Cellular biology of myomas: interaction of sex steroids with cytokines and growth factors

Dairy and related nutrient intake and risk of uterine leiomyoma: a prospective cohort study

STUDY QUESTION

Is there an association between consumption of dairy foods and related nutrients and risk of uterine leiomyoma?

SUMMARY ANSWER

While dairy consumption was not consistently associated with uterine leiomyoma risk, intake of yogurt and calcium from foods may reduce risk of uterine leiomyoma.

WHAT IS KNOWN ALREADY

Two studies have examined the association between dairy intake and uterine leiomyoma risk with inconsistent results. Dairy foods have been inversely associated with inflammation and tumorigenesis, suggesting that vitamins and minerals concentrated in these dietary sources may influence uterine leiomyoma risk.

STUDY DESIGN, SIZE, DURATION

A prospective cohort study was carried out using data collected from 81 590 premenopausal women from 1991 to 2009 as part of the Nurses' Health Study II cohort.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Diet was assessed with a validated food frequency questionnaire every 4 years. Cases were restricted to self-reported ultrasound or hysterectomy-confirmation uterine leiomyoma. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% CI.

MAIN RESULTS AND THE ROLE OF CHANCE

Eight thousand one hundred and forty-two cases of ultrasound or hysterectomy-confirmed uterine leiomyoma were diagnosed over an 18-year period. When compared to participants who consumed two servings a week of total dairy foods, participants who consumed four or more servings had a borderline significant 8% reduced risk of uterine leiomyoma (HR = 0.92, 95% CI = 0.85, 1.00; ptrend = 0.19). When the association between specific dairy foods and uterine leiomyoma was examined, the relation between dairy-food intake and uterine leiomyoma appeared to be driven primarily by yogurt consumption (HR for 2+ servings/day = 0.76; 95% CI = 0.55, 1.04 compared to <=4 servings/week; ptrend = 0.03); however, there was a small number of cases in the 2+ servings/day group (n = 39). Of the nutrients examined, the association was strongest for calcium from foods (HR fifth quintile = 0.92, 95% CI = 0.86, 0.99; ptrend = 0.04).

LIMITATIONS, REASONS FOR CAUTION

Some cases of uterine leiomyoma were likely misclassified, particularly those that were asymptomatic. It is possible that dairy product constituents reduce uterine leiomyoma symptomology rather than development, giving the appearance of a protective effect on leiomyoma development: no data on uterine leiomyoma symptomology were available. We did not have vitamin and mineral concentrations from actual blood levels. Similarly, there is the potential for misclassification of participants based on predicted 25(OH)D, and changes in vitamin D supplementation over time may have impacted prediction models for 25(OH)D. Further, some error in the self-reporting of dietary intake is expected. Given our prospective design, it is likely that these misclassifications were non-differential with respect to the outcome, likely biasing estimates toward the null.

WIDER IMPLICATIONS OF THE FINDINGS

While no clear association between overall dairy consumption and uterine leiomyoma risk was observed, our findings suggest that intake of yogurt and calcium from foods may reduce risk of uterine leiomyoma.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by research grant HD081064 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The Nurses' Health Study II is supported by the Public Health Service grant UM1 CA176726 from the National Cancer Institute, NIH, U.S. Department of Health and Human Services. H.R.H. is supported by the National Cancer Institute, National Institutes of Health (K22 CA193860). There are no conflicts of interest to declare.

CXCL12 Attracts Bone Marrow-Derived Cells to Uterine Leiomyomas

Uterine leiomyomas, also known as fibroids or myomas, are a common benign gynecologic tumor found in women of reproductive age. Though advances have been made in understanding leiomyomas, the etiology and pathogenesis of this disease are not fully characterized. Current evidence supports a role of putative human uterine stem/progenitor cells in the onset of uterine disease such as uterine myomas. In this study, we report that increased expression of CXCL12 in leiomyomas recruits bone marrow-derived cells (BMDCs) that may contribute to leiomyoma growth. Tissue was collected from leiomyomas or control myometrium from women with or without leiomyomas. qRT-PCR analysis showed increased expression of CXCL12 and decreased CXCR4 expression in the leiomyoma and myometrium of women with leiomyoma compared with normal myometrium. Increased CXCL12 protein secretion from cultured myoma cells was confirmed by ELISA. Further, we found that BMDCs migration was increased toward leiomyoma conditioned medium compared with conditioned medium from normal myometrium. CXCR4 antagonist AMD3100 completely blocked this migration. Engraftment of BMDCs significantly increased in myoma of mouse uteri treated with CXCL12 compared with placebo. We conclude that CXCL12 may play a role in leiomyomas growth by attracting bone marrow-derived cells to leiomyoma. Therefore, CXCL12 and its receptors are novel targets for leiomyoma therapy.

EC313-a tissue selective SPRM reduces the growth and proliferation of uterine fibroids in a human uterine fibroid tissue xenograft model

Uterine fibroids (UFs) are associated with irregular or excessive uterine bleeding, pelvic pain or pressure, or infertility. Ovarian steroid hormones support the growth and maintenance of UFs. Ulipristal acetate (UPA) a selective progesterone receptor (PR) modulator (SPRM) reduce the size of UFs, inhibit ovulation and lead to amenorrhea. Recent liver toxicity concerns with UPA, diminished enthusiasm for its use and reinstate the critical need for a safe, efficacious SPRM to treat UFs. In the current study, we evaluated the efficacy of new SPRM, EC313, for the treatment for UFs using a NOD-SCID mouse model. EC313 treatment resulted in a dose-dependent reduction in the fibroid xenograft weight (p < 0.01). Estradiol (E2) induced proliferation was blocked significantly in EC313-treated xenograft fibroids (p < 0.0001). Uterine weight was reduced by EC313 treatment compared to UPA treatment. ER and PR were reduced in EC313-treated groups compared to controls (p < 0.001) and UPA treatments (p < 0.01). UF specific desmin and collagen were markedly reduced with EC313 treatment. The partial PR agonism and no signs of unopposed estrogenicity makes EC313 a candidate for the long-term treatment for UFs. Docking studies have provided a structure based explanation for the SPRM activity of EC313.

[Growth mechanisms and morphological structural features of large uterine leiomyoma]

OBJECTIVE

To investigate the growth mechanisms of large uterine leiomyoma (LULM) on the basis of a clinical morphology examination, by providing immunohistochemical (IHC) characteristics of the expression of growth factors (transforming growth factor-beta (TGFβ) and platelet-derived endothelial cell growth factor (PD-ECGF)) and markers of stemness (CD117/c-kit, Connexin 43, Nestin) and proliferation (Ki-67).

SUBJECT AND METHODS

The investigators examined surgical specimens from 38 women diagnosed with simple uterine leiomyoma (ULM), who had been divided into two groups: 1) 21 patients with LULM (>6 cm in diameter) (a study group); 2) 17 patients with small ULM (<4 cm in diameter) (a comparison group). Each group was also divided into two age subgroups (younger (<45 years) and older (≥45 years) subgroups (1a (n=12), 1b (n=9), 2a (n=8) and 2b (n=9), respectively. Histological specimens were used to make IHC examination with antibodies against TGFβ, PD-ECGF, CD117/c-kit, Connexin 43, Nestin, and Ki-67.

RESULTS

The growth mechanisms of LULM of simple histological structure were found to be associated with the larger number of growth zones in the tumors, with their enhanced cellular proliferative activity, and with the appearance of cells with signs of stemness, which is combined with the preserved subsequent maturation of tumor cells and determines the benign nature of LULM.

CONCLUSION

There were differences in the molecular profile of LULM and small ULM, as well as LULM in perimenopausal and young women by the expression levels of Ki-67, TGFβ, PD-ECGF, CD117, and Connexin 43, which can be used for diagnosis, prediction, and development of targeted therapies.

LARGE UTERINE LEIOMYOMAS: PATHOGENETIC MECHANISMS OF GROWTH

The pathogenesis of uterine fibroids remains controversial and raises many questions. The causes and mechanism of development of large leiomyoma are unknown. In the work the pathogenic mechanisms of large leiomyomas growth were estimated for different age groups.The research was based on studying of the expression of TGF-β, CD117, PD-ECGF, Ki67, connexin and nestin in postoperative material by comparing the clinical and morphological data. The most pronounced activity of growth areas, identified by molecular markers, was found in women over 45 years with LMMB-size, which requires the vigilance of cancer.

Uterine Leiomyoma and Prolapse in a Live-stranded Atlantic Spotted Dolphin (Stenella frontalis)

A uterine prolapse associated with a leiomyoma (fibroid) was observed in a live-stranded Atlantic spotted dolphin (Stenella frontalis). A 7 cm segment of the reproductive tract including the cervix, uterine neck and caudal uterine body had intussuscepted and prolapsed into the cranial vaginal vault. In the leading edge of the intussuscepted/prolapsed uterine wall was a 6 × 3 × 3.5 cm leiomyoma expanding the myometrium. The leiomyoma and prolapse were associated with necrotizing exposure endometritis. This is the first report of a uterine prolapse associated with a leiomyoma in a cetacean. This lesion was believed to be the underlying cause of the live stranding.

Is myomectomy in women aged 45 years and older an effective option?

OBJECTIVES

The aim of this study was to evaluate the recurrence and reoperation rate after myomectomy in women aged 45 years and older, who want to preserve their uterus.

STUDY DESIGN

We performed a retrospective review of women aged ≥45 years that underwent myomectomy between January 2000 and December 2010. The inclusion criteria were premenopausal status, myomectomy through abdominal or laparoscopic surgery, and at least 12 months interval from surgery. The clinical outcomes, including symptomatic change, recurrence of myoma on transvaginal ultrasonography (TVS), and reoperation data were collected and analyzed.

RESULTS

A total 92 patients were included in this study. The median age of the patient was 47 years (range 45-53 years), and the median follow-up duration was 30.5 months (range 12-95 months). On follow-up TVS, the recurrence of myoma was detected in 20 of 82 (24.4%) patients. Ten (10.9%) patients were not subjected to follow-up TVS. However, during their pelvic examination, the uterus was normal size, and all the 10 patients experienced symptomatic improvement and none of them needed additional surgical management. Using the Kaplan-Meier method, the cumulative recurrence rate at 36 months after myomectomy was calculated as 17.1%. Three patients underwent hysterectomy during the follow-up periods, and only one underwent hysterectomy due to myoma. The overall reoperation rate after myomectomy in this age group was 3.3%, and the reoperation for myoma rate was only 1.1%.

CONCLUSION

Considering the natural regression of myoma after menopause, myomectomy might be an effective option for women aged 45 years and older, who want to preserve their uterus.

Overt hypothyroidism is associated with the presence of uterine leiomyoma: a retrospective analysis

OBJECTIVE

A possible correlation between uterine leiomyoma and thyroid disease was reported decades ago. We aimed to evaluate the possible associations between the presence of uterine leiomyomas and (i) the presence of overt hypothyroidism, (ii) the level of anti-thyroid peroxidase antibodies (TPO-Ab) and thyroglobulin antibodies (TG-Ab), and (iii) thyroid stimulating hormone (TSH) levels.

STUDY DESIGN

In a retrospective study, all 215 sterile women who underwent reproductive surgery (hysteroscopy and laparoscopy/laparotomy) at our department from January 2007 to January 2011 were included. All leiomyomas suspected on gynecologic ultrasound were verified during surgery. As risk factors for uterine leiomyomas, thyroid parameters, age, African heritage, age at menarche, parity, and body mass index were included.

RESULTS

One or more uterine leiomyomas were found in 51 cases (23.7%). After multivariate analysis, three parameters remained significant, with African heritage the most important (odds ratio, OR, 27.80), followed by overt hypothyroidism (OR 3.10) and increasing age (OR 1.23). Larger leiomyomas were found in women with overt hypothyroidism than in those without overt hypothyroidism (median, 70 mm; range, 5-88 vs. median, 30 mm; range, 2-93, respectively; p=0.007).

CONCLUSIONS

Overt hypothyroidism, but not autoantibodies against the thyroid gland, was associated with the presence of uterine leiomyoma in our study.

T-cadherin expression in uterine leiomyoma

OBJECTIVE

T-cadherin is a tumor-suppressor with low expression in many malignant tumors, but with high expression in endothelial cells and so on. In this study we investigated whether T-cadherin was expressed and if together with bFGF play a role in the occurrence and development of uterine leiomyoma.

METHOD

Uterine leiomyoma, the adjacent normal myometrium, control normal myometrium without uterine leiomyoma and vascular features of myoma were collected. Immunohistochemistry, western blot and relative quantitative real time PCR were used to evaluate bFGF and T-cadherin on the three specimens. Data were statistically analysed.

RESULTS

T-cadherin was observed on the leiomyoma cellular layers but not in the endochylema, extracellular matrix and leiomyoma vascular endothelial cell, bFGF in the leiomyoma endochylema but not observed in the extracellular matrix and leiomyoma vascular endothelial cell. The protein and mRNA expression of bFGF and T-cadherin in uterine leiomyoma were significantly with higher expression than that in adjacent normal myometrium and control normal myometrium. In addition, T-cadherin correlated well with bFGF. There was relationship between T-cadherin and color Doppler flow imaging (CDFI).

CONCLUSION

bFGF and T-cadherin have high expressions in uterine leiomyoma, and T-cadherin is associated with CDFI, indicating that a cross talk between bFGF and T-cadherin plays an important role in the occurrence and development of uterine leiomyoma or even malignant tumors.

Uterine leiomyoma: available medical treatments and new possible therapeutic options

CONTEXT

Uterine leiomyomas (fibroids or myomas) are benign tumors of the uterus and are clinically apparent in up to 25% of reproductive-age women. Heavy or abnormal uterine bleeding, pelvic pain or pressure, infertility, and recurrent pregnancy loss are generally associated with leiomyoma. Although surgical and radiological therapies are frequently used for the management of this tumor, medical therapies are considered the first-line treatment of leiomyoma.

EVIDENCE ACQUISITION AND SYNTHESIS

A review was conducted of electronic and print data comprising both original and review articles on pathophysiology and medical treatments of uterine leiomyoma retrieved from the PubMed or Google Scholar database up to June 2012. These resources were integrated with the authors' knowledge of the field.

CONCLUSION

To date, several pathogenetic factors such as genetic factors, epigenetic factors, estrogens, progesterone, growth factors, cytokines, chemokines, and extracellular matrix components have been implicated in leiomyoma development and growth. On the basis of current hypotheses, several medical therapies have been investigated. GnRH agonist has been approved by US Food and Drug Administration for reducing fibroid volume and related symptoms. In addition, the FDA also approved an intrauterine device, levonorgestrel-releasing intrauterine system (Mirena), for additional use to treat heavy menstrual bleeding in intrauterine device users only. Currently, mifepristone, asoprisnil, ulipristal acetate, and epigallocatechin gallate have been shown to be effective for fibroid regression and symptomatic improvement which are all in clinical trial. In addition, some synthetic and natural compounds as well as growth factor inhibitors are now under laboratory investigation, and they could serve as future therapeutic options.

Are uterine leiomyoma a consequence of a chronically inflammatory immune system?

The cumulative incidence of uterine leiomyoma at age 50 is ≈ 70% in White women and >80% in Black women. Although risk factor research is limited, increasing age, and being premenopausal, nulliparous or Black are risk factors for leiomyomas. Black women tend to have larger leiomyomas and be younger at diagnosis. Surprisingly little is known about the etiology or pathogenesis of uterine leiomyomas. Women with diagnosed uterine leiomyomas have higher healthcare costs - more than 2.5 times that of women without a diagnosis. In the United States, leiomyomas are the leading indication for hysterectomy. The proposed hypothesis is that leiomyomas are caused in part by a systemic immune milieu that is chronically inflammatory - one that predominates in T helper 17 (Th17) cytokines. Inflammation can be problematic if it is not well regulated. Should an inflammatory imbalance be demonstrated to be associated with leiomyoma development and growth, this would provide an avenue for development of preventative treatments (e.g., focus on anti-inflammatory pathways), which would substantially reduce the morbidity costs of these tumors and reduce a known health disparity.

Effect of a selective progesterone receptor modulator on induction of apoptosis in uterine fibroids in vivo

Aim. To determine if hormonal treatment induces apoptosis in uterine fibroids. Methods. Immunohistochemical examination of fibroid tissue, using avidin-biotin complex and cleaved caspase-3 antibody for detecting apoptosis, was performed in premenopausal women who underwent 12-week treatment with oral SPRM (6 patients with 5 mg and 5 patients with 10 mg of ulipristal acetate per day) or gonadoliberin agonist (GnRHa, 17 patients) and subsequent myomectomy or hysterectomy for symptomatic uterine fibroids. Ten patients with no presurgical hormonal treatment were used as controls. Results. Apoptosis was present in a significantly higher proportion of patients treated with ulipristal acetate compared to GnRHa (P = 0.01) and to patients with no hormonal treatment (P = 0.01). In contrast to an AI of 158.9 in SPRM patients, the mean AI was 27.5 and 2.0 in GnRHa and control groups, respectively. No statistical difference in the AI was observed between the two groups of patients treated with ulipristal acetate (5 mg or 10 mg). Conclusion. Treatment with ulipristal acetate induces apoptosis in uterine fibroid cells. This effect of SPRM may contribute to their positive clinical effect on uterine fibroids.

Intake of fruit, vegetables, and carotenoids in relation to risk of uterine leiomyomata

BACKGROUND

US black women have higher rates of uterine leiomyomata (UL) and lower intakes of fruit and vegetables than do white women. Whether fruit and vegetable intake is associated with UL in black women has not been studied.

OBJECTIVE

We assessed the association of dietary intake of fruit, vegetables, carotenoids, folate, fiber, and vitamins A, C, and E with UL in the Black Women's Health Study.

DESIGN

In this prospective cohort study, we followed 22,583 premenopausal women for incident UL (1997-2009). Diet was estimated by using food-frequency questionnaires in 1995 and 2001. Cox regression was used to derive incidence rate ratios (IRRs) and 95% CIs for the association between each dietary variable (in quintiles) and UL.

RESULTS

There were 6627 incident cases of UL diagnosed by ultrasonography (n = 4346) or surgery (n = 2281). Fruit and vegetable intake was inversely associated with UL (≥4 compared with <1 serving/d; IRR: 0.90; 95% CI: 0.82, 0.98; P-trend = 0.03). The association was stronger for fruit (≥2 servings/d compared with <2 servings/wk; IRR: 0.89; 95% CI: 0.81, 0.98; P-trend = 0.07) than for vegetables (≥2 servings/d compared with <4 servings/wk: IRR: 0.97; 95% CI: 0.89, 1.05; P-trend = 0.51). Citrus fruit intake was inversely associated with UL (≥3 servings/wk compared with <1 serving/mo: IRR: 0.92; 95% CI: 0.86, 1.00; P-trend = 0.01). The inverse association for dietary vitamin A (upper compared with lower quintiles: IRR: 0.89; 95% CI: 0.83, 0.97; P-trend = 0.01) appeared to be driven by preformed vitamin A (animal sources), not provitamin A (fruit and vegetable sources). UL was not materially associated with dietary intake of vitamins C and E, folate, fiber, or any of the carotenoids, including lycopene.

CONCLUSION

These data suggest a reduced risk of UL among women with a greater dietary intake of fruit and preformed vitamin A.

The effect of cadmium on steroid hormones and their receptors in women with uterine myomas

Cadmium (Cd) is one of the environmental metalloestrogens, and its role in uterine tissues has not yet been fully elucidated. The aim of the study was to investigate estrogenic properties of Cd in uterine tissues by analyzing the expression of estrogen receptor (ER) and progesterone receptor (PR) as well as estrogen and progesterone levels in serum and Cd concentrations in blood and tissues. The samples of tissues (leiomyoma and surrounding myometrium) collected intrasurgically and blood samples drawn from 53 women (age 39 to 52 years) with uterine myomas were thoroughly analyzed. In the study group, blood Cd concentration ranged from 0.33 to 3.5 μg/L. Cd concentration in leiomyoma tissues was twice as low [corrected] as that in surrounding myometrium (0.047 and 0.075 μg Cd/g [corrected] wet tissue, respectively), albeit the difference was not statistically significant. Cd concentrations in blood significantly correlated with Cd concentrations in tissues (leiomyoma and surrounding myometrium). The measurement of ER expression showed no difference between leiomyoma tissues and surrounding myometrium. The statistical analysis showed a significant correlation between ER expression and Cd concentration in both tissues under study. An additional statistical analysis (path analysis) demonstrated the correlation of uterine tissue levels of Cd and ER expression. However, there was no association between ER expression in both tissues and E(2) level in serum. Our results suggest a metalloestrogenic effect of Cd by way of ER stimulation in the uterus.

Proinflammatory and profibrotic mediators: principal effectors of leiomyoma development as a fibrotic disorder

Leiomyomas are believed to derive from the transformation of myometrial smooth muscle cells/connective tissue fibroblasts. Although the identity of the molecule(s) that initiate such cellular transformation and orchestrate subsequent growth is still unknown, conventional evidence indicates that ovarian steroids are essential for leiomyoma growth. Ovarian steroid action in their target cell/tissue is mediated in part through local expression of various growth factors, cytokines, and chemokines. These autocrine/paracrine molecules with proinflammatory and profibrotic activities serve as major contributing factors in regulating cellular transformation, cell growth and apoptosis, angiogenesis, cellular hypertrophy, and excess tissue turnover, events central to leiomyoma growth. This review addresses the key regulatory functions of proinflammatory and profibrotic mediators and their molecular mechanisms, downstream signaling that regulates cellular events that result in transformation, and commitments of specific cells into forming a cellular environment with a possible role in development and subsequent growth of leiomyomas.

Levonorgestrel inhibits proliferation and induces apoptosis in uterine leiomyoma cells

BACKGROUND

The levonorgestrel intrauterine system (LNG-IUS) is a widely recognized intrauterine anti-fertility system, which can alleviate symptoms of uterine leiomyoma. This study aims to evaluate leimyoma cell growth inhibition induced by high concentrations of LNG.

STUDY DESIGN

After treatment with LNG, the growth rate of the cultured primary uterine leiomyoma cells was studied with methyl thiazolyl tetrazolium (MTT) assay. Cell apoptosis rate was determined by morphological changes and flow cytometry. Reverse transcription polymerase chain reaction (RT-PCR) and Western blotting were performed to measure the differential mRNA and protein expression levels.

RESULTS

The proliferation rate of uterine leiomyoma cells was suppressed after treatment with LNG at a minimum concentration of 10 mcg/mL. The inhibitive effect was positively correlated with the LNG concentration and with the incubation time. Flow cytometry showed that the apoptosis rate was increased with the LNG concentration. The mRNA levels of IGF-1, Bcl-2 and survivin were down-regulated significantly after treatment with 10 mcg/mL LNG. Western blot analysis confirmed that the expression of Bcl-2 and survivin was decreased significantly, and the p38 phosphorylation level was increased and caspase 3 was activated remarkably 72 h after treatment with 10 and 20 mcg/mL LNG.

CONCLUSIONS

This study demonstrated that LNG may suppress the proliferation and induce apoptosis of the uterine leiomyoma cells.

What are the hallmarks of cancer?

The seminal article by Douglas Hanahan and Robert Weinberg on the hallmarks of cancer is 10 years old this year and its contribution to how we see cancer has been substantial. But, in embracing this view, have we lost sight of what makes cancer cancer?

A prospective study of dairy intake and risk of uterine leiomyomata

Rates of uterine leiomyomata are 2-3 times higher among black women than white women. Dietary factors that differ in prevalence between these populations that could contribute to the disparity include dairy intake. During 1997-2007, the authors followed 22,120 premenopausal US Black Women's Health Study participants to assess dairy intake in relation to uterine leiomyomata risk. Because soy may be substituted for dairy, the effect of soy intake was also evaluated. Diet was estimated by using food frequency questionnaires in 1995 and 2001. Incidence rate ratios and 95% confidence intervals were estimated with Cox regression. There were 5,871 incident cases of uterine leiomyomata diagnosed by ultrasound (n = 3,964) or surgery (n = 1,907). Multivariable incidence rate ratios comparing 1, 2, 3, and > or =4 servings/day with <1 serving/day of total dairy were 0.94 (95% confidence interval (CI): 0.88, 1.00), 0.87 (95% CI: 0.78, 0.98), 0.84 (95% CI: 0.70, 1.01), and 0.70 (95% CI: 0.58, 0.86), respectively (P-trend <0.001). Incidence rate ratios comparing the highest (> or =2 servings/day) with the lowest (<1 serving/week) intake categories were 0.81 (95% CI: 0.66, 0.99) for high-fat dairy, 0.80 (95% CI: 0.70, 0.91) for low-fat dairy, and 0.78 (95% CI: 0.68, 0.89) for milk. Soy intake was unrelated to uterine leiomyomata risk. This large prospective study of black women provides the first epidemiologic evidence of reduced uterine leiomyomata risk associated with dairy consumption.

Transforming growth factor beta3 regulates the versican variants in the extracellular matrix-rich uterine leiomyomas

Uterine leiomyoma are common, benign tumors that are enriched in extracellular matrix. The tumors are characterized by a disoriented and loosely packed collagen fibril structure similar to other diseases with disrupted Transforming growth factor beta (TGF-beta) signaling. Here we characterized TGF-beta3 signaling and the expression patterns of the critical extracellular matrix component versican in leiomyoma and myometrial tissue and cell culture. We also demonstrate the regulation of the versican variants by TGF-beta3. Using leiomyoma and matched myometrium from 15 patients, messenger RNA (mRNA) from leiomyoma and myometrium was analyzed by semiquantitative real time reverse transcription-polymerase chain reaction (RT-PCR), while protein analysis was done by western blot. Transforming growth factor beta3 transcripts were increased 4-fold in leiomyoma versus matched myometrium. Phosphorylated-TGF-beta RII and phosphorylated-Smad 2/3 complex were greater in leiomyoma as documented by Western blot. The inhibitor Smad7 transcripts were decreased 0.44-fold. The glycosaminoglycan (GAG)-rich versican variants were elevated in leiomyoma versus myometrial tissue: specifically V0 (4.27 +/- 1.12) and V1 (2.01 +/- 0.27). Treatment of leiomyoma and myometrial cells with TGF-beta3 increased GAG-rich versican variant expression 7 to 12 fold. Neutralizing TGF-beta3 antibody decreased the expression of the GAG-rich versican variants 2 to 8 fold in leiomyoma cells. Taken together, the aberrant production of excessive and disorganized extracellular matrix that defines the leiomyoma phenotype involves the activation of the TGF-beta signaling pathway and excessive production of GAG-rich versican variants.

A low concentration of genistein induces estrogen receptor-alpha and insulin-like growth factor-I receptor interactions and proliferation in uterine leiomyoma cells

BACKGROUND

Previously, we found that genistein at low concentrations stimulates the growth of human uterine leiomyoma (LM) cells, but not uterine smooth muscle (myometrial) cells (SMC). The aim of this study was to understand the molecular mechanism whereby genistein causes hyperproliferation of LM cells.

METHODS

The effects of genistein at 1 microg/ml on LM cells and SMC were evaluated using estrogen response element gene reporter, real-time RT-PCR, western blot, immunoprecipitation and cell proliferation assays.

RESULTS

Elevated estrogen receptor (ER) transactivation, increased mRNA expression of early estrogen-responsive genes, progesterone receptor and insulin-like growth factor-I (IGF-I), and decreased protein levels of ER-alpha (ER alpha) were found in genistein-treated LM cells, but not SMC. Additionally, extracellular regulated kinase (ERK), Src homology/collagen (Shc) and ER alpha were transiently activated, and interactions between ER alpha and IGF-I receptor (IGF-IR) were rapidly induced by genistein in LM cells. Using ER antagonist ICI 182,780 and MAPK/ERK kinase (MEK) inhibitor PD98059, we found that these early events were inhibited and the proliferative effect of genistein on LM cells was abrogated.

CONCLUSIONS

ER alpha is involved in the transient activation of ERK/mitogen activated protein kinase (MAPK) by genistein via its early association with IGF-IR, leading to hyper-responsiveness of LM cells and confirming that ER signaling is enhanced by activation of ERK/MAPK in LM cells.

Perceived racial discrimination and risk of uterine leiomyomata

BACKGROUND

The incidence of uterine leiomyomata (fibroids, myomas) is 2-3 times higher in black women than white women. Black women also report higher levels of racial discrimination. We evaluated the hypothesis that greater exposure to racism increases myoma risk in black women.

METHODS

Data were derived from the Black Women's Health Study, a prospective cohort study of US black women age 21-69 years in 1995. In 1997, women reported on "everyday" and "lifetime" experiences of racism. From 1997 through 2003, we followed 22,002 premenopausal women to assess the association between self-reported racism and risk of myomas. Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were estimated from Cox regression models.

RESULTS

During 107,127 person-years of follow-up, 3440 new cases of uterine myomas confirmed by ultrasound (n = 2774) or surgery (n = 666) were reported. All IRRs for "lifetime" and "everyday" experiences of racism were above 1.0. Using a summary variable that averaged the responses from 5 "everyday" racism items, multivariable IRRs comparing quartiles 2, 3, and 4 to quintile 1 (lowest) were 1.16 (95% CI = 1.04-1.29), 1.19 (1.06-1.32), and 1.27 (1.14-1.43), respectively. Multivariable IRRs comparing women who reported 1, 2, or 3 lifetime occurrences of major discrimination (ie, job, housing, or police) relative to those who reported none were 1.04 (0.96-1.13), 1.17 (1.07-1.28), and 1.24 (1.10-1.39), respectively. Results did not vary according to case definition (ultrasound vs. surgery) or health care utilization. Associations were weaker among foreign-born women and among women with higher coping skills.

CONCLUSIONS

Perceived racism was associated with an increased risk of uterine myomas in US-born black women.