VEGF modulates the effects of gonadotropins in granulosa cells.

Follicle selection is associated with an increase in the expression of vascular endothelial growth factor (VEGF) and its receptors in granulosa cells, however, the roles of VEGF in regulating the function of these or other non-endothelial cells in the ovary have not been explored in detail. The current study used bovine cell cultures to investigate potential roles of VEGF in the regulation of granulosa cell function during follicle development. Granulosa cells were obtained from morphologically healthy follicles 4 to 8 mm or 9 to 14 mm in diameter (corresponding to diameters before and after the establishment of dominance, respectively, during a bovine follicular wave) and exposed to a range of VEGF concentrations (1 to 100 ng/mL) encompassing concentrations found naturally in bovine dominant follicles. A concentration of VEGF of 1 ng/mL induced significant proliferation of granulosa cells from 4- to 8-mm follicles (P=0.024) and increased the proliferative response of these cells to follicle-stimulating hormone (FSH; P=0.045); whereas higher doses of VEGF had no effect on proliferation (P=0.9). Treatment with VEGF induced an overall increase in mean extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation (P=0.02). In contrast, VEGF, alone or in combination with FSH, had no effect on expression of the steroidogenic enzyme, CYP11A1, by cells from 4- to 8-mm follicles (P=0.9). Granulosa cells from 9- to 14-mm follicles responded to 1 ng/mL VEGF with an increase in expression of the ovulation-associated gene, PTGS2 (P=0.003) but higher VEGF doses had no effect (P=0.9). The PTGS2 response to 1 ng/mL VEGF was similar to that induced by treatment with luteinizing hormone (LH). Interestingly, the stimulatory effects of LH on ERK1/2 phosphorylation (P=0.003) and PTGS2 expression (P<0.01) in granulosa cells from 9- to 14-mm follicles were abolished (P=0.2) by specific chemical inhibition of VEGF receptor 2 (VEGFR2). These results suggest novel and important roles of VEGF and its receptor, VEGFR2, in mediating and/or enhancing the effects of gonadotropins in granulosa cells.

Regulation of the proliferative activity of ovarian surface epithelial cells by follicular fluid.

Despite critical roles of the ovarian surface epithelium (OSE) in ovulation and post-ovulatory wound repair, little is known about the physiological mechanism regulating OSE proliferation. A role of follicles and corpora lutea in locally regulating the proliferative activity of OSE has been suggested. In this study, the effects of follicular and luteal products on proliferation of cultured OSE cells were tested using cells obtained from seasonally anoestrous ewes. Follicular fluid but not luteal extracts induced OSE cell proliferation (2.5-fold relative to untreated controls; P<0.0001). The response of OSE cells was not affected by follicle size or previous charcoal-extraction of follicular fluid (P>0.1). Treatment with IGF-1 (2.2-fold; P<0.01), EGF (1.9-fold; P<0.01) and, to a lesser extent, FSH (P<0.05) also induced OSE cell proliferation. In contrast, oestradiol or progesterone did not induce cell proliferation or enhance the effects of FSH on proliferation (P>0.1). It was concluded that follicular fluid can directly stimulate ovine OSE cell proliferation and that this effect is attributable to non-steroidal mitogens.

Seasonal effects on the response of ovarian follicles to IGF1 in mares.

The response of follicles to IGF1 was compared between the transition into the ovulatory season (transitional period) and the ovulatory season (ovulatory period) in eight mares using a cross-over experimental design within periods. Granulosa cells were collected from follicles 15-24 or 25-34 mm and expression of IGF1R, IGF2R, FSHR, LHCGR and PAPPA was determined by qPCR. In addition, 10 mg IGF1 or vehicle were injected into the largest follicle (transitional period) or the second largest follicle (ovulatory period) of a follicular wave before the beginning of diameter deviation between the two largest follicles (mean diameters at injection 19.2 and 20.0 mm during transitional and ovulatory periods respectively). Follicular fluid was collected 24 h after injection for determination of free IGF1, IGFBP, inhibin A and oestradiol levels. Granulosa cells from follicles 25-34 mm, but not follicles 15-24 mm, expressed higher levels of IGF1R (P=0.01), FSHR (P<0.007) and LHCGR (P=0.09) during the ovulatory period than during the transitional period, whereas IGF2R expression was higher in transitional than ovulatory follicles (P=0.06). Follicular IGFBP2 levels were not different (P>0.1) between periods and treatments, whereas IGFBP5 levels were higher (P<0.05) during the ovulatory period. Finally, IGF1 injection before the beginning of deviation induced an approximately twofold increase (P=0.01) in follicular inhibin A levels during each period and did not affect oestradiol (P>0.1). These results suggest that, as during ovulatory waves, equine follicles during transitional waves are responsive to IGF1 before the beginning of deviation and that, therefore, inadequate IGF1 responsiveness before deviation may not underlie the deficient development of dominant follicles during transition.

Osteoid osteoma of the hand.

A review of all cases of osteoid osteoma of the hand seen by four hand surgeons over the last 10 years was performed. Seven cases were documented. Average follow-up was 28.3 months. Average age of the patients was 21.1 years. Five men and two women participated. Six lesions were in the right and one in the left upper extremity. Delay from presenting symptoms to definitive treatment averaged 13.5 months with a range of 7 to 30 months. Surgical excision was curative in all cases. We concluded that although a very unusual occurrence, osteoid osteoma of the hand should be considered in the differential diagnosis of pain in the hand.