Rationale and study design of a randomized, placebo-controlled, double-blind phase 2b trial to evaluate efficacy, safety, and tolerability of an oral glutaminyl cyclase inhibitor varoglutamstat (PQ912) in study participants with MCI and mild AD-VIVIAD.

BACKGROUND: Varoglutamstat (formerly PQ912) is a small molecule that inhibits the activity of the glutaminyl cyclase to reduce the level of pyroglutamate-A-beta (pGluAB42). Recent studies confirm that pGluAB42 is a particular amyloid form that is highly synaptotoxic and plays a significant role in the development of AD. METHODS: This paper describes the design and methodology behind the phase 2b VIVIAD-trial in AD. The aim of this study is to evaluate varoglutamstat in a state-of-the-art designed, placebo-controlled, double-blind, randomized clinical trial for safety and tolerability, efficacy on cognition, and effects on brain activity and AD biomarkers. In addition to its main purpose, the trial will explore potential associations between novel and established biomarkers and their individual and composite relation to disease characteristics. RESULTS: To be expected early 2023 CONCLUSION: This state of the art phase 2b study will yield important results for the field with respect to trial methodology and for the treatment of AD with a small molecule directed against pyroglutamate-A-beta. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04498650.

Matrix Metalloproteinase Mediated Type I Collagen Degradation - An Independent Risk Factor for Mortality in Women.

Chronic fibro-proliferative diseases are associated with nearly 45% of all deaths in the developed world. Matrix metalloproteinase (MMP) mediated remodeling of the extracellular matrix (ECM) plays an important role in disease development. Degradation of type I collagen is considered having a major role in this matter. C1M is a biomarker measuring type I collagen degradation fragments in blood. The aim of the current study was to investigate whether MMP mediated type I collagen degradation (C1M) was predictive of mortality in a large prospective cohort of Danish women aged 48-89 (n = 5855). Subjects with high serum C1M showed significant increased mortality. The adjusted three year HR was 2.02 [95% CI: 1.48-2.76] for all-cause mortality, 2.32 [95% CI: 1.51-3.56] for cancer and 1.77 [95% CI: 0.98-3.17] for cardiovascular diseases. The adjusted nine year HR was 1.50 [95% CI: 1.28-1.75] for all-cause mortality, 1.49 [95% CI: 1.16-1.90] for cancer and 1.69 [95% CI: 1.27-2.24] for cardiovascular diseases. High MMP-mediated type I collagen degradation was associated with increased mortality. Subjects with high C1M had a 2-fold increase in mortality compared to subjects with low levels of this collagen degradation product.

OA phenotypes, rather than disease stage, drive structural progression--identification of structural progressors from 2 phase III randomized clinical studies with symptomatic knee OA.

BACKGROUND/PURPOSE: The aim of this study was to identify key characteristics of disease progression through investigation of the association of radiographic progression over two years with baseline Joint Space Width (JSW), Kellgren-Lawrence (KL) grade, Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain, Joint Space Narrowing (JSN), and BMI. METHODS: Data from 2206 subjects (4390 knees) were combined for this post-hoc analysis of two randomized, double-blind, multi-center, placebo-controlled phase III trials (NCT00486434 and NCT00704847) that evaluated the efficacy and safety of 2-years treatment with oral salmon calcitonin of subjects with painful knee osteoarthritis (OA). RESULTS: There was a clear positive and significant correlation between KL grade and WOMAC pain and total WOMAC, albeit the variance in pain measures was from min-to-max for all KL categories, emphasizing the heterogeneity of this patient population and pain perception. 32% of target knees did not progress, and only 51% had changes over minimum significant change (MSC). BMI, KL-Score and WOMAC pain was diagnostic, but only KL-score and pain had prognostic value, albeit pain in a non-linear manner. CONCLUSION: These data clearly describe significant associations between KL grade, JSW, pain and BMI in patients with symptomatic knee OA. KL grade, BMI and WOMAC pain were diagnostically associated with OA based on JSW but only KL-score and pain in a non-linier fashion was prognostic. 50% of patients did not progress more than MSC, highlighting the importance for identification of structural progressors and the phenotypes associated with these. These results suggest that disease phenotypes, rather than disease status, are responsible for disease progression.

Treatment of symptomatic knee osteoarthritis with oral salmon calcitonin: results from two phase 3 trials.

PURPOSE: To evaluate the structure-modifying and symptom efficacy, as well as safety and tolerability of oral salmon calcitonin (sCT) formulated with a 5-CNAC carrier (a molecule based on Eligen(®) technology), in osteoarthritis (OA) patients with moderate to severe knee pain and joint structural damage classified as Kellgren and Lawrence (KL)2-3. METHODS AND DESIGN: This is the combined reporting of two randomized, double-blind, multi-center, placebo-controlled trials (CSMC021C2301 and CSMC021C2302), evaluating the efficacy and safety of oral sCT in patients with painful knee OA with structural manifestations, enrolling 1176 and 1030 patients, respectively. Study subjects were randomized (1:1) to oral sCT 0.8 mg twice daily or placebo (PBO) for 24 months. The primary efficacy objectives were to examine the treatment effect compared to placebo on change over 24 months in joint space width (JSW) in the signal knee measured by X-ray, and to examine the change in pain and function using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) questionnaire. Other study parameters included patient and physician global assessment, and biochemical markers of bone (CTX-I) and cartilage degradation (CTX-II). RESULTS: At the 24 month endpoint there was no statistically significant treatment effect on joint space narrowing (JSN) in any of the two studies. In CSMC021C2301 there was a treatment effect on WOMAC (sum of pain, function, stiffness, and total scores) as well as on the biomarkers of bone and joint metabolism, but due to the hierarchical testing procedure the treatment effect was not claimed statistically significant. CONCLUSIONS: The present formulation of oral sCT did not provide reproducible clinical benefits in patients with symptomatic knee OA (NCT00486434, NCT00704847).

Evaluation of the efficacy, safety and pharmacokinetic profile of oral recombinant human parathyroid hormone [rhPTH(1-31)NH(2)] in postmenopausal women with osteoporosis.

CONTEXT: Treatment of osteoporosis with subcutaneous (SC) injections of rhPTH(1-34) or rhPTH(1-84) is associated with significant improvements in BMD and reductions in osteoporotic fractures. However, subcutaneous injections can be associated with discomfort and thus deteriorating compliance. OBJECTIVE: The UGL-OR1001 trial aimed to establish the efficacy and safety parameters of a novel oral tablet formulation of rhPTH(1-31)NH(2) and matching placebo tablets and open-label teriparatide positive control in postmenopausal women with osteoporosis. DESIGN: 24 weeks of randomized, double-blind treatment with once daily doses of 5mg oral treatment or corresponding placebo, or open-label subcutaneous teriparatide. PATIENTS OR OTHER PARTICIPANTS: Women diagnosed with postmenopausal osteoporosis as detected by lumbar spine DXA, with an exclusion of those with prior treatment with bone active agents. INTERVENTION(S): Orally formulated recombinant human PTH(1-31)NH(2) and placebo, or open-label subcutaneous teriparatide as a positive control. MAIN OUTCOME MEASURE(S): The primary endpoint was to characterize the percent change from baseline in bone mineral density (BMD) at L1-L4 axial lumbar spine after 24 weeks in the rhPTH(1-31)NH(2) arm. Secondary and exploratory endpoints included safety and tolerability of the oral formulation, measurement of biochemical markers of bone turnover, and evaluation of the PK profile at first and last dose. The study was registered at ClinicalTrials.gov with the identifier: NCT01321723. RESULTS: The oral tablet formulation of rhPTH(1-31)NH(2) resulted in similar PK profiles at both timepoints with mean C(max) values similar to subcutaneous administration. In the rhPTH(1-31)NH(2) arm, a 2.2% increase in lumbar spine BMD was observed compared to baseline (p<0.001), while no change was observed in the placebo arm. Open-label teriparatide resulted in a 5.1% increase in LS BMD (p<0.001). In the oral PTH study arm, the bone formation marker osteocalcin was increased by 32%, 21% and 23% at Weeks 4, 12 and 24, respectively. There was no significant increase in the level of the bone resorption marker CTx-1. CONCLUSIONS: In summary, these data demonstrate that enteric-coated oral tablet formulation technology consistently generated robust levels of exposure of rhPTH(1-31)NH(2) leading to induction of bone formation without inducing bone resorption resulting in significantly increased levels of LS BMD. Few adverse events were observed, recommending this orally delivered drug candidate for further development.

Investigation of two novel biochemical markers of inflammation, matrix metalloproteinase and cathepsin generated fragments of C-reactive protein, in patients with ankylosing spondylitis.

OBJECTIVES: Ankylosing spondylitis (AS) is a chronic inflammation of the spine and the sacroiliac joints. Current markers of inflammation, such as C-reactive protein (CRP), are reflecting the production of an acute phase reactant rather than tissue specific inflammation, but the use of CRP as a diagnostic and prognostic marker for AS has not provided the sought accuracy and specificity. We hypothesized that local enzymatic activity in the disease-affected tissue, which is associated with extensive tissue turnover may, by cleavage, modify the CRP produced in the liver. These cleavage products may provide additional information on systemic inflammation as compared to that of full-length CRP. We investigated whether these CRP degradation products would provide additional diagnostic value in AS patients compared to full-length CRP. METHODS: CRP fragments were identified by mass-spectrometry. Two fragments were selected for ELISA development. One assay exclusively identified a matrix metalloproteinase (MMP) generated fragment, CRP-MMP, whereas the other assay identified a cathepsin generated fragment, CRP-CAT. Full-length CRP, CRP-MMP and CRP-CAT were measured in serum samples from 40 AS patients and 40 sex- and age-matched controls. RESULTS: Full-length CRP was not elevated in AS patients compared to controls, whereas CRP-MMP was elevated by 25% (p<0.001) and CRP-CAT by 50% (p<0.0001). The Area Under Curve of the Receiver-Operator Characteristic curve of CRP-CAT was the highest with 77%. CONCLUSIONS: MMP and cathepsin degraded CRP provided more discriminative diagnostic potential compared to that of full-length CRP in this current study. These data suggest that different pools of CRP may provide insight into the inflammation processes in AS.

Strontium ranelate effect in postmenopausal women with different clinical levels of osteoarthritis.

OBJECTIVE: The objective of this post hoc analysis was to investigate the effect of strontium ranelate on a cartilage degradation marker in postmenopausal women who participated in a randomized, placebo-controlled osteoporosis study. Women were stratified according to reported symptoms of osteoarthritis and to the baseline levels of a cartilage degradation marker. METHODS: The analysis included the 2617 postmenopausal women (75 years old) with osteoporosis randomized to strontium ranelate or placebo for a 36-month period. Cartilage degradation was evaluated using a validated urinary marker adjusted for creatinine (CTX-II/cr), whereas bone resorption was assessed by serum CTX-I. The presence of osteoarthritis was determined by individual interviews. RESULTS: CTX-II was significantly elevated at baseline in subjects with a history of osteoarthritis (OA+) compared to subjects who did not (OA-) (p < 0.0001), whereas CTX-I was unaffected by osteoarthritis status. Strontium ranelate caused a significant decrease from baseline in CTX-II over a 12-month period whatever the osteoarthritis status. Strontium ranelate-treated patients had a significant decrease in CTX-II compared to placebo in both OA+ and OA- groups up to 12 months, the difference remaining still significant at 36 months in patients from the OA- group (p < 0.001). CONCLUSIONS: The CTX-II profile of changes over 3 years may reflect efficacy of strontium ranelate against cartilage degradation, with an enhanced beneficial effect in subjects with early or mild clinical osteoarthritis, probably exerting its putative chondroprotective influence in early stages of the disease. Carefully controlled studies in targeted populations with early osteoarthritis are warranted to assess the role of strontium ranelate halting osteoarthritis progression.

Should subchondral bone turnover be targeted when treating osteoarthritis?

OBJECTIVE: Osteoarthritis (OA) is the most common form of arthritic disease, and it is a major cause of disability and impaired quality of life in the elderly. OA is a complex disease of the entire joint, including bone and cartilage, thereby presenting alternative approaches for treatment. This review summarizes emerging observations from cell biology to preliminary clinical trials, describing interactions between the bone and cartilage components. We speculate whether a treatment for OA would be possible without targeting the bone compartment? METHODS: Peer-reviewed articles found using pre-defined search criteria and published in the PubMed database until June 2007 are summarized. In addition, abstracts from the OsteoArthritis Research Society International (OARSI) conferences in the time period 2000-2007 were included. RESULTS: Bone and cartilage health seem to be tightly associated. Ample evidence is found for bone changes during progression of OA, including, but not limited to, increased turnover in the subchondral bone, thinning of the trabecular structure, osteophytes, bone marrow lesions and sclerosis of the subchondral plate. In addition, a range of investigations has described secondary positive effects on cartilage health when bone resorption was suppressed, or deterioration of the cartilage when resorption is increased. CONCLUSION: An optimal treatment for OA might include targeting both the bone and cartilage compartments. Hence, as several cell systems are to be targeted in a safe manner, limited options seem possible.

The influence of smoking on uterine bleeding during continuous and interrupted oral hormone therapy.

OBJECTIVE: To study the influence of smoking on uterine bleeding patterns during continuous and interrupted oral hormone therapy (HT). METHODS: Using a post-hoc strategy, we included five oral HT groups from three studies. The therapies consisted of continuous estrogen (estradiol, estradiol valerate or piperazine estrone sulfate) in combination with continuous progestogen (cyproterone acetate, gestodene or norethisterone acetate) or in combination with interrupted progestogen (norethisterone) given on days 4-6, 10-12, 16-18, 22-24 and 28-30. A total of 145 healthy postmenopausal women (54 smokers and 91 non-smokers), who had been followed for 2 years, were included in the analyses. Uterine bleeding data were collected from bleeding calendars. RESULTS: In general, smoking women experienced significantly less days with uterine bleeding per cycle than non-smoking women during continuous and interrupted HT (0.53 +/- 0.1 vs. 1.6 +/- 0.1; p < 0.001). Smoking women were also more likely than non-smoking women to be amenorrheic during these therapies (48.2% vs. 29.7%; p < 0.05). Finally, more smoking than non-smoking women attained amenorrhea during HT (94.4% vs. 76.9%p < 0.01). CONCLUSIONS: In healthy postmenopausal women, smoking may reduce uterine bleeding during interrupted and continuous HT regimens containing a broad selection of estrogens and progestogens. Further study with appropriate stratification for smoking status is warranted.

Links between cardiovascular disease and osteoporosis in postmenopausal women: serum lipids or atherosclerosis per se?

INTRODUCTION AND HYPOTHESIS: Epidemiological observations suggest links between osteoporosis and risk of acute cardiovascular events and vice versa. Whether the two clinical conditions are linked by common pathogenic factors or atherosclerosis per se remains incompletely understood. We investigated whether serum lipids and polymorphism in the ApoE gene modifying serum lipids could be a biological linkage. METHODS: This was an observational study including 1176 elderly women 60-85 years old. Women were genotyped for epsilon (epsilon) allelic variants of the ApoE gene, and data concerning serum lipids (total cholesterol, triglycerides, HDL-C, LDL-C, apoA1, ApoB, Lp(a)), hip and spine BMD, aorta calcification (AC), radiographic vertebral fracture and self-reported wrist and hip fractures, cardiovascular events together with a wide array of demographic and lifestyle characteristics were collected. RESULTS: Presence of the ApoE epsilon 4 allele had a significant impact on serum lipid profile, yet no association with spine/hip BMD or AC could be established. In multiple regression models, apoA1 was a significant independent contributor to the variation in AC. However, none of the lipid components were independent contributors to the variation in spine or hip BMD. When comparing the women with or without vertebral fractures, serum triglycerides showed significant differences. This finding was however not applicable to hip or wrist fractures. After adjustment for age, severe AC score (>or=6) and/or manifest cardiovascular disease increased the risk of hip but not vertebral or wrist fractures. CONCLUSION: The contribution of serum lipids to the modulators of BMD does not seem to be direct but rather indirect via promotion of atherosclerosis, which in turn can affect bone metabolism locally, especially when skeletal sites supplied by end-arteries are concerned. Further studies are needed to explore the genetic or environmental risk factors underlying the association of low triglyceride levels to vertebral fractures.

An update on biomarkers of bone turnover and their utility in biomedical research and clinical practice.

BACKGROUND: Maintenance of the structural and functional integrity of the skeleton is a critical function of a continuous remodeling driven by highly associated processes of bone resorption and synthetic activities driven by osteoclasts and osteoblasts, respectively. Acceleration of bone turnover, accompanied with a disruption of the coupling between these cellular activities, plays an established role in the pathogenesis of metabolic bone diseases, such as osteoporosis. During the past decades, major efforts have been dedicated to the development and clinical assessment of biochemical markers that can reflect the rate of bone turnover. Numerous studies have provided evidence that serum levels or urinary excretion of these biomarkers correlate with the rate of bone loss and fracture risk, proving them as useful tools for improving identification of high-risk patients. OBJECTIVE: The aim of the present review is to give an update on biomarkers of bone turnover and give an overview of their applications in epidemiological and clinical research. DISCUSSION: Special attention is given to their utility in clinical trials testing the efficacy of drugs for the treatment of osteoporosis and how they supplement bone mass measurements. Recent evidence suggests that biochemical markers may provide information on bone age that may have indirectly relates to bone quality; the latter is receiving increasing attention. A more targeted use of biomarkers could further optimize identification of high-risk patients, the process of drug discovery, and monitoring of the efficacy of osteoporosis treatment in clinical settings.

The long-term impact of 2-3 years of hormone replacement therapy on cardiovascular mortality and atherosclerosis in healthy women.

OBJECTIVE: The effect of hormone replacement therapy (HRT) on cardiovascular risk is intensely debated. The aim of this study was to investigate the long-term effects of HRT given for a few years on all-cause and cardiovascular mortality and the severity of atherosclerosis. METHODS: This analysis was based on a cohort of 1,458 postmenopausal women (55.8 +/- 6.1 years old) who previously participated in a number of randomized, placebo-controlled, clinical trials assessing the efficacy of 2-3 years of therapy with various estrogen plus progestin combinations for preventing bone loss. Women were followed on average for 9.8 years and came for a follow-up visit. Outcome variables were all-cause and cardiovascular mortality and the severity of atherosclerosis, as estimated by semi-quantitative scoring of vascular calcification in the lumbar aorta on lateral radiographs. RESULTS: A total of 174 women died during the observation period. All-cause mortality was decreased by 30% in the HRT+ group compared with the HRT- group (hazard ratio (HR) 0.70; 95% confidence interval (CI) 0.50-0.97) after adjusting for age, body mass index and smoking. Under the same conditions, similar results characterized mortality from cardiovascular disease (n = 61 deaths; 35.1% of all deaths) and coronary heart disease (n = 39 deaths; 22.4% of all deaths), which were decreased by 46% (HR 0.54, 95% CI 0.29-0.98, p = 0.045) and 53% (HR 0.47, 95% CI 0.21-1.03, p = 0.062), respectively. Furthermore, the mean severity score of aortic calcification at follow-up was significantly lower in hormone-treated compared to non-treated women (p < 0.0001). CONCLUSION: Women who receive 2-3 years of HRT after menopause do not have increased all-cause mortality, and results of the present study suggest relative cardiovascular benefits compared to those who had not used hormones.

Radiographic measure of aorta calcification is a site-specific predictor of bone loss and fracture risk at the hip.

OBJECTIVE: To investigate whether aorta calcification (AC) - a surrogate marker of atherosclerosis - is an independent indicator of low bone mass density (BMD), accelerated bone loss, and risk of future fractures in postmenopausal women. DESIGN: A prospective epidemiological study. Follow-up period was 7.5 years. SETTING: Community-based sample followed by a research institute. SUBJECTS: A total of 2662 generally healthy postmenopausal women with a mean age of 65.0 +/- 7.1 years at baseline. MAIN OUTCOME MEASURES: Annual rate of changes in BMD (DEXA) and AC (X-rays), vertebral fractures (X-rays), hip fractures (questionnaire). RESULTS: Advanced AC at baseline was significantly associated with lower BMD and accelerated bone loss from the proximal femur. In a multivariate logistic regression model, age (OR 1.1, 95% CI 1.0-1.2, P = 0.02), body mass index (BMI; OR 0.9, 95% CI 0.8-1.0, P = 0.03) and the severity of AC (OR 2.3, 95% CI 1.1-4.8, P = 0.03) were independent predictors of hip fractures. Adjusted OR for vertebral fracture was 1.2 (95% CI 1.0-1.5, P = 0.12). CONCLUSIONS: Aorta calcification seems to independently contribute to the development of osteoporosis in the proximal femur. Further studies are needed to clarify whether effective atherosclerosis prevention lowers hip fracture risk.

Smoking reduces breast tenderness during oral estrogen-progestogen therapy.

OBJECTIVE: We wished to study the influence of smoking upon the occurrence of breast tenderness during oral estrogen-progestogen therapy (EPT). METHODS: Data from 626 healthy postmenopausal women participating in three double-blind, randomized, controlled long-term trials of EPT versus placebo were included. The studies covered sequential, continuous and interrupted regimens of estradiol opposed by a selection of progestins. All studies were mono-center studies and performed in the period 1988-1997. Data on breast tenderness were collected from adverse event reporting and information on smoking status was obtained by interview. RESULTS: Smoking was associated with an earlier age at menopause (difference: 1.3 years, p < 0.001) and a slightly lower body mass index (difference: 0.8 kg/m2, p < 0.01). Smoking women in the EPT groups had significantly lower on-treatment estradiol levels compared to non-smoking women (p < 0.001), whereas no differences were observed in the placebo group. In parallel, the incidence of breast tenderness during EPT was reduced by about one-half (p < 0.001) in smokers compared to non-smokers, whereas no differences were seen on placebo. CONCLUSION: Current smoking reduces the incidence of breast tenderness in women receiving oral EPT. This may be caused by the increased degradation of estradiol during smoking.

Number of years since menopause: spontaneous bone loss is dependent but response to hormone replacement therapy is independent.

In this study we examine the influence of number of years since menopause on spontaneous bone loss and response to hormone replacement therapy (HRT) in 274 women (56.1 +/- 4.2 years) completing two placebo-controlled HRT studies of 2 or 3 year duration. Both cross sectionally and longitudinally, bone loss in untreated women was greatest closest to menopause and declined thereafter (r = 0.34, p < 0.01 for lumbar spine bone loss and r = 0.25, p < 0.05 for femoral neck bone loss when correlated with number of years since menopause), such that the loss was eliminated in the femoral neck and bone mass increased in the spine in women >10 years after menopause. In contrast, bone turnover was consistently elevated throughout postmenopause, both cross-sectionally and longitudinally. The association with number of years since menopause was counteracted by both 1 and 2 mg estradiol combined with gestodene, piperazine, estrone sulfate in combination with norethisterone, and a combination of 2 mg estradiol and 1 mg norethisterone acetate. In addition, the response to various HRT regimens was independent of baseline bone mass. Whereas bone loss was significantly related to number of years since menopause, all HRT regimens applied arrested bone loss in healthy postmenopausal women, regardless of number of years since menopause.

Mechanism of circadian variation in bone resorption.

The diurnal variation in bone resorption markers is poorly understood and may contain essential information about regulation of bone resorption. To explore the acute regulation of bone resorption we studied bone turnover in 14 postmenopausal women during a randomized, crossover, 24 h study of oral glucose tolerance test (OGTT), normal diet, or fasting. Whereas fasting counteracted variation in bone resorption, as measured by serum C-telopeptide fragments of collagen type 1 degradation (s-CTx), OGTT and normal diet induced a 50% reduction (p < 0.001) over 2 h. For OGTT, s-CTx reverted to baseline levels after 6 h, and for normal diet s-CTx remained suppressed during the afternoon and returned to baseline overnight. Repeated OGTT at 8:00 A.M. and 8:00 P.M. in nine postmenopausal women demonstrated that identical reductions in s-CTx could be obtained at both timepoints with an intermediate return to baseline between tests. A 2 h randomized, crossover study of OGTT and fasting in 23 men and premenopausal women similarly revealed a 50% decrease in s-CTx. A randomized, crossover 2 h study of insulin tolerance test compared with fasting in six men and premenopausal women demonstrated a 20%-30% decrease in s-CTx (p < 0.01-0.05). Nine hour follow-up of ten healthy individuals during a crossover experiment of OGTT, protein, and fat intake revealed a comparable 50% reduction in s-CTx, but distinct profiles of serum glucose and serum insulin. Bone resorption was reduced by intake of food, glucose, fat, and protein and counteracted by fasting, and this seems to have been be independent of age and gender. Both exogenous and endogenous insulin stimulation tests induced a reduction in bone resorption, but this was only partial when compared with the reduction observed during food intake.

Influence of female and male sex steroids on body composition in the rabbit model.

OBJECTIVE: To study the influence on body composition of estrogen replacement therapy (ERT) in female rabbits and of replacement therapy with testosterone (TRT) in male rabbits using dual-energy X-ray absorptiometry (DEXA). METHODS: Cholesterol-fed female and male rabbits receiving a weight-restricted diet (100 g/day) were used. Total lean tissue mass (LTM), total body fat tissue mass (FTM) and total tissue mass (TTM) were determined by DEXA at baseline, after which the animals were gonadectomized and treated with sex steroids. Soft body composition was then determined again after 30-31 weeks of treatment. RESULTS: Relative to controls, ERT with estradiol (E2) doses of 2 and 4 mg/day significantly increased LTM (p < 0.001), whereas E2 0.5 and 1 mg/day had a neutral effect on LTM. The change in fat mass, however, was not statistically significant between groups. In male rabbits, compared with castrated control rabbits, LTM decreased in testosterone-treated animals (by 7-12%; p < 0.001) but FTM decreased relatively more (by 66-79%; p < 0.0001). In both genders, body weight correlated with TTM as determined by DEXA (r = 0.89-0.91, p < 0.0001). CONCLUSION: In this in vivo model of growing rabbits, estrogen replacement significantly increased LTM in female animals, whereas testosterone replacement significantly decreased FTM in males, suggesting that soft body composition of both genders is significantly affected by replacement with sex steroids. Until comparable human data are available, it is speculated that similar changes in soft body composition may occur in humans treated with sex steroids.

Dietary phytoestrogens and estrogen inhibit experimental atherosclerosis.

OBJECTIVE: The effect of phytoestrogen intake in combination with estrogen replacement therapy (ERT) on atherogenesis is largely unknown. The aim was thus to study the impact of phytoestrogens alone, or combined with oral estrogen, on experimental atherosclerosis in cholesterol-fed rabbits. METHODS: Two separate studies were performed in ovariectomized, cholesterol-fed female rabbits. In Study A, 45 rabbits were randomized to either a soy-free diet with or without oral 17 beta-estradiol (E2) 4 mg/day, or a soy-rich diet without any hormone for 14 weeks. In Study B, 100 rabbits were randomized into five groups (oral E2 0.5, 1, 2 or 4 mg/day, or no hormone) based on a soy-rich diet for 30 weeks. RESULTS: By the end of treatment in Study A, aortic cholesterol content was twice the amount in the group treated with the soy-free diet compared with the soy-rich group and with the soy-free plus E2 group (p < 0.001). In Study B, aortic cholesterol content showed no significant difference between the groups (ANOVA, p = 0.49), but a tendency towards a lower aortic cholesterol content in the E2-treated animals compared with placebo was observed. CONCLUSION: Dietary phytoestrogens significantly reduce aortic cholesterol content with a potency comparable to that of ERT, and seem to enhance (although mildly) the antiatherogenic effect of E2 in this model.