Increases in PYY and uncoupling of bone turnover are associated with loss of bone mass after gastric bypass surgery

Kim, Tiffany Y.; Shoback, Dolores M.; Black, Dennis M.; Rogers, Stanley J.; Stewart, Lygia; Carter, Jonathan T.; Posselt, Andrew M.; King, Nicole J.; Schafer, Anne L.

Affiliations

¹Departments of Medicine, University of California, San Francisco, San Francisco, USA

²Endocrine Research Unit, San Francisco VA Health Care System, San Francisco, USA

³Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, USA

⁴Department of Surgery, University of California, San Francisco, San Francisco, USA

⁵Surgical Services, San Francisco VA Health Care System, San Francisco, USA

Abstract and keywords

Context: The gut hormones peptide YY (PYY) and ghrelin mediate in part the metabolic benefits of Roux-en-Y gastric bypass (RYGB) surgery. However, preclinical data suggest these hormones also affect the skeleton and could contribute to postoperative bone loss.

Objective: We investigated whether changes in fasting serum total PYY and ghrelin were associated with bone turnover marker levels and loss of bone mineral density (BMD) after RYGB.

Design, setting, participants: Prospective cohort of adults undergoing RYGB (n = 44) at San Francisco academic hospitals.

Main outcome : We analyzed 6-month changes in PYY, ghrelin, bone turnover markers, and BMD by dual-energy x-ray absorptiometry (DXA) and quantitative computed tomography (QCT). We calculated the uncoupling index (UI), reflecting the relative balance of bone resorption and formation.

Results: Postoperatively, there was a trend for an increase in PYY (+25 pg/mL, p = 0.07) and a significant increase in ghrelin (+192 pg/mL, p < 0.01). PYY changes negatively correlated with changes in spine BMD by QCT (r=-0.36, p = 0.02) and bone formation marker P1NP (r=-0.30, p = 0.05). Relationships were significant after adjustments for age, sex, and weight loss. No consistent relationships were found between ghrelin and skeletal outcomes. Mean 6-month UI was -3.3; UI correlated with spine BMD loss by QCT (r = 0.40, p = 0.01).

Conclusions: Postoperative PYY increases were associated with attenuated increases in P1NP and greater declines in spine BMD by QCT. Uncoupling of bone turnover correlated with BMD loss. These findings suggest a role for PYY in loss of bone mass after RYGB and highlight the relationship between intestinal and skeletal metabolism.

Keywords: PYY; Ghrelin; BMD; Bone turnover; Roux-en-Y gastric bypass surgery

Links

DOI: 10.1016/j.bone.2019.115115

PubMed: 31689523

WoS: 000507697800009

History

Received: 2019-07-10

Revised: 2019-10-07

Accepted: 2019-10-17

Online: 2019-11-02

Cited Works (1)

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Cited By (2)

Year	Entry
2022	Paccou J, Tsourdi E, Meier C, Palermo A, Pepe J, Body J-J, Zillikens MC. Bariatric surgery and skeletal health: a narrative review and position statement for management by the European Calcified Tissue Society (ECTS). Bone. January 2022;154:116236.
2023	Zahedi B, Daley EJ, Brooks DJ, Bruce M, Townsend RL, Berthoud H-R, Bouxsein ML, Yu EW. The PYY/Y2R-deficient male mouse is not protected from bone loss due to Roux-en-Y gastric bypass. Bone. February 2023;167:116608.