Studies on leptin and leptin receptor gene expression in myometrium and uterine myomas of gnRH analogue-treated women

AIM: To test if treatment with GnRH analogue, which leads to a significant reduction in myoma volume, changes expression of leptin genes and gene coding leptin receptor isoforms in uterine myomas and in the surrounding unaltered myometrium. METHODS: Using RT-PCR, expression of leptin genes and leptin receptor genes was studied in myomas and in the surrounding myometrium in women with uterine myomas, untreated or treated with GnRH analogue. In the randomly selected cases presence of leptin protein and of leptin receptor proteins was examined also by Western blotting. RESULTS: Expression of leptin genes was demonstrated both in myomas and in the surrounding myometrium, and a similar pattern of expression was found for leptin receptor isoforms. The results of RT-PCR were confirmed by Western blotting, which documented the identical distribution of leptin proteins and leptin receptor proteins in studied tissues. Treatment with GnRH analogue had no effect on the expression pattern of studied genes. CONCLUSION: The results of the present study on the administration of GnRH analogue to females with myomas suggest that no direct or immediate inter-relationship exists between expression of leptin genes in uterine myomas on one hand and estrogen, progesterone and leptin levels in the blood on the other. Expression seems to be of a more durable nature but factors that induce such expression remain unknown.     

Acetaldehyde differentially affects the growth of uterine leiomyomata and myometrial cells in tissue cultures

OBJECTIVE: To examine the effect of alcohol and its derivatives on leiomyomata versus normal myometrium in cell culture. DESIGN: A study on human tissue cultures. SETTING: A tertiary-care university hospital. PATIENT(S): Premenopausal women with uterine myomas. INTERVENTION(S): Obtaining paired cultures of normal myometrium and myomas from women undergoing hysterectomy. MAIN OUTCOME MEASURE(S): Analysis of the effect of ethanol and acetaldehyde on cell growth and the expression of relevant proteins. RESULT(S): Acetaldehyde statistically significantly inhibited the growth of myoma cells compared with normal myometrium. The level of alcohol dehydrogenase 1 (ADH1) protein was lower in myoma than in myometrial cells. The acetaldehyde dehydrogenase 1 (ALDH1) protein level was higher in myoma cells. Treatment with acetaldehyde resulted in a relative reduction of ALDH1 level in the myoma cells. CONCLUSION(S): Acetaldehyde has an inhibitory effect on cell growth of myoma compared with normal myometrium. The reduced level of ADH1 and the increased level of ALDH1 proteins observed in myoma cell culture reduces the acetaldehyde level and thus may be involved in myoma cell growth.     

Cadmium concentration in uterine myomas, myometrium and peripheral blood from women living in Lower Silesia

The author has studied the cadmium concentration in uterine myomas, myometrial tissue and peripheral blood in 72 women living in Lower Silesia. The highest cadmium concentration was observed in myometrial tissue, lower in uterine myomas and the lowest in the peripheral blood. The differences among the tissues were statistically significant. There were no significant differences in the cadmium concentration concerning the women's age. There was significant positive correlation in the cadmium concentration between the myomas and the myometrium.     

子宫肌瘤与肌肉组织雌孕激素受体含量与月经周期及子宫内膜组织相关系的探讨

应用放射受体分析法测定４０例子宫肌瘤患者子宫肌瘤、肌肉组织雌激素受体（ＥＲ）、孕激素受体（ＰＲ）的含量，月经周期根据月经史及子宫内膜组织相来判断，比较两种组织ＥＲ、ＰＲ含量与月经周期及子宫内膜组织相的关系。结果：子宫肌瘤组织的ＥＲ、ＰＲ含量高于同一子宫正常肌层的含量（Ｐ＜０．０５）；子宫肌瘤与肌肉两种组织中ＥＲ含量在子宫内膜增殖期高于分泌期（Ｐ＜０．０２５，Ｐ＜０．０５），ＰＲ含量分泌期高于增殖期（Ｐ＜０．０２５）。２３例有正常月经周期者，１５例与子宫内膜组织相符合，８例与子宫内膜组织相不符合。１５例无正常月经周期者，子宫内膜组织相多为增殖期改变，占８０％。提示：子宫肌瘤的发生、发展与雌、孕激素及其受体含量有关，孕激素在肿瘤发生、发展中可能起协同作用，提示抗孕激素治疗子宫肌瘤的可能性。     

Decreased serum leptin levels in women with uterine leiomyomas

OBJECTIVE: To analyze the possible involvement of leptin in uterine leiomyomas. STUDY DESIGN: Serum leptin levels, determined by radioimmunoassay, were compared in myomatic (n = 50) and the normal (n = 50) women. RESULTS: A significant correlation was found between serum leptin levels and body mass index in both the myomatic women (r = 0.76, p < 0.001) and the normal women (r = 0.56, p < 0.001). Serum leptin levels in the myomatic women (9.3 +/- 0.6 ng/mL) were significantly lower (p < 0.001) than those in the normal women (13.6 +/- 1.2 ng/mL). In addition, the ratios of serum leptin levels/body mass index in the myomatic women (0.38 +/- 0.02) were significantly lower than those in the normal women (0.57 +/- 0.04) (p < 0.001). A significant correlation was found between the ratios of serum leptin levels/body mass index and body mass index (r = 0.59, p < 0.001) in the normal women, but not in the myomatic women (r = 0.27, p = 0.061). CONCLUSION: The lower plasma leptin levels observed in the women with myomas were independent of body mass index, and unlike the normal women there was no significant up-regulation of leptin production in response to increased adiposity.     

Presence and localization of connexins 43 and 26 in cell cultures derived from myometrial tissues from nonpregnant and pregnant women and from leiomyomas

OBJECTIVE: Our objective was to study the appearance and distribution of connexins 43 and 26 in various human myometrial cell cultures. STUDY DESIGN: Scrape loading, Western blotting, and immunohistochemical techniques were applied to cultured cells derived from myometrial tissues obtained from nonpregnant and pregnant women (upper and lower uterine segments) and from leiomyomas (tumor and analogous myometrial tissues). RESULTS: Scrape loading revealed the presence of metabolic coupling in all tissues. Indirect immunohistochemical studies showed membrane localization of connexin 43 in all myometrial cultures. Western blots and indirect immunohistochemical studies showed the presence and localization of the connexin 26 protein and associated gap junctions in tissues from myomas and from nonpregnant and pregnant women except for those derived from the upper segment of the pregnant uterus. CONCLUSION: These results show that human myometrial cultures express various gap junction proteins and that there are regional differences in expression of connexins in tissues from pregnant women.     

瘦素和瘦素长受体在胚胎停止发育中的表达

目的:探讨瘦素(Leptin)和瘦素长受体(OB-RL)mRNA及蛋白在胚胎停止发育(胚停育)中的表达及意义。方法:应用RT-PCR检测48例胚胎停育妇女(胚停育组)及30例正常早孕人工流产妇女(对照组)绒毛组织的Leptin、OB-RLmRNA。应用免疫组化技术检测两组妇女绒毛的Leptin和OB-RL蛋白。结果:RT-PCR检测表明,胚停育组Leptin mRNA及OB-RLmRNA表达明显低于对照组,有统计学意义(P<0.01,P<0.01)。免疫组化法检测Leptin及OB-RL蛋白,胚停育组及对照组呈阳性至强阳性表达,胚停育组Leptin、OB-RL蛋白均明显低于对照组(P<0.01)。经两种方法检测,Leptin、OB-RLmRNA和蛋白均明显低于对照组。结论:瘦素在胚胎发育中起重要作用,瘦素和瘦素长受体降低,可能预示胚胎停止发育。     

Fibromyomas and uterine activity

Intra-uterine pressure was recorded with a triple-channelled microtransducer catheter in women with fibromyomas prior to hysterectomy or myomectomy and in women due to undergo hysterectomy because of other gynecological disorders. In most of the patients with myomas the uterine activity differed from that in the women without myomas and from findings in previous studies on uterine activity in healthy subjects. Thus, small and irregular contractions were frequently seen in the pressure recordings from the receptors placed in the vicinity of myomas. In women with dysmenorrhea secondary to the development of myomas, increased uterine activity was registered. It is concluded that myomas may have a clinically significant effect on uterine activity.     

Insulin receptor tyrosine kinase activity and substrate 1 (IRS-1) expression in human myometrium and leiomyoma

BACKGROUND: Uterine leiomyomas are the commonest tumors of the genital tract. Growth factors seem to be implicated in the development of leiomyoma. OBJECTIVE: To determine the insulin receptor (IR) tyrosine kinase activity--phosphorylation of exogenous substrate poly(Glu 4: Tyr 1)--and insulin receptor substrate 1 expression in normal myometrium and leiomyoma. STUDY DESIGN: The study group consisted of 12 women with leiomyoma undergoing routine hysterectomy. Samples of leiomyoma and adjacent normal myometrium were obtained at the time of operation. Plasma membrane fractions were prepared and samples were incubated with and without insulin and incubated with exogenous substrate poly(Glu 4: Tyr 1). IRS-1 expression was studied in the whole lysate via Western blotting using specific antibodies. Data were analyzed using Student's t-test. RESULTS: The phosphorylation of the exogenous substrate poly(Glu 4: Tyr 1) in myometrium (1.566+/-0.177) and in leiomyoma (1.98+/-0.612) were similar (P=0.774). The IRS-1 levels in myometrium (0.190+/-0.022) and in leiomyoma (0.226+/-0.022) were not different (P=0.184). CONCLUSIONS: There was no difference in IR tyrosine kinase activity (phosphorylation of exogenous substrate) and IRS-1 expression between normal myometrium and leiomyomata. Other steps in the insulin signaling cascade require further study to investigate the role of insulin receptor in leiomyomata.     

基质成纤维细胞活化促子宫肌瘤细胞增殖作用的研究

目的:观察基质成纤维细胞活化促进子宫肌瘤细胞的增殖作用,探讨基质成纤维细胞在子宫肌瘤发病机制中的作用。方法:采用免疫磁珠法分选子宫肌瘤组织和平滑肌组织的成纤维细胞。用免疫荧光及Western blot法检测成纤维细胞活化标记物(FAP)的表达;观察肌瘤基质成纤维细胞培养上清对平滑肌基质成纤维细胞(Fib)、平滑肌细胞(SMC)、肌瘤细胞(UFC)的活化作用及增殖活力的影响。采用RNAi技术沉默肌瘤基质成纤维细胞的FAP基因,观察细胞增殖活力及ECM、生长因子的表达变化,同时观察细胞增殖通路相关信号分子的改变。结果:肌瘤组织成纤维细胞中FAP表达高于Fib;肌瘤基质成纤维细胞培养上清能增加Fib的FAP表达强度,并促进细胞增殖活力;沉默FAP基因,可抑制肌瘤基质成纤维细胞ECM(collgen I、fibronectin、laminin)、生长因子(TGF-β、IGF-1)及细胞增殖通路相关信号分子(Akt、ERK、c-Fos、MEK)的表达。结论:子宫肌瘤基质成纤维细胞的活化程度高于子宫平滑肌组织基质成纤维细胞;活化的基质成纤维细胞具有促细胞增殖效应,提示活化的基质成纤维细胞在子宫肌瘤发生过程可能具有重要作用。     

血清瘦素及瘦素受体基因Gln223Arg多态性与妊娠期糖尿病的相关性研究

目的:探讨血清瘦素水平及瘦素受体基因Gln223Arg多态性与妊娠期糖尿病的相关性。方法:应用放射免疫分析法(RIA)及聚合酶链反应-限制性内切酶片段长度多态性(PCR-RFLP)技术,检测62例妊娠期糖尿病(GDM)患者及60例正常孕妇(NGT)血清瘦素及瘦素受体基因Gln223Arg多态性。结果:(1)GDM组血清瘦素水平为14.2±4.3μg/L,NGT组为10.1±2.6μg/L,二者差异有统计学意义(P<0.05)。(2)GDM组孕妇瘦素受体基因Gln223Arg基因型GG、(GA+AA)频率分别为61.29%、38.71%,正常孕妇组分别为81.67%、18.33%,两组比较差异有统计学意义(P<0.05);GDM组孕妇瘦素受体基因Gln223Arg等位基因频率G、A分别为77.42%、22.58%,正常孕妇组孕妇分别为89.17%、10.83%,两组比较差异有统计学意义(P<0.05);(3)GDM组中基因型为GA+AA的孕妇瘦素水平为15.3±4.1μg/L,GG基因型为13.5±3.7μg/L,二者差异有统计学意义(P<0.05)。结论:瘦素,瘦素受体基因Gln223Arg多态性与GDM相关,GDM患者瘦素受体基因Gln223Arg变异可能影响血清瘦素水平。     

Different expression of estrogen receptors alpha and beta in human myometrium and leiomyoma during the proliferative phase of the menstrual cycle and after GnRHa treatment.

Uterine leiomyomas (uterine fibroids) are sex-steroid dependent benign tumors. Limited knowledge is available regarding the role of estrogen and their receptors in the regulation of fibroids in premenopausal women, and in their shrinkage after treatment with a gonadotropin-releasing hormone analogue (GnRHa). The expression of the two subtypes of the estrogen receptor (ER), ER alpha and ER beta, was studied in leiomyoma and homologous myometrium from women in the proliferative phase of the menstrual cycle and from women treated with GnRHa. The mRNA levels of ER alpha and ER beta were monitored by solution hybridization and in situ hybridization, and receptor proteins were detected and localized by immunohistochemistry. Both ER alpha and ER beta were present in the leiomyomas and homologous myometrium. The ER alpha mRNA level in the leiomyomas was higher than in the surrounding myometrium. The ER beta mRNA level was lower than that of ER alpha in both groups. ER beta immunoreactivity was lower in leiomyomas when compared with the myometrium after GnRHa treatment, while ER alpha was higher in the leiomyomas. The present results imply that the increased ratio of ER alpha/ER beta observed in the fibroids after GnRHa treatment could reflect or be the cause of the shrinkage of the leiomyoma, which is the clinical outcome of this treatment.     

Childbirth and myoma treatment by uterine artery occlusion: do they share a common biology?

When the uterine arteries are bilaterally occluded, either by uterine artery embolization or by laparoscopic obstruction, women with myomas experience symptomatic relief. After the uterine arteries are occluded, most blood stops flowing in myometrial arteries and veins, and the uterus becomes ischemic. It is postulated that myomas are killed by the same process that kills trophoblasts: transient uterine ischemia. When the uterine arteries are bilaterally occluded, either by uterine artery embolization (UAE) or by laparoscopic obstruction, women with myomas experience symptomatic relief. After the uterine arteries are occluded, most blood stops flowing in myometrial arteries and veins, and the uterus becomes ischemic. Over time, stagnant blood in these arteries and veins clots. Then, tiny collateral arteries in the broad ligament (including communicating arteries from the ovarian arteries) open, causing clot within myometrium to lyse and the uterus to reperfuse. Myomas, however, do not survive this period of ischemia. This is unique organ response to clot formation and ischemia. What allows the uterus to survive a relatively long period of ischemia while myomas perish? Childbirth appears to be the predicate biology. Following placental separation, the uteroplacental arteries and the draining veins of the placenta are torn apart at their bases in the junctional zone of the myometrium and bleed directly into the uterine cavity. Left unchecked, every woman would bleed to death in less than 10 minutes after placental delivery. Most women do not bleed to death because vessels in the uterus clot after placental delivery. During pregnancy, clotting and lytic factors in blood increase many fold. Following delivery, uterine contractions continue, intermittently, periodically slowing the velocity of flowing blood through myometrium. The combination of slowed blood flow, elevated clotting proteins, and torn placental vessels (known as Virchow's triad) causes blood in myometrial arteries and veins to clot. Fibrinolytic enzymes later lyse clot in arteries and veins not associated with placenta perfusion, and the uterus is reperfused. Remnant placental tissue - primarily uteroplacental arteries and veins - does not survive this period of ischemia. Placental tissue dies and over weeks is sloughed into the uterine cavity. At the same time, residual endometrial tissue grows under the sloughing placental tissue thus re-establishing the endometrial lining. It is postulated that myomas are killed by the same process that kills trophoblasts - transient uterine ischemia.     

Glycogen metabolism of normal human myometrium and leiomyoma--possible hormonal control

Glycogen concentration and the activities of enzymes of glycogen metabolism in myometrium of pre- and postmenopausal and pregnant women and in myomas were determined. Glycogen concentration in muscle from nonpregnant women was about 3 mg/g and rose to 13 mg/g in tissues obtained during cesarean sections. The activities of glycogen synthase phosphatase and phosphorylase were also markedly higher in myometrium of pregnant women. In 5 out of 8 myomas glycogen concentration and enzyme activities were similar to those found at the end of pregnancy. These observations suggest that glycogen metabolism of the myometrium is under the control of hormones and that the local hormonal environment of myomas may be different from that of the surrounding tissue.     

Increased expression of tuberin in human uterine leiomyoma

Female Eker rats harboring an insertional deletion in one copy of the tuberous sclerosis complex 2 (Tsc2) gene develop uterine leiomyoma, but the underlying mechanism of human uterine leiomyoma is not completely understood. To examine whether down-regulation of tuberin, a TSC2 gene product, is present in human uterine leiomyoma, we analyzed leiomyoma and matched myometrium tissues from 22 Chinese patients with Western blotting and real-time polymerase chain reaction analyses, and found that the expression of tuberin was significantly increased in leiomyoma tissues compared with matched myometrium tissues with inhibition of both the mammalian target of rapacmycin pathway and mitogen-activated protein kinase pathways.     

孕激素受体亚型在子宫肌瘤组织中的表达

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