MIBI scintigraphy, indicators of cell proliferation and histology of parathyroid glands in uraemic patients

Abstract

Background. Although scintigraphy with 99m Tcsestamibi (MIBI) has been used to localize parathyroid glands prior to surgery for hyperparathyroidism, using it to evaluate parathyroid function remains controversial. The purpose of this study was to evaluate the possible association of MIBI uptake with gland weight, histological pattern and proliferative activity of parathyroid cells. Methods. We studied 18 patients with secondary hyperparathyroidism (SHP); mean age 38±3 years, 55% female, mean time on haemodialysis 7.7±0.9 years. All patients had parathyroidectomy (PTx). The weights of the removed glands were estimated, and parathyroid hyperplasia was classified as diffuse (n ¼ 28) or nodular (n ¼ 29). The expression of proliferative cell nuclear antigen (PCNA) was evaluated by immunohistochemistry. Before PTx, all patients underwent MIBI evaluation and were categorized using a 0-3 uptake scoring system. Low uptake (scores of 0 and 1) was seen in 39 glands and high uptake (scores of 2 and 3) in 18. Results. Estimated gland weights, percentage of nodular hyperplasia and PCNA expression were greater in glands with high MIBI scores than in those with low scores (P<0.01). In glands with nodular hyperplasia, PCNA expression was higher (318±66 cells/mm 2 ) than in those with diffuse hyperplasia (104±16 cells/mm 2 ; P<0.001). Conclusions. High MIBI scores were associated with high estimated gland weight, degree of cell proliferation and presence of nodular hyperplasia. MIBI scintigraphy is useful in clinical practice for localizing parathyroid glands, and it could guide the management of SHP by indicating the degree of its severity.

Technetium-99m Sestamibi Scintigraphy Pattern in Patients with Secondary Hyperparathyroidism

“…This concurs with the findings of previous reports [12,13,16]. The association between high trace uptake and nodular hyperplasia on histological examination in this study was expected.…”

“…Piga et al stated that 99m Tc MIBI scans do not simply reveal parathyroid enlargement but rather identify hyperfunctioning parathyroid glands in uremic patients with SHP [12]. In the present study, Tc MIBI scan [13]. An important factor that may influence the rate of positive scintigraphy findings in patients with SHP and parathyroid adenoma is the variable expression of metabolism transporters, such as p-glycoprotein (P-GP) or multidrug resistanceassociated protein (MRP) in the parathyroid glands, which may function as a drug transporter for 99m Tc MIBI [14,15].…”

Does Vitamin D Receptor and Calcium Receptor Activation Therapy Play a Role in the Histopathologic Alterations of Parathyroid Glands in Refractory Uremic Hyperparathyroidism?

“…Furthermore, a stepwise multiple regression analysis showed unequivocally that the predominant role was played by cinacalcet. We have to keep in mind three background points: (a) We and others have shown that oxyphil cells are well represented in NH (9,11). Recently, it was shown that oxyphil cells produce actively PTH-related protein and that oxyphil cells have a level of proliferation lower than that of chief cells (14); PTH-related protein could act through an autocrine/paracrine mechanism to regulate proliferation and differentiation of parathyroid cells (14), favoring their metaplastic change into the oxyphil phenotype (14,15); (b) CaR are expressed in many tissues, with the highest density being found in the chief cells of the parathyroid glands (2); (c) furthermore, very recently, it was also shown that CaR activation by the calcimimetic R-568 accelerates chief cell death, probably through an apoptotic mechanism in uremic rats in vitro (16).…”

“…The weight (g) was estimated as already reported (9). Histologic studies of the parathyroid glands with light microscopy were performed by the same pathologist on seven serial sections of the glands in a blinded manner.…”

“…DH was defined as an increased number of parenchymal cells with normal lobular structures, and NH was defined as at least one well-circumscribed, encapsulated, and virtually fat cell-free accumulation of parenchymal cells (10). Such nodules are composed of more tightly packed cells featuring larger nuclei and a greater prevalence of cell-cycle markers, oxyphil cells, and acinar cells (9,11,12). Besides defining the type of hyperplasia, a semiquantitative analysis was performed to assess the prevalence of the two major cell populations, chief and oxyphil cells; it was expressed as oxyphil/chief cell ratio (13).…”