Specific binding protein for 17β-estradiol in prostate with adenocarcinoma

A specific binding protein for 17β-estradiol has been detected in prostates of patients with prostatic adenocarcinoma, who had no endocrine manipulation prior to the removal of their prostates. Both the sucrose density gradient centrifugation and dextran-coated charcoal techniques were employed. The 17β-estradiol binding protein has an approximate sedimentation coefficient of 3.6S and is distinct from cytosolic dihydrotestosterone binding protein.     

Adenocarcinoma of prostate: Role of 17β-estradiol and 5α-dihydroterosterone binding proteins

Presence of a specific 17β-estradiol-binding protein in prostates of patients with adenocarcinoma without hormonal manipulation prior to surgical resection has been reported by us earlier.' The present study involves 40 patients with carcinoma of prostate analyzed during the period December, 1974, through June, 1978. Thirty-four patients had metastatic disease, 26 of these were manipulated hormonally after and 8 prior to receptor protein assay. The other 6 were in clinical Stage C and were subjected to transurethral resection alone. The study confirms our earlier report and outlines the role of 17β-estradiol (E₂) and possibly 5_α-dihydrotestosterone (DHT) receptor protein in hormonally responsive and refractory patients. Based on the preliminary findings it seems possible to classify the prostatic carcinoma similar to human mammary cancer for the purpose of selecting patients for endocrine manipulation or treatment with other available modalities.     

Induction of benign prostatic hyperplasia in intact dogs by near-physiological levels of 5α-dihydrotestosterone and 17β-estradiol

Benign prostatic hyperplasia was induced in mongrel dogs treated for 60 days with one silastic implant containing 17β-estradiol and four containing 5α-dihydrotestosterone. The condition was characterized by (1) a marked increase of the stromal elements, particularly the stromal septa between the individual glands, (2) a slight increase in prostatic volume, and (3) a morphology that resembled spontaneous complex benign prostatic hyperplasia in the dog. Other groups of animals that remained untreated or received only 17β-estradiol or only 5α-dihydrotestosterone did not develop this condition. Prostate volumes decreased by 14% in the estrogen-treated dogs, whereas they increased in the androgen-treated animals by 6% compared to pretreatment prostate volumes. The morphology of the epithelium of the prostates of androgen-treated animals was not different from that of controls despite the increase in prostate volume. The serum 17β-estradiol and 5α-dihydrotestosterone concentrations were increased from 25 ± 2 (mean ± SEM) and 256 ± 42 pg/mL, respectively, in control dogs to 52 ± 37 and 562 ± 37 pg/mL, respectively, in the dogs treated with the hormone combination. Thus, hormone concentrations were two- to three-fold higher than control values, and the ratio of estradiol-17β to 5α-dihydrotestosterone was increased by up to 19%. These data demonstrate that treatment of dogs with low levels of estrogen and androgen may be an excellent model for the study of spontaneous complex benign prostatic hyperplasia in aging men.     

Estrogen receptor α36 mediates a bone‐sparing effect of 17β‐estrodiol in postmenopausal women

Recently, a membrane‐based estrogen receptor (ER), ER‐α36, was identified and cloned that transduces membrane‐initiated estrogen signaling such as activation of the mitogen‐activated protein kinase/extracellular signal‐regulated kinase (MAPK/ERK) signaling pathway. Here we show that the postmenopausal level of estradiol (E2) induces mitogenic, antiapoptotic, and antiosteogenic effects and proapoptotic effects in postmenopausal osteoblasts and osteoclasts with high levels of ER‐α36 expression, respectively. We also found that ER‐α36 mediated the effects of postmenopausal‐level E₂ on proliferation, apoptosis, and differentiation of osteoblasts through transient activation of the MAPK/ERK pathway, whereas ER‐α36‐mediated postmenopausal‐level E₂ induces apoptosis of osteoclasts through prolonged activation of the MAPK/ERK pathway with the involvement of reactive oxygen species. We also show that the levels of ER‐α36 expression in bone are positively associated with bone mineral density but negatively associated with bone biochemical markers in postmenopausal women. Thus the higher levels of ER‐α36 expression are required for preserving bone mass in postmenopausal and menopausal women who become osteoporotic if ER‐α36‐mediated activities are dysregulated. © 2011 American Society for Bone and Mineral Research.     

Modulation of wound contracture α‐smooth muscle actin and multispecific vitronectin receptor integrin αvβ3 in the rabbit's experimental model

The myofibroblast, a major component of granulation tissue, is a key cell during wound healing, tissue repair and connective tissue remodelling. Persistence of myofibroblasts within a fibrotic lesion leads to excessive scarring impairing function and aesthetics. Various wound‐healing cytokines can be modulated by topical application of active agents to promote optimal wound healing and improve scar quality. Thus, the myofibroblast may represent an important target for wound‐healing modulation to improve the evolution of conditions such as hypertrophic scars. The purpose of this work is to study the modulation of myofibroblasts and integrin αvβ3 in a full thickness wound performed on rabbits treated with different topical agents using: (1) saline, (2) Tegaderm occlusive dressing (3) silver sulfadiazine and (4) moist exposed burn ointment (MEBO). The reepithelialisation was 4 days faster in the MEBO group compared with the other therapies with less oedema formation, delayed contraction, less inflammatory cells and the lowest transepidermal water loss (TEWL) resulting in a soft scar. Although α‐smooth muscle actin (α‐SMA) was the highest around day 12 in the MEBO group, wound contraction and myofibroblast's activity were the least for the same period probably because of a downregulation of the integrin αvβ3. It seems that the effect of MEBO could be more pronounced on force transmission rather then on force generation. Greater insight into the pathology of scars may translate into non surgical treatments in the future and further work in myofibroblast biology will eventually result in efficient pharmacological tools, improving the evolution of healing and scar formation.     

Recognition of cryptic sites in human and mouse laminins by rat osteoclasts is mediated by β3 and β1 integrins

Laminins may be encountered by osteoclasts and their precursors in basement membranes when they migrate from periosteal vasculature during skeletal development and in pathological situations. We have examined the recognition by osteoclasts of intact laminins and their proteolytic derivatives, and analysed the mechanism of adhesion. Rat osteoclasts fail to bind intact mouse Engelbreth-Holm-Swarm (EHS) laminin (3% adhesion relative to adhesion to foetal calf serum proteins) and bind only weakly to native human placental laminin (13%) or human merosin (9%). Pepsin treatment of native mouse EHS and human laminins increased osteoclast adhesion. Rat osteoclasts adhered to mouse EHS laminin-derived P1 fragment (70%), but failed to bind the E8 fragment, which contains adhesion sites recognised by some integrins. Binding to human and mouse P1 laminins was abolished by treatment with RGD-containing peptides and required divalent cations, but not by YIGSR peptide. Combinations of monoclonal antibodies to rat β3 and ∝v integrins reduced binding to P1 fragment by 91% and to human laminin by 72%, demonstrating that the major integrin involved in rat osteoclast adhesion to proteolysed laminin is ∝vβ3. Antiserum to β1 integrin inhibited adhesion to human laminin by 40%, but to P1 fragment by only 8%; this suggests that β1 integrin(s) contribute to osteoclast adhesion to human laminin but probably not to P1 fragment. The involvement of ∝vβ3 integrin was confirmed using a recombinant human ∝vβ3 solid phase binding assay. ∝vβ3 bound to mouse P1 fragment and proteolytically digested human laminin, but not intact lamming. Binding of the ∝vβ3 receptor to both laminins was significantly inhibited by RGD peptides and by monoclonal antibody 9C9 to human β3 integrin. In conclusion, our findings demonstrate that rat osteoclasts bind to laminin only when cryptic peptide sites become functional after exposure by proteolytic cleavage, and that both β3 and, to a lesser degree, β1 integrins are involved in this process.     

Biochemical changes in malignant hyperthermia susceptible swine: cyclic AMP,inositol phosphates, α1, β1- and β2-adrenoceptors in skeletal and cardiac muscle

It has been presumed that alteration in the concentrations of second messengers leads to alterations in the function of the ryanodine receptor. Consequently, we have determined the basal content of cyclic AMP and inositol phosphates in skeletal and cardiac muscle of malignant hyperthermia (MH) susceptible (MHS) and healthy normal control (MHN) swine. Since α,- and β-adrenoceptors are linked to these second messenger systems, the densities of α₁,- and β-adrenoceptors were also determined. In skeletal as well as cardiac muscle, a higher basal concentration of almost all of the inositol phosphates was found. Of all inositol phosphates measured, the presumed second messenger inositol 1,4,5-trisphosphate (1,4,5-IP3) was mostly concentrated in both tissues. Each MHS sample contained more 1,4,5,-IP3 than the highest value observed in MHN muscle, indicating that a threshold of 1,4,5-IP3 concentration for determination of MHS or MHN status can be defined. In addition, MHS skeletal muscle contained more cAMP than MHN, whereas there was no difference between MHS and MHN in cardiac muscle. The changes observed in the different inositol phosphate and cAMP contents were not accompanied by an altered α₁,- or β-adrenoceptor density in skeletal or cardiac muscle between MHS and MHN. However, the total number of β-adrenoceptors of MHN and MHS was significantly higher in cardiac (about 80 fmol/mg protein) than skeletal muscles (about 30 fmol/ mg protein). The cardiac muscles revealed about 80% β₁,- and 20% β₂-adrenoceptors, whereas skeletal muscles were characterised by over 95% β₂-adrenoceptors. In conclusion, the present study supports the view that altered second messenger systems and, thereby, altered intracellular calcium regulations are at least in part involved in the modulation and development of MH. Moreover, in addition to the skeletal muscle, multiple other organs, e.g. heart, may be affected in MH.     

The role of activation functions 1 and 2 of estrogen receptor‐α for the effects of estradiol and selective estrogen receptor modulators in male mice

Estradiol (E2) is important for male skeletal health and the effect of E2 is mediated via estrogen receptor (ER)‐α. This was demonstrated by the findings that men with an inactivating mutation in aromatase or a nonfunctional ERα had osteopenia and continued longitudinal growth after sexual maturation. The aim of the present study was to evaluate the role of different domains of ERα for the effects of E2 and selective estrogen receptor modulators (SERMs) on bone mass in males. Three mouse models lacking either ERαAF‐1 (ERαAF‐1⁰), ERαAF‐2 (ERαAF‐2⁰), or the total ERα (ERα^?/?) were orchidectomized (orx) and treated with E2 or placebo. E2 treatment increased the trabecular and cortical bone mass and bone strength, whereas it reduced the thymus weight and bone marrow cellularity in orx wild type (WT) mice. These parameters did not respond to E2 treatment in orx ERα^?/? or ERαAF‐2⁰ mirx ERαAF‐1⁰ mice were tissue‐dependent, with a clear response in cortical bone parameters and bone marrow cellularity, but no response in trabecular bone. To determine the role of ERαAF‐1 for the effects of SERMs, we treated orx WT and ERαAF‐1⁰ mice with raloxifene (Ral), lasofoxifene (Las), bazedoxifene (Bza), or vehicle. These SERMs increased total body areal bone mineral density (BMD) and trabecular volumetric BMD to a similar extent in orx WT mice. Furthermore, only Las increased cortical thickness significantly and only Bza increased bone strength significantly. However, all SERMs showed a tendency toward increased cortical bone parameters. Importantly, all SERM effects were absent in the orx ERαAF‐1⁰ mice. In conclusion, ERαAF‐2 is required for the estrogenic effects on all evaluated parameters, whereas the role of ERαAF‐1 is tissue‐specific. All evaluated effects of Ral, Las and Bza are dependent on a functional ERαAF‐1. Our findings might contribute to the development of bone‐specific SERMs in males. © 2013 American Society for Bone and Mineral Research.