Morphological analysis of patchy thickening and reddish discoloration of active hair growth areas in the skin of New Zealand White rabbits.

Patchy thickening and reddish discoloration of active hair growth areas of skin in rabbits are occasionally found, and this gross feature could affect precise evaluation when conducting a dermal irritation test. Since little is known about the mechanism of this phenomenon, we examined the dorsal skin of New Zealand White rabbits morphologically and immunohistochemically in order to identify the possible mechanism responsible for developing these skin changes in relation to the hair cycle. Skin samples from 4 rabbits were divided into three groups (5 samples/group) based on their macroscopic characteristics: a thickened skin, erythematous skin, and smooth skin group. Histomorphological examination revealed that the percentage of hair follicles in the anagen phase, hair follicle length, hair follicle area, and proliferating cell nuclear antigen-positive cells in the hair follicles were greater in the thickened skin and erythematous skin groups than in the smooth skin group. Unlike mice and rats, the dermis was nearly adjacent to the muscular layer with a thin hypodermis, and the whole lengths of hair follicles in the anagen phase were located in the dermis in the rabbit skin. These results suggest that large hair follicles in the anagen phase compressed the surrounding dermis; therefore, the skin was grossly raised and showed thickening. A higher number of CD31-positive blood vessels, suggesting the occurrence of angiogenesis, was observed around the hair follicles in the erythematous skin group, and they seemed to affect the reddish discoloration of skin noted grossly.

Influence of the estrus cycle on the evaluation of a vaginal irritation study in intact and ovariectomized rats.

When conducting vaginal irritation studies, ovariectomized rats or rabbits are typically used according to practical reports. In the present study, we evaluated the influence of the estrus cycle in a vaginal irritation study using intact rats and ovariectomized rats, which exhibit a late diestrus-like condition, to determine whether intact rats can be useful for evaluating vaginal irritancy. Rats were divided into 4 groups: proestrus, estrus, and metestrus or diestrus in intact rats and ovariectomized rats. All the rats in each group were treated with a vehicle or sodium dodecyl sulfate, as the irritant, in single-dose and 4-day repeat-dose vaginal irritation studies. Each rat's vagina was examined histopathologically, and the irritation score was calculated using a semiquantitative scoring system. In the single-dose study, the irritation scores for the proestrus or ovariectomized groups treated with sodium dodecyl sulfate were higher than those of the estrus group or metestrus or diestrus group. In the 4-day repeat-dose study, a significant histopathological difference was not found among the intact rats (proestrus, estrus, and metestrus or diestrus groups), and the irritation score range of the intact rats was similar to that of the ovariectomized rats, though the mean score of the intact rats was slightly lower than that of the ovariectomized rats. These results suggest that intact rats might be well suited for 4-day vaginal irritation studies and useful for evaluating vaginal irritancy using not only the mean score, but also individual irritation score ranges, whereas the estrus cycle would need to be identified in single-dose vaginal irritation studies.

Evaluation of potential activity of luseogliflozin on vascular proliferation in the mesenteric lymph node with or without vascular tumors in Sprague-Dawley rats in a carcinogenicity study.

The incidence of mesenteric lymph node vascular tumors can vary in rats, and appropriate assessment of potential risk of tumorigenicity is needed when the incidence is higher in treated groups than in a control group. In a 2-year rat carcinogenicity study of luseogliflozin, a selective sodium-dependent glucose co-transporter 2 inhibitor for the treatment of type 2 diabetes mellitus, there was a slight but statistically significant increase in the total number of hemangiomas and hemangiosarcomas in the mesenteric lymph nodes in males at a high-dose. As part of the risk assessment for luseogliflozin, its effect on the vascular proliferation potential in the mesenteric lymph nodes was examined in a rat carcinogenicity study by performing an image analysis using specimens with double immunohistochemical staining for PCNA and CD34 in control and high-dose males. In addition, immunohistochemical staining for VEGF was performed to detect enhanced angiogenesis. In the high-dose males that did not have a hemangioma/hemangiosarcoma, neither an increased number of PCNA/CD34-positive cells nor changes in the expression pattern of VEGF was observed. On the other hand, in the high-dose males that had a hemangioma/hemangiosarcoma, the number of PCNA-positive cells was increased in the tumor areas, and the number in the hemangioma/hemangiosarcoma was approximately one-half of that in the hemangiosarcoma in the control male. In conclusion, no potential change leading to vascular proliferation/tumors was detected in the mesenteric lymph nodes of high-dose males receiving luseogliflozin.

Regulation of adipocyte differentiation of 3T3-L1 cells by PDZRN3.

PDZRN3, a member of the PDZRN (or LNX) family of proteins, is essential for the differentiation of mesenchymal stem cells into myotubes, but it plays an inhibitory role in the differentiation of these cells into osteoblasts. Given that mesenchymal stem cells also differentiate into adipocytes, we examined the possible role of PDZRN3 in adipogenesis in mouse 3T3-L1 preadipocytes. The expression of PDZRN3 decreased at both the mRNA and protein levels during adipogenic differentiation. RNAi-mediated depletion of PDZRN3 enhanced the differentiation of 3T3-L1 cells into adipocytes as assessed on the basis of lipid accumulation. The upregulation of aP2 and CCAAT/enhancer-binding protein (C/EBP)-ß during adipocyte differentiation was also enhanced in the PDZRN3-depleted cells, as was the induction of peroxisome proliferator-activated receptor-γ (PPARγ), an upstream regulator of aP2 and C/EBPα, at both the mRNA and protein levels. Among transcription factors that control the expression of PPARγ, we found that STAT5b, but not STAT5a, was upregulated in PDZRN3-depleted cells at both mRNA and protein levels. Tyrosine phosphorylation of STAT5b, but not that of STAT5a, was also enhanced at an early stage of differentiation by PDZRN3 depletion. In addition, the expression of C/EBPß during the induction of differentiation was enhanced at the mRNA and protein levels in PDZRN3-depleted cells. Our results thus suggest that PDZRN3 negatively regulates adipogenesis in 3T3-L1 cells through downregulation of STAT5b and C/EBPß and consequent suppression of PPARγ expression.

PDZRN3 negatively regulates BMP-2-induced osteoblast differentiation through inhibition of Wnt signaling.

PDZRN3 is a member of the PDZ domain-containing RING finger family of proteins. We previously showed that PDZRN3 is essential for the differentiation of C2C12 mouse mesenchymal progenitor cells into myotubes. Mesenchymal progenitor cells differentiate into osteoblasts, chondrocytes, and adipocytes in addition to myotubes, and we have now examined the potential role of PDZRN3 in the differentiation of C2C12 cells into osteoblasts. The abundance of PDZRN3 in C2C12 cells was increased after the induction of osteoblast differentiation by exposure to bone morphogenetic protein (BMP)-2 in low-serum medium. Depletion of PDZRN3 in C2C12 cells by RNA interference resulted in marked enhancement of the BMP-2-induced up-regulation of alkaline phosphatase (ALP) activity. Dkk1, an inhibitor of Wnt signaling, markedly attenuated the enhancement of the BMP-2-induced increase in ALP activity by PDZRN3 depletion. The up-regulation of ALP activity by Wnta3a was also promoted by depletion of PDZRN3. Furthermore, the expression and Wnt3a-induced phosphorylation of LRP6 as well as the increase in the cytosolic abundance of ß-catenin induced by Wnt3a were potentiated in PDZRN3-depleted cells. These results indicate that PDZRN3 plays an important role in negative feedback control of BMP-2-induced osteoblast differentiation in C2C12 cells through inhibition of Wnt-ß-catenin signaling.

Cytokine receptor-like factor 1 is highly expressed in damaged human knee osteoarthritic cartilage and involved in osteoarthritis downstream of TGF-beta.

Osteoarthritis (OA) is the most prevalent joint disease and is characterized by pain and functional loss of the joint. However, the pathogenic mechanism of OA remains unclear, and no drug therapy for preventing its progress has been established. To identify genes related to the progress of OA, the gene expression profiles of paired intact and damaged cartilage obtained from OA patients undergoing joint substitution were compared using oligo microarrays. Using functional categorization combined with gene ontology and a statistical analysis, five genes were found to be highly expressed in damaged cartilage (HBEGF, ASUS, CRLF1, LOX, CDA), whereas three genes were highly expressed in intact tissues (CHST2, PTPRD, CPAN6). Among these genes, the upregulated expression of CRLF1 was reconfirmed using real-time PCR, and the in vivo expression of CRLF1 was detected in clusters of chondrocytes and fibrocartilage-like cells in damaged OA cartilages using in situ hybridization. In vitro, the transcriptional level of CRLF1 was positively regulated by TGF-beta1 in the mouse chondrogenic cell line ATDC5. Additionally, the CRLF1/CLC complex promoted the proliferation of ATDC5 cells and suppressed the expression level of aggrecan and type II collagen. Our data suggest that the CRLF1/CLC complex disrupts cartilage homeostasis and promotes the progress of OA by enhancing the proliferation of chondrocytes and suppressing the production of cartilage matrix. A component of the complex, CRLF1, may be useful as a biomarker of OA; and the corresponding receptor is a potential new drug target for OA.

Calcitonin induces connective tissue growth factor through ERK1/2 signaling in renal tubular cells.

Calcitonin (CT), a polypeptide hormone, plays important roles in a variety of physiological processes. CT has been used clinically to treat osteoporosis and humoral hypercalcemia of malignancy. In order to clarify the pharmacological effects of CT in the kidney, we identified potential downstream genes induced by CT in the renal cells. Using a cDNA subtraction hybridization method, we identified connective tissue growth factor (CTGF) as a CT-induced gene in the porcine renal cell line, LLC-PK1. Furthermore, we found that CT-mediated induction of the gene was not inhibited by cycloheximide, which suggests that CTGF gene was not induced by an increased synthesis of regulating proteins. Therefore, CTGF is an immediate early gene. We further demonstrated that the regulation of CTGF gene expression by CT involved the ERK1/2 pathway, because PD98059, a MEK1 inhibitor, partially inhibited the mRNA expression of CTGF induced by CT. CT-induced CTGF protein expression was also observed in vivo. Our present findings suggest that CT induces the transcription of CTGF through ERK1/2 phosphorylation. We also identified twelve other genes induced by CT that, like CTGF, were related to wound healing. These results suggest that CT may have an effect on renal differentiation and wound healing in the kidney.

Downregulated expression in high IgA (HIGA) mice and the renal protective role of meprinbeta.

This study discusses the critical role of the metalloproteinase meprinbeta in the progression of glomerulonephritis. Using a microarray technique, the gene expression profiles in glomeruli isolated from high serum IgA (HIGA) mice with a purity of 97% or greater were examined. HIGA mice are a valid model of human IgA nephropathy (IgAN), with the typical pathological features of this condition, including a consistently high serum IgA level as well as dominant mesangial IgA deposition and mesangial enlargement. Among the many upregulated/downregulated genes after the development of IgAN, the downregulation of meprinbeta was intriguing. The expression level of the meprinbeta gene at 40 weeks of age was 52% of that observed at 8 weeks of age (prior to the development of IgAN), although in the control BALB/c mice, a 2.19-fold elevation was seen. These results were also confirmed by semi-quantitative RT-PCR and immunostaining analyses. As meprinbeta is a subunit of metalloproteinase meprins (meprin A, meprin B) and meprins are capable of proteolytically degrading extracellular matrix (ECM) components and proteolytically processing bioactive peptides, the downregulation of meprinbeta may contribute to the progression of glomerulonephritis and the eventual glomerular scarring. This working hypothesis was examined using an in vivo meprinbeta inhibition study. The inhibition of meprins by actinonin exacerbated some parameters of renal injury in mice afflicted with anti-glomerular basement membrane (anti-GBM) antibody-associated nephritis. These in vitro and in vivo results suggest that meprinbeta may play a protective role against the progression of renal injury through the degradation of ECM and bioactive peptides.

Suppression of renal alpha-dicarbonyl compounds generated following ureteral obstruction by kidney-specific alpha-dicarbonyl/L-xylulose reductase.

Renal unilateral ureteral obstruction (UUO) causes acute generation of alpha-dicarbonyl stress substances, such as glyoxal, 3-deoxyglucosone, and methylglyoxal, in the kidneys. These alpha-dicarbonyl compounds are prone to form advanced glycation end products (AGEs) via the nonenzymatic Maillard reaction. Using transgenic (Tg) mice overexpressing a kidney-specific short-chain oxidoreductase, alpha-dicarbonyl/L-xylulose reductase (DCXR), we measured generation of alpha-dicarbonyls following UUO by means of electrospray ionization/liquid chromatography/mass spectrometry in their kidney extracts. The accumulation of 3-deoxyglucosone was significantly reduced in the kidneys of the mice Tg for DCXR compared to their wild-type littermates, demonstrating 4.91 +/- 2.04 vs. 6.45 +/- 1.85 ng/mg protein (P = 0.044) for the obstructed kidneys, and 3.68 +/- 1.95 vs. 5.20 +/- 1.39 ng/mg protein (P = 0.026) for the contralateral kidneys. Despite the reduction in accumulated alpha-dicarbonyls, collagen III content in kidneys of the Tg mice and their wild-type littermates showed no difference as monitored by in situ hybridization. Collectively, DCXR may function in the removal of renal alpha-dicarbonyl compounds under oxidative circumstances, but it is not sufficient to suppress acute renal fibrosis during 7 days UUO.

Selective loss of nigral dopamine neurons induced by overexpression of truncated human alpha-synuclein in mice.

Parkinson's disease is characterized by loss of nigral dopaminergic neurons and presence of Lewy bodies, whose major component is alpha-synuclein. In the present study, we generated transgenic mice termed Syn130m that express truncated human alpha-synuclein (amino acid residue number: 1-130) in dopaminergic neurons. Notably, dopaminergic neurons were selectively diminished in the substantia nigra pars compacta of Syn130m, while transgenic mice that expressed comparable amount of full-length human alpha-synuclein did not develop such pathology. Therefore, the truncation of human alpha-synuclein seems to be primarily responsible for the loss of nigral dopaminergic neurons. The nigral pathology resulted in impairment of axon terminals in the striatum and concomitant decrease in striatal dopamine content. Behaviorally, spontaneous locomotor activities of Syn130m were reduced, but the abnormality was ameliorated by treatment with L-DOPA. The loss of nigral dopaminergic neurons was not progressive and seemed to occur during embryogenesis along with the onset of expression of the transgene. Our results indicate that truncated human alpha-synuclein is deleterious to the development and/or survival of nigral dopaminergic neurons.

Early induction of osteoactivin expression in rat renal tubular epithelial cells after unilateral ureteral obstruction.

In this study, we examined the expression of osteoactivin in the rat kidney after unilateral ureteral obstruction. Male Wistar rats were sacrificed at 6h, and on days 1, 2, 3 and 7 after the obstruction. The renal tubular lumens gradually dilated, and marked interstitial fibrosis was confirmed histologically on day 3 after the obstruction. The expressions of osteoactivin and collagen type III were examined by quantitative real-time RT-PCR. An 8-fold increase in osteoactivin mRNA expression as compared with that in the sham-operated group was observed at 6h after the obstruction, whereas no elevation of collagen type III mRNA expression was observed at this early stage. Furthermore, semi-quantitative RT-PCR was performed to identify upregulation of expression of matrix metalloproteinase-13 mRNA relative to that in the sham-operated control, and normalized to the expression level of beta-actin. Intense osteoactivin expression localized in the dilated tubular epithelium and interstitial fibroblasts in the obstructive kidney was detected by immunohistochemistry and by in situ hybridization. These results suggested that the early-phase upregulation of osteoactivin expression in the tubular epithelium in response to renal injury might play a role in triggering renal interstitial fibrosis via activation of matrix metalloproteinase expression and collagen remodeling in rats.

Accumulation of phosphorylated alpha-synuclein in dopaminergic neurons of transgenic mice that express human alpha-synuclein.

Parkinson's disease is neuropathologically characterized by the presence of Lewy bodies, whose major component is alpha-synuclein. We had previously generated transgenic mice that expressed human alpha-synuclein carrying an Ala53Thr point mutation (halpha-syn140m) under the control of the rat tyrosine hydroxylase promoter and found that halpha-syn140m was localized not only in the cytoplasm but also in the nuclei of mesencephalic dopaminergic neurons. In the present study, we carried out immunohistochemical analysis of the brain of Tg mice using anti-PSer129, an antibody that specifically recognizes alpha-synuclein phosphorylated at Ser129. The antibody detected only phosphorylated halpha-syn140m, whereas phosphorylation of endogenous alpha-synuclein, if any, was below the detection limit of the method employed. The analysis showed that approximately one-third of the halpha-syn140m-positive neurons in the midbrain of heterozygous Tg mice were concomitantly reactive to anti-PSer129. The ratio almost doubled in homozygotes, indicating that the phosphorylation level depends directly on the amount of substrate. In addition, the ratio did not change at least up to 48 weeks of age. These data strongly suggest that halpha-syn140m underwent constitutive phosphorylation and that the phosphorylation level was maintained to a certain level until the aged stages. Remarkably, halpha-syn140m localized in the nuclei seemed to be preferentially phosphorylated compared with that in the cytoplasm. Among kinases that have been reported to be involved in the phosphorylation of alpha-synuclein, the beta subunit of casein kinase-2 was detected in the nuclei by immunohistochemistry. These data imply that at least casein kinase-2 is involved in the phosphorylation of halpha-syn140m in the Tg mice.

Molecular pathological evaluation of clusterin in a rat model of unilateral ureteral obstruction as a possible biomarker of nephrotoxicity.

In the present study, to determine the validity of considering clusterin as a possible biomarker of nephrotoxicity, the expression and distribution of clusterin in the rat UUO kidney were investigated. Real-time RT-PCR revealed an immediate increase in the clusterin mRNA level in the kidney, within 6 hours after UUO, and also maintenance of the mRNA expression level from day-1 to day-3 was 60-fold higher in the UUO kidney than in the sham kidney. ISH analysis revealed clusterin mRNA signals in the UUO renal tubular epithelium, whereas no signal was observed in the sham kidney. Detection of clusterin-alpha and -beta was conducted using the subtype-specific antibodies, by both of western blotting and immunohistochemistry. Although clusterin-alpha was predominant in the UUO urine, only faint signals were noted at the brush border of the tubular epithelium or intraductal. On the other hand, strong signals of clusterin-beta were detected in the UUO kidney homogenate, and the molecule was localized in the renal tubular epithelium. These results suggest that clusterin was translated in the renal tubular epithelium after de novo expression induced by renal injury. Thus, detection of clusterin mRNA and clusterin-beta in the kidney or clusterin-alpha in the urine may be useful for predicting nephrotoxicity.

Suppression of AGE precursor formation following unilateral ureteral obstruction in mouse kidneys by transgenic expression of alpha-dicarbonyl/L-xylulose reductase.

Unilateral ureteral obstruction (UUO) of kidneys causes acute generation of carbonyl stress. By electrospray ionization/liquid chromatography/mass spectrometry (ESI/LC/MS) we measured the content of methyl glyoxal, glyoxal, and 3-deoxyglucosone in mouse kidney extracts following UUO. UUO resulted in elevation of these dicarbonyls in the obstructed kidneys. Furthermore, the accumulation of 3-deoxyglucosone was significantly reduced in the kidneys of mice transgenic for alpha-dicarbonyl/L-xylulose reductase (DCXR) as compared to their wild-type littermates, demonstrating 4.91+/-2.04 vs. 6.45+/-1.85 ng/mg protein (P=0.044) for the obstructed kidneys, and 3.68+/-1.95 vs. 5.20+/-1.39 ng/mg protein (P=0.026) for the contralateral kidneys. On the other hand, collagen III content in kidneys showed no difference as monitored by in situ hybridization. Collectively, DCXR may function in the removal of renal alpha-dicarbonyl compounds under oxidative circumstances, but it was not sufficient to suppress acute renal fibrosis during 7 d of UUO by itself.

Expression of calcitonin receptor in rat mammary gland during lactation.

Calcitonin (CT) and calcitonin receptor (CTR) have been reported to play an important role in mammary tissue during pregnancy, lactation, and involution. In the present study, the expression and distribution of CTR mRNA in rat mammary tissue during pregnancy and lactation were investigated. As measured by real-time RT-PCR, CTR mRNA levels were increased only slightly during pregnancy, but increased markedly immediately postpartum and remained elevated through lactation, with the highest levels observed 14 days postpartum. In situ hybridization analysis showed that intense CTR mRNA signals were detected in the whole mammary gland. We performed immunohistochemistry to determine distribution of CTR in the mammary epithelium. CTR has been reported to act as an amylin receptor when heterodimerized with receptor activity modifying protein-1 (RAMP1) or RAMP3. mRNA expression of RAMP1 and RAMP3 in mammary tissue decreased during pregnancy and lactation, and amylin mRNA was undetectable, suggesting that up-regulated CTR in lactating mammary tissues binds CT rather than amylin. In primary cultures of mammary cells isolated from rat dams 14 days postpartum, CT produced a statistically significant decrease in thymidine incorporation. These results suggest that up-regulation of CTR during lactation may contribute to inhibition of mammary epithelial cell proliferation.

Calcitonin inhibits invasion of breast cancer cells: involvement of urokinase-type plasminogen activator (uPA) and uPA receptor.

There is a growing body of evidence indicating that calcitonin (CT) and calcitonin receptor (CTR) are involved in the regulation of cell growth, differentiation, and survival and in tissue development. However, the precise functional role of CT/CTR in breast cancer is still unknown. It is well established that the urokinase plasminogen activator (uPA) system plays an important role in breast cancer invasion and metastasis. The goal of this study was to investigate the effects of CT on regulation of the uPA system and invasive capacity of breast cancer cells. In the highly invasive MDA-MB-231 cell line, 10(-8) M CT decreased both uPA and uPAR mRNA and protein expression which was associated with inhibition of the extracellular signal-regulated kinase (ERK) 1/2 pathway. Furthermore, two weeks of CT administration to nude mice inhibited the expression of uPA mRNA in primary tumors by 25% (P<0.05), as compared to control, untreated animals. CT also inhibited the invasiveness of MDA-MB-231 cells by 37% (10(-8) M CT, P<0.05), as determined by a Matrigel invasion assay. To the best of our knowledge, this is the first report describing a direct effect of CT on breast cancer cell invasion. Our data might suggest a close link between CT signaling, the uPA-mediated pathway, and breast cancer invasion.

Transgenic mice over-expressing dicarbonyl/L-xylulose reductase gene crossed with KK-Ay diabetic model mice: an animal model for the metabolism of renal carbonyl compounds.

Carbonyl compounds in the blood stream tend to accumulate in the kidney of diabetic or end stage renal failure subjects. Previously we isolated cDNA encoding dicarbonyl/L-xylulose reductase (DCXR) from a mouse kidney cDNA library. In the present study, transgenic (Tg) mice were generated to study the functional role of DCXR in the kidney. With a six-fold increase in the DCXR protein expression levels in the kidney, the homozygous Tg mice did not show any notable histological abnormalities. While the elevated DCXR expression was observed throughout the body, its renal distribution was similar to that of the endogenous DCXR protein, namely, the major expression site was the collecting tubules, along with moderate expression in other tubules and Bowman's capsule, but it was absent from the interstitial area and glomeruli. The Tg mice were crossed with KK-A(y) diabetic model mice to examine the role of DCXR in the progression of diabetic nephropathy. The resulting progeny, Tg/A(y), showed lighter body weight, lower levels of blood glucose, water uptake and creatinine clearance compared to their +/A(y) littermates. Although remarkable pathological differences were not observed at the microscopic level and in the renal accumulation of carboxymethyl lysine, the data imply that DCXR might function in the metabolism of glucose or carbonyl compounds, and play a protective role in a kidney which is under hyperglycemic pressure. The DCXR Tg mice and the Tg x KK-A(y) hybrid mice, therefore, serve as specific models for carbonyl metabolism in the kidney with diabetic background.

Ultrastructure of goblet-cell metaplasia from Clara cell in the allergic asthmatic airway inflammation in a mouse model of asthma in vivo.

Mucus overproduction from goblet cells, a characteristic feature of the allergic asthmatic inflammation induced by ovalbumin (OVA) in mice, was examined morphologically. In OVA-untreated (normal) mice, there were no goblet cells in intrapulmonary bronchus and bronchiole. However, goblet cells with or without hyperplasia in the mucosa of inflamed bronchus-bronchiole were recognized in the allergic asthmatic mice. The non-ciliated epithelium containing electron lucent granules (mucus) showed many similarities to Clara cells, which have characteristic secretory granules and many mitochondria, except for the less-developed smooth endoplasmic reticulum seen in normal mice. Ciliated Clara cells with or without mucus were rarely recognized. In addition, mucus was found in neither ciliated nor basal epithelium. The present study suggests that goblet-cell metaplasia in the bronchus and bronchiole of inflamed mucosa may be derived, at least in part, from Clara cells.

Significance of hormone receptor status and tumor vessels in normal, hyperplastic and neoplastic endometrium.

The aims of this study were to identity the roles of tumor vessels and hormone receptor status in normal, hyperplastic, and neoplastic endometrium, and to explore their relationships with other prognostic factors of endometrial adenocarcinoma. Endometrial curettage specimens of proliferative phase and secretory phase endometrium, simple hyperplasia with or without atypia, complex hyperplasia with or without atypia, and grade 1 adenocarcinoma were examined for estrogen receptor alpha (ER alpha), progesterone receptor (PgR), Ki-67 labeling index (LI), cyclin D1, microvessel density (MVD), and area of venules (AV) using an immunoperoxidase method. The results showed high levels of ER alpha in complex hyperplasia, and high levels of PgR in simple hyperplasia without atypia. Expression of ER alpha in the endometrium decreased in a stepwise manner from complex hyperplasia without atypia to grade 1 adenocarcinoma. Expression of PgR in the endometrium decreased in a stepwise manner from simple hyperplasia without atypia to grade 1 adenocarcinoma. In contrast, the expressions of Ki-67 LI, cyclin D1, MVD and AV in the endometrium increased in a stepwise manner from normal, simple or complex hyperplasia with or without atypia to grade 1 adenocarcinoma. These changes may become irreversible on progression from simple or complex hyperplasia to neoplasia.