Interferon-alpha is a potent inhibitor of basic fibroblast growth factor-stimulated cell proliferation in human uterine cells

Mast cell in infantile hemangioma

Infantile hemangioma (IH) is the most common benign vascular tumor characterized by three phases - proliferation, early involution and late involution. Mast cells (MCs) play an important role in allergic reactions and numerous diseases, including tumors. While the mechanisms underlying MCs migration, activation and function in the life cycle of IH remain unclear, previous studies suggested that MCs circulate through the vasculature and migrate into IH, and subsequently mature and get activated. Estradiol (E2) emerges as a potential attractant for MC migration into IH and their subsequent activation. In various stages of IH, activated MCs secrete both proangiogenic and anti-angiogenic modulators, absorbed by various cells adjacent to them. Imbalances in these modulators may contribute to IH proliferation and involution.

Estrogen is involved in hemangioma regression associated with mast cells

BACKGROUND

Estrogen plays a role in infantile hemangioma (IH) development, but the underlying mechanism remains unclear. This study aimed to assess estrogen and estrogen receptor (ER) localization and expression levels in IH. In addition, the unexpected relationship between mast cells (MCs) and estrogen in human IH was discussed.

METHODS

IH (n = 29), vascular malformation (VMs, n = 33) and normal skin (n = 15) specimens were assessed. IH was classified into proliferative (n = 9; age, 3.56 ± 1.01 months), early involuting (n = 10; age, 8.90 ± 2.69 months) and late involuting (n = 10; age, 20.10 ± 4.93 months) groups. Estradiol (E2), ER-a, ER-β, and tryptase (MC marker) levels were determined immunohistochemically and/or by double immunofluorescence staining. Quantification and localization of tryptase, ER-a, and E2 were assessed for each specimen.

RESULTS

ER-a, E2, and tryptase were expressed in the cytoplasm and nucleus of MCs in IH. The IH specimens showed significantly more tryptase, ER-a, and E2 positive MCs (30.6 ± 12.7, 9.7 ± 5.6, and 19.8 ± 8.7 cells/high-power field [HPF], respectively) compared with VM specimens (9.0 ± 9.8, 1.5 ± 2.4, and 2.5 ± 4.1 cells/HPF, respectively) and normal skin (6.1 ± 8.5, 0.5 ± 1.2, and 1.9 ± 3.4 cells/HPF, respectively). Proliferating IH displayed fewer E2 positive MCs (14.0 6.3 cells/HPF) compared with early (22.3 ± 10.2 cells/HPF, P = 0.023) and late (22.4 ± 6.8 cells/HPF, P = 0.006) involuting specimens. In addition, proliferating IH showed fewer tryptase positive MCs (24.7 ± 10.8 cells/HPF) compared with early involuting specimens (35.7 ± 15.3 cells/HPF, P = 0.043). All IH specimens were ER-a positive and ER-β negative.

CONCLUSIONS

E2 and ER-a are expressed on MCs and not on IH endothelial cells. Furthermore, activated MCs may be involved in IH regression.

Influence of vitamin D and transforming growth factor β3 serum concentrations, obesity, and family history on the risk for uterine fibroids

OBJECTIVE

To evaluate the influence of 25-hydroxyvitamin D and transforming growth factor β3 (TGF-β3) serum concentrations, weight, and family history on the risk of developing uterine fibroids.

DESIGN

Retrospective cohort study.

SETTING

University hospital.

PATIENT(S)

A total of 188 women, including patients admitted for uterine fibroid surgery (n = 105) as the study group and healthy women of similar age (n = 83) as controls.

INTERVENTION(S)

Medical history and completion of specially designed questionnaire, transvaginal or transabdominal genital ultrasound scan, blood sampling, and measurement of vitamin D and TGF-β3 serum concentrations.

MAIN OUTCOME MEASURE(S)

Evaluation of the impact of family history, vitamin D, and TGF-β3 serum concentrations on the risk of developing uterine fibroids.

RESULT(S)

Mean 25-hydroxyvitamin D serum concentrations were 21.9 ± 8.9 ng/mL and 26.7 ± 11.9 ng/mL in patients with uterine fibroids and controls, respectively. The difference was statistically significant. The TGF-β3 serum concentrations in the fibroid-positive group ranged from 1.20 to 436.15 pg/mL (half the patients had concentrations >16.25 pg/mL). Concentrations in the control group ranged from 0.96 to 49.08 pg/mL (half the women had concentrations of >11.80 pg/mL). The differences were statistically significant. Higher body mass index (BMI) and positive family history were also found to be among the risk factors for uterine fibroids.

CONCLUSION(S)

Our study confirmed higher BMI, positive family history, and lower vitamin D and higher TGF-β3 serum concentrations as risk factors for uterine fibroids.

Uterine fibroids: clinical manifestations and contemporary management

Uterine fibroids (leiomyomata) are extremely common lesions that are associated with detrimental effects including infertility and abnormal uterine bleeding. Fibroids cause molecular changes at the level of endometrium. Abnormal regulation of growth factors and cytokines in fibroid cells may contribute to negative endometrial effects. Understanding of fibroid biology has greatly increased over the last decade. Although the current armamentarium of Food and Drug Administration-approved medical therapies is limited, there are medications approved for use in heavy menstrual bleeding that can be used for the medical management of fibroids. Emergence of the role of growth factors in pathophysiology of fibroids has led researchers to develop novel therapeutics. Despite advances in medical therapies, surgical management remains a mainstay of fibroid treatment. Destruction of fibroids by interventional radiological procedures provides other effective treatments. Further experimental studies and clinical trials are required to determine which therapies will provide the greatest benefits to patients with fibroids.

Medical management of fibroids

The ideal medical therapy for fibroids is, arguably, a tablet that is taken by mouth, once a day or, even better, once a week, with minimal, if any, side-effects, that induces fibroid regression and thus a resolution of symptoms rapidly, but without affecting fertility. Such a magic bullet does not yet exist, and there are no indications that one is on the horizon. Driven by the observation that fibroid growth is hormone dependent, current medical treatments mainly involve hormonal manipulations. Gonadotrophin-releasing hormone analogues (GnRHa) have been the most widely used, and while they do cause fibroid regression, they can only be used in the short term, as temporizing measures in the perimenopausal woman, or pre-operatively to reduce fibroid size, influence the type of surgery, restore haemoglobin levels and apparently reduce blood loss at operation. They are notorious for rebound growth of the fibroids upon cessation of therapy, and have major side-effects. GnRH antagonists avoid the initial flare effect seen with GnRHa therapy, but otherwise do not appear to have any additional advantages over GnRHa. Selective oestrogen receptor modulators, such as raloxifene, have been shown to induce fibroid regression effectively in post-, but not pre-, menopausal women; even in the former group, experience with these drugs is limited, and they are associated with significant side-effects. Aromatase inhibitors only appear to be effective in postmenopausal women, have potentially significant long-term side-effects, and experience with their use is also limited. There are suggestions that the levonorgestrel intra-uterine system can cause dramatic reduction in menstrual flow in women with fibroids, but to date there have been no RCTs of its use in these women, in whom rates of expulsion of the device appear to be high. The progesterone antagonists mifepristone and asoprisnil have shown significant promise and warrant further research, as they appear to show efficacy in inducing fibroid regression without major side-effects. However, they and the other hormonal therapies that alter oestrogen and progesterone production or function significantly (danazol, gestrinone) are not compatible with reproduction. Therefore, the quest for the ideal medical therapy for fibroid disease continues, and increasing understanding of fibroid biology is ushering in non-hormonal therapies, although all are confined to laboratory experimentation at present. In the meantime, surgical and radiological approaches remain the mainstay effective therapies.

A sub-population of high proliferative potential-quiescent human mesenchymal stem cells is under the reversible control of interferon alpha/beta

Type I interferon (IFN) is shown to control the reversible quiescence of a primitive human bone marrow mesenchymal stem cell (MSC) subpopulation. A 24 h pre-treatment of Stro1+/GlycoA- or CD45-/GlycoA- subpopulations with a monoclonal antibody (mAb) against the IFNAR1 chain of the human type I IFN receptor (64G12), or with a polyclonal anti-IFNalpha antibody, resulted in a marked increase in the number of very large colonies (CFU-F >3000 cells) obtained in the presence of low, but necessary, concentrations of bFGF. Over a 2-month culture period, this short activation promoted a faster and greater amplification of mesenchymal progenitors for adipocytes and osteoblasts. Activation correlated with inhibition of STAT1 and STAT2 phosphorylation and of STAT1 nuclear translocation. A non-neutralizing anti-IFNAR1 mAb was ineffective. We demonstrate that control and activated MSCs express ST3GAL3, a sialyltransferase necessary to produce the embryonic antigens SSEA-3 and -4. Interestingly, activated MSC progeny expressed SSEA-3 and -4 at a higher level than control cultures, but this was not correlated with a significant expression of other embryonic markers. As MSCs represent an essential tool in tissue regeneration, the use of 64G12, which rapidly recruits a higher number of primitive cells, might increase amplification safety for cell therapy.

Stimulation of primary human endothelial cell proliferation by IFN

The IFN family of cytokines has pleiotropic roles in immunity and development. In this study, we provide evidence that IFN can stimulate the proliferation of primary human endothelial cells. This is in contrast to the growth-suppressive effects of IFN observed on transformed human cells, thereby underscoring the distinctive responses of primary human cells. The growth-stimulatory effect of IFN was determined by an increase in DNA synthesis assessed with [(3)H]thymidine incorporation, an increase in G(2) and M cell cycle phases assessed with flow cytometric analysis, and an increase in cell number. Distinct cell types, including primary human fibroblast and smooth muscle cells, were also growth stimulated by IFN. Neutralizing Abs to IFN were used to demonstrate the growth response was mediated specifically by the IFN cytokine. The signaling pathway of type I IFNs activates STAT1 and STAT2. In primary endothelial cells, we demonstrate that STAT3 and STAT5 are also activated, and these STATs may contribute to cellular proliferation. To evaluate possible effectors of positive growth, DNA microarray analyses were performed to assess gene induction in response to IFN. These results reveal changes in the RNA levels of genes in endothelial cells that encode proteins involved in cellular proliferation.

A benefit-risk assessment of medical treatment for uterine leiomyomas

The growth of a uterine leiomyoma growth stops and regresses after the menopause suggesting that leiomyoma growth is dependent on ovarian steroids. Therefore, estrogen has received much attention as the major factor responsible for the development of uterine leiomyomas, but progesterone also plays an important role in development of this disease. Cytogenetic analyses of resected samples has revealed that about 40 to 50% of leiomyomas show karyotypically detectable chromosomal abnormalities. Gonadotrophin releasing hormone (GnRH) agonists exert their action through the suppression of endogenous gonadotrophins and gonadal steroid secretion. Significant reductions of uterine/leiomyoma volume under GnRH agonist therapy has been reported in several studies. However, the leiomyoma generally returns to its pretreatment volume within a few months after discontinuation of the GnRH agonist. To minimise the adverse effects of hypoestrogenism during GnRH agonist treatment, add back therapy can be used (estrogen-progestin, progestin alone and recently tibolone). Antiprogestins have a potential clinical utility in uterine leiomyomas. Mifepristone is a synthetic steroid with both antiprogesterone and antiglucocorticoid activities, that may have an inhibitory effect on growth of leiomyoma. Danazol is an isoxazole of 17beta-ethinyl testosterone, a synthetic steroid, which has a suppressive effect on sex hormone binding globulin concentrations, resulting in efficacy in the short-term treatment of uterine leiomyomas. Gestrinone is a tri-enic steroid with antiestrogen and antiprogesterone properties and has been shown to reduce uterine volume and stop bleeding. Growth factors play a relevant role on the pathophysiology of uterine leiomyoma and probably the inhibition of the action of growth factors on the myometrium will be the basis for future therapy. A number of agents are under investigation for treating uterine leiomyoma. Agents developed from increasing genetic knowledge of this condition could represent, in the next few years, new trends in the medical treatment of uterine leiomyomas.

Interactions of cytokines, growth factors, and the extracellular matrix in the cellular biology of uterine leiomyomata

OBJECTIVE

To review the available information regarding the role of cytokines, growth factors, and the extracellular matrix in the pathophysiology of uterine leiomyomata and to integrate this information in a suggested model of disease at the cellular level.

DESIGN

A thorough literature and MEDLINE search was conducted to identify the relevant studies in the English literature published between January, 1966 and October, 2001. A model of disease at the cellular level was developed using the most likely cytokines to be involved in the pathogenesis of leiomyomata as determined by our assessment of the available literature.

RESULT(S)

A number of cytokines and growth factors, including transforming growth factor-beta (TGF-beta), epidermal growth factor, monocyte chemotactic protein-1, insulin-like growth factors 1 and 2, prolactin, parathyroid-hormone-related peptide, basic fibroblast growth factor, platelet-derived growth factor, interleukin-8, and endothelin, have been investigated in myometrium and leiomyoma. Among these cytokines, TGF-beta appears to be the only growth factor that has been shown to be overexpressed in leiomyoma vs. myometrium, be hormonally-regulated both in vivo and in vitro, and be both mitogenic and fibrogenic in these tissues. In addition to the cytokines, extracellular matrix components such as collagen, fibronectin, proteoglycans, matrix metalloproteinases, and tissue inhibitors of metalloproteinases seem to play pivotal roles in the pathogenesis of leiomyomata.

CONCLUSION(S)

We believe that, given the extent and depth of the current research on the cellular biology of leiomyomata, the cellular mechanisms responsible in the pathogenesis of leiomyomata will be identified clearly within the foreseeable future. This will enable researchers to develop therapy directed against the molecules and mechanisms at the cellular level.

Identification of new therapies for leiomyomas: what in vitro studies can tell us

Leiomyomas are a significant problem in women's health. An understanding of the biology of these tumors and how their growth is regulated is emerging from in vitro studies using tissue specimens and cultured cells. These studies have clarified how the ovarian steroid hormones regulate growth of uterine SMCs and how the ovarian steroid ligand-receptor system has been altered in leiomyomas. Such information will allow investigators to identify steroid hormone antagonists and steroid hormone receptor modulators that may be useful for treatment of leiomyomas. We are now also developing a much better understanding of the growth factors that are produced by SMCs of leiomyoma tumors. These growth factors not only regulate the proliferation, apoptosis, and extra-cellular matrix production of the SMCs but also regulate proliferation and migration of vascular endothelial cells. Targeting these growth factors and their receptors can reduce leiomyoma growth through two different mechanisms. One targets the SMCs and the other targets the vascular system that supports the growth of the tumor. Another important lesson that can be learned from reading the scientific literature is that there are striking similarities between the biology of uterine leiomyomas and other pathologic diseases that involve mesenchymally derived cells. These include benign keloids, other fibrotic diseases such as pulmonary fibrosis, and vascular diseases such as atherosclerosis. Compounds that are developed to treat these conditions may also be beneficial for treatment of uterine leiomyomas. The next few years will undoubtedly yield many new drug discoveries for these diseases.

Uterine fibroids

Uterine leiomyomas (fibroids or myomas), benign tumours of the human uterus, are the single most common indication for hysterectomy. They are clinically apparent in up to 25% of women and cause significant morbidity, including prolonged or heavy menstrual bleeding, pelvic pressure or pain, and, in rare cases, reproductive dysfunction. Thus, both the economic cost and the effect on quality of life are substantial. Surgery has been the mainstay of fibroid treatment, and various minimally invasive procedures have been developed in addition to hysterectomy and abdominal myomectomy. Formation of new leiomyomas after these conservative therapies remains a substantial problem. Although medications that manipulate concentrations of steroid hormones are effective, side-effects limit long-term use. A better approach may be manipulation of the steroid-hormone environment with specific hormone antagonists. There has been little evidence-based evaluation of therapy. New research into the basic biology of these neoplasms may add new treatment options for the future as the role of growth factors and genetic mutations in these tumours are better understood.

Relationship of myoma cell size and menopausal status in small uterine leiomyomas

CONTEXT

Although myomas shrink after menopause, the cellular mechanism for this phenomenon has received little attention. It was recently demonstrated that fibrous degeneration is significantly associated with postmenopausal status in both small and large myomas.

OBJECTIVE

The purpose of the present study was to evaluate whether reduction in myoma cell size is also associated with postmenopausal status in small myomas.

DESIGN

Tumor size and patient age have also been related to fibrous degeneration in small (<1 cm) myomas. Therefore, in the present study, 10 pairs of premenopausal and postmenopausal small myomas were matched within 3 years for patient age, within 1 mm for size, and within 1 grade for degree of fibrous degeneration. Most of the women were in their 50s, the decade during which postmenopausal fibrous degeneration in small myomas is most prevalent. Myoma cell size was derived by morphometric evaluation of relative myoma cell area (correcting for percentage of stroma, as measured by point counting) and by direct counting of the number of myoma cells per unit area in trichrome-stained sections.

RESULTS

Small myomas from postmenopausal women had significantly (P <.05) smaller cell sizes than did size-matched myomas from age-matched premenopausal women. Myoma cell sizes and nucleus-cell (N/C) ratios were highly variable, especially in premenopausal myomas.

CONCLUSIONS

Reduction in myoma cell size is significantly associated with postmenopausal status in small uterine leiomyomas and may be an important mechanism for postmenopausal shrinkage of myomas. In addition, the high variability of myoma cell size and N/C ratio may further support the somatic mutation theory (ie, the theory that diverse mutations may account not only for variations in the growth potential of uterine myomas, but also for variations in their cellular details).