Bone and high-density lipoprotein: The beginning of a beautiful friendship

Area of Science:

• Metabolic pathways and bone/cartilage homeostasis.
• Lipid metabolism and its impact on skeletal health.
• Biochemistry of high-density lipoprotein (HDL) in disease.

Background:

• A strong connection exists between bone and lipid metabolic pathways.
• High-density lipoprotein (HDL) plays a role in bone diseases like osteoarthritis (OA) and osteoporosis.
• Epidemiological and in vitro data suggest reduced or dysfunctional HDL is linked to cartilage destruction and OA development.

Purpose of the Study:

• To explore the role of HDL in the pathobiology of bone diseases, specifically osteoarthritis and osteoporosis.
• To investigate the functional links between HDL and osteoarthritis, considering OA as a potential metabolic syndrome component.
• To understand HDL's impact on bone mineral density, osteoblastogenesis, osteoclastogenesis, and bone marrow adiposity.

Main Methods:

• Review of epidemiological data.
• Analysis of in vitro experimental findings.
• Examination of animal studies investigating HDL's effects on bone cells and bone marrow adiposity.

Main Results:

• Reduced HDL levels or dysfunctional HDL are associated with cartilage destruction and osteoarthritis development.
• HDL influences osteoblastogenesis, bone synthesis, osteoclastogenesis, and osteoclast bone resorption.
• Lower HDL levels correlate with increased bone marrow adiposity, negatively impacting bone cell function.

Conclusions:

• HDL plays a significant role in maintaining bone and cartilage homeostasis.
• Osteoarthritis may be considered a chronic manifestation of metabolic syndrome, involving HDL dysfunction.
• Elucidating HDL's mechanisms in bone health could lead to new therapeutic strategies for bone and cartilage disorders.