Effects of ospemifene, a novel SERM, on biochemical markers of bone turnover in healthy postmenopausal women.

Ospemifene is a novel selective estrogen receptor modulator (SERM). Here we studied the effects of ospemifene on bone turnover in postmenopausal women. This was a randomized, double-blind study in which 159 healthy postmenopausal women received 30 (n = 40), 60 (n = 40) or 90 mg (n = 40) of ospemifene or placebo (n = 39) for 3 months. Bone resorption was assessed by measuring the urinary outputs of N- and C-terminal crosslinking telopeptides of type I collagen (NTX and CTX, respectively). Bone formation was assessed by measuring the levels of procollagen type I N propeptide (PINP), procollagen type I C propeptide (PICP), and bone-specific alkaline phosphatase (bone ALP) in serum. All markers were studied at baseline, 3 months, and 2-4 weeks after cessation of the medication. Ospemifene decreased bone resorption dose-dependently, as seen from falls in NTX by 6.1, 9.4 and 12.9% in the 30, 60 and 90 mg ospemifene groups, respectively (p < 0.05 for all dose levels when compared to placebo). CTX values decreased in the 90 mg ospemifene group by 4.8% (p < 0.05). A dose-dependent decrease was also observed in the bone formation markers: PINP values decreased by 9.8 (p < 0.05) and 15.3% (p < 0.01), and PICP values by 12.0 and 11.9% in the 60 and 90 mg ospemifene groups, respectively. Bone ALP decreased in 60 and 90 mg ospemifene groups by 1.9 and 2.6%, respectively (p < 0.05 for both dose levels when compared to placebo). These results show that ospemifene is effective in reducing bone turnover in postmenopausal women.     

Gene therapy for restenosis: current status

Atherosclerosis is a major cause of morbidity and mortality in Western world. Vascular occlusion caused by atherosclerosis usually requires invasive treatment, such as surgical bypass or angioplasty. However, bypass graft failure and restenosis limit the usefulness of these procedures, with 20% of patients needing a new revascularisation procedure within 6 months of angioplasty. Numerous pharmacological agents have been investigated for the prevention of restenosis but none has shown undisputed efficacy in clinical medicine. Gene transfer offers a novel approach to the treatment of restenosis because of easy accessibility of vessels and already existing gene delivery methods. It can be used to overexpress therapeutically important proteins locally without high systemic toxicity, and the therapeutic effect can be targeted to a particular pathophysiological event. Promising results have been obtained from many pre-clinical experiments using therapeutic genes or oligonucleotides to prevent restenosis. Early clinical trials have shown that plasmid- and adenovirus-mediated vascular gene transfers can be conducted safely and are well tolerated. Ex vivo gene therapy with E2F-decoy succeeded in reducing graft occlusion rate after surgical bypass in a randomised, double-blind clinical trial. In the future, further development of gene delivery methods and vectors is needed to improve the efficacy and safety of gene therapy. Also, better knowledge of vascular biology at the molecular level is needed to find optimal strategies and gene combinations to treat restenosis. Provided that these difficulties can be solved, gene therapy offers an enormous potential for clinical medicine in the future.     

Gonadotropin receptors of human corpus luteum during menstrual cycle and pregnancy.

Specific high-affinity low-capacity binding of human chorionic gonadotropin (hCG) and lutropin (hLH) was demonstrated in the plasma membrane fractions of human corpora lutea. The number of binding sites for both hormones increased from early to late luteal phase, whereas regressing corpus luteum from proliferative phase did not bind either hormone. On the basis of apparent dissociation constants the affinity of the receptor for hLH is highest during early luteal phase and decreases toward the end of the cycle, which may reflect an increasing insensitivity of the corpus luteum to circulating hLH. By contrast, the affinity of the receptor for hCG is highest in the midluteal phase. There are gonadotropin binding sites in the human corpus luteum also during pregnancy, but they are saturated by endogenous hCG. Evidence for this was obtained by elution of hCG with 0.15M sodium chloride at pH 2.3 from washed plasma membrane fractions of luteal tissue from six to 16 week's gestation. After acid treatment and neutralization these preparations showed specific binding for 125I-labeled hCG, but not for 125I-labeled hLH. Our results demonstrate a shift in the balance of affinity of the gonadotropin receptor from hLH to hCG during the course of luteal phase, and during pregnancy the binding sites appear to be available for hCG only.     

Human endometrium and menstrual fluid contain placental protein 5 (PP5)

Placental protein 5 (PP5), a serine protease inhibitor, wasfound in the endometrium and menstrual fluid of non-pregnantwomen. PP5 was present in all 16 endometrial samples taken atvarious phases of the menstrual cycle. In the secretory phase,the endometrial PP5 content was higher (median 17.4 µg/gprotein; n = 8) than in the proliferative phase (median 3.8µg/g protein; n = 8). In gel filtration, endometrial tissuehomogenates yielded one immunoreactive peak corresponding toa mol. wt of 28 000 daltons, whereas placental PP5 eluted at32 000 daltons. In sodium dodecyl sulphate polyacrylamide gelelectrophoresis, endometrial PP5 co-migrated with purified placentalPP5 corresponding to a mol. wt of 30 000 daltons. All menstrualfluid samples (n = 14) contained immunoreactive PP5 at concentrationsfrom 77 to 1150 µg/1. The mol. wt of menstrual fluid PP5-immunoreactivitywas 13 000 daltons. The dose-response curves of purified PP5standard and endometrial and menstrual fluid PP5 were parallelin the PP5 radioimmunoassay. The higher concentration of PP5in secretory endometrium indicates association of PP5 with endocrineevents of the menstrual cycle.     

Immunohistochemical localization of the insulinlike growth factor binding protein-1 in female reproductive tissues by monoclonal antibodies

Human insulinlike growth factor binding protein-1 (hlGFBP-1) is a secretory protein that modulates the receptor-binding and biological actions of the insulinlike growth factor I (IGF-I). Human endometrium expresses the mRNA for IGFBP-1, and this protein is secreted by the secretory phase and pregnancy endometrium as well as by ovarian granulosa cells in vitro. In this study, we examined the cellular localization of IGFBP-1 in female reproductive tissues by using a purified monoclonal antibody Mab 6303 with an immunoperoxidase technique. Proliferative- and early secretory-phase endometrium as well as all extrauterine tissues except decidualized cells at the implantation site on the ovaries of ovarian pregnancies were negative for IGFBP-1. In midsecretory-phase endometrium, focal staining was first observed in the cytoplasm of glandular epithelial cells, with weaker staining in the stromal cells. In late secretoryphase endometrium, strong immunostaining was observed in predecidualized stromal cells, with weak focal staining remaining in some of the glandular epithelial cells. In early pregnancy, intense staining was detected in the cytoplasm of decidualized stromal cells of zona compacta in each sample, whereas the nondecidualized stromal cells remained unstained. Strong to medium staining was detected simultaneously in the glandular epithelial cells in 70% of the early pregnancy specimens. In term pregnancy, IGFBP-1 was localized in decidual cells of placental bed and decidua parietalis. Immunolocalization of IGFBP-1 to both endometrial epithelial and stromal cells, although only stromal cells express the gene of IGFBP-1 [14], supports the hypothesis of paracrine actions between these cells. The localization of IGFBP-1 to decidualized cells at the extrauterine implantation sites implies its association with decidual differentiation.     

Insulin-like growth factors in obstetrics

Data from a number of studies reported during the past two decades indicate that the insulin-like growth factor (IGF) system, including IGF-I and IGF-II, their receptors and six high-affinity binding proteins, is involved in the control of foetal and placental growth and development. Recent studies that addressed the role of the IGF system in pregnancy and the clinical usefulness of IGF and IGF-binding protein measurements in obstetrics are reviewed and discussed.     

Markers of collagen metabolism and insulin-like growth factor binding protein-1 in term infants

AIM: To study the relation between fetal growth and markers of collagen metabolism and insulin-like growth factor binding protein-1 (IGFBP-1) in term infants. METHODS: Cord vein plasma was obtained from 67 term infants of gestational age 37.1-41.7 weeks (39 appropriate for gestational age (AGA), 11 large for gestational age (LGA; relative birth weight >/= 2.0 SD), and 17 small for gestational age (SGA; relative birth weight 0.05). CONCLUSIONS: In the term fetus, collagen metabolism is primarily dependent on maturity and not on intrauterine growth status, whereas IGFBP-1 reflects intrauterine growth independently of maturity.     

Single nucleotide polymorphisms of the melanocortin-3 receptor gene are associated with substrate oxidation and first-phase insulin secretion in offspring of type 2 diabetic subjects

CONTEXT: The melanocortin-3 receptor (MC3R) is a part of the melanocortin system that regulates appetite and energy metabolism. The Thr/Thr 6 and Val/Val81 [corrected] polymorphisms of the MC3R gene have been previously associated with high insulin levels and obesity in children. OBJECTIVE: The objective was to determine whether single nucleotide polymorphisms (SNPs) of MC3R are associated with glucose, lipid, and energy metabolism. DESIGN, SETTING, AND PARTICIPANTS: We screened the Lys/Thr6 and Ile/Val81 mutations and six noncoding SNPs of MC3R in a cross-sectional study of 216 middle-aged nondiabetic Finnish subjects who were offspring of type 2 diabetic patients. MAIN OUTCOME MEASURES: Insulin secretion was evaluated by an iv glucose tolerance test, and insulin sensitivity and energy metabolism by the hyperinsulinemic euglycemic clamp and indirect calorimetry. RESULTS: Carriers of the Lys 6 and Ile 81 [corrected] alleles had significantly lower rates of lipid oxidation [0.85 +/- 0.38 vs. 1.00 +/- 0.43 mg/kg of lean body mass (LBM)/min; P = 0.022, adjusted for sex, body mass index, age, and family relationship] and higher rates of glucose oxidation in the fasting state (11.28 +/- 4.64 vs. 9.71 +/- 4.53 micromol/kg of LBM/min; P = 0.031) than subjects with the Thr/Thr 6 and Val/Val 81 [corrected] genotypes. They had lower rates of lipid oxidation during the hyperinsulinemic clamp (0.32 +/- 0.41 vs. 0.44 +/- 0.34 mg/kg of LBM/min; P = 0.021) and higher insulin levels in an iv glucose tolerance test (insulin under the curve during the first 10 min, 3220 +/- 1765 vs. 2454 +/- 1538 pmol/liter.min; P = 0.025) compared to subjects with the common genotypes. CONCLUSIONS: Our results suggest that SNPs of MC3R may regulate substrate oxidation and first-phase insulin secretion.     

Uterine endocrinology and paracrinology: insulin-like growth factor binding protein-1 and placental protein 14 revisited

A large number of proteins and peptides have been identifiedin the endometrium where they are likely to exert local biologicaleffects. These substances may be enzymes, their inhibitors,proteinases, proteinase inhibitors, hormones, or bioactive peptideswith diverse functions. Endometrial function and embryo—endometrialinteractions require synchronized actions between endocrineand local factors. As examples of local factors recent studieson the insulin-like growth factor (IGF) system and placentalprotein 14 (PP14) are reviewed. IGF binding protein-1 (IGFBP-1)and PP14 are products of the secretory phase endometrium: IGFBP-1is produced by decidualized stromal cells and PP14 by glandularepithelial cells. IGFBP-1 may inhibit the action of IGFs atthe endometrial-trophoblastic interphase, and it may also havea role in stromal—epithelial interaction. PP14 has immunosuppressiveproperties, and recent findings indicate that it may play apart in the fertilization process by inhibiting binding of spermatozoato the zona.