Effect of ipriflavone on bone mass in elderly osteoporotic women

Isoflavone intervention and its impact on bone mineral density in postmenopausal women: a systematic review and meta-analysis of randomized controlled trials

Due to estrogen deficiency, postmenopausal women may suffer from an imbalance in bone metabolism that leads to bone fractures. Isoflavones, a type of phytoestrogen, have been suggested to improve bone metabolism and increase bone mass. Therefore, isoflavones are increasingly recognized as a promising natural alternative to hormone replacement therapy for postmenopausal women who face a heightened risk of osteoporosis and are susceptible to bone fractures.

PURPOSE

This study aimed to evaluate the efficacy of isoflavone interventions on bone mineral density (BMD) in postmenopausal women by means of systematic review and meta-analysis.

METHODS

The electronic database searches were performed on PubMed, Embase, Scopus, and Cochrane Library databases, covering literature up to April 20, 2023. A random-effects model was used to obtain the main effect estimates, with a mean difference (MD) and its 95% confidence interval (CI) as the effect size summary. The risk of bias assessment was conducted using the Risk of Bias 2 (RoB2) tool.

RESULTS

A total of 63 randomized controlled trials comparing isoflavone interventions (n = 4,754) and placebo (n = 4,272) were included. The results indicated that isoflavone interventions significantly improved BMD at the lumbar spine (MD = 0.0175 g/cm2; 95% CI, 0.0088 to 0.0263, P < 0.0001), femoral neck (MD = 0.0172 g/cm2; 95% CI, 0.0046 to 0.0298, P = 0.0073), and distal radius (MD = 0.0138 g/cm2; 95% CI, 0.0077 to 0.0198, P < 0.0001) in postmenopausal women. Subgroup analysis showed that the isoflavone intervention was effective for improving BMD when the duration was ≥ 12 months and when the intervention contained genistein of at least 50 mg/day.

CONCLUSION

This systematic review and meta-analysis suggests that isoflavone interventions, especially those containing genistein of at least 50 mg/day, can effectively enhance BMD in postmenopausal women.

Women's health: selected topics

Complementary and alternative medicine (CAM) therapies have become increasingly popular for the treatment of a variety of conditions. The World Health Organization has recognized the value of traditional healing techniques, which are classified as CAM, for 30 years. In the United States nearly 50% of women use CAM for common medical conditions, significantly more than men. This pattern is frequently seen in the treatment of women's health conditions such as infertility, premenstrual syndrome, and menopause. This article provides an integrative approach for conditions commonly encountered in the primary care setting among women, discusses alternative therapies used to treat these health conditions, and provides an evidence-based summary of recommendations based on a review of the literature.

Effects of ipriflavone on augmented bone using a guided bone regeneration procedure

: This study investigated the effects of ipriflavone (IP) on augmented bone using a guided bone regeneration (GBR) procedure. In 15 rabbits, two titanium caps were placed into calvarial bone for GBR. The animals were divided into three groups: the No-IP (no intake of IP), Post-IP (IP orally, 10 mg/kg/day after GBR), and Pre-IP (IP intake beginning before GBR) groups. One cap was removed from each rabbit after 3 months, and the remaining site was a control. One month after one cap removal, all the animals were euthanized, and histologic and histomorphometric analyses were performed. In all of the groups, the newly generated tissue was of varying size, and it consisted of thin pieces of mineralized bone and large marrow spaces with fat cells and some hematopoietic cells. In all of the control sites, the newly generated tissue was noted and almost filled the space under the cap. There was a significant difference between groups No-IP and Pre-IP (93.8+/-4.6% vs. 98.5+/-0.8%, P<0.05). The tissue generated at the test sites in all of the groups was resorbed, and its original shape and volume were not maintained 1 month after one cap removal. In particular, the greatest percentage, approximately 20% of the newly generated tissue, was resorbed in the No-IP group (93.8+/-4.6% vs. 73.9+/-3.7%, P<0.05), and approximately 11% and 15% in groups Post-IP and Pre-IP, respectively. The relative amount of mineralized bone generated at the control and test sites was significantly larger in groups Post-IP and Pre-IP when compared with group No-IP, except for the test site between groups No-IP and Post-IP (P<0.05). Therefore, the amount of mineralized tissue generated appeared to increase with an increase in the total IP dose. Within the limitations of this rabbit experimental model, we conclude that the daily intake of IP before or after GBR inhibits the resorption of augmented tissue and would be useful for improving the quality of newly generated bone beyond the skeletal envelope.

Anabolic agents and the bone morphogenetic protein pathway

A major unmet need in the medical field today is the availability of suitable treatments for the ever-increasing incidence of osteoporosis and the treatment of bone deficit conditions. Although therapies exist which prevent bone loss, the options are extremely limited for patients once a substantial loss of skeletal bone mass has occurred. Patients who have reduced bone mass are predisposed to fractures and further morbidity. The FDA recently approved PTH (1-34) (Teriparatide) for the treatment of postmenopausal osteoporosis after both preclinical animal and clinical human studies indicated it induces bone formation. This is the only approved bone anabolic agent available but unfortunately it has limited use, it is relatively expensive and difficult to administer. Consequently, the discovery of low cost orally available bone anabolic agents is critical for the future treatment of bone loss conditions. The intricate process of bone formation is co-ordinated by the action of many different bone growth factors, some stored in bone matrix and others released into the bone microenvironment from surrounding cells. Although all these factors play important roles, the bone morphogenetic proteins (BMPs) clearly play a central role in both bone cartilage formation and repair. Recent research into the regulation of the BMP pathway has led to the discovery of a number of small molecular weight compounds as candidate bone anabolic agents. These agents may usher in a new wave of more innovative and versatile treatments for osteoporosis as well as orthopedic and dental indications.

Phytoestrogen genistein acts as an estrogen agonist on human osteoblastic cells through estrogen receptors alpha and beta

Genistein, a soybean isoflavone, has estrogen-like activity in mammals, including the prevention of bone loss. However, whether its mechanism of action on bone turnover is distinct from that of estrogen or raloxifene is unknown. Although genistein has been reported to bind both estrogen receptor (ER) isoforms (alpha and beta), little is known concerning differential activation of gene expression via these ER isoforms. To examine this question, comparison of the responses of normal fetal osteoblast (hFOB) cells stably expressing either ERalpha (hFOB/ERalpha9) or ERbeta (hFOB/ERbeta6), to treatment with genistein, 17beta-estradiol (E(2)) or raloxifene were conducted. In hFOB/ERalpha9 cells, both genistein and E(2) increased the endogenous gene expression of the progesterone receptor (PR), the proteoglycan versican, and alkaline phosphatase (AP), but inhibited osteopontin (OP) gene expression and interleukin-6 (IL-6) protein levels. Raloxifene had no effect on these bone markers. Genistein, but not raloxifene, also mimicked E(2) action in the hFOB/ERbeta6 cells increasing PR gene expression and inhibiting IL-6 production. To determine whether the gene regulatory actions of genistein in human osteoblast cells occur at the level of transcription, its action on the transcriptional activity of a PR-A promoter-reporter construct was assessed. Both genistein and E(2) were found to stimulate the PR promoter in the hFOB cell line when transiently co-transfected with either ERalpha or ERbeta. Whereas hFOB cell proliferation was unaffected by E(2), raloxifene or genistein at low concentrations, higher concentrations of genistein, displayed significant inhibition. Together, these findings demonstrate that genistein behaves as a weak E(2) agonist in osteoblasts and can utilize both ERalpha and ERbeta.

Fitoestrogênios: posicionamento do Departamento de Endocrinologia Feminina da Sociedade Brasileira de Endocrinologia e Metabologia (SBEM)

Para avaliar a utilidade dos fitoestrogênios (FE) na terapia de reposição hormonal da menopausa (TRHM), o Departamento de Endocrinologia Feminina da SBEM reuniu um grupo de especialistas para fazer uma revisão bibliográfica e selecionar trabalhos nos quais a metodologia adotada demonstrasse rigor científico. Os FE têm ações estrogênicas e antiestrogênicas, predominantemente sobre os receptores de estrogênios (E) beta, com potência estrogênica muito inferior à do estradiol. O conteúdo de FE nas suas fontes vegetais é variável, dependendo da forma de cultivo, safra, armazenamento e industrialização. Também a conversão dos precursores em fitormônios ativos no organismo humano tem grande variabilidade individual. A maior parte das pesquisas com FE é realizada in vitro ou com animais de laboratório, nem sempre podendo ser extrapoladas para humanos. Com relação à síndrome do climatério, alguns estudos sugerem discreta melhora dos fogachos, sem modificação do ressecamento vaginal ou das alterações do humor. No metabolismo lipídico, alimentação rica em soja, mas não isoflavonas isoladamente, promove redução do colesterol total, do LDL-col e dos triglicerídeos, mas não elevam o HDL-col, como os E, e podem causar aumento da lipoproteína (a), que os E contribuem para diminuir. Embora alguns estudos de curta duração sugiram aumento da densidade mineral óssea com uso de isoflavonas, não há demonstração de redução de fraturas. Conclui-se que não há evidências convincentes que justifiquem o uso de FE ou alimentação rica em soja como alternativa para a TRHM.

Phytoestrogens and healthy aging: gaps in knowledge. A workshop report

There is an increasing public interest in foods and dietary supplements containing phytoestrogens for the maintenance of health. A workshop was convened to assess evidence for the potential benefits of phytoestrogen-containing foods or supplements on diseases or conditions affecting older populations. Preclinical, clinical, and epidemiologic data on the cardiovascular system, various cancers, bone diseases, and menopausal symptoms were the focus of the discussions. Research on the basis of consumer food choices as well as a presentation from the FDA regarding approval of the use of soy foods to reduce the risk of cardiovascular disease were also presented. Based on the information presented, isoflavone-containing soy foods may have favorable effects on the cardiovascular system, but major knowledge gaps still exist regarding effects ofphytoestrogen supplements on bone diseases, various cancers, menopausal symptoms, and cognitive function.

Prevention and treatment of osteoporosis in women with breast cancer

Women who have had breast cancer may be at higher risk for osteoporosis than other women. First, they are more likely to undergo early menopause, due to chemotherapy-induced ovarian failure or oopherectomy. In addition, chemotherapy may have a direct adverse effect on bone mineral density (BMD), and osteoclastic activity may increase from the breast cancer itself. While estrogen therapy is considered standard for the prevention and treatment of osteoporosis, use of estrogen in women with a history of breast cancer is usually contraindicated. The approach to osteoporosis in women with breast cancer is also affected by the use of tamoxifen in many, as this drug appears to have opposite effects on BMD in premenopausal and postmenopausal women. We have reviewed therapeutic alternatives for the prevention and treatment of osteoporosis, focusing on patients with a history of breast cancer. Alendronate and raloxifene are currently approved in the United States for the prevention of osteoporosis; alendronate, raloxifene, and calcitonin are approved for treatment. Alendronate has the greatest positive effect on BMD and reduces the incidence of vertebral and nonvertebral fractures. Raloxifene and calcitonin appear to reduce the incidence of vertebral fractures; their effects on the incidence of nonvertebral fractures are not yet proven. Although no published studies specifically address the use of these approved agents for osteoporosis in women with breast cancer, understanding their relative effects on BMD in postmenopausal women in general will facilitate therapy selection in this population. Postmenopausal women with a history of breast cancer should undergo bone mineral analysis. Normal results and absence of other risk factors ensure that calcium and vitamin D intake are adequate. If osteopenia or other risk factors are present, preventive therapy with alendronate or raloxifene should be considered. For osteoporosis, treatment with alendronate should be strongly considered. Raloxifene and calcitonin are alternatives when alendronate is contraindicated. Further studies are needed to evaluate the optimal timing of initial bone mineral analysis in premenopausal women after breast cancer diagnosis and to determine the value of preventive treatment in women scheduled to undergo chemotherapy.

Steroid-induced osteoporosis in systemic lupus erythematosus

The patient with SLE is at considerable risk of osteoporosis, because of the inflammatory disease itself, its consequences, and its treatments. Because of their extensive use, glucocorticoids are thought to be the most frequent cause of drug-related osteoporosis and may be responsible for much of the bone loss in lupus. This article focuses on the mechanisms of steroid-induced osteoporosis in SLE and outlines strategies for prevention and treatment.

Bone density changes in postmenopausal women with the administration of ipriflavone alone or in association with low-dose ERT

Ipriflavone is a synthetic flavonoid that has been shown to exert a direct inhibitory effect on osteoclastic activity and possibly stimulate the osteoblast activity in different experimental models. The aim of the present study was to evaluate the effects of either ipriflavone alone or ipriflavone plus low dose hormone replacement therapy (HRT) in the prevention of postmenopausal bone loss. Patients were randomly allocated to different treatment groups receiving calcium (500 mg/day, control group), continuous HRT (25 or 50 micrograms/day of transdermal 17 beta-estradiol) plus medrogestone 5 mg/day for 12 days/month, ipriflavone at the standard dose of 600 mg/day, or finally ipriflavone 600 mg/day plus 17 beta-estradiol 25 micrograms/day plus medrogestone 5 mg/day for 12 days/month. No significant differences in basal levels of biochemical markers of bone turnover or in basal bone mineral density (BMD) values were evident in the different groups. In the control group after 12 months, spine BMD showed a significant (p < 0.05) 3.41% decrease. The pattern of BMD modification was significantly different from controls in the high dose HRT group (+1.84%), the ipriflavone group (+0.11%), and the combined ipriflavone/HRT group (-0.22%). Conversely, the BMD pattern in the low dose HRT group (-0.55%) was similar to that observed in controls. Thus, present results confirm that ipriflavone and 50 micrograms/day of transdermal 17 beta-estradiol are effective measures in the prevention of postmenopausal osteopenia. A lower transdermal estrogen dose is unable to increase the antiresorptive effect of ipriflavone and did not exert any further action in the prevention of postmenopausal osteopenia.

Intestinal uptake and biliary excretion of the isoflavone genistein in rats

The intestinal absorption, biliary excretion and metabolism of genistein, a potent and specific protein tyrosine kinase inhibitor that occurs naturally in soy foods, was examined in anesthetized, adult female rats fitted with indwelling biliary cannulas. 4-14C-Genistein, when infused into the duodenum, was rapidly absorbed from the intestine, taken up by the liver and excreted into the bile as its 7-O-beta-glucuronide conjugate. Cumulative recovery of 14C-radioactivity in the bile over a 4-h period was 70-75% of the dose. When genistein was infused into the portal vein, it was also taken up efficiently by the liver, conjugated with glucuronic acid and transported into bile. However, portal blood collected after duodenal infusions of genistein contained mostly genistein 7-O-beta-glucuronide, suggesting that in vivo glucuronidation occurred in the intestinal wall rather than the liver. This was confirmed using everted intestinal sac preparations. Reinfusion of genistein 7-O-beta-glucuronide into the duodenum or into the mid small intestine resulted in its reappearance in the bile, albeit more slowly than when genistein was infused. Over a 4-h collection period, the cumulative recovery of 14C-radioactivity in bile was 27 and 70-75% of the administered dose for duodenal and ileal infusions, respectively. These data indicate that genistein is highly bioavailable in rats and because of its enterohepatic circulation may accumulate within the gastrointestinal tract.

Effects on cultured neonatal mouse calvaria of the flavonoids isolated from Boerhaavia repens

A MeOH extract from the whole plant of Boerhaavia repens was found to inhibit bone resorption induced by parathyroid hormone (PTH) in tissue culture. Systematic separation of the MeOH extract afforded one new and two known flavonoid glycosides, namely, eupalitin 3-O-beta-D-galactopyranosyl-(1-->2)-beta-D-glucopyranoside (1), eupalitin 3-O-beta-D-galactopyranoside (2), and 6-methoxykaempferol 3-O-beta-D-(1-->6)-robinoside (3). The structure of the new compound 1 was determined using spectroscopic techniques. The inhibitory activity of these substances toward bone resorption induced by PTH was evaluated, and compounds 1 and 2 were found to exhibit significant activity.

Effects of ipriflavone and its metabolites on human articular chondrocytes cultivated in clusters

Ipriflavone (IP) is an isoflavone derivative that was suggested to have bone-sparing effects in post-menopausal and senile osteoporosis. A moderate stimulatory effect of IP and its metabolites on proliferation of osteoblastic cells was reported in rat osteoblastic osteosarcoma cell line. We investigated the effects of different concentrations (0, 1, 10 and 100 micrograms/ml) of IP and its metabolites (MET I, II, III and V) on the incorporation of [3H] thymidine and production of proteoglycans (PG) and type II collagen (COL II) by human articular chondrocytes during a 12-day period, in a three-dimensional chondrocyte culture model. [3H]thymidine uptake was measured in chondrocyte clusters, and specific PG and COL II radioimmunoassays were performed every 4 days on the culture medium and cell clusters. Incubation with IP or its metabolites did not affect [3H]thymidine uptake regardless of the dose. PG released into the culture medium and PG cluster content rose significantly (P < 0.025) in presence of IP (1, 10 and 100 micrograms/ml). MET I increased PG release in culture medium (10 and 100 micrograms/ml) and PG cluster content (100 micrograms/ml). MET II has no effect on PG production. MET III increased PG in culture medium (100 microgram/ml) but did not influence PG cluster content while MET V (100 micrograms/ml) increased both PG release in culture medium and PG cluster content. COL II release in culture medium and COL II cluster content were significantly (P < 0.025) increased in presence of IP (10 and 100 micrograms/ml), MET III (1, 10 and 100 micrograms/ml) or MET V (100 micrograms/ml). MET I and II did not significantly affect COL II production.

Efficacy of ipriflavone and 1 alpha vitamin D therapy for the cessation of vertebral bone loss

OBJECTIVE

This study investigated whether a combined regimen of ipriflavone and 1 alpha vitamin D is effective in stopping postmenopausal bone loss.

METHODS

Ninety-eight postmenopausal women were recruited and randomly assigned to one of four groups: group 1, ipriflavone alone; group 2, 1 alpha vitamin D alone; group 3, combined regimen of ipriflavone and 1 alpha vitamin D; group 4, no treatment. Vertebral bone mineral density, measured by dual energy X-ray absorptiometry, serum alkaline phosphatase, calcitonin, parathyroid hormone, osteocalcin, urinary calcium and hydroxyproline were measured before and at the 6th, 12th and 18th month of the study. All comparisons were made using Student's t-test of means.

RESULT

There was a significant reduction in vertebral bone loss in the patients receiving the combined therapy (mean loss after 18 months 0.33% in the combination group vs. 2.37%, 1.15% and 3.70% in the ipriflavone alone, 1 alpha vitamin D alone, and control groups, respectively; P < 0.001).

CONCLUSION

These findings suggest that the combined regimen could prevent postmenopausal bone loss.

Metabolic and bone effects after administration of ipriflavone and salmon calcitonin in postmenopausal osteoporosis

Forty postmenopausal women with bone mineral density (BMD) > 2 standard deviations below the mean value for healthy age matched controls were enrolled into an open controlled study to evaluate the metabolic and bone effects of ipriflavone (IP) versus salmon calcitonin (sCT) over a 12 month period. Both treatments significantly increased BMD after 6 and 12 months. A 4.3% increase of BMD was obtained in the IP treated group and a 1.9% in the sCT treated group after 12 months (p < 0.001 between treatments). Bone metabolism markers (serum osteocalcin, alkaline phosphatase, urinary calcium and hydroxyproline/creatinine ratio) were significantly reduced in both groups (p < 0.001). The reduction of urinary hydroxyproline/creatinine ratio was significantly greater (p < 0.05) in the IP group after 12 months. Both treatments were well tolerated. Four patients in the IP group reported gastralgia while two patients in the sCT group reported pruritus and one patient epistaxis.

Ipriflavone: pharmacological properties and usefulness in postmenopausal osteoporosis

Ipriflavone (IP) is an isoflavone derivative available in several countries for investigational and/or therapeutic use. Inhibition of bone resorption was demonstrated in several models, both in vitro and in vivo for IP and its metabolites. Their mechanisms of action on bone are not yet fully elucidated but some of them are widely accepted. IP does not possess, per se, any estrogenic activity. It appears that IP-related inhibition of bone resorption might be mediated by an indirect effect on osteoclast and related to an inhibition of recruitment and/or differentiation of pre-osteoclast, maybe through a modulation of osteoblast response to PTH. Clinical studies in Paget's disease of bone or primary hyperparathyroidism have confirmed preferential inhibition of bone resorption suggesting a clinical interest in postmenopausal osteoporosis. Preliminary (1 year) results of double blind placebo controlled studies designed in postmenopausal and senile osteoporosis confirm a reduction in bone turnover rate in patients treated with 600 mg/day of IP, resulting in a significant bone-sparing effect both at lumbar and radial levels. All clinical and pharmacological trials confirm a very good tolerance of IP with a frequency of adverse reactions equal to that observed during administration of a placebo. Providing ongoing studies will confirm the actual promising preliminary results, IP seems a very interesting new non hormonal approach for prevention and treatment of postmenopausal and senile osteoporosis.

New treatment strategies: ipriflavone, strontium, vitamin D metabolites and analogs

Drugs used to treat osteoporosis can be grouped in two main categories: those that decrease bone resorption and those that increase bone formation. Antiresorptive drugs are active in preventing bone fractures in patients characterized by a negative calcium balance. However, because antiresorptive agents are often coupled to inhibition of bone formation, inhibitors of bone resorption may not be candidates as potential curative drugs in osteoporosis. Conversely, drugs that act by increasing bone formation produce an increase in bone mass above the fracture threshold; therefore, these agents are good candidates for the treatment of osteoporosis. The ideal curative drug in osteoporosis should have the ability both to decrease bone resorption and to maintain a relatively high rate of bone formation, thus inducing a favorable uncoupling of bone remodeling.