(556.22) Weight Gain, Fibroblast Growth Factor-23, and Vascular Function in Liver Transplant Recipients

Poster Board Number: E114

Linsey Martin (Virginia Commonwealth University), Domenico Chavez (Virginia Commonwealth University), Natalie Bohmke (Virginia Commonwealth University), Austin Miller (Virginia Commonwealth University), Chandra Bhati (Virginia Commonwealth University), Susan Wolver (Virginia Commonwealth University), Mohammad Siddiqui (Virginia Commonwealth University), Danielle Kirkman (Virginia Commonwealth University)

INTRODUCTION Liver transplant (LT) recipients experience significant weight gain and an increased risk of cardiovascular disease (CVD) after transplant. The pathophysiology of this cardiometabolic burden is not fully understood. In the general population, weight gain and increased adiposity are associated with elevated circulating levels of fibroblast growth factor-23 (FGF-23). Increased FGF-23 has been linked with CVD in other disease populations. This study tested the working hypothesis that weight gain after LT is associated withincreased levels of FGF-23, that subsequently contribute to vascular dysfunction, an established precursor of CVD. METHODS We enrolled 21 LT patients (M/F: 9/12; Mean ± SEM, Age: 55 ± 2 yrs) and 8 age matched healthy controls (HC; M/F: 2/6; 47 ± 6 yrs). Vascular endothelial function was assessed with flow-mediated dilation (FMD) of the brachial artery using duplex ultrasound. Aortic pressure waves were synthesized from radial artery waveforms acquired by applanation tonometry and the use of a generalized transfer function. Serum levels of FGF-23 were assessed by enzyme linked immunosorbent assay (ELISA). RESULTS Higher body mass index (BMI) values were reported in LT patients (37 ± 1 kg/m2) compared to HC  (26 ± 1 kg/m2, p = lt;0.001). Weight gain (BMI) was positively associated with serum FGF-23 values (r = 0.5, p = 0.01). Central systolic pressures (125 ± 3 vs. 110 ± 6 mmHg, p = 0.01) and central pulse pressures (51 ± 4 vs. 39 ± 4 mmHg, p = 0.05) were higher in LT patients compared with controls. There was no difference in endothelial function (FMD) in LT patients (4.59 ± 0.55%) compared to their HC counterparts (6.08 ± 0.48%, p = 0.12). FGF-23 values were not associated with measures of vascular function. CONCLUSION Weight gain is evident in LT patients and is correlated with higher serum FGF-23 values. However, our findings do not suggest a relationship between serum levels of FGF-23 and vascular function in LT recipients.

Funding provided by the APS Undergraduate Research Fellowship program and National Institutes of Health UL1TR002649.