiomyocytes and that of the vascular wall of the aorta and large vessels in chronic kidney disease (CKD).

SUBJECTS AND METHODS

A total of 110 patients (57 men and 53 women) aged 25 to 65 years (mean age 56 ± 2.2 years) with different stages of CKD were examined. FGF-23 and troponin I in the sera from all the patients were investigated using enzyme immunoassay kits. Doppler echocardiography was carried out to evaluate the morphofunctional state of the left ventricle (LV). Peak systolic blood flow velocity in the aortic arch and common carotid intima-media thickness were estimated to assess the wall of the aorta and large arteries.

RESULTS

As renal failure progressed, just at the early CKD stages the patients were found to have elevating FGF-23 and troponin I levels forestalling an increase in parathyroid hormone concentrations and changes in other calcium-phosphorus metabolism indicators. The levels of FGF-23 and the morphofunctional indicators of LV lesion showed a strong direct correlation that preserved its significance in analyzing the factors under study in relation to the function of the kidneys.

CONCLUSION

The morphogenetic protein FGF-23 seems to play a significant role not only in bone remodeling processes, but also in the development of cardiovascular events in CKD. However, the mechanisms of its implication in the development of heart disease, like the possibilities of using its level changes as early diagnostic criteria for cardiovascular involvement, call for further investigation.