Ambulante Nachsorge aus gesundheitsökonomischer Sicht

Abstract

The extracellular matrix (ECM) promotes and/or inhibits many cellular processes, including but not limited to proliferation, differentiation, and survival, which must occur for follicle growth and oocyte maturation. The ECM regulation of cellular processes in ovarian cells is being investigated in many animal models, including avian, rat, bovine, porcine, rabbit, sheep, human, and mouse. Granulosa cells are more frequently employed; however, the culture of intact follicles and ovaries has been developed and enables ECM functions in folliculogenesis to be studied. ECMcomponents that have been examined are used individually (collagen, laminin, fibronectin) or collectively (Matrigel, isolated basal lamina, and ECM produced by cell lines) in both two-and three-dimensional model systems. In granulosa cell cultures, ECM affects morphology, aggregation and communication, survival, proliferation, and steroidogenesis; whereas follicle and ovary cultures demonstrate a regulation of folliculogenesis. This article describes the ECM functionality on ovarian cells throughout development, and highlights the potential of developing technologies to identify structure-function relationships in follicle maturation. KeywordsExtracellular matrix; granulosa cells; morphology; proliferation; survival Ovarian follicle development is regulated by endocrine, paracrine, and autocrine factors in a spatially and temporally regulated manner, and is characterized by dramatic changes throughout maturation. The ovary contains a large reserve of inactive primordial follicles arrested in prophase I, with a small cohort activated daily. Prior to activation, these immature follicles contain nongrowing oocytes and nondividing, flattened (squamous) pregranulosa cells surrounded by a basal lamina. Following activation, follicle growth begins with the transformation of squamous pregranulosa cells into a single layer of cuboidal granulosa cells surrounding a growing oocyte. Granulosa cells proliferate to form multiple layers, requiring expansion of the basal lamina, and leading to two-layered and multilayered follicle stages. At this time, an outer layer of cells, termed the theca layer, is recruited (or differentiated from existing stroma 1 ) and surrounds the basal lamina. A fluid-filled antral cavity, or antrum, forms in the granulosa cell compartment of the follicle later in folliculogenesis. Small antral follicles develop into mature preovulatory follicles in the presence of follicle-stimulating hormone

Comparing various protocols of human and bovine ovarian tissue decellularization to prepare extracellular matrix-alginate scaffold for better follicle development in vitro

“…Furthermore, the rates of oocyte maturation in alginate with ECM compartments were higher than alginate alone [ 20 ]. Decellularized tissue can improve follicles viability and growth by providing natural ECM composition, growth factors, and porous structure [ 21 ]. Due to the features of the decellularized tissue, it can be used as a scaffold for follicle culture.…”

“…In order to use ECM proteins in the follicle three-dimensional culture system, ECM molecules were combined with alginate to create synthetic ECM hydrogel. The results of follicle culture in alginate-ECM protein hydrogel showed that it had a positive effect on estrogen production, follicle development, and oocyte maturation [ 21 , 26 ].…”

Evaluation of in vitro culture systems for goat preantral follicles using reused ovaries from reproductive biotechniques: An alternative to maximize the potential of reproduction

“…The 3D culture system is based on mimicking the physiological environment of the ovarian stroma, preserving the integrity and morphology of the follicle, since it preserves the communicating channels between the oocyte and somatic cells. The conservation of the follicular structure is primordial, since it contributes to the development and maturation of the oocyte (Berkholtz, Shea, & Woodruff, 2006). During the three-dimensional culture procedure, the use of an alginate matrix is employed, which represents a method of encapsulation that is conducive to in vitro follicular growth.…”

Three-dimensional in vitro follicle growth: overview of culture models, biomaterials, design parameters and future directions

“…The natural scaffolding upon which cells are organized in vivo , known as the extracellular matrix (ECM), is composed of collagen, along with laminin and fibronectin. ECM has been shown to play an important role in regulating cell behavior, differentiation and secretory activity (reviewed in [ 30 ]). One commercially available ECM tested for follicle growth is matrigel [ 49 , 66 , 67 ].…”

“…The source and type of ECM could also play a role in regulating follicle growth during 3-D culture. The size of ECM molecules can present problems and an alternative solution has been to adsorb known sequences of matrix peptides, such as RGD (Arg-Gly-Asp) or laminin-derived peptide sequences on to synthetic matrices (reviewed in [ 30 ]).…”