Endocrine Abstracts

Introduction: Primary hyperparathyroidism (PHPT) clinic occurs when the parathyroid glands secrete excess parathormone (PTH) due to hyperplasia, adenomatous or carcinomatous change. In the pathogenesis of the disease, dysregulation has been observed in extracellular signal-regulated 1/2 (ERK 1/2) pathways from the mitogen activated protein kinase (MAPK) family, c-Jun N-terminal kinase (JNK) pathways, and phosphatidylinositol-3 kinase (PI3K) pathways. Progranulin (PGRN) is a glycoprotein found in many tissues in the body, activation of MAPK, JNK and PI3K pathways by PGRN has been observed in studies. Based on these shared pathways, PGRN expression in parathyroid adenomas and its clinical effects were investigated.

Methods: 182 cases were included in our study, consisting of 102 PHPT patients who were operated on with adenomas and 80 cases in the control group. The biochemical and clinical data was evaluated. Anti-GRN antibody was applied at 1/300 dilution to the parathyroid samples and statistical analysis was performed. Tissues without staining were considered negative, staining between 1% and 25% were considered weak positive and tissues with staining above 25% were considered strong positive.

Results: While the mean age of the patients was 59.63±12.15 years, the mean age of the control group was 57.01±12.47 years. 91 of 102 patients were female and 11 were male; in the control group 67 were female and 13 were male. No statistical significance was found in terms of age and gender distribution (P=0.156, P=0.378). Of 102 patients, staining with anti-GRN was negative in 59, mild in 26 and strong in 17. All samples in the control group showed strong staining. PGRN expression was significantly lower in the patient group (P<0.001). Staining scores were compared with biochemical and clinical parameters, no significant difference was found (P>0.05). The mean calcium levels in the patient and control group were 11.33±0.9 and 9.31±0.45 mg/dl respectively. The mean PTH in the patient group was 173.80±95.35 pg/ml. Biochemical and clinical parameters were compared in the patient group, positive correlation was found with calcium and PTH levels (P<0.001); phosphorus and forearm bone density were negatively correlated with PTH levels (r=-0.38, P<0.001; r=-0.32 P=0.015). Calcium and phosphorus levels were also negatively correlated (r=-0.40 P<0.001).

Conclusion: We found that PGRN expression was significantly decreased in sporadic parathyroid adenomas compared to the control group. PGRN may be an important factor in pathogenesis of parathyroid adenomas, more comprehensive studies are needed to investigate the clinical associations and examine the underlying molecular pathways.