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.

Aspirin Has A Gender-Dependent Impact on Antiinflammatory 15-Epi-Lipoxin A 4 Formation

Objective— Aspirin blocks thromboxane production that contributes to its well-appreciated antiplatelet action. Aspirin also initiates the biosynthesis of novel antiinflammatory mediators from arachidonic acid, namely aspirin-triggered 15-epi-lipoxin A 4 . We recently conducted a double-blinded clinical trial with healthy subjects in whom low-dose aspirin (81 mg daily) significantly increased aspirin-triggered 15-epi-lipoxin A 4 and concomitantly inhibited thromboxane. Here, we assessed whether plasma aspirin–triggered 15-epi-lipoxin A 4 was age or gender dependent in subjects taking low-dose aspirin.

Methods and Results— A total of 128 subjects were allocated to: placebo, 81, 325, or 650 mg daily aspirin for an 8-week period. Plasma thromboxane B 2 and aspirin-triggered 15-epi-lipoxin A 4 were assessed from blood collected at baseline and the conclusion of the trial. We then performed a post-trial analysis in the group receiving low-dose aspirin. In female subjects, we found a positive correlation between age and aspirin-triggered 15-epi-lipoxin A 4 (increase of 0.37 ng/mL per decade), and a negative correlation was observed in men (decrease of 0.29 ng/mL per decade). These trends were significantly different from each other ( P =0.045).

Conclusions— Low-dose aspirin has a gender-specific impact on aspirin-triggered 15-epi-lipoxin A 4 production, which may contribute to the gender-dependent clinical benefits of aspirin. Also, they may provide a molecular rationale for low-dose aspirin therapies in elderly women to reduce inflammation-related disorders.

Additive effects of estrogen and mechanical stress on nitric oxide and prostaglandin E2 production by bone cells from osteoporotic donors

Mechanical loading is thought to provoke a cellular response via loading-induced flow of interstitial fluid through the lacuno-canalicular network of osteocytes. This response supposedly leads to an adaptation of local bone mass and architecture. It has been suggested that loss of estrogen during menopause alters the sensitivity of bone tissue to mechanical load, thereby contributing to the rapid loss of bone. The present study aimed to determine whether estrogen modulates the mechanoresponsiveness of bone cells from osteoporotic women. Bone cell cultures from nine osteoporotic women (aged 62-90 years) were pre-cultured for 24 h with 10(-11) mol/l 17beta-estradiol (E2) or vehicle, and subjected to 1 h of pulsating fluid flow (PFF) or static culture. E2 alone enhanced prostaglandin E(2) (PGE(2)) and nitric oxide (NO) production by 2.8-fold and 2.0-fold, respectively, and stimulated endothelial nitric oxide synthase protein expression by 2.5-fold. PFF, in the absence of E2, stimulated PGE(2) production by 3.1-fold and NO production by 3.9-fold. Combined treatment with E2 and PFF increased PGE(2) and NO production in an additive manner. When expressed as PFF-treatment-over-control ratio, the response to fluid shear stress was similar in the absence or presence of E2. These results suggest that E2 does not affect the early response to stress in bone cells. Rather, E2 and shear stress both promote the production of paracrine factors such as NO and PGE(2) in an additive manner.

17beta-estradiol decreases vascular tone in cerebral arteries by shifting COX-dependent vasoconstriction to vasodilation

We have previously shown that estrogen treatment increases cerebrovascular cyclooxygenase-1, prostacyclin synthase, and production of prostacyclin. Therefore, vascular tone and prostanoid production were measured to investigate functional consequences of estrogen exposure. Middle cerebral arteries were isolated from ovariectomized female Fischer-344 rats with or without chronic in vivo 17beta-estradiol treatment. In vivo 17beta-estradiol treatment increased cerebral artery diameter; functional endothelium was required for expression of these differences. The nonspecific cyclooxygenase inhibitor indomethacin constricted, whereas arachidonic acid dilated, cerebral arteries from estrogen-treated animals. Estrogen exposure increased production of prostacyclin by cerebral arteries. Conversely, in estrogen-deficient animals, indomethacin dilated and arachidonic acid constricted cerebral blood vessels. This correlated with vasorelaxation following inhibition of the thromboxane-endoperoxide receptor with SQ-29548 but not after selective blockade of thromboxane synthase with furegrelate, suggesting prostaglandin endoperoxide (i.e., PGH2) activity. Removal of the endothelium or selective blockade of cyclooxygenase-1 with SC-560 abolished estrogen-mediated differences in the effects of arachidonate on vessel diameter and on prostacyclin production by cerebral arteries. These data suggest 17beta-estradiol decreases cerebrovascular tone by shifting the primary end product of the endothelial cyclooxygenase-1 pathway from the constrictor prostaglandin PGH2 to the vasodilator prostacyclin. These effects of estrogen may contribute to the heightened thromboresistance and enhanced cerebral blood flow documented in pre-versus postmenopausal women.

Effect of estradiol administration on splanchnic perfusion after trauma-hemorrhage and sepsis

PURPOSE OF REVIEW

This review focuses on the latest mechanistic understanding of the effects of estradiol on the splanchnic circulation and the possibility of estradiol treatment as an adjunct for the treatment of trauma-hemorrhage and sepsis.

RECENT FINDINGS

Systemic hypotension induced by shock accompanies marked alterations in blood flow to various organs. Decreased splanchnic perfusion is frequently observed after insults, such as severe hemorrhage or sepsis, which leads to the destruction of the intestinal mucosal barrier and hepatic dysfunction. Studies suggest that estradiol acts as a facilitator of the intestinal blood flow via the increased production of nitric oxide, decreased production of vasoconstrictors, attenuated neutrophil adhesion, and decreased formation of oxygen free radicals.

SUMMARY

Trauma-hemorrhage results in decreased circulating blood volume. In contrast, sepsis is an inflammatory state mainly mediated by bacterial products. However, these divergent insults show similar pathophysiologic alterations in terms of the splanchnic circulation. Because estradiol effectively protects the organs from circulatory failure after various adverse circulatory conditions, many studies are being performed to clarify the molecular mechanism of estradiol action with regard to tissue circulation. Estradiol improves the macro- and microcirculation of the splanchnic organs by multiple mechanisms. Nonetheless, it remains unclear which mechanism plays the most important role in the treatment of trauma-hemorrhage and sepsis. Additional studies are required to elucidate the precise mechanism of estradiol action and to determine the usefulness of estradiol treatment for severe hemorrhage and sepsis in patients.

Estrogen reduces angiotensin II-induced nitric oxide synthase and NAD(P)H oxidase expression in endothelial cells

OBJECTIVE

Angiotensin II (AII) has been shown to increase endothelial NAD(P)H oxidase activity, which is a source of superoxide anion that in turn may induce the formation of peroxynitrite. Estrogen (E2) has been reported to have vascular protective effects. In this study, we hypothesized that E2 reduces the AII-induced expression of NAD(P)H oxidase and peroxynitrite in endothelial cells.

METHODS AND RESULTS

Endothelial cells were cultured and stimulated with AII in the absence or presence of E2. Western blots were used to assess nitric oxide synthase (NOS) and NAD(P)H oxidase expression. Immunofluorescence of nitrotyrosine provided evidence of peroxynitrite formation. Our data indicate that AII increased the expression of endothelial NOS, inducible NOS, and NAD(P)H oxidase in a dose-dependent manner, which was attenuated by incubation with either E2, superoxide dismutase, or the AII type 1 receptor (AT1R) inhibitor candesartan. Estrogen as well as superoxide dismutase also inhibited AII-induced AT(1)R expression and nitrotyrosine staining. The effects of E2 on the AII responses were not inhibited by the E2 receptor antagonist ICI-182,780.

CONCLUSIONS

AII stimulation of endothelial cells increases expression of NAD(P)H oxidase and NOS, which may contribute to oxidative stress, as evidenced by peroxynitrite formation. E2 inhibits these AII effects, possibly through reduced AT1R expression.

Estrogen replacement reduces PGHS-2-dependent vasoconstriction in the aged rat

The reduction in estrogen in postmenopausal women contributes to an increase in vascular dysfunction. Models of aging have shown that this is due, in part, to increased prostaglandin H synthase (PGHS)-dependent vasoconstriction. We showed previously that inducible PGHS-2-dependent vasoconstriction is increased with aging. In the present study, we hypothesized that estrogen suppresses PGHS-2-dependent constriction in the aged rat. Isolated mesenteric arteries from placebo- or estrogen-treated, ovariectomized aged (24 mo) Fisher rats were assessed for endothelium-dependent relaxation in the absence or presence of PGHS inhibitors. PGHS inhibition (meclofenamate, 1 micromol/l) enhanced methacholine-induced relaxation only in the placebo group. Specific PGHS-2 inhibition (NS-398, 10 micromol/l) increased arterial relaxation to a greater extent than PGHS-1 inhibition (valeryl salicylate, 3 mmol/l). Estrogen prevented the PGHS-dependent constrictor effect but did not enhance nitric oxide-dependent relaxation in this model. PGHS-1 and endothelial nitric oxide synthase were not altered by estrogen, whereas PGHS-2 expression was decreased in the estrogen-replaced rats (P < 0.05). In summary, estrogen replacement improved vasodilation in aged rats by decreasing PGHS-dependent constriction.