Iberian pig early pregnancy: vascular endothelial growth factor receptor system expression in the maternofetal interface in healthy and arresting conceptuses.

In Iberian pigs, a high conceptus loss occurs during the first 30 days of gestation. Although the exact causes for these losses have not been determined to date, the importance of blood vessel development during early pregnancy has been noted. The aim of this study was to analyze the messenger RNA (mRNA) and protein expression of VEGF-rs (vascular endothelial growth factor, the VEGFR1, and the VEGFR2 receptor system) and elucidate a possible relationship with the conceptus status (healthy or arrested) on gestational Days (gd) 22 and 32. Both mRNA and protein expression for VEGF-rs molecules were consistently expressed in conceptuses and endometrium during the pregnancy period analyzed. In endometrium, a significant increase in VEGF mRNA and VEGFR2 mRNA expression in healthy sites was observed as pregnancy advances (P < 0.001 and P < 0.05, respectively), whereas VEGFR1 mRNA expression was maintained at a constant level. Interestingly, a significantly elevated VEGFR2 mRNA expression (P < 0.05) was observed on gd 22 in endometrium from arrested conceptuses. Furthermore, VEGF mRNA and VEGFR1 mRNA expression in trophoblasts from healthy conceptuses decreased as pregnancy proceeded (P < 0.001). Arrested trophoblasts on gd 32 showed higher VEGFR2 mRNA expression than healthy conceptuses (P < 0.05). Although, in endometrium attachment sites, the pattern of VEGF-rs immunostaning was not affected by conceptus status, the immunoexpression of VEGF-rs in healthy attachment sites increased slightly but consistently as gestation proceeded. In arresting trophoblasts, VEGF and VEGFR2 staining decreased from gd 22 to 32. Moreover, the number of VEGF and VEGFR1-positive capillaries in the subepithelial vascular plexus of endometrium was related to the conceptus status, showing a moderate increase in healthy sites as pregnancy advances. In conclusion, it appears that VEGF-rs is expressed and related to vascular development in Iberian pigs between gd 22 and 32. The upregulated expression of VEGF mRNA and VEGFR2 mRNA in healthy uterine sites suggests a significant role for these angiogenic factors in early pregnancy.

Cooperative role between p21cip1/waf1 and p27kip1 in premature senescence in glandular proliferative lesions in mice.

Cellular senescence has been considered a novel target for cancer therapy. It has also been pointed out that p21(cip1/waf1) and p27(kip1) cyclin-dependent kinase inhibitors (CKIs) play a role in cellular senescence in some tumor types. Therefore, in order to address the possibility of a cooperative role between p21 and p27 proteins in senescence in vivo we analyzed cellular senescence in spontaneous glandular proliferative lesions (adrenal, thyroid and pituitary glands) in a double-KO mice model, using γH2AX, p53, p16, PTEN and Ki67 as senescence markers. The results obtained showed that p21p27 double-null mice had the lowest number of γH2AX positive cells in glandular hyperplasias and benign tumors. Also, in this group, Ki67 proliferation index correlated with a lower immunohistochemical expression of γH2AX and p53. The expression of p16 and PTEN do not seem to cause synergism of senescence in the benign lesions analyzed in p21p27 double-KO mice. These observations suggest an intrinsic cooperation between p21 and p27 CKIs in the activation of stress-induced cellular senescence and tumor progression in vivo, which would be a physiological mechanism to prevent tumor cell proliferation.

Different influence of ovine estrus synchronization treatments on caruncular early angiogenesis.

The present study compares two protocols for ovine estrus synchronization by assessing the caruncular angiogenic response to the establishment of pregnancy. The analysis consisted of the immunohistochemical evaluation of Vascular Endothelial Growth Factor (VEGF), Platelet Endothelial Cell Adhesion Molecule-1 (PECAM-1, CD31) and Von Willebrand Factor (vWF) in ovine caruncular stroma. A flock of thirty-eight adult ewes was divided in two groups and synchronized with either progestagens (Group P) or prostaglandin analogues (Group PG). Immunohistochemistry was performed in uterine samples obtained from pregnant ewes (P, n=15; PG, n=13) on days 15 post coitus (pc), 17pc and 21pc (day 0 =day of estrus). Each factor was assessed by total vascular density (TVD, total positive blood vessels/mm2), capillary vascular density (CVD, positive blood capillaries/mm2) and arteriolar vascular density (AVD, positive arterioles/mm2). Group P demonstrated higher VEGF-CVD (P=0.045) when compared to prostaglandin treated animals. Vascular CD31-expression decreased on days 15pc and 21pc (TVD, P=0.007 and CVD, P=0.014) in both groups. vWF analysis did not show significant differences between groups or days of study. These results demonstrate a different influence of progestagen-based and prostaglandin analogues-based synchronization treatments over VEGF vascular expression during caruncular development taking place in response to pregnancy establishment. In addition, observations pointed out in this study support the involvement of CD31 in the angiogenic stimulus that occurs during early maternal placentation in the ewe.

Differences in uterine immunoexpression of PR, ERα and OTR when comparing prostaglandin- to progestagen-based protocols for ovine estrus synchronization.

The aim of this work was to compare PR, ERα and OTR uterine expression between days 9 and 21 of pregnancy in ewes whose estrus had been synchronized with two different protocols. Sixty-four adult Manchega ewes were synchronized with either conventional progestagens (P) or prostaglandin analogues (PG), and mated. Uterine samples were obtained from pregnant animals (group P, n=24; group PG, n=25) on days 9 post coitus (pc), 13pc, 15pc, 17pc and 21pc. Immunohistochemical detection of progesterone receptor (PR), estrogen receptor-α (ERα) and oxytocin receptor (OTR) was assessed in different uterine cell compartments including luminal and glandular epithelium, stroma and myometrium. Interaction day × treatment was obtained when assessing PR expression in the caruncular stroma (P=0.027) and myometrium (P=0.000), as well as for ERα in the superficial stroma (P=0.05). Significant "day post coitus" effect was found regarding to PR (P<0.01, with the exception of the superficial stroma, deep stroma and myometrium), ERα (P<0.01), and OTR (P<0.05, except in the deep compartments). No significant "treatment" effect was found for PR, ERα or OTR protein immunoexpression. This study supports the implication of PR, ERα and OTR within days 9-21 of the ovine pregnancy. Moreover, different expression pattern of PR and ERα proteins has been found between treatments in various compartments studied. Collectively, these results indicate that PR, ERα and OTR expression during early pregnancy is similar between ewes treated with either progestagens or prostaglandin analogues-based protocols for estrus synchronization.

Endometrial expression of IFNAR-1 and oxytocin receptor (OTR) is not improved by prostaglandin analogues when compared to progestagens in ewes.

The objective of this study was to investigate differences on the endometrial immunoexpression of type I IFN receptor subunit 1 (IFNAR1) and oxytocin receptor (OTR) during the time of maternal recognition of pregnancy in sheep, when oestrus is synchronized with either prostaglandin analogues (group PG) or conventional progestagens (group P). Plasma progesterone was measured from day 0 to 21 post-coitus (pc) (day 0 = day of oestrus). Immunohistochemistry was performed in samples of uterine horns from pregnant sheep on days 9pc, 13pc, 15pc, 17pc and 21pc to locate IFNAR1 and OTR expression in different endometrial compartments. Mean levels of plasma progesterone were different between treatments, obtaining higher levels in the PG group than in the P group (p < 0.05). Comparing days of pregnancy, IFNAR1 protein expression was different in the luminal epithelium (LE) (p < 0.05), while OTR was different in the LE and in the superficial glandular epithelium (SG) (p < 0.05). Temporal variation on the expression of both proteins from day 9pc to 21pc has been evidenced. IFNAR1 and OTR expression did not show significant differences between treatments. However, the response observed in the endometrium was highly inconsistent when prostaglandin analogues were used. Therefore, the protocol based on prostaglandin analogues still needs to be optimized before being considered as a better alternative to progestagens for oestrous synchronization in sheep.

Effects of oestrus induction with progestagens or prostaglandin analogues on ovarian and pituitary function in sheep.

The aim of the current study was to determine possible differences in ovarian and pituitary features explaining lower fertility rates in sheep with oestrus induced with intravaginal progestagens or prostaglandin analogues (group FGA and PGF, n=8 in both) when compared to a control group (group C, n=8). The growth profiles and the mean individual sizes of preovulatory follicles were similar between groups; however, the number of preovulatory follicles per ewe and, consequently, the number of ovulations were higher in groups FGA and PGF (2.3±0.3 and 2.0±0.1, respectively) than in group C (1.4±0.1, P<0.05). However, plasma oestradiol concentrations were similar between groups suggesting a defective function in some preovulatory follicles of groups FGA and PGF. In group FGA, the basal LH levels during the follicular phase were lower (0.21±0.0 ng/mL, P<0.005) than in groups C (0.41±0.1 ng/mL) and PGF (0.55±0.1 ng/mL); the onset of preovulatory discharge being later (21.0±2.3h vs. 12.8±1.5 in C and 14.5±1.5 in PGF; P<0.05 for both). Finally, luteal activity was also found to be affected in group FGA; the rate of progesterone secretion per total luteal tissue was lower (range: 0.46-0.65 ng/mL/cm(2)) than in ewes treated with cloprostenol (2.1-3.3 ng/mL/cm(2)) and control sheep (2.0-3.4 ng/mL/cm(2)).

Deleterious effects of progestagen treatment in VEGF expression in corpora lutea of pregnant ewes.

The aim of the current study was to determine the possible effects of progestagen oestrous synchronization on vascular endothelial growth factor (VEGF) expression during sheep luteogenesis and the peri-implantation period and the relationship with luteal function. At days 9, 11, 13, 15, 17 and 21 of pregnancy, the ovaries from 30 progestagen treated and 30 ewes cycling after cloprostenol injection were evaluated by ultrasonography and, thereafter, collected and processed for immunohistochemical evaluation of VEGF; blood samples were drawn for evaluating plasma progesterone. The progestagen-treated group showed smaller corpora lutea than cloprostenol-treated and lower progesterone secretion. The expression of VEGF in the luteal cells increased with time in the cloprostenol group, but not in the progestagen-treated group, which even showed a decrease between days 11 and 13. In progestagen-treated sheep, VEGF expression in granulosa-derived parenchymal lobule capillaries was correlated with the size of the luteal tissue, larger corpora lutea had higher expression, and tended to have a higher progesterone secretion. In conclusion, the current study indicates the existence of deleterious effects from exogenous progestagen treatments on progesterone secretion from induced corpora lutea, which correlate with alterations in the expression of VEGF in the luteal tissue and, this, presumably in the processes of neoangiogenesis and luteogenesis.

Substantiation of ovarian effects of leptin by challenging a mouse model of obesity/type 2 diabetes.

The goal of the current was to elucidate if treatment with gonadotrophins and leptin can circumvent infertility in obese mice and to establish whether reproductive effects of leptin are influenced at the hypothalamus-hypophysis or ovarian level by using a leptin deficient mouse model of obesity/type 2 diabetes (ob/ob) treated with leptin. The ovulatory response and the fertilization success were compared with the results obtained in ob/ob dams pretreated with a gonadotrophin-replacement therapy or in two groups (ob/ob and wild-type) of control non-pretreated females. The number of corpora lutea was significantly lower in control ob/ob mice than in wild-type dams. Treatment with gonadotrophin-replacement therapy did not increase significantly the ovulation rate in ob/ob, but the administration of leptin-replacement treatment allowed the authors to obtain a number of corpora lutea and oocytes/zygotes similar to those obtained in wild-type females. Furthermore, the leptin supply succeeded in producing fertilized zygotes, although in a lower number than found in the wild-type control. Thus, the hypogonadotrophic state in obese mice may be circumvented by the administration of a gonadotrophin-replacement therapy combined with a protocol for controlled ovarian stimulation, but fertile ovulations are only obtained after applying leptin-replacement therapy. Current results strongly support the existence of direct local effects of leptin on the ovary.

Mammary tumor phenotypes in wild-type aging female FVB/N mice with pituitary prolactinomas.

Prolactin-secreting pituitary adenomas are common spontaneous lesions in aging FVB females. Prolactin-secreting pituitary proliferations play a significant role in mouse mammary tumorigenesis generally producing adenosquamous carcinomas. Since genetically engineered FVB mice are frequently used to study mammary tumor biology, we have examined a cohort of 64 aging wild-type FVB/N females to establish the prevalence and the nature of spontaneous mammary and pituitary tumors. Tissues from mammary and pituitary glands were studied by histopathology and immunohistochemistry. Of the 64 examined mice, 20 had pituitary tumors and 20 had mammary tumors. Mammary and pituitary tumors were associated in 17 mice. All pituitary tumors were prolactin-positive by immunohistochemistry and classified as prolactinomas. Fourteen mammary tumors, including 12 cases with and 2 without concurrent prolactinomas, were adenocarcinomas with different combinations of epithelial growth patterns. Five mice with prolactinomas had mammary tumors characterized by the epithelial-mesenchymal transition (EMT) phenotype. Estrogen receptor alpha (ERalpha)-positivity was observed for 14 of the 18 mammary tumors tested, including both adenocarcinomas with nuclear immunoreactivity and EMT-phenotype tumors with both nuclear and cytoplasmic immunoreactivity. No immunoreactivity for the progesterone receptor was observed. This study confirms that spontaneous prolactinomas and mammary tumors are both common and significantly associated lesions in FVB mice. Parity and age represented risk factors for the development of these tumors. Compared with previous reports, prolactinoma-associated mammary tumors displayed a broader morphologic spectrum, including cases with the EMT phenotype. The elevated number of prolactinoma-associated and ERalpha-positive mammary tumors opens intriguing possibilities concerning the role of ERalpha cytoplasmic localization during EMT tumorigenesis.

Ovarian follicular dynamics and plasma steroid concentrations are not significantly different in ewes given intravaginal sponges containing either 20 or 40 mg of fluorogestone acetate.

Although various progestagens are often used to induce and synchronize estrus and ovulation in ruminants, concerns regarding residues are the impetus to develop alternative approaches, including reduced doses of progestagens. Therefore, the objective was to determine whether ovarian function was affected by halving the dose of fluorogestone acetate in intravaginal sponges for synchronizing ovulation in sheep during the physiologic breeding season. Twenty Manchega ewes, 4-6-year-old, were randomly allocated to receive an intravaginal sponge containing either 20mg (P20, n=10) or 40 mg of fluorogestone acetate (P40, n=10). Cloprostenol (125 microg) was given at sponge insertion, and all sponges were removed after 6d. Ovarian follicular dynamics (monitored by daily ultrasonography) and other aspects of ovarian function did not differ significantly between the two groups. Ovulatory follicles (OF) grew at a similar growth rate (r=0.62; P<0.001), with comparable initial and maximum diameters (4.2+/-0.4 to 6.0+/-0.3mm in P20 vs. 4.6+/-0.6 to 5.7+/-0.2 mm in P40, mean+/-S.E.M.). Plasma estradiol concentrations (determined once daily) increased linearly during the 72 h interval after sponge removal (1.3+/-0.1 to 3.3+/-0.1 pg/mL for P20, P<0.005 and 1.4+/-0.1 to 3.1+/-0.2 pg/mL for P40, P<0.005). Ten days after sponge removal, ovulation rates (1.2+/-0.2 for P20 and 1.4+/-0.3 for P40), and plasma progesterone concentrations (3.8+/-0.35 ng/mL for P20 and 3.9+/-0.38 ng/mL for P40) were similar. In conclusion, reducing the dose of fluorogestone acetate from 40 to 20mg did not affect significantly ovarian follicular dynamics or other aspects of ovarian function.

Histopathological and immunohistochemical characteristics of two canine lipid-rich mammary carcinomas.

Clinicopathological and immunohistochemical findings of two uncommon canine lipid-rich mammary carcinomas are described. The predominant histological feature in both tumours was the presence of at least 80% of cells with intracytoplasmic vacuoles which stained positively with Sudan IV but not with alcian-blue periodic acid-schiff method. In both tumours, small groups of non-vacuolated cells were identified among the vacuolated cells. However, histological and immunohistochemical differences were also found between these tumours. Thus, one of them was composed of tumour cells with a large and single vacuole, which were arranged in lobular pattern, while the other neoplasm showed an intraductal growth of tumour cells with a fine vacuolated cytoplasm. Immunohistochemically, in the first tumour most vacuolated cells were positive for CK (cytokeratin)8-7, indicating a secretory epithelial immunophenotype while CK5 and CK8-7-expressing non-vacuolated cells were associated with luminal duct immunophenotype. However, in the second tumour the expression of CK14 in most of vacuolated cells and alpha-smooth muscle actin (alpha-SMA) in non-vacuolated cells, alone or in combination with CK5 suggested a myoepithelial immunophenotype for both cell types. These results suggest heterogeneity of the cell type and growth pattern for this type of canine tumour as has been described in women but not in dogs.

Biological characterization of ovarian granulosa cell tumours of slaughtered cattle: assessment of cell proliferation and oestrogen receptors.

Of 1489 slaughtered cattle, 11 had ovarian granulosa cell tumours (GCTs). These GCTs were examined immunohistochemically for proliferating cell nuclear antigen (PCNA) and oestrogen receptor (ER) in relation to histopathological features (growth pattern, nuclear atypia and mitotic count). On the basis of nuclear atypia and mitotic count, the prognosis for GCTs with a diffuse growth pattern appeared less favourable than that for GCTs with a follicular or trabecular pattern. Increased PCNA expression was significantly associated with nuclear atypia but not with histological growth pattern or mitotic count. A novel finding was the presence of ERbeta but not ERalpha in bovine ovarian GCTs. However, ERbeta expression did not appear to be related to the histopathological features examined. The results indicate that PCNA expression may be of value in establishing the biological behaviour of bovine GCTs. However, a larger series of bovine GCTs should be examinated to assess the prognostic significance of ERbeta.

Expression of cytokeratins and vimentin in normal and neoplastic tissue from the bovine female reproductive tract.

The distribution of cytokeratins (CKs) and vimentin in the normal genital tract of calves and cows at different stages of the oestrous cycle and in epithelial tumours of the tract was studied immunohistochemically. Few differences in CK and vimentin immunolabelling were detected in relation to age or stage of the oestrous cycle. Coexpression of CKs in simple epithelia and in basal cells of stratified epithelia was detected in the oviduct and endocervix; this coexpression was different from that previously described in women. The demonstration of CKs but not vimentin in the neoplastic cells of a serous superficial ovarian papilloma suggested an origin from the ovarian surface epithelium, while the coexpression of CKs and vimentin in serous papillary and mucinous cystadenomas pointed to a possible origin from the rete ovarii. Studies on three uterine adenocarcinomas and the ovarian metastases from two of these showed an endometrial-CK phenotype. The intermediate filament profile of normal endometrium, conserved in uterine adenocarcinomas and their ovarian metastases, may be useful in discriminating between ovarian metastases from endometrial carcinomas and those originating from primary carcinomas in other organs.

Effects of retinoic acid exposure in utero on mouse vibrissal follicle development.

It is known that topical all-trans-retinoic acid (RA) modulates growth and differentiation of skin and its cutaneous appendages. To examine whether a pre-natal exposure to a potentially non-teratogenic dosage of all-trans-RA had any effect on vibrissal follicle development, the histologic and immunohistochemical responses to RA during its morphogenesis in NMRI mouse were investigated. After a single oral dose of 30 mg/kg body weight of all-trans-RA on day 11.5 of gestation, no fetal malformations were detected and the histological features and the distribution of keratin (K) proteins in comparable stages of vibrissal development were similar for the untreated, vehicle-treated and RA-treated mice. The absence of teratogenic response and of adverse effects on the vibrissae under the experimental conditions indicates that this protocol may be useful for investigation of the effects of pre-natal exposure to RA on the post-natal development of experimental tumours in the mouse skin.

Malignant fibrous histiocytoma (giant cell type) associated with a malignant mixed tumor in the salivary gland of a dog.

A 12-year-old male Boxer dog presented with a 5 x 5 x 7-cm partially encapsulated mass in the right mandibular salivary gland. Histologically, the mass was composed of neoplastic epithelial and mesenchymal cells. The mesenchymal component consisted of two cell populations arranged in different patterns: coalescing nodules of neoplastic mononuclear cells with rare osteoid and numerous osteoclastlike giant cells; and sheets of neoplastic spindle cells intermingled with neoplastic epithelial cells and containing osteoid and well-formed bone trabeculae lined by osteoblasts and few osteoclastlike giant cells. On the basis of these histological features, two malignant salivary tumors were diagnosed: a malignant fibrous histiocytoma (giant cell type) and a malignant mixed tumor. Immunohistochemical studies demonstrated keratin 5 and 8 expression by the neoplastic epithelial cells, indicating a probable salivary ductal origin, and vimentin expression by all mesenchymal elements, suggesting a fibroblastic line of differentiation.

Optimization of the immunohistochemical demonstration of keratins in paraffin wax-embedded mouse skin.

The purpose of this study was to develop an immunoperoxidase technique for the detection of cytokeratins in samples of paraffin wax-embedded adult and fetal skin from NMRI mice, with various antibodies (Troma-1, LL001, 8.60, MCK5, MCK6, AF129) that have been tested mainly on fresh-frozen sections. Each antibody was tested with three different fixatives (10% neutral buffered formalin, Bouin's fluid, and 70% ethanol) and two distinct pretreatments (enzymatic digestion with trypsin, or heat treatment). The best results, in terms of non-specific background labelling, morphological preservation and intensity of specific labelling, were obtained (1) for adult skin, by the use of Bouin's fluid, heat pretreatment and antibodies LL001, MCK5, MCK6 or AF129, and (2) for fetal skin, by the use of 70% ethanol, heat pretreatment and antibody Troma-1. Monoclonal antibody 8.60 gave the best results when the use of 70% ethanol was combined with either enzymatic digestion or heat pretreatment.