Research Article Functional Characteristics of Multipotent Mesenchymal Stromal Cells from Pituitary Adenomas Kaspars Megnis, 1 Ilona Mandrika, 1 Ramona Petrovska, 1 Janis Stukens, 2 Vita Rovite, 1 Inga Balcere, 3 Laima Sabine Jansone, 1 Raitis Peculis, 1 Valdis Pirags, 1,3 and Janis Klovins 1 1 Latvian Biomedical Research and Study Centre, Ratsupites Street 1 k-1, Riga LV-1067, Latvia 2 Clinic of Neurosurgery, Pauls Stradins Clinical University Hospital, 13 Pilsonu Street, Riga LV-1002, Latvia 3 Centre of Endocrinology, Pauls Stradins Clinical University Hospital, 13 Pilsonu Street, Riga LV-1002, Latvia Correspondence should be addressed to Janis Klovins; klovins@biomed.lu.lv Received 8 March 2016; Accepted 11 May 2016 Academic Editor: Heinrich Sauer Copyright © 2016 Kaspars Megnis et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Pituitary adenomas are one of the most common endocrine and intracranial neoplasms. Although they are theoretically monoclonal in origin, several studies have shown that they contain diferent multipotent cell types that are thought to play an important role in tumor initiation, maintenance, and recurrence afer therapy. In the present study, we isolated and characterized cell populations from seven pituitary somatotroph, nonhormonal, and lactotroph adenomas. Te obtained cells showed characteristics of multipotent mesenchymal stromal cells as observed by cell morphology, cell surface marker CD90, CD105, CD44, and vimentin expression, as well as diferentiation to osteogenic and adipogenic lineages. Tey are capable of growth and passaging under standard laboratory cell culture conditions and do not manifest any hormonal cell characteristics. Multipotent mesenchymal stromal cells are present in pituitary adenomas regardless of their clinical manifestation and show no considerable expression of somatostatin 1–5 and dopamine 2 receptors. Most likely obtained cells are a part of tissue-supportive cells in pituitary adenoma microenvironment. 1. Introduction Pituitary adenomas are typically slowly progressing benign intracranial endocrine tumors. Tey can be found in up to 14,4%–22,5% of population [1, 2]. Latest improvement in diagnostic techniques has led to an increasing incidence from 3,9 cases per 100 000 population in Sweden to 115,6 cases per 100 000 population in Iceland [3, 4]. Manifestation of clinically active adenomas can occur in three ways. Firstly, the adenoma can cause mass lesions by expanding in surrounding tissues, subsequently giving rise to headaches, visual feld defects, and similar symptoms. Other two cases may lead to either pituitary hormone insufciency or excess. Such hormonal alterations can lead to several syndromes, including acromegaly and Cushing’s disease as well as several more common and less specifc symptoms [5, 6]. Current medical therapies include transsphenoidal resection, pharmacotherapy with somatostatin or dopamine analogs, and irradiation but they have been proven to be insufcient in number of cases [7, 8]. Despite the suggested monoclonal origin of pituitary adenomas, several studies showed that more than one cell type can be found in pituitary adenoma [9, 10]. Tis can be explained by the fact that pituitary tumors may contain several tumor clones arising independently from expansion of individual cells [11]. On the other hand, there is a hypothesis that pituitary adenomas contain a subpopulation of tumor stem cells or other multipotent cells that drive their composition, growth, invasion, and resistance to therapy. Tey are suggested to be capable of sustaining themselves as well as diferentiating into other cell types of the tumour [12]. It has been shown that pituitary adenomas contain self- renewing sphere-forming cell population that can give rise to stemness markers expressing spheres and it is considered as characteristic of cancer stem cells [13]. Although the concept of sphere formation in suspension culture as a proof of stemness has its drawbacks [14], expression of stem cell characteristic proteins, like nestin (NES), sex determining region Y box 2 (SOX2) or prominin 1 (PROM1, also known Hindawi Publishing Corporation Stem Cells International Volume 2016, Article ID 7103720, 11 pages http://dx.doi.org/10.1155/2016/7103720