Enzymatic dissociation of ovarian and uterine tissues

New developments in corneal endothelial cell replacement

Corneal transplantation is currently the most effective treatment to restore corneal clarity in patients with endothelial disorders. Endothelial transplantation, either by Descemet membrane endothelial keratoplasty (DMEK) or by Descemet stripping (automated) endothelial keratoplasty (DS(A)EK), is a surgical approach that replaces diseased Descemet membrane and endothelium with tissue from a healthy donor eye. Its application, however, is limited by the availability of healthy donor tissue. To increase the pool of endothelial grafts, research has focused on developing new treatment options as alternatives to conventional corneal transplantation. These treatment options can be considered as either 'surgery-based', that is tissue-efficient modifications of the current techniques (e.g. Descemet stripping only (DSO)/Descemetorhexis without endothelial keratoplasty (DWEK) and Quarter-DMEK), or 'cell-based' approaches, which rely on in vitro expansion of human corneal endothelial cells (hCEC) (i.e. cultured corneal endothelial cell sheet transplantation and cell injection). In this review, we will focus on the most recent developments in the field of the 'cell-based' approaches. Starting with the description of aspects involved in the isolation of hCEC from donor tissue, we then describe the different natural and bioengineered carriers currently used in endothelial cell sheet transplantation, and finally, we discuss the current 'state of the art' in novel therapeutic approaches such as endothelial cell injection.

Androstenedione and progesterone production in vitro by the inner or the outer theca cells in preovulatory follicles of gonadotropin stimulated calves

This study reports some of the steroidogenic characteristics of the interna and externa theca cells taken from young and eCG primed calves. These cells were isolated from large healthy follicles. The were separately cultured for 3 days in absence or in presence of steroid substrates. Androstenedione (A4) and progesterone (P4) were measured by radioimmunoassay (RIA). In control conditions, A4 levels, higher in interna than in externa cells (P < 0.001), decreased during cultures (P < 0.01). In both cell types, A4 increased in presence of 17 alpha-hydroxypregnenolone (17OHP5), pregnenolone (P5) and 22R-hydroxycholesterol (22R-chol)(*P < 0.05) but not with P4 or 17 alpha-hydroxyprogesterone (17OHP4)(P > 0.05). The most efficient substrate was dehydroepiandrosterone (DHEA) (P < 0.005). In control conditions, P4 levels increased in both cell types. They were higher in externa than in interna cells on day 1, the reverse was observed on day 3. P4 levels increased after addition of 22 R-chol and P5 (P < 0.005) but not with 17OHP5, 17OHP4 and DHEA (P > 0.05) from day 1 in externa cells and only on day 3 in internal cells. P4 levels measured on day 1 were lower than the quantity of P4 added as a substrate. These results, obtained with theca cells from young calf follicles, indicate: 1/A4 is synthesized by the delta5 pathway and 17 alpha-hydroxylase activity decreases in vitro, 2/externa and interna cells differ by the quantities of A4 and P4 produced, 3/both lack precursors to produce A4 and P4 but their 3 beta-hydroxysteroid dehydrogenase activity subsists, 4/P4 could be metabolized during the first 2 days in both cell cultures.

Steroid productions by co-cultures of granulosa cells with inner and outer theca cells in preovulatory follicles of gonadotropin stimulated calves

Granulosa, interna and externa theca cells were isolated from large follicles of equine-chorionic-gonadotropin (eCG)-primed calves and co-cultured during 3 days in the absence or in the presence of dehydroepiandrosterone (DHEA). Co-cultures were performed by adding defined numbers of theca and/or granulosa cells which represented 0, 10, 20, 50 or 100% of total cells per well. Secretion of oestradiol-17beta (E2), androstenedione (A4) and progesterone (P4) depended on the type of theca cells (P < 0.001), on the percentage of seeded granulosa cells (P < 0.001) and on the day of culture (P < 0.001). DHEA increased (P < 0.001) E2 and A4, but not P4 (P > 0.05) productions. Interactions existed between these factors (P < 0.01). On day 1, A4 production was nil in granulosa cells alone. E2 production was negligible in theca cells alone but it increased when granulosa cells were added. E2 and A4 varied in an opposite manner according to the percentage of granulosa cells and with the type of theca cells. On day 3, without DHEA, E2 and A4 were low. On day 3 with DHEA, E2 production was maintained in granulosa cells alone but not with any combination of theca cells. In these conditions, A4 production was maintained in the presence of theca cells but not in granulosa cells alone. Granulosa cells alone secreted more P4 than theca cells. P4 increased as a function of the percentage of granulosa in co-cultures with externa but not interna theca cells with which it remained low. In conclusion, theca cells in culture have two effects in relation to the granulosa cells, which differ according to the steroid concerned and to the cell combination. Both types of theca cells have an inhibitory effect on E2 secretion whereas only interna theca cells are able to alter P4 production.

Development of a method to isolate and culture highly purified populations of stromal and epithelial cells from human endometrial biopsy specimens

Appropriate endometrial maturation is of paramount importance to achieve reproductive success. Practical and ethical considerations require that in vitro methods be available to evaluate regulation of human endometrial function. Additionally, tissue complexity requires separation of individual cell populations. This report describes an improved method for isolation of endometrial epithelial and stromal cells, using biopsy specimens as a tissue source. Separated cells were obtained using selective enzymatic digestion in conjunction with physical separation procedures. Isolated populations exhibited over 95% homogeneity, ascertained immunocytochemically. Using this system, isolated cells from normal endometrium can readily be obtained for in vitro studies. Within the defined conditions of a culture system, important areas of current concern in the endometrium such as ectopic endometrial growth and implantation can be addressed.

Thecal cell 3-beta hydroxysteroid dehydrogenase activity: modulation by human chorionic gonadotropin, progesterone, estradiol-17 beta and dihydrotestosterone

Thecal cell steroidogenesis plays a major role in folliculogenesis within the porcine ovary. Accordingly, the effects of physiological concentrations of steroids on 3 beta-hydroxysteroid dehydrogenase activity (3 beta-HSD) were determined. Theca was excised from large porcine follicles and prepared in a monolayer culture in 1 ml of serum-free media. Cells were treated 24 h after culture as follows: (1) control, (2) hCG (5 IU); (3) progesterone (P, 3 micrograms); estradiol-17 beta (E, 4 micrograms); 5 beta-dihydrotestosterone (DHT, 1 microgram); (4) hCG + P or E or DHT. At 3, 6, 12, 24 and 48 h after treatment, media were assessed for P levels. For 3 beta-HSD activity, P formation by microsomal fractions incubated with 1 microM pregnenolone + 5 microM NAD+ for 1 h (37 degrees C) was monitored. Thecal cell P secretion increased from 27 to 72 h. hCG significantly (P less than 0.05) increased P levels after 36 h compared to controls. E or E + hCG decreased P levels at 36, 48, and 72 h and DHT prevented the hCG-induced increase in P secretion. 3 beta-HSD activity in thecal microsomes increased significantly from 27 to 72 h. hCG had little effect on 3 beta-HSD activity compared with controls from 27 to 36 h, but significantly (P less than 0.05) decreased 3 beta-HSD activity at 48 and 72 h. However, P or P + hCG significantly (P less than 0.05) decreased 3 beta-HSD activity at all times. In addition, E or E + hCG significantly (P less than 0.05) decreased 3 beta-HSD activity at 48 and 72 h. DHT prevented the hCG-induced decrease in 3 beta-HSD activity. In conclusion, porcine thecal secretion of P and microsomal 3 beta-HSD activity increased during 72 h of culture. Paradoxically, the addition of hCG to cultures enhanced media P concentrations but inhibited 3 beta-HSD activity. Further, the addition of E to cultures decreased media concentrations of P while P or E decreased 3 beta-HSD activity. Therefore, paracrine/autocrine effects of locally produced steroids may play a role in modulating thecal cell steroidogenesis.