leptin and Hyperparathyroidism--Primary

Leptin has been implicated in bone metabolism, but the association with parathyroid gland function has not been fully clarified. This review aimed to summarize evidence of the association between leptin and hyperparathyroidism, both primary and secondary, elucidating the potential pathophysiologic and therapeutic consequences between leptin and parathyroid hormone, hopefully prompting the design of new studies.. Experimental studies indicate a positive loop between leptin and parathyroid hormone in primary hyperparathyroidism. Dissimilar, parathyroid hormone seems to inhibit leptin expression in severe secondary hyperparathyroidism. Data from clinical studies indicate higher leptin levels in patients with primary hyperparathyroidism than controls, but no association between parathyroid hormone and leptin levels, as well as a minimal or neutral effect of parathyroidectomy on leptin levels in patients with primary hyperparathyroidism. Clinical data on secondary hyperparathyroidism, mainly derived from patients with chronic kidney disease, indicate a potential inverse association between leptin and parathyroid hormone in some, but not all studies. This relationship may be affected by the diversity of morbidity among these patients.. Data from experimental studies suggest a different association between leptin and parathyroid hormone in primary and secondary hyperparathyroidism. Data from clinical studies are conflicting and potentially affected by confounders. More focused, well-designed studies are warranted to elucidate a potential association between leptin and parathyroid hormone, which may have specific clinical implications, i.e., targeting obesity and hyperleptinemia in patients with hyperparathyroidism.

Topics: Adipose Tissue, White; Animals; Anti-Obesity Agents; Chief Cells, Gastric; Hormone Replacement Therapy; Humans; Hyperparathyroidism, Primary; Hyperparathyroidism, Secondary; Insulin Resistance; Leptin; Models, Biological; Obesity; Parathyroid Glands; Parathyroid Hormone; Recombinant Proteins; Reproducibility of Results; Severity of Illness Index

Surgical treatment for primary hyperparathyroidism (PHPT) improves bone metabolism. Osteocalcin (OC) and its undercarboxylated form (ucOC) are associated with bone and energy metabolism. Osteopontin (OPN), a multifunctional protein expressed in bone, is involved in resorption, along with β-carboxyl-terminal cross-linking telopeptide of type 1 collagen (β-CTX), and osteoprotegerin (OPG). Our aim was to investigate these biomarkers of bone metabolism in patients with PHPT.. We examined 30 individuals with PHPT, in a clinical research facility, before and 1 month following parathyroidectomy. Circulating levels of OC, ucOC, OPN, β-CTX, and OPG were examined as bone biomarkers along with inflammatory markers (e.g., interleukin-6 [IL-6], lipocalin-2), insulin resistance (i.e., homeostasis model assessment for insulin resistance [HOMA-IR]), adiposity (i.e., leptin, adiponectin), PTH, calcium, 25-hydroxyvitamin D, creatinine, and demographics.. The lower 1-month postoperative OPN and ucOC levels in PHPT seem to indicate reduced bone resorption. Decreased ucOC levels may also suggest lower energy demands postoperatively.

Topics: Adiponectin; Aged; Female; Follow-Up Studies; Humans; Hyperparathyroidism, Primary; Insulin Resistance; Interleukin-6; Leptin; Male; Middle Aged; Osteocalcin; Osteopontin; Osteoprotegerin; Parathyroidectomy

Primary hyperparathyroidism is one of the most common causes of hypercalcemia. Most cases result from sporadic benign monoclonal adenomas or hyperplasia. Increased body weight is consistently present in cohorts of patients with primary hyperparathyroidism. It has been shown that fat mass is the major determinant of serum parathyroid hormone levels independent of vitamin D status. Leptin, an adipocyte-derived hormone with mitogenic activity, regulates energy homeostasis and mineral metabolism. Serum leptin levels increase in parallel to the amount of adipose stores. Interestingly, a positive association between leptin and parathyroid hormone levels is observed. Patients with primary hyperparathyroidism have higher serum leptin levels than healthy subjects. In addition, leptin administration in mice increases circulating levels of parathyroid hormone. We hypothesize that leptin involves pathogenesis of primary hyperparathyroidism and represents a link between hyperparathyroidism and increased body weight.

Topics: Energy Metabolism; Homeostasis; Humans; Hyperparathyroidism, Primary; Leptin; Overweight