Comparison of plasma and salivary meteorin-like protein levels in patients with newly diagnosed Type-2 diabetes and treated with metformin

OBJECTIVE

The present study compares the plasma and salivary Metrnl levels of patients newly diagnosed with type-2 diabetes who were treated with metformin for three months with those of a healthy volunteer group and immunohistochemically analyzes Metrnl in salivary glands.

PATIENTS AND METHODS

30 healthy volunteers and 30 newly diagnosed type-2 diabetes patients were included in the study. The newly diagnosed diabetes patients were treated with metformin for three months, and the plasma and salivary metformin levels of both groups were measured at baseline and after the three months of metformin treatment in the patient group. Plasma HbA1c, low-density lipoprotein (LDL-C) and Triglyceride (TG) values of all groups were also measured at baseline following three months of metformin treatment. Biopsies were taken from the parotid and submandibular glands and immunohistochemical staining was performed to show Metrnl immunoreactivity.

RESULTS

Plasma Metrnl, HbA1c, LDL-C and TG levels were higher in the newly diagnosed diabetes group than in the other group, and salivary Metrnl levels were higher than in the control group after three months of metrformin treatment. An examination of the immunohistochemical staining of salivary gland biopsies under light microscope revealed Metrnl immunoreactivity in the intralobular and interlobular ducts of the parotid gland, while Metrnl immunoreactivity was observed in the acinar cells in the intralobular striated duct and interlobular ducts in the submandibular gland.

CONCLUSIONS

Plasma Metrnl, HbA1c, LDL-C and TG levels were higher in the newly diagnosed diabetes group than in the other group. Metrnl immunoreactivity was detected in the parotid and submandibular glands. The relationship between Metrnl and DM should be investigated in larger groups.

Immunostaining characteristics of irisin in benign and malignant renal cancers

We investigated the expression of irisin in renal cancers using immunocytochemistry. Irisin has been reported to exhibit anticancer properties. The study groups consisted of 22 cases each of control renal tissue, oncocytoma, chromophobe renal cell carcinoma (RCC), clear cell RCC (Fuhrman nuclear grades 1, 2, 3 and 4) and papillary RCC. We evaluated 10 slides for each of 176 cases. Slides were immunostained for irisin and histoscores were calculated for the prevalence and strength of immunostaining. Fuhrman nuclear grade 1, 2, 3 clear cell RCC and papillary RCC exhibited no irisin immunoreactivity. Irisin immunoreactivity was observed in some Fuhrman nuclear grade 4 RCCs. We found a significant decrease in irisin staining in chromophobe RCC compared to the control. Immunoreactivity in the oncocytoma tissue was comparable to the control group. Irisin immunoreactivity in chromophobe RCC decreased and no immunoreactivity was observed in Fuhrman nuclear grade 1, 2, 3 clear cell RCC and papillary RCC. Immunistochemical screening of irisin in renal oncocytomas and renal cancers may be useful for differential diagnosis.