Effects of diabetes drugs on the skeleton.
Type 2 diabetes is associated with increased fracture risk and the mechanisms underlying the detrimental effects of diabetes on skeletal health are only partially understood. Antidiabetic drugs are indispensable for glycemic control in most type 2 diabetics, however, they may, at least in part, modulate fracture risk in exposed patients. Preclinical and clinical data clearly demonstrate an unfavorable effect of thiazolidinediones on the skeleton with impaired osteoblast function and activated osteoclastogenesis. The negative effect of thiazolidinediones on osteoblastogenesis includes decreased activity of osteoblast-specific transcription factors (e.g. Runx2, Dlx5, osterix) and decreased activity of osteoblast-specific signaling pathways (e.g. Wnt, TGF-β/BMP, IGF-1). In contrast, metformin has a positive effect on osteoblast differentiation due to increased activity of Runx2 via the AMPK/USF-1/SHP regulatory cascade resulting in a neutral or potentially protective effect on bone. Recently marketed antidiabetic drugs include incretin-based therapies (GLP-1 receptor agonists, DPP-4 inhibitors) and sodium-glucose co-transporter 2 (SGLT2)-inhibitors. Preclinical studies indicate that incretins (GIP, GLP-1, and GLP-2) play an important role in the regulation of bone turnover. Clinical safety data are limited, however, meta-analyses of trials investigating the glycemic-lowering effect of both, GLP-1 receptor agonists and DPP4-inhibitors, suggest a neutral effect of incretin-based therapies on fracture risk. For SGLT2-inhibitors recent data indicate that due to their mode of action they may alter calcium and phosphate homeostasis (secondary hyperparathyroidism induced by increased phosphate reabsorption) and thereby potentially affect bone mass and fracture risk. Clinical studies are needed to elucidate the effect of SGLT2-inhibitors on bone metabolism. Meanwhile SGLT2-inhibitors should be used with caution in patients with high fracture risk, which is specifically true for the use of thiazolidinediones.
Division of Endocrinology, Diabetes and Metabolism, University Hospital, Basel, Switzerland. Electronic address: christian.meier@unibas.ch.
Christian
C
Meier
Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA.
Ann V
AV
Schwartz
Division of Endocrinology, Diabetes and Metabolism, University Hospital, Basel, Switzerland.
Andrea
A
Egger
Department of Orthopedic Surgery, Center for Diabetes and Endocrine Research, University of Toledo College of Medicine, Toledo, OH, USA; Department of Physiology and Pharmacology, Center for Diabetes and Endocrine Research, University of Toledo College of Medicine, Toledo, OH, USA.
Beata
B
Lecka-Czernik
D000818:Animals; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D003920:Diabetes Mellitus / Q000188:drug therapy* / Q000453:epidemiology* / Q000378:metabolism; D054873:Dipeptidyl-Peptidase IV Inhibitors / Q000009:adverse effects; D050723:Fractures, Bone / Q000139:chemically induced* / Q000453:epidemiology* / Q000378:metabolism; D052216:Glucagon-Like Peptide 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000009:adverse effects*; D007334:Insulin-Like Growth Factor I / Q000037:antagonists & inhibitors / Q000378:metabolism; D008687:Metformin / Q000009:adverse effects
D001786:Blood Glucose; D054873:Dipeptidyl-Peptidase IV Inhibitors; D007004:Hypoglycemic Agents; D007334:Insulin-Like Growth Factor I; D052216:Glucagon-Like Peptide 1; D008687:Metformin
DPP-4 inhibitors; Diabetes mellitus; Incretins; Metformin; SGLT2 inhibitors; TZDs