Category Archives: Hormones

Melatonin Benefits Bones in Old Rats

Abstract

Melatonin dietary supplement as an anti-aging therapy for age-related bone loss.

Introduction: Previous studies have shown that melatonin, an antioxidant molecule secreted from the pineal gland, is a positive regulator of bone mass. However, melatonin potential effects on bone mass have never been investigated in old population yet. The aim of this study was to assess the effects of dietary melatonin supplementation on mass accrual and biomechanical properties of old rat femora. Methods: Twenty 22-months-old male Wistar rats were divided into 2 randomly assigned groups. The first group was treated for 10 weeks with melatonin, whereas the second group left untreated (control). Rat femurs were collected, and their phenotypes and biomechanical properties were investigated by micro-computed tomography, histomorphometry and 3-point-bending test. Statistical analyses were performed by Student’s two-tailed unpaired t-test. In all experiments, a value of p < 0.05 was considered significant. Results: Rats treated with melatonin had higher bone volume, bone trabecular number, trabecular thickness and cortical thickness in comparison to control group. Histomorphometric analyses confirmed the increase of bone volume in melatonin-treated rats. In agreement with these findings, melatonin-treated rats demonstrated with higher bone stiffness, flexural modulus and ultimate load compared to controls. Conclusion: These compelling results are the first evidence indicating that dietary melatonin supplementation is able to exert beneficial effects against age-related bone loss in old rats; improving the microstructure and biomechanical properties of aged bones.

Tresguerres IF, Tamimi F, Eimar H, Barralet J…
Rejuvenation Res Mar 2014
PMID: 24617902

Review: Melatonin Induces Osteoblastogenesis and Inhibits Osteoclastogenesis

Abstract

Melatonin effects on bone: potential use for the prevention and treatment for osteopenia, osteoporosis, and periodontal disease and for use in bone-grafting procedures.

An important role for melatonin in bone formation and restructuring has emerged, and studies demonstrate the multiple mechanisms for these beneficial actions. Statistical analysis shows that even with existing osteoporotic therapies, bone-related disease, and mortality are on the rise, creating a huge financial burden for societies worldwide. These findings suggest that novel alternatives need to be developed to either prevent or reverse bone loss to combat osteoporosis-related fractures. The focus of this review describes melatonin’s role in bone physiology and discusses how disruption of melatonin rhythms by light exposure at night, shift work, and disease can adversely impact on bone. The signal transduction mechanisms underlying osteoblast and osteoclast differentiation and coupling with one another are discussed with a focus on how melatonin, through the regulation of RANKL and osteoprotegerin synthesis and release from osteoblasts, can induce osteoblastogenesis while inhibiting osteoclastogenesis. Also, melatonin’s free-radical scavenging and antioxidant properties of this indoleamine are discussed as yet an additional mechanism by which melatonin can maintain one’s bone health, especially oral health. The clinical use for melatonin in bone-grafting procedures, in reversing bone loss due to osteopenia and osteoporosis, and in managing periodontal disease is discussed.

Maria S, Witt-Enderby PA
J. Pineal Res. Dec 2013
PMID: 24372640

Hypothesis: Melatonin for Osteoporosis

Abstract

Is postmenopausal osteoporosis related to pineal gland functions?

There is currently considerable interest in the pathogenesis of postmenopausal osteoporosis, which is the most common metabolic bone disease. Osteoporosis affects approximately 20 million persons in the United States, 90% of whom are postmenopausal women. Although there is evidence that estrogen deficiency is an important contributory factor, the pathogenesis of osteoporosis is multifactorial and presently poorly understood. There is evidence that pineal melatonin is an anti-aging hormone and that the menopause is associated with a substantial decline in melatonin secretion and an increased rate of pineal calcification. Animal data indicate that pineal melatonin is involved in the regulation of calcium and phosphorus metabolism by stimulating the activity of the parathyroid glands and by inhibiting calcitonin release and inhibiting prostaglandin synthesis. Hence, the pineal gland may function as a “fine tuner” of calcium homeostasis. In the following communication, we propose that the fall of melatonin plasma levels during the early stage of menopause may be an important contributory factor in the development of postmenopausal osteoporosis. Consequently, plasma melatonin levels taken in the early menopause could be used as an indicator or perhaps as a marker for susceptibility to postmenopausal osteoporosis. Moreover, light therapy, administration of oral melatonin (2.5 mg at night) or agents which induce a sustained release of melatonin secretion such as 5-methoxypsoralen, could be useful agents in the prophylaxis and treatment of postmenopausal osteoporosis. Finally, since application of external artificial magnetic fields has been shown to synchronize melatonin secretion in experimental animals and humans, we propose that treatment with artificial magnetic fields may be beneficial for postmenopausal osteoporosis.

Sandyk R, Anastasiadis PG, Anninos PA, Tsagas N
Int. J. Neurosci. Feb 1992
PMID: 1305608

Teriparatide Increases Bone Strength More Than Density

Abstract

Femoral strength in osteoporotic women treated with teriparatide or alendronate.

To gain insight into the clinical effect of teriparatide and alendronate on the hip, we performed non-linear finite element analysis of quantitative computed tomography (QCT) scans from 48 women who had participated in a randomized, double-blind clinical trial comparing the effects of 18-month treatment of teriparatide 20 μg/d or alendronate 10mg/d. The QCT scans, obtained at baseline, 6, and 18 months, were analyzed for volumetric bone mineral density (BMD) of trabecular bone, the peripheral bone (defined as all the cortical bone plus any endosteal trabecular bone within 3 mm of the periosteal surface), and the integral bone (both trabecular and peripheral), and for overall femoral strength in response to a simulated sideways fall. At 18 months, we found in the women treated with teriparatide that trabecular volumetric BMD increased versus baseline (+4.6%, p<0.001), peripheral volumetric BMD decreased (-1.1%, p<0.05), integral volumetric BMD (+1.0%, p=0.38) and femoral strength (+5.4%, p=0.06) did not change significantly, but the ratio of strength to integral volumetric BMD ratio increased (+4.0%, p=0.04). An increase in the ratio of strength to integral volumetric BMD indicates that overall femoral strength, compared to baseline, increased more than did integral density. For the women treated with alendronate, there were small (<1.0%) but non-significant changes compared to baseline in all these parameters. The only significant between-treatment difference was in the change in trabecular volumetric BMD (p<0.005); related, we also found that, for a given change in peripheral volumetric BMD, femoral strength increased more for teriparatide than for alendronate (p=0.02). We conclude that, despite different compartmental volumetric BMD responses for these two treatments, we could not detect any overall difference in change in femoral strength between the two treatments, although femoral strength increased more than integral volumetric BMD after treatment with teriparatide.

Keaveny TM, McClung MR, Wan X, Kopperdahl DL…
Bone Jan 2012
PMID: 22015818

Teriparatide Decreases Bone Density, but Not Strength

Abstract

Changes in trabecular and cortical bone microarchitecture at peripheral sites associated with 18 months of teriparatide therapy in postmenopausal women with osteoporosis.

We used high-resolution peripheral quantitative computed tomography (HR-pQCT) to monitor changes in bone microarchitecture and strength at the distal radius and tibia associated with 18 months of teriparatide therapy in postmenopausal women with osteoporosis. Despite treatment-associated declines in total and cortical BMD, trabecular thinning and reduced trabecular bone volume, bone strength did not change significantly from baseline.
Teriparatide is an established anabolic therapy for osteoporosis; however, treatment effects at the distal radius are unclear. Therefore, we aimed to monitor changes in bone microarchitecture and estimated strength at the distal radius and tibia in osteoporotic postmenopausal women.
We used high-resolution peripheral quantitative computed tomography (Scanco Medical, Switzerland) to perform a standard three-dimensional morphological analysis of the distal radius and tibia in 11 osteoporotic postmenopausal women (mean age, 68.7 ± 12.7 years) at baseline, 6, 12, and 18 months after initiation of 20 μg/day of teriparatide. Ten of the women received bisphosphonate therapy prior to starting on teriparatide. In addition to the standard analysis, we quantified cortical bone mineral density (BMD), porosity, and thickness using an automated segmentation procedure and estimated bone strength (ultimate stress) using finite element analysis.
After 18 months, we observed a decrease in total BMD (p = 0.03) at the distal radius and a decrease in cortical BMD at the distal radius (p = 0.05) and tibia (p = 0.01). The declines in cortical BMD were associated with trends for increased cortical porosity at both sites. At the distal radius, 18 months of teriparatide treatment was also associated with trabecular thinning (p = 0.009) and reduced trabecular bone volume ratio (p = 0.08). We observed similar trends at the distal tibia. Despite these changes in bone quality, bone strength was maintained over the 18-month follow-up.
The observed changes in cortical bone structure are consistent with the effects of parathyroid hormone on intracortical bone remodeling. Controlled trials involving larger sample sizes are required to confirm the effects of teriparatide therapy on trabecular and cortical microarchitecture in the peripheral skeleton.

Macdonald HM, Nishiyama KK, Hanley DA, Boyd SK
Osteoporos Int Jan 2011
PMID: 20458576 | Full Text


Although our sample size was small, our results are consistent with previous reports of declines in cortical BMD at the radius [8, 9, 18] and at the femoral neck [6] with teriparatide therapy. The decrease in cortical BMD in the present study was coupled with increased cortical porosity at both sites; however, cortical porosity was only statistically different from baseline at the distal tibia after 12 months. Despite a more porous cortex, FE analysis indicated that bone strength did not appear to be compro- mised with teriparatide treatment. This finding supports observations from animal models in which treatment with PTH activated intracortical remodeling and lead to in- creased intracortical porosity [19, 20], but did not compro- mise bone strength [20]. This was likely due to localization of the porosity near the endocortical surface where its influence on bone’s mechanical properties is minimal [20], although this spatial distribution needs to be confirmed in future HR-pQCT studies. In the present study, a slightly thicker cortical shell and enlarged cortical area may also have offset the higher cortical porosity at the distal tibia. Similar changes in cortical bone geometry were observed in rabbits [19] and monkeys [20] treated with PTH and were attributed to increased bone formation on the endocortical surface. In addition, postmenopausal women treated with teriparatide for a median of 18 months had significantly larger cortical area at the distal radius compared with untreated women as measured with pQCT, but no pretreatment com- parison was obtained [18]. Whether PTH has an anabolic effect on the periosteal surface remains unclear [19, 20]….

We acknowledge limitations of our study including the small sample size and the fact that all but one of the women had received prior therapy with bisphosphonates. The degree to which prior bisphosphonate therapy blunts the bone response to teriparatide remains unclear, as in some instances, it does not appear to do so [4, 23]. Since distal radius fractures are recognized indicators of osteoporosis [24], there is an obvious need for larger clinical trials that employ HR-pQCT to monitor and compare the treatment- related effects of teriparatide on bone microarchitecture and strength in treatment-naïve subjects and subjects with a history of bisphosphonate therapy.

Teriparatide Stimulates Bone Formation and Resorption, and Decreases Fracture Risk

Abstract

Effect of parathyroid hormone (1-34) on fractures and bone mineral density in postmenopausal women with osteoporosis.

Once-daily injections of parathyroid hormone or its amino-terminal fragments increase bone formation and bone mass without causing hypercalcemia, but their effects on fractures are unknown.
We randomly assigned 1637 postmenopausal women with prior vertebral fractures to receive 20 or 40 microg of parathyroid hormone (1-34) or placebo, administered subcutaneously by the women daily. We obtained vertebral radiographs at base line and at the end of the study (median duration of observation, 21 months) and performed serial measurements of bone mass by dual-energy x-ray absorptiometry.
New vertebral fractures occurred in 14 percent of the women in the placebo group and in 5 percent and 4 percent, respectively, of the women in the 20-microg and 40-microg parathyroid hormone groups; the respective relative risks of fracture in the 20-microg and 40-microg groups, as compared with the placebo group, were 0.35 and 0.31 (95 percent confidence intervals, 0.22 to 0.55 and 0.19 to 0.50). New nonvertebral fragility fractures occurred in 6 percent of the women in the placebo group and in 3 percent of those in each parathyroid hormone group (relative risk, 0.47 and 0.46, respectively [95 percent confidence intervals, 0.25 to 0.88 and 0.25 to 0.861). As compared with placebo, the 20-microg and 40-microg doses of parathyroid hormone increased bone mineral density by 9 and 13 more percentage points in the lumbar spine and by 3 and 6 more percentage points in the femoral neck; the 40-microg dose decreased bone mineral density at the shaft of the radius by 2 more percentage points. Both doses increased total-body bone mineral by 2 to 4 more percentage points than did placebo. Parathyroid hormone had only minor side effects (occasional nausea and headache).
Treatment of postmenopausal osteoporosis with parathyroid hormone (1-34) decreases the risk of vertebral and nonvertebral fractures; increases vertebral, femoral, and total-body bone mineral density; and is well tolerated. The 40-microg dose increased bone mineral density more than the 20-microg dose but had similar effects on the risk of fracture and was more likely to have side effects.

Neer RM, Arnaud CD, Zanchetta JR, Prince R…
N. Engl. J. Med. May 2001
PMID: 11346808 | Free Full Text


Parathyroid hormone stimulates bone formation and resorption and can increase or decrease bone mass, depending on the mode of administration. Continuous infusions and daily subcutaneous injections of parathyroid hormone stimulate bone formation similarly but have different effects on bone resorption and bone mass.1,2 Continuous infusions, which result in a persistent elevation of the serum parathyroid hormone concentration, lead to greater bone resorption than do daily injections, which cause only transient increases in the serum parathyroid hormone concentration.3

Garlic < Lovastatin < Estrogen Effective in suppressing Bone loss in Ovariectomized Rats

Abstract

Effects of garlic oil on postmenopausal osteoporosis using ovariectomized rats: comparison with the effects of lovastatin and 17beta-estradiol.

The purpose of this study was to examine the antiosteoporosis effects of garlic oil in an ovariectomized (Ovx) rat model of osteoporosis and to compare its efficacy with lovastatin (a synthetic hypocholesterolemic drug) and 17beta-estradiol (a potent antiosteoporotic agent). Animals were divided into five groups: sham-operated control, ovariectomized, ovariectomized supplemented with lovastatin, ovariectomized supplemented with garlic oil and ovariectomized supplemented with 17beta-estradiol. In our study, the development of a high rate of bone turnover and osteoporosis in the ovariectomized animals were confirmed by significant alterations of serum alkaline phosphatase activity, serum tartrate-resistant acid phosphatase activity, urinary excretion of calcium, phosphate, hydroxyproline and urinary calcium to creatinine ratio, when compared with the sham-operated control group. Supplementation of these animals with either garlic oil or lovastatin or 17beta-estradiol, in addition to their hypocholesterolemic effect, could counterbalance all these changes. The results revealed that all three compounds significantly protected the hypogonadal bone loss as reflected by higher bone densities and higher bone mineral contents than the ovariectomized group of animals. The results emphasize that, like 17beta-estradiol, the hypocholesterolemic compounds garlic oil and lovastatin are also effective in suppressing bone loss owing to estrogen deficiency and their efficacy in the order of lower to higher is garlic < lovastatin < 17beta-estradiol.

Mukherjee M, Das AS, Das D, Mukherjee S…
Phytother Res Jan 2006
PMID: 16397916

Ghrelin Stimulates Bone Formation in Rat Osteoblasts

Abstract

Ghrelin directly regulates bone formation.

To clarify the role of ghrelin in bone metabolism, we examined the effect of ghrelin in vitro and in vivo. Ghrelin and its receptor, GHS-R1a, were identified in osteoblasts, and ghrelin promoted both proliferation and differentiation. Furthermore, ghrelin increased BMD in rats. Our results show that ghrelin directly affects bone formation.
Ghrelin is a gut peptide involved in growth hormone (GH) secretion and energy homeostasis. Recently, it has been reported that the adipocyte-derived hormone leptin, which also regulates energy homeostasis and opposes ghrelin’s actions in energy homeostasis, plays a significant role in bone metabolism. This evidence implies that ghrelin may modulate bone metabolism; however, it has not been clarified. To study the role of ghrelin in skeletal integrity, we examined its effects on bone metabolism both in vitro and in vivo.
We measured the expression of ghrelin and growth hormone secretagogue receptor 1a (GHS-R1a) in rat osteoblasts using RT-PCR and immunohistochemistry (IHC). The effect of ghrelin on primary osteoblast-like cell proliferation was examined by recording changes in cell number and the level of DNA synthesis. Osteoblast differentiation markers (Runx2, collagen alpha1 type I [COLI], alkaline phosphatase [ALP], osteocalcin [OCN]) were analyzed using quantitative RT-PCR. We also examined calcium accumulation and ALP activity in osteoblast-like cells induced by ghrelin. Finally, to address the in vivo effects of ghrelin on bone metabolism, we examined the BMD of Sprague-Dawley (SD) rats and genetically GH-deficient, spontaneous dwarf rats (SDR).
Ghrelin and GHS-R1a were identified in osteoblast-like cells. Ghrelin significantly increased osteoblast-like cell numbers and DNA synthesis in a dose-dependent manner. The proliferative effects of ghrelin were suppressed by [D-Lys(3)]-GHRP-6, an antagonist of GHS-R1a, in a dose-dependent manner. Furthermore, ghrelin increased the expression of osteoblast differentiation markers, ALP activity, and calcium accumulation in the matrix. Finally, ghrelin definitely increased BMD of both SD rats and SDRs.
These observations show that ghrelin directly stimulates bone formation.

Fukushima N, Hanada R, Teranishi H, Fukue Y…
J. Bone Miner. Res. May 2005
PMID: 15824852

Risedronate, Atorvastatin, Estrogen, Raloxifene, and Clomiphene Compared in Ovariectomized Rats

Abstract

Comparative effects of risedronate, atorvastatin, estrogen and SERMs on bone mass and strength in ovariectomized rats.

The aim of this study was to investigate bone protective effects of risedronate, atorvastatin, raloxifene and clomiphene citrate in ovariectomized rats.
Our study was conducted on 63 rats at Experimental Research Center of Celal Bayar University. Six-month-old rats were divided into seven groups. There were five drug administered ovariectomized groups, one ovariectomized control group without drug administration and one non-ovariectomized control group without drug administration. Eight weeks postovariectomy, rats were treated with the bisphosphonate risedronate sodium, the statin atorvastatin, the estrogen 17beta-estradiol and the selective estrogen receptor modulators (SERMs) raloxifene hydrochloride and clomiphene citrate by gavage daily for 8 weeks. At the end of the study, rats were killed under anesthesia. For densitometric evaluation, left femurs and tibiae were removed. Left femurs were also used to measure bone volume. Right femurs were used for three-point bending test.
Compared to ovariectomized group, femur cortex volume increased significantly in non-ovariectomized group (p=0.016). Compared to non-ovariectomized group, distal femoral metaphyseal and femur midshaft bone mineral density values were significantly lower in ovariectomized group (p=0.047). In ovariectomy+atorvastatin group, whole femur and femur midshaft bone mineral density and three-point bending test maximal load values were significantly higher than ovariectomized group (p=0.049, 0.05, and 0.018). When compared to the ovariectomized group, no significant difference was found with respect to femoral maximum load values in groups treated with risedronate, estrogen, raloxifene and clomiphene (p=0.602, 0.602, 0.75, and 0.927). In ovariectomy+risedronate group, femur midshaft bone mineral density values were significantly higher than the values in ovariectomized group (p=0.023). When compared to ovariectomized group, no significant difference was found with respect to femur midshaft bone mineral density values in groups treated with estrogen, raloxifene and clomiphene (p=0.306, 0.808, and 0.095).

While risedronate sodium prevented the decrease in bone mineral density in ovariectomized rats, atorvastatin maintained mechanical characteristics of bone and also prevented the decrease in bone mineral density as risedronate sodium.

Uyar Y, Baytur Y, Inceboz U, Demir BC…
Maturitas Jul 2009
PMID: 19386450

Video: Dr. Hofflich “Osteoporosis Update 2013” – Stein Institute for Research on Aging

Here is a nice talk by Dr. Heather Hofflich from May 15, 2013. She’s an Associate Professor of Medicine at UCSD. She gives an overview of osteoporosis and discusses the causes and therapies used to treat it. She also takes a look at recent controversies in treatment plans and vitamin usage.

One thing that bothers me about her talk is that she claims Teriparatide is the only thing in the world that builds bone by increasing osteoblast activity. I’ve posted many studies that found increases in osteoblasts from a variety of things. She also didn’t mention any other potentially helpful dietary supplements besides Calcium and Vitamin D. Like most MDs, she is probably unaware of anything that is not FDA approved.