A synergistic bone sparing effect of curcumin and alendronate in ovariectomized rat

Protective effects of curcumin against osteoporosis and its molecular mechanisms: a recent review in preclinical trials

Osteoporosis (OP) is one of the most common metabolic skeletal disorders and is commonly seen in the elderly population and postmenopausal women. It is mainly associated with progressive loss of bone mineral density, persistent deterioration of bone microarchitecture, and increased fracture risk. To date, drug therapy is the primary method used to prevent and treat osteoporosis. However, long-term drug therapy inevitably leads to drug resistance and specific side effects. Therefore, researchers are constantly searching for new monomer compounds from natural plants. As a candidate for the treatment of osteoporosis, curcumin (CUR) is a natural phenolic compound with various pharmacological and biological activities, including antioxidant, anti-apoptotic, and anti-inflammatory. This compound has gained research attention for maintaining bone health in various osteoporosis models. We reviewed preclinical and clinical studies of curcumin in preventing and alleviating osteoporosis. These results suggest that if subjected to rigorous pharmacological and clinical trials, naturally-derived curcumin could be used as a complementary and alternative medicine for the treatment of osteoporosis by targeting osteoporosis-related mechanistic pathways. This review summarizes the mechanisms of action and potential therapeutic applications of curcumin in the prevention and mitigation of osteoporosis and provides reference for further research and development of curcumin.

Milk kefir therapy improves the skeletal response to resistance exercise in rats submitted to glucocorticoid-induced osteoporosis

Glucocorticoid-induced osteoporosis (GIO) has emerged as a challenge after long-term glucocorticoids (GCs) administration. Exercise has been an important non-pharmacological option, while medications modulate bone remodeling despite adverse effects. In this way, milk Kefir (MK) therapy stands out as a safe alternative to improve bone metabolism. Our study aimed to investigate the effect of MK associated to resistance exercise on bone loss in rats with GIO. For this, sixty male Wistar rats were divided into 2 groups: normal (N) and subjected to GIO, which was subdivided into 4 groups: control (C), milk kefir therapy (K), Exercise (Ex), and Exercise+K (ExK). GIO was induced by dexamethasone (7 mg/kg - i.m.; 1×/wk, 5 wk). MK was administered daily (1×/day; 0.7 ml/animal) and the climb exercise with load was performed 3×/wk; both for 16 wk. Femur was collected for assessment of bone microarchitecture, quality and metabolism. GIO markedly reduced trabecular bone volume density (BV/TV) (-35 %), trabecular thickness (Tb.Th) (-33 %), mineral content of femur (-26 %) as well as bone collagen content (-56 %). Bone strength and its biomechanical properties given by flexural strength (-81 %), fracture load (-80 %), and the number of osteocytes (-84 %) were lowered after GIO. GCs reduced osteoblast number and function while increased osteoclast number, altering bone remodeling (p < 0.05). On the other hand, ExK significantly improved bone microarchitecture and quality, marked by fractal dimension increase (+38 %), cortical volume (+34 %), BV/TV (+34 %), Tb.Th (+33 %), mineral content and collagen maturity, while reduced the space between trabecula (-34 %). The Ex and ExK increased the number of osteocytes (p < 0.05) and they were able to reverse the lower osteoblast number. Both treatments used alone significantly enhanced bone biomechanical properties, but the ExK showed a more significant improvement. ExK ameliorated bone strength and biomechanics (p < 0.05) and stimulated bone formation and modulated bone remodeling (p < 0.05). MK and exercise administered isolated or in association increased the percentage of collagen bone filling after GIO (p < 0.05), but only ExK improved collagen maturity. Our results showed that MK associated to resistance exercise enhanced bone microarchitecture, quality and metabolism, being therefore an interesting tool to improve skeletal response during GIO.

Rutin Improves Bone Histomorphometric Values by Reduction of Osteoclastic Activity in Osteoporosis Mouse Model Induced by Bilateral Ovariectomy

Objective

Osteoporosis is a disease of unbalanced bone metabolism that results in low bone mineral density with increased bone fragility and propensity for fractures. The increased rate of bone fracture due to osteoporosis places a significant burden on public health care expenditures. Therefore, numerous studies have been designed and performed to identify the drugs or health foods that can improve the bone quality or quantity. This study was designed to evaluate and analyze the therapeutic effects of rutin on histomorphometric values of the spine and femur in an osteoporotic mouse model induced by bilateral ovariectomy.

Methods

Thirty female ICR mice (8 weeks old) underwent either a sham operation (only abdominal incision, sham group, n=10) or bilateral ovariectomy (n=20). The ovariectomized (OVX) animals were randomly divided into two groups : untreated OVX group (OVX-C, n=10), or rutin-administered group (OVX-R, n=10). The OVX-C group received weight-adjusted doses of saline vehicle and the OVX-R group received 50 mg/kg of rutin intraperitoneally, starting 1 day after surgery. At 4 and 8 weeks after surgery, serum estrogen, osteocalcin, alkaline phosphatase (ALP), and the telopeptide fragment of type I collagen C-terminus (CTX-1) were analyzed. Interleukin (IL)-1β, IL-6, IL-10, and tumor necrosis factor (TNF)-α were also analyzed. Bone histomorphometric parameters of the 4th lumbar vertebra and femur were determined by micro-computed tomography.

Results

In OVX-C group, ALP, osteocalcin, CTX-1, IL-1β, IL-6, and TNF-α levels were significantly increased at 4 and 8 weeks compared to sham operation group. Rutin administration after OVX statistically significantly reduced ALP, CTX-1, IL-1β, IL-6, and TNF-α levels at 4 and 8 weeks. Rutin administration also improves bone histomorphometric parameters including trabecular bone volume fraction, trabecular thickness, and trabecular number. Trabecular separation was also decreased in OVX-R group compared to OVX-C group.

Conclusion

The present study demonstrated that rutin has therapeutic effects on improving bone histomorphometric values in an OVX mouse model. The improvement in histomorphometric values may be associated with the reduction of osteoclastic activity via inhibition of IL-1β, IL-6, and TNF-α. In future studies, the mechanism for the effect of rutin on osteoporosis should be demonstrated more clearly to use rutin in human osteoporosis.

Combination therapy of curcumin and alendronate modulates bone turnover markers and enhances bone mineral density in postmenopausal women with osteoporosis

OBJECTIVE

This study evaluated the effects of combination therapy of curcumin and alendronate on BMD and bone turnover markers in postmenopausal women with osteoporosis.

SUBJECTS AND METHODS

In a randomized, double-blind trial study, 60 postmenopausal women were divided into three groups: control, alendronate, and alendronate + curcumin. Each group included 20 patients. Total body, total hip, lumbar spine and femoral neck BMDs were measured by dual-energy X-ray absorptiometry (DXA) at baseline and after 12 months of therapy. Bone turnover markers such as bone-specific alkaline phosphatase (BALP), osteocalcin and C-terminal cross-linking telopeptide of type I collagen (CTx) were measured at the outset and 6 months later.

RESULTS

Patients in the control group suffered a significant decrease in BMD and increased bone turnover markers at the end of study. The group treated with only alendronate showed significantly decreased levels of BALP and CTx and increased levels of osteocalcin compared to the control group. The alendronate group also showed significant increases in the total body, total hip, lumbar spine and femoral neck BMDs at the end of study compared to the control group. In the curcumin + alendronate group, BALP and CTx levels decreased and osteocalcin levels increased significantly at the end of study compared to the control and alendronate groups. BMD indexes also increased in four areas significantly at the end of study compared to the control and alendronate groups.

CONCLUSION

The combination of curcumin and alendronate has beneficial effects on BMD and bone turnover markers among postmenopausal women with osteoporosis. Arch Endocrinol Metab. 2018;62(4):438-45.

Effect of a bisphosphonate and selective estrogen receptor modulator on bone remodeling in streptozotocin-induced diabetes and ovariectomized rat model

BACKGROUND CONTEXT

Diabetes and menopause can cause severe osteoporosis. In general, menopause and diabetes can lead to an imbalance in bone turnover, which results in secondary osteoporosis. However, the efficacy of antiresorptive drugs against this form of osteoporosis has not been extensively evaluated.

OBJECTIVE

The aim of this study was to determine the changes in vertebral bone remodeling when postmenopausal osteoporosis is accompanied by diabetes and to compare the efficacy of bisphosphonates and selective estrogen-receptor modulators (SERMs) against these outcomes.

STUDY DESIGN

Streptozotocin-induced diabetic, ovariectomized Sprague-Dawley rats were used as the disease model. Alendronate and raloxifene were used as the bisphosphonate and SERM, respectively.

METHODS

We divided 62 female rats into five groups: (1) control (n=14), (2) DM (diabetes) (n=12), (3) DM+OVX (diabetes+ovariectomy) (n=12), (4) DM+OVX+A (diabetes+ovariectomy+alendronate) (n=12), and (5) DM+OVX+R (diabetes+ovariectomy+raloxifene) (n=12). Serum biochemical markers of bone turnover, including osteocalcin and the C-telopeptide of type I collagen (CTX-1), were analyzed. We measured histomorphometric parameters of the fourth lumbar vertebrae using microcomputed tomography. Mechanical strength was evaluated by a compression test.

RESULTS

In the DM and DM+OVX group, only the levels of osteocalcin significantly decreased compared with those of the control group at 8 weeks after OVX. At 12 weeks, the serum CTX-1 levels in the DM+OVX+A and DM+OVX+R groups were significantly lower than those of the DM+OVX group, but there were no changes in the levels of osteocalcin. Bone mineral density and mechanical strength were higher in the DM+OVX+A and DM+OVX+R groups than in the DM and DM+OVX groups (p<.05).

CONCLUSIONS

Even if postmenopausal osteoporosis is accompanied by diabetes in this animal model, both alendronate and raloxifene seem to show antiresorptive effects, decreased bone turnover rates, and improved bone mechanical strength. Therefore, alendronate and raloxifene are effective in the treatment of osteoporosis even for bone loss caused by DM and postmenopausal osteoporosis.

Effects of Curcumin on Bone Loss and Biochemical Markers of Bone Turnover in Patients with Spinal Cord Injury

BACKGROUND

Osteoporosis is one of the most common problems of patients with spinal cord injuries (SCIs). The current study aimed to evaluate the antiosteoporotic effects of curcumin on densitometry parameters and biomarkers of bone turnovers among patients with SCI.

MATERIALS AND METHODS

The current controlled clinical trial was conducted among 100 patients with SCI referred to an outpatient clinic of rehabilitation in Ilam City, Iran, in 2013-2015. The intervention group received 110/mg/kg/day curcumin for 6 months and the control group received placebo. Bone mineral density (BMD) was measured in all patients. The level of procollagen type I N-terminal propeptide, serum carboxy-terminal telopeptide of type I collagen, osteocalcin, and bone-specific alkaline phosphates were compared before and after study.

RESULTS

BMD indicators of lumbar, femoral neck, and total hip in the control group significantly decreased compared with the beginning of study. However, in the curcumin group, a significant increase was observed in BMD indicators of lumbar, femoral neck, and hip at the end of study compared with the beginning. There was also a significant difference between interventional and control groups for the mean BMD of femoral neck and hip at the end of study (0.718 ± 0.002 g/cm² vs. 0.712 ± 0.003 g/cm² and 0.742 ± 0.031 g/cm² vs. 0.692 ± 0.016 g/cm², respectively).

CONCLUSIONS

Curcumin, via modulation of densitometry indices and bone resorption markers, showed inhibitory effects on the process of osteoporosis. Treatment with curcumin was significantly associated with a decrease in the osteoporosis progression and bone turnover markers of patients with SCI after 6 months.

Innovative evaluation of local injective gel of curcumin on the orthodontic tooth movement in rats

Background

Curcumin is the most active compound in turmeric. It can suppress the nuclear factor kappa-light-chain-enhancer of activated B cells pathway and prevent the osteoclastogenesis procedure. This study aimed to be the first to evaluate the effect of curcumin on the rate of orthodontic tooth movement (OTM).

Materials and Methods

Forty rats were used as follows in each group: (1) negative control: Did not receive any appliance or injection; (2) positive control: received 0.03 cc normal saline and appliance; (3) gelatin plus curcumin (G): Received 0.03 cc hydrogel and appliance; and (4) chitosan plus curcumin (Ch): Received 0.03 cc hydrogel and appliance. They were anesthetized and closed nickel-titanium coil springs were installed between the first molars and central incisors unilaterally as the orthodontic appliance. After 21 days, the rats were decapitated, and the distance between the first and second molars was measured by a leaf gauge. Howship's lacunae, blood vessels, osteoclast-like cells, and root resorption lacunae were evaluated in the histological analysis. Data were analyzed by one-way ANOVA, Tukey's test, and t-test (P < 0.05 consider significant).

Results

No significant difference was found in OTM between groups delivered orthodontic forces. Curcumin inhibited root and bone resorption, osteoclastic recruitment, and angiogenesis significantly.

Conclusion

Curcumin had no significant inhibitory effect on OTM. While it had a significant role on decreasing bone or root resorption (P > 0.05).

Effect of Curcumin on the Diversity of Gut Microbiota in Ovariectomized Rats

Curcumin has been proven to have a weight-loss effect in a menopausal rat model induced by ovariectomy. However, the effects of curcumin on gut microfloral communities of ovariectomized (OVX) rats remains unclear. Here, we used high-throughput 16S rDNA sequencing to explore the effects of curcumin on microbial diversity in the gut of OVX rats. Female Wistar rats were subjected to either ovariectomy or a sham operation (SHAM group). The OVX rats were treated with vehicle (OVX group) or curcumin (CUR group) by oral gavage. After 12-week treatments, the weights of the bodies and uteri of rats were recorded, the levels of estradiol in the serum were assayed by electrochemiluminescence immunoassay (ECLIA). Then, the fragments encompassing V3–V4 16S rDNA hypervariable regions were PCR amplified from fecal samples, and the PCR products of V3–V4 were sequenced on an Illumina MiSeq for characterization of the gut microbiota. Our results showed that, compared to rats in the SHAM group, rats in the OVX group had more weight gain and lower levels of estradiol in the serum, and curcumin could cause significant weight loss in OVX rats but did not increase the levels of estradiol. Sequencing results revealed the presence of 1120, 1114, and 1119 operational taxonomic units (OTUs) found in the SHAM, OVX, and CUR groups, respectively. The percentage of shared OTUs was 86.1603%. Gut microbiota of rats from the SHAM or CUR group had higher levels of biodiversity and unevenness estimations than those from the OVX group. At the phyla level, compared to rats in SHAM group, rats in the OVX group had a higher ratio of phyla Firmicutes and Bacteroidetes in the gut; at the genus level, four differential gut microbiota (Incertae_Sedis, Anaerovorax, Anaerotruncus, and Helicobacter) between SHAM and OVX groups were found, whereas seven differential gut microbiota (Serratia, Anaerotruncus, Shewanella, Pseudomonas, Papillibacter, Exiguobacterium, and Helicobacter) between OVX and CUR groups were found. In conclusion, estrogen deficiency induced by ovariectomy caused changes in the distribution and structure of intestinal microflora in rats, and curcumin could partially reverse changes in the diversity of gut microbiota.

The Therapeutic Effects of Combination Therapy with Curcumin and Alendronate on Spine Fusion Surgery in the Ovariectomized Rats

Objective

The purpose of this study was to evaluate the therapeutic effects of combination therapy with curcumin and alendronate on spine fusion surgery in ovariectomized rats.

Methods

Thirty-two female Sprague-Dawley rats (12 weeks old) underwent bilateral ovariectomy (OVX). Eight weeks after surgery, animals underwent intertransverse spine fusion at L4–5. The rats were randomly distributed amongst 4 groups; untreated OVX group, curcumin administered group, alendronate administered group, and the combination therapy group. At 8 weeks after fusion surgery, the animals were sacrificed and the fusion mass was assessed by manual palpation, radiographic scan, and micro-computed tomographic scan. In addition, mechanical strength was determined by a 3-point bending test.

Results

Based on the results of manual palpation testing and 3-dimensional micro-computed tomography scanning, solid bone fusion rate was 50% (4 of 8) in the OVX group, 75% (6 of 8) in the alendronate-only and curcumin-only group, and 87.5% (7 of 8) in the combination therapy group, respectively. The combination therapy group had a higher fusion rate compared with the other treatment groups, though not statistically significantly (p>0.05). And the combination therapy group had a significant increase in fusion volume at 8 weeks after spine fusion surgery compared with curcumin-only group (p=0.039). The 3-point bending test showed that combination therapy group had a significantly greater maximal load value compared to that of curcumin-only group (p=0.024).

Conclusion

The present study demonstrated that additional treatment of curcumin and alendronate after spine fusion surgery in rat can promote higher fusion volume, and improve bone mechanical strength.

Role of Curcumin in Common Musculoskeletal Disorders: a Review of Current Laboratory, Translational, and Clinical Data

The Indian spice turmeric, in which the active and dominant biomolecule is curcumin, has been demonstrated to have significant medicinal properties, including anti-inflammatory and anti-neoplastic effects. This promise is potentially very applicable to musculoskeletal disorders, which are common causes of physician visits worldwide. Research at the laboratory, translational and clinical levels that supports the use of curcumin for various musculoskeletal disorders, such as osteoarthritis, osteoporosis, musculocartilaginous disorders, and sarcoma is here in comprehensively summarized. Though more phase I-III trials are clearly needed, thus far the existing data show that curcumin can indeed potentially be useful in treatment of the hundreds of millions worldwide who are afflicted by these musculoskeletal disorders.

Kefir improves bone mass and microarchitecture in an ovariectomized rat model of postmenopausal osteoporosis

SUMMARY

Kefir treatment in ovariectomized (OVX) rats could significantly decrease the levels of bone turnover markers and prevent OVX-induced bone loss, deterioration of trabecular microarchitecture, and biomechanical dysfunction that may be due to increase intracellular calcium uptake through the TRPV6 calcium channel.

INTRODUCTION

Osteoporosis is a disease characterized by low bone mass and structural deterioration of bone tissue, leading to an increased fracture risk. The incidence of osteoporosis increases with age and occurs most frequently in postmenopausal women due to estrogen deficiency, as the balance between bone resorption and bone formation shifts towards increased levels of bone resorption. Among various methods of prevention and treatment for osteoporosis, an increase in calcium intake is the most commonly recommended preventive measure. Kefir is a fermented milk product made with kefir grains that degrade milk proteins into various peptides with health-promoting effects, including immunomodulating-, antithrombotic-, antimicrobial-, and calcium-absorption-enhancing bioactivities.

METHODS

The aim of this study is to investigate the effect of kefir on osteoporosis prophylaxis in an ovariectomized rat model. A total of 56 16-week-old female Sprague-Dawley (SD) rats were divided into 7 experimental groups: sham (normal), OVX/Mock, OVX/1X kefir (164 mg/kg BW/day), OVX/2X kefir (328 mg/kg BW/day), OVX/4X kefir (656 mg/kg BW/day), OVX/ALN (2.5 mg/kg BW/day), and OVX/REBONE (800 mg/kg BW/day). After 12-week treatment with kefir, the bone physiology in the OVX rat model was investigated. Accordingly, the aim of this study was to investigate the possible transport mechanism involved in calcium absorption using the Caco-2 human cell line.

RESULTS

A 12-week treatment with kefir on the OVX-induced osteoporosis model reduced the levels of C-terminal telopeptides of type I collagen (CTx), bone turnover markers, and trabecular separation (Tb. Sp.). Additionally, treatment with kefir increased trabecular bone mineral density (BMD), bone volume (BV/TV), trabecular thickness (Tb. Th), trabecular number (Tb. N), and the biomechanical properties (hardness and modulus) of the distal femur with a dose-dependent efficacy. In addition, in in vitro assay, we found that kefir increased intracellular calcium uptake in Caco-2 cell through TRPV6 calcium channels and not through L-type voltage-operated calcium channels.

CONCLUSION

The protective effect of kefir in the OVX rat model may occur through increasing intracellular calcium uptake through the TRPV6 calcium channel.

Changes of bone metabolism based on the different interventions with exercise type or additional intake material in ovariectomized rats

[Purpose]

This study is aimed at providing clear guidance on treatment and prevention of osteoporosis by comparing and analyzing some well-known methods out of drug and exercise therapies.

[Methods]

For this purpose, eight-week experiments (drug therapy and exercise therapy) were carried out by using rats whose menopause was induced by the removal of an ovary. In the treatment of the drug therapy, the effects of soy protein, one of the well-known alendronate and estrogen replacement therapy, were compared and analyzed. In the treatment of the exercise therapy, endurance exercise using a treadmill and resistance exercise through climbing a special cage were compared and analyzed. Based on these results, this study will be able to suggest the most appropriate way to deal with osteoporosis which requires long-term treatment. Sixty eight-week-old Sprague-Dawley female rats had a week to adapt to the new environment. After that, they were randomly divided into four groups (Sham-Sedentary; SS, ovariectomized-control; OC, ovariectomized-soy protein; OS: ovariectomized-alendronate; OA, ovariectomized-endurance exercise; OE, ovariectomized-resistance exercise; OR) before having an operation for the removal of an ovary. After surgery, the rats convalesced for a week. Alendronate (0.4mg / kg of body weight) and isoflavones (200g / 1 kg of feed) were given to two groups respectively for eight weeks. The rats in the other two groups performed resistance exercise (climbing) and endurance exercise (20 m/min; 60min/day) five days a week for eight weeks.

[Results]

Ovariectomy increased the body weight and body fat like menopause did. Soy protein and alendronate intake for eight weeks had no effect on body weight but reduced the body fat increased by ovariectomy to the level of the SS group. The menopause induced by ovariectomy did not affect total bone density and bone mass as well as bone density in specific areas of the body. Soy protein and alendronate intake for eight weeks did not significantly affect them either. However, the eight-week treatment with soy protein and alendronate significantly reduced the level of osteocalcin in blood. Resistance exercise more noticeably increased body weight and bone mass than running on the low-intensity treadmill but serum osteocalcin levels were notably increased in both cases.

[Conclusion]

These results show that soy protein which is natural produce and low-intensity, regular endurance exercise also have an effect on the treatment and prevention of osteoporosis caused by menopause.

An NMR metabolomic study on the effect of alendronate in ovariectomized mice

Alendronate sodium (Fosamax) is most widely used for the prevention and treatment of osteoporosis. It is a type of anti-resorptive agent that reduces the risk of fractures by changing bone turnover and bone mineral density. We investigated the effect of Fosamax on a mouse model of osteoporosis. Twenty-seven female C57BL/6JNarl mice were divided into three groups: sham, ovariectomized (OVX) and OVX + Fosamax (Fosamax). After 23 weeks, bone density of femurs was analyzed using microcomputed tomography (micro-CT), and serum was analyzed for osteoblast and osteoclast activity, as well as metabolites using nuclear magnetic resonance (NMR) spectroscopy. Fosamax increased bone mineral density and cortical bone thickness, and decreased osteoblast activity slightly. Fosamax did not significantly change osteoclast activity. Serum metabolomics revealed that Fosamax had profound effects on overall metabolism, as significantly higher concentrations of metabolites associated with energy metabolism (including TCA-cycle intermediates and glucose), 3-hydroxybutyrate, taurine, allantoin, acetate, and ethanol, as well as lower concentrations of aspartate were observed in the Fosamax-treated mice compared with the OVX mice. These results suggest that alendronate may work by increasing bone density through altered metabolic activity.

Drug release from calcium sulfate-based composites

To help reduce the need for autografts, calcium sulfate (CS)-based bone graft substitutes are being developed to provide a stable platform to aid augmentation while having the ability to release a broad range of bioactive agents. CS has an excellent reputation as a biocompatible and osteoconductive substance, but addition of bioactive agents may further enhance these properties. Samples were produced with either directly loaded small, hydrophobic molecule (i.e., simvastatin), directly loaded hydrophilic protein (i.e., lysozyme), or 1 and 10 wt % of fast-degrading poly(β-amino ester) (PBAE) particles containing protein. Although sustained release of directly loaded simvastatin was achieved, direct loading of small amounts of lysozyme resulted in highly variable release. Direct loading of a larger amount of protein generated a large burst, 65% of total loading, followed by sustained release of protein. Release of lysozyme from 1 wt % of PBAE particles embedded into CS was more controllable than when directly loaded, and for 10 wt % of protein-loaded PBAE particles, a higher burst was followed by sustained release, comparable to the results for the high direct loading. Compression testing determined that incorporation of directly loaded drug or drug-loaded PBAE particles weakened CS. In particular, PBAE particles had a significant effect on the strength of the composites, with a 25 and 80% decrease in strength for 1 and 10 wt % particle loadings, respectively. CS-based composites demonstrated the ability to sustainably release both macromolecules and small molecules, supporting the potential for these materials to release a range of therapeutic agents.

Visualization of network target crosstalk optimizes drug synergism in myocardial ischemia

Numerous drugs and compounds have been validated as protecting against myocardial ischemia (MI), a leading cause of heart failure; however, synergistic possibilities among them have not been systematically explored. Thus, there appears to be significant room for optimization in the field of drug combination therapy for MI. Here, we propose an easy approach for the identification and optimization of MI-related synergistic drug combinations via visualization of the crosstalk between networks of drug targets corresponding to different drugs (each drug has a unique network of targets). As an example, in the present study, 28 target crosstalk networks (TCNs) of random pairwise combinations of 8 MI-related drugs (curcumin, capsaicin, celecoxib, raloxifene, silibinin, sulforaphane, tacrolimus, and tamoxifen) were established to illustrate the proposed method. The TCNs revealed a high likelihood of synergy between curcumin and the other drugs, which was confirmed by in vitro experiments. Further drug combination optimization showed a synergistic protective effect of curcumin, celecoxib, and sililinin in combination against H₂O₂-induced ischemic injury of cardiomyocytes at a relatively low concentration of 500 nM. This result is in agreement with the earlier finding of a denser and modular functional crosstalk between their networks of targets in the regulation of cell apoptosis. Our study offers a simple approach to rapidly search for and optimize potent synergistic drug combinations, which can be used for identifying better MI therapeutic strategies. Some new light was also shed on the characteristic features of drug synergy, suggesting that it is possible to apply this method to other complex human diseases.

Therapeutic advantages of treatment of high-dose curcumin in the ovariectomized rat

Objective

Although curcumin has a protective effect on bone remodeling, appropriate therapeutic concentrations of curcumin are not well known as therapeutic drugs for osteoporosis. The purpose of this study was to compare the bone sparing effect of treatment of low-dose and high-dose curcumin after ovariectomy in rats.

Methods

Forty female Sprague-Dawley rats underwent either a sham operation (the sham group) or bilateral ovariectomy (OVX). The ovariectomized animals were randomly distributed among three groups; untreated OVX group, low-dose (10 mg/kg) curcumin administered group, and high-dose (50 mg/kg) curcumin group. At 4 and 8 weeks after surgery, serum biochemical markers of bone turnover were analyzed. Bone histomorphometric parameters of the 4th lumbar vertebrae were determined by micro-computed tomography (CT). In addition, mechanical strength was determined by a three-point bending test.

Results

High-dose curcumin group showed significantly lower osteocalcin, alkaline phosphatase, and the telopeptide fragment of type I collagen C-terminus concentration at 4 and 8 weeks compared with the untreated OVX group as well as low-dose curcumin group. In the analyses of micro-CT scans of 4th lumbar vertebrae, the high-dose curcumin treated group showed a significant increase in bone mineral densities (p=0.028) and cortical bone mineral densities (p=0.036) compared with the low-dose curcumin treated group. Only high-dose curcumin treated group had a significant increase of mechanical strength compared with the untreated OVX group (p=0.015).

Conclusion

The present study results demonstrat that a high-dose curcumin has therapeutic advantages over a low-dose curcumin of an antiresorptive effect on bone remodeling and improving bone mechanical strength.

The role of carnitine on ovariectomy and inflammation-induced osteoporosis in rats

This study was carried out to assess the protective bone-sparing effect of carnitine with anti-inflammatory properties on chronic inflammation-induced bone loss in ovariectomised (OVX) rats. A total of 64 rats were divided into eight groups. Sixteen rats were sham-operated (SH) while the others were ovariectomised (OVX). (1) SH, (2) sham + inflammation (SHinf), (3) OVX, (4) ovariectomy + inflammation (OVXinf), (5) OVX + CAR1, (6) OVX + CAR2, (7) OVXinf + CAR1, (8) OVXinf + CAR2. After the ovariectomy surgery, all the groups (3, 4, 5, 6, 7, and 8) were allowed to recover for two months. Sixty days after the OVX, inflammation was induced by subcutaneous injections of talc in groups 2, 4, 7, and 8. Group 5 and 7 were given 50 mg/kg CAR; Group 6 and 8 were given 100 mg/kg CAR from the 60th to the 80th day. Serum levels of TNF-α, IL-1, IL-6, OP, and OC were assessed to determine inflammation and to evaluate osteoblastic activity. Bone mineral density (BMD) was assessed by dual energy X-ray absorptiometry in femur bones of rats. Carnitine administration was able to restore BMD up to values measured in both the OVX and the SH animals. The serum levels of TNF-α, IL-1β, and IL-6 were increased significantly in the OVXinf rats compared with the SH group. In OVX rats, inflammation which is evaluated by serum cytokine levels exacerbated this bone loss, as supported by values of BMD of the total femur. The two different doses of carnitine reduced bone loss and improved inflammatory biomarkers.

Bioerodible calcium sulfate/poly(β-amino ester) hydrogel composites

The capacity to quickly regenerate or augment bone lost as a result of resorption is crucial to ensure suitable application of prosthetics for restoring masticatory function. Calcium sulfate hemihydrate (CS)-based bone graft substitute composites containing poly(β-amino ester) (PBAE) biodegradable hydrogel particles were developed to act as a 'tenting' barrier to soft tissue infiltration, potentially providing adequate space to enable vertical bone regeneration. CS has long been recognized as an osteoconductive biomaterial with an excellent reputation as a biocompatible substance. Composite samples were fabricated with varying amounts (1 or 10 wt%) and sizes (53-150 or 150-250 μm) of gel particles embedded in CS. The swelling and degradation rates of PBAE gels alone were rapid, resulting in complete degradation in less than 24h, an important characteristic to aid in controlled release of drug. MicroCT images revealed a homogeneous distribution of gel particles within the CS matrix. All CS samples degraded via surface erosion, with the amount of gel particles (i.e., 10 wt% gel particles) having only a small, but significant, effect on the dissolution rate (4% vs. 5% per day). Compression testing determined that the amount, but not the size, of gel particles had a significant effect on the overall strength of the composites. As much as a 75% drop in strength was seen with a 10 wt% loading of particles. A pilot study using PBAE particles loaded with the multipotential drug curcumin demonstrated sustained release of drug from CS composites. By adjusting the amount and/or size of the biodegradable gel particles embedded in CS, mechanical strength and degradation rates of the composites, as well as the drug release kinetics, can be tuned to fabricate, multi-functional 'space-making' bone grafting substitutes.