Advantage of ostarine over raloxifene and their combined treatments for muscle of estrogen-deficient rats

PURPOSE

Selective androgen (ostarine, OST) and estrogen (raloxifene, RAL) receptor modulators with improved tissue selectivity have been developed as alternatives to hormone replacement therapy. We investigated the combined effects of OST and RAL on muscle tissue in an estrogen-deficient rat model of postmenopausal conditions.

METHODS

Three-month-old Sprague Dawley rats were divided into groups: (1) untreated non-ovariectomized rats (Non-OVX), (2) untreated ovariectomized rats (OVX), (3) OVX rats treated with OST, (4) OVX rats treated with RAL, (5) OVX rats treated with OST and RAL. Both compounds were administered in the diet. The average dose received was 0.6 ± 0.1 mg for OST and 11.1 ± 1.2 mg for RAL per kg body weight/day. After thirteen weeks, rat activity, muscle weight, structure, gene expression, and serum markers were analyzed.

RESULTS

OST increased muscle weight, capillary ratio, insulin-like growth factor 1 (Igf-1) expression, serum phosphorus, uterine weight. RAL decreased muscle weight, capillary ratio, food intake, serum calcium and increased Igf-1 and Myostatin expression, serum follicle stimulating hormone (FSH). OST + RAL increased muscle nucleus ratio, uterine weight, serum phosphorus, FSH and luteinizing hormone and decreased body and muscle weight, serum calcium. Neither treatment changed muscle fiber size. OVX increased body and muscle weight, decreased uterine weight, serum calcium and magnesium.

CONCLUSION

OST had beneficial effects on muscle in OVX rats. Side effects of OST on the uterus and serum electrolytes should be considered before using it for therapeutic purposes. RAL and RAL + OST had less effect on muscle and showed endocrinological side effects on pituitary-gonadal axis.

Which Factors Are Associated With Rerupture After Superior Capsular Reconstruction of the Shoulder With Autologous Long Biceps Tendon? - A Systematic Review

Based on a systematic review, the present work analyses factors associated with the rerupture rate or non-healing after superior capsular reconstruction with autologous long biceps tendon in the reconstruction of the rotator cuff of the shoulder.A systematic review of the U.S. National Library of Medicine/National Institutes of Health (PubMed) database and the Cochrane Library was conducted in September 2021 using the PRISMA checklist. Articles were identified and analysed that contained data on the rerupture rate after superior capsular reconstruction with autologous long biceps tendon in reconstruction of the rotator cuff of the shoulder. The aim was to identify factors associated with rerupture or non-healing. The risk of bias was determined using the Newcastle-Ottawa scale.Primarily 86 hits could be generated. Seven articles from 2020 and 2021 met the inclusion criteria and were further analysed in terms of content. The evidence level was III to IV. Follow-up was between 12 (minimum) and 24 to 48 months. The risk of bias was not low. Factors that may be associated with rerupture or non-healing are diabetes mellitus and high-grade fatty degeneration of the subscapularis, infraspinatus, or teres minor as preoperative factors. Age, percent footprint coverage, tear size, symptom duration, number of bundles, acromioplasty performed, and tear configuration were not significant factors. Gender, degree of fatty degeneration of the supraspinatus and lesions of the subscapularis tendon were rated differently.According to the literature, but still currently with short-term observation periods, superior capsular reconstruction with an autologous long biceps tendon is another treatment option in the case of massive tears and elderly patients, if there is no high-grade fatty degeneration of the subscapularis, infraspinatus or teres minor. Diabetes mellitus has an unfavorable prognosis. Additional acromioplasty has so far not been associated with better outcomes.

Effects of ligandrol as a selective androgen receptor modulator in a rat model for osteoporosis

INTRODUCTION

The selective androgen receptor modulator ligandrol (LGD-4033 or VK5211) has been shown to improve muscle tissue. In the present study, the effect of ligandrol on bone tissue was investigated in ovariectomized rat model.

MATERIALS AND METHODS

Three-month-old Sprague Dawley rats were either ovariectomized (OVX, n = 60) or left intact (NON-OVX, n = 15). After 9 weeks, OVX rats were divided into four groups: untreated OVX (n = 15) group and three OVX groups (each of 15 rats) treated with ligandrol orally at doses of 0.03, 0.3, or 3 mg/kg body weight. After five weeks, lumbar vertebral bodies (L), tibiae, and femora were examined using micro-computed tomographical, biomechanical, ashing, and gene expression analyses.

RESULTS

In the 3-mg ligandrol group, bone structural properties were improved (trabecular number: 38 ± 8 vs. 35 ± 7 (femur), 26 ± 7 vs. 22 ± 6 (L), 12 ± 5 vs. 6 ± 3 (tibia) and serum phosphorus levels (1.81 ± 0.17 vs.1.41 ± 0.17 mmol/l), uterus (0.43 ± 0.04 vs. 0.11 ± 0.02 g), and heart (1.13 ± 0.11 vs. 1.01 ± 0.08 g) weights were increased compared to the OVX group. Biomechanical parameters were not changed. Low and medium doses did not affect bone tissue and had fewer side effects. Body weight and food intake were not affected by ligandrol; OVX led to an increase in these parameters and worsened all bone parameters.

CONCLUSION

Ligandrol at high dose showed a subtle anabolic effect on structural properties without any improvement in biomechanical properties of osteoporotic bones. Considering side effects of ligandrol at this dose, its further investigation for the therapy of postmenopausal osteoporosis should be reevaluated.

Treatment of osteoporosis using a selective androgen receptor modulator ostarine in an orchiectomized rat model

PURPOSE

The selective androgen receptor modulator ostarine has been shown to have advantageous effects on skeletal tissue properties, reducing muscle wasting and improving physical function in males. However, data on effects in male osteoporosis remain limited. In this study, the effects of ostarine on osteoporotic bone were evaluated in a rat model of male osteoporosis and compared with those of testosterone treatments.

METHODS

Eight-month-old male Sprague-Dawley rats were either non-orchiectomized to serve as a healthy control (Non-Orx, Group 1) or orchiectomized (Orx, Groups 2-6) and then grouped (n = 15/group): (1) Non-Orx, (2) Orx, (3) Ostarine Therapy, (4) Testosterone Therapy, (5) Ostarine Prophylaxis and (6) Testosterone Prophylaxis. Prophylaxis treatments started directly after orchiectomy and continued for 18 weeks, whereas Therapy treatments were initiated 12 weeks after Orx. Ostarine and Testosterone were applied orally at daily doses of 0.4 and 50 mg/kg body weight, respectively. The lumbar vertebral bodies and femora were analyzed using biomechanical, micro-CT, ashing, and gene expression analyses.

RESULTS

Ostarine Prophylaxis showed positive effects in preventing osteoporotic changes in cortical and trabecular bone (femoral trabecular density: 26.01 ± 9.1% vs. 20.75 ± 1.2% in Orx and in L4: 16.3 ± 7.3% vs 11.8 ± 2.9% in Orx); biomechanical parameters were not affected; prostate weight was increased (0.62 ± 0.13 g vs 0.18 ± 0.07 g in Orx). Ostarine Therapy increased solely the cortical density of the femur (1.25 ± 0.03 g/cm3 vs. 1.18 ± 0.04 g/cm3 in Orx); other bone parameters remained unaffected. Testosteron Prophylaxis positively influenced cortical density in femur (1.24 ± 0.05 g/cm3 vs. 1.18 ± 0.04 g/cm3 in Orx); Test. Therapy did not change any bony parameters.

CONCLUSION

Ostarine Prophylaxis could be further investigated as a preventative treatment for male osteoporosis, but an androgenic effect on the prostate should be taken into consideration, and combination therapies with other anti-osteoporosis agents could be considered.

Inflammasome in Skeletal Muscle: NLRP3 Is an Inflammatory Cell Stress Component in Inclusion Body Myositis

Inclusion body myositis (IBM) is a chronic, mostly treatment-resistant, inflammatory myopathy with a pathology that centers around specific interactions between inflammation and protein accumulation. The study aimed to identify the inflammasome as a key event in the complex network of pathomechanisms. Regulation of the inflammasome was assessed in a well-established pro-inflammatory cell culture model using human myoblasts and primary human myotubes. By quantitative PCR, western blot and immunocytochemistry, inflammasome markers including NLRP3 were assessed in muscle cells exposed to the cytokines IL-1β and IFN-γ. The data were corroborated by analysis of muscle biopsies from patients with IBM compared to other myositis subtypes. In the cell culture model of IBM, the NLRP3 inflammasome was significantly overexpressed, as evidenced by western blot (p = 0.03) and quantitative PCR (p < 0.01). Target genes that play a role in inflammasome assembly, T-cell migration, and MHC-I expression (p = 0.009) were highly co-upregulated. NLRP3 was significantly overexpressed in muscle biopsies from IBM samples compared to disease controls (p = 0.049), including other inflammatory myopathies. Due to the extraordinary features of the pathogenesis and the pronounced upregulation of NLRP3 in IBM, the inflammasome could serve as a key molecule that drives the inflammatory cascade as well as protein accumulation in the muscle. These data can be useful for future therapeutic developments.

Retrospective In-Hospital Mortality Analysis of GeriatricPatients Treated in a Level 1 Trauma Center

The aim of this study is to determine the critical time intervals and influencing covariates for in-hospital mortality in geriatric trauma and orthopedic patients. During a period of five years, we retrospectively review patients aged > 60 years who were hospitalized at the Department of Trauma, Orthopedic, and Plastic Surgery. The primary outcome is the mean time to death. Survival analysis is performed using an accelerated failure time model. A total of 5388 patients are included in the analysis. Two-thirds underwent surgery (n = 3497, 65%) and one-third were conservatively treated (n = 1891, 35%). The in-hospital mortality rate is 3.1% (n = 168; surgery, n = 112; conservative, n = 56). The mean time to death is 23.3 days (±18.8) after admission in the surgery group and 11.3 days (±12.5) in the conservative treatment group. The greatest accelerating effect on mortality is found in the intensive care unit (16.52, p < 0.001). We are able to identify a critical time interval for in-hospital mortality between days 11 and 23. The day of death on weekend days/holidays, hospitalization for conservative treatment, and treatment at the intensive care unit significantly increase the risk of in-hospital mortality. Early mobilization and a short hospitalization duration seem to be of major importance in fragile patients.

A combined treatment with selective androgen and estrogen receptor modulators prevents bone loss in orchiectomized rats

PURPOSE

Enobosarm (EN), a selective androgen receptor modulator and raloxifene (RAL), a selective estrogen receptor modulator, have been shown to improve bone tissue in osteoporotic males. The present study evaluated the effects of a combination therapy of EN and RAL on bone properties in orchiectomized rats compared to the respective single treatments.

METHODS

Eight-month-old male Sprague-Dawley rats were either left intact (Non-Orx) or orchiectomized (Orx). The Orx rats were divided into four groups (n = 15 each): 1) Orx, 2) EN treatment (Orx + EN), 3) RAL treatment (Orx + RAL), 4) combined treatment (Orx + EN + RAL). EN and RAL (0.4 mg and 7 mg/kg body weight/day) were applied immediately after Orx with a soy-free pelleted diet for up to 18 weeks. The lumbar spine and femora were examined by micro-CT, biomechanical, histomorphological, ashing, and gene expression analyses.

RESULTS

EN exhibited an anabolic effect on bone, improving some of its parameters in Orx rats, but did not affect biomechanical properties. RAL exhibited antiresorptive activity, maintaining the biomechanical and trabecular parameters of Orx rats at the levels of Non-Orx rats. EN + RAL exerted a stronger effect than the single treatments, improving most of the bone parameters. Liver weight increased after all treatments; the kidney, prostate, and levator ani muscle weights increased after EN and EN + RAL treatments. BW was reduced due to a decreased food intake in the Orx + RAL group and due a reduced visceral fat weight in the Orx + EN + RAL group.

CONCLUSION

The EN + RAL treatment appeared to be promising in preventing male osteoporosis, but given the observed side effects on liver, kidney, and prostate weights, it requires further investigation.

Genetic ablation of fibroblast activation protein alpha attenuates left ventricular dilation after myocardial infarction

Introduction

Regulating excessive activation of fibroblasts may be a promising target to optimize extracellular matrix deposition and myocardial stiffness. Fibroblast activation protein alpha (FAP) is upregulated in activated fibroblasts after myocardial infarction (MI), and alters fibroblast migration in vitro. We hypothesized that FAP depletion may have a protective effect on left ventricular (LV) remodeling after MI.

Materials and methods

We used the model of chronic MI in homozygous FAP deficient mice (FAP-KO, n = 51) and wild type mice (WT, n = 55) to analyze wound healing by monocyte and myofibroblast infiltration. Heart function and remodeling was studied by echocardiography, morphometric analyses including capillary density and myocyte size, collagen content and in vivo cell-proliferation. In non-operated healthy mice up to 6 months of age, morphometric analyses and collagen content was assessed (WT n = 10, FAP-KO n = 19).

Results

Healthy FAP-deficient mice did not show changes in LV structure or differences in collagen content or cardiac morphology. Infarct size, survival and cardiac function were not different between FAP-KO and wildtype mice. FAP-KO animals showed less LV-dilation and a thicker scar, accompanied by a trend towards lower collagen content. Wound healing, assessed by infiltration with inflammatory cells and myofibroblasts were not different between groups.

Conclusion

We show that genetic ablation of FAP does not impair cardiac wound healing, and attenuates LV dilation after MI in mice. FAP seems dispensable for normal cardiac function and homeostasis.

Hip Fractures: Therapy, Timing, and Complication Spectrum

Objective

Investigation of the treatment of femur fractures and the type of femur fracture‐associated complications regarding timing of surgery and length of hospital stay.

Methods

In this retrospective cohort study, a total of 358 hip fractures were evaluated retrospectively from 1 January 2008 until 31 December 2010 at a level I trauma center in Germany. Inclusion criteria was age >18 years and a proximal femur fracture. Both sexes were evaluated. Mean age was 75.5 years, most patients were female (63.7%). Intervention was the operative treatment of proximal femur fracture. Outcome parameters were time until surgery, complications, reoperations, mortality, and length of hospital stay.

Results

Among the proximal femur fractures (n = 358), 46.6% were pertrochanteric, 11.2% subtrochanteric, and 42.2% femoral neck fractures. Operation upon hip fractures was managed regularly within 24 hours of injury (73%; mean for femoral neck: 28.3 hrs.; mean for pertrochanteric fractures: 21.4 hrs.; mean for subtrochanteric fractures: 19.5 hrs.). Delayed treatment, as well as implantation of hip total endoprosthesis (TEP), increased the overall length of hospital stay (15.4 vs 17.6 days; 18.1 vs 15.8 days). Accordingly, surgical procedures performed within 24 hours of injury resulted in a shorter hospital residence. Longest delay of operation was measured for hip fractures (28.3 hrs.).

In 351 patients, secondary injuries were detected in 94 individuals (26%), with fractures being the most common secondary injury (n = 40). We recorded postoperative complications of nonsurgical and surgical origin, and 33.6% of our patient cohort displayed complications. Complications were distributed among 118 patients. There was no significant difference in complications regarding the time of operation, with most nonsurgical and surgical complications appearing within 24 hours after operation (n = 110 vs n = 31). Nonsurgical complications, such as anemia (n = 49) and electrolyte imbalances (n = 30), were observed more frequently than surgical complications (n = 107 vs n = 34); however, these complications were reduced by delay in surgery (82.0% in 6–24 hrs. vs 74.2% in ≥24 hrs.). Anticoagulant therapy and age did not affect postoperative complications. The hospital mortality of patients was 6.2%. Follow‐up was restrained to ambulatory visits in the clinic.

Conclusions

Surgical management of hip fractures performed within 24 hours of injury minimizes hospital stay. We did not detect significant differences in the spectrum or number of complications regarding delay of surgery. Surgical complications mainly occur with rapid primary care, and medical complications can be reduced by more intensive preparation of patient and operation procedures.

Effect of alendronate or 8-prenylnaringenin applied as a single therapy or in combination with vibration on muscle structure and bone healing in ovariectomized rats

Bisphosphonate alendronate (ALN), phytoestrogen 8-prenylnaringenin (8-PN) and the whole body vibration exert a favorable effect on osteoporotic bone. However, the impact of these treatments and the combination of pharmacological therapies with biomechanical stimulation on muscle and bone has not yet been explored in detail. The effect of ALN and 8-PN and their combination with the vibration (Vib) on skeletal muscle and bone healing was investigated in ovariectomized (Ovx) rats.

Three-month old rats were Ovx (n = 78), or left intact (Non-Ovx; n = 12). Five weeks after Ovx, all rats were treated according to the group assignment (n = 12/13): 1) Non-Ovx; 2) Ovx; 3) Ovx + Vib; 4) Ovx + ALN; 5) Ovx + ALN + Vib; 6): Ovx + 8-PN; 7) Ovx + 8-PN + Vib. Treatments with ALN (0.58 mg/kg BW, in food), 8-PN (1.77 mg/kg BW, daily s.c. injections) and/or with vertical vibration (0.5 mm, 35 Hz, 1 g, 15 min, 2×/day, 5×/week) were conducted for ten weeks. Nine weeks after Ovx, all rats underwent bilateral tibia osteotomy with plate osteosynthesis and were sacrificed six weeks later.

Vibration increased fiber size and capillary density in muscle, enlarged callus area and width, and decreased callus density in tibia, and elevated alkaline phosphatase in serum. ALN and ALN + Vib enhanced capillarization and lactate dehydrogenase activity in muscle. In tibia, ALN slowed bone healing, ALN + Vib increased callus width and density, enhanced callus formation rate and expression of osteogenic genes. 8-PN and 8-PN + Vib decreased fiber size and increased capillary density in muscle; callus density and cortical width were reduced in tibia. Vibration worsened 8-PN effect on bone healing decreasing the callus width and area.

Our data suggest that Vib, ALN, 8-PN, or 8-PN + Vib do not appear to aid bone healing. ALN + Vib improved bone healing; however application is questionable since single treatments impaired bone healing. Muscle responds to the anti-osteoporosis treatments and should be included in the evaluation of the drugs.

•

Vibration (Vib) was beneficial for muscle structure, it tended to interfere with early bone healing.

•

Alendronate (ALN) enhanced capillary density and metabolism in muscle, slowed bone healing.

•

8-Prenylnaringenin (8-PN) had favorable effects on muscle, for bone healing it was disadvantageous.

•

8PN + Vib further worsened 8-PN effect on bone, ALN + Vib improved bone healing.

•

Muscles respond to anti-osteoporosis treatments, their analysis should be included in the evaluation of drugs.

Evaluation of ostarine as a selective androgen receptor modulator in a rat model of postmenopausal osteoporosis

Selective androgen receptor modulators (SARMs) have shown beneficial effects on muscle wasting, general physical function and bone properties in male mammals. However, data on the effects of SARMs in postmenopausal osteoporotic bone are scarce. We evaluated the effects of the SARM drug ostarine on postmenopausal osteoporotic bone in a rat osteoporosis model. Ovariectomy was performed on 46 of 56 3-month-old female Sprague-Dawley rats. Eight weeks after ovariectomy, ostarine was orally administered daily for 5 weeks in dosages of 0.04 (low, OVX + Ost. 0.04), 0.4 (intermediate, OVX + Ost. 0.4), and 4 mg/kg (high, OVX + Ost. 4) body weight. Another ovariectomized group received no ostarine. Lumbar vertebrae and femora were removed for biomechanical, gene expression, ashing, and computer tomography analyses. Low dose showed no effects. The effects of intermediate and high doses were comparable overall. Improvements were mainly seen in structural properties such as bone mineral density and bone volume density. However, the effects in femora were superior to effects in vertebrae. Ostarine treatment for 5 weeks did not improve significantly biomechanical properties. mRNA expression of the receptor activator of NF-κB ligand decreased after treatment, and uterine weight increased. Serum levels of phosphorus increased following ostarine treatment in intermediate and high-dose groups. Short-term treatment of osteoporotic bone with ostarine leads to improvement of several microstructural bone indices. While we did not observe changes in biomechanics, it is conceivable that longer treatment may also improve biomechanical properties. Further studies are needed to characterize longer time effects and side effects of ostarine in osteoporosis.

Effects of RANKL Knockdown by Virus-like Particle-Mediated RNAi in a Rat Model of Osteoporosis

Rebalancing of the RANKL/OPG system seems to be an effective treatment strategy in postmenopausal osteoporosis. Here, we evaluate the knockdown of RANKL by in-vivo-delivered siRNA in a rat model of osteoporosis. Virus-like-particles (VLPs) derived from polyoma JC virus were used for delivering RANKL siRNA in ovariectomized (OVX) rats. 48 rats were ovariectomized and treated with either 17β-estradiol (E2), VLPs containing RANKL siRNA (siRANKL), or VLPs containing non-cognate siRNA (siCtrl). All OVX groups were subdivided into the prophylaxis group (PG) and the therapy group (TG). The PG received treatment directly after being OVX for 10 weeks. The TG received treatment 5 weeks after being OVX for 5 weeks. Rats were sacrificed 10 weeks after being OVX. Bone and blood samples were analyzed. E2 and siRANKL showed a significant knockdown of RANKL mRNA. A protein knockdown was observed with E2 and siRANKL in the TG but not in the PG. No distinct improvements in biomechanical and morphological properties of the bones were observed after siRANKL treatment. In the PG, E2 protected the bone structure. We demonstrated successful mRNA and protein knockdown by VLP-mediated RNAi in vivo. Knockdown of membranous RANKL did not result in significant improvements of bone properties in this model of early-stage postmenopausal osteoporosis.

The Advantages of Bilateral Osteotomy Over Unilateral Osteotomy for Osteoporotic Bone Healing

Most models of osteoporotic bone fractures are performed unilaterally (UL). We investigated healing of tibia osteotomy performed either UL or bilaterally (BL) in ovariectomized rats. Behavior of animals and muscle structure were assessed. Three-month-old female Sprague-Dawley rats were ovariectomized (n = 32). After 10 weeks, half the rats underwent UL osteotomy of tibia metaphysis (right limb) with plate osteosynthesis. The other rats were osteotomized BL. Half of the rats in each group received either standard pain treatment with carprofen (5 mg/kg body weight (BW), 1x/day for 2 days) or carprofen and buprenorphine (5 mg/kg BW, 1x/day and 0.03 mg/kg BW, 2x/day for 5 days) after osteotomy. The UL rats started to load the injured limb from day 27 ± 9; BL rats did this from day 4 ± 4 onward. The UL rats more frequently loaded only one hind limb; BL rats more often loaded both hind limbs. Osteotomy was not bridged in 20% of UL rats and in 4% of BL rats. Callus volume and bone volume fraction were lower in UL group. Weight and fiber size of UL-intact limb muscles were enhanced, compared to the osteotomized limb and those in BL group. Most of the other parameters which assess physiology, activity, body posture, head, or coat were not different. The effect of two pain therapies was not significant on any variable studied. Welfare of the animals was acceptable in all rats. In UL rats, bone healing was delayed. The more advanced healing in BL rats suggested a positive effect of earlier loading. In studies on bone healing, it is advisable to perform BL osteotomy.

Effect of Strontium Ranelate on the Muscle and Vertebrae of Ovariectomized Rats

Osteoporosis is often accompanied by sarcopenia. The effect of strontium ranelate (SR) on muscle tissue has not been investigated sufficiently. In this study, the effect of different SR treatments on muscle was studied. Additionally, the lumbar vertebrae were analyzed. Three-month-old female rats were divided into five groups (n = 12): Group 1: untreated (NON-OVX); Group 2: ovariectomized and left untreated (OVX); Group 3: SR after OVX until the study ended (13 weeks, SR prophylaxis and therapy = pr+th); Group 4: OVX and SR for 8 weeks (SR prophylaxis = pr); Group 5: SR for 5 weeks from the 8 week after OVX (SR therapy = SR th). SR was applied in food (630 mg/kg body weight). The size of muscle fibers, capillary density, metabolic enzymes, and mRNA expression were assessed in soleus, gastrocnemius, and longissimus muscles. The vertebral bodies underwent micro-CT, biomechanical, and ashing analyses. In general, SR did not alter the muscle histological parameters. The changes in fiber size and capillary ratio were related to the body weight. Myostatin mRNA was decreased in Sr pr+th; protein expression was not changed. SR th led to increase in mRNA expression of vascular endothelial growth factor (Vegf-B). In lumbar spine, SR pr+th enhanced biomechanical properties, bone mineral density, trabecular area, density, and thickness and cortical density. The reduced calcium/phosphate ratio in the SR pr+th group indicates the replacement of calcium by strontium ions. SR has no adverse effects on muscle tissue and it shows a favorable time-dependent effect on vertebrae. A functional analysis of muscles could verify these findings.

Effect of zileuton on osteoporotic bone and its healing, expression of bone, and brain genes in rats

Estrogen deficiency and aging are associated with osteoporosis, impaired bone healing, and lower cognitive performance. Close functional and physical connections occur between bone and the central nervous system. An anti-inflammatory drug, zileuton (which is an inhibitor of arachidonate 5-lipoxygenase), is known to have a positive effect on bone tissue repair and brain ischemia. We studied the effect of zileuton on osteopenic bone and its healing and on the genes considered to be crucial for the cross talks between bone and brain. Three-month-old Sprague-Dawley rats were ovariectomized or left untreated. After 8 wk, bilateral metaphyseal tibia osteotomy with plate osteosynthesis was performed in all rats. Ovariectomized rats were fed with food containing zileuton (1, 10, or 100 mg/kg body wt) for 5 wk. In tibiae, bone volume, callus and cortical volume, and gene expression of osteocalcin and alkaline phosphatase were enhanced by zileuton (10 or 100 mg); biomechanical properties and bone density were not changed. In femur, zileuton enlarged cortical volume distal and trabecular volume proximal, decreasing their density. The expression level of brain Sema3a, known to regulate bone mass positively, was downregulated after ovariectomy. In contrast, bone Sema4d, a negative regulator of bone mass, was upregulated in the tibia callus after ovariectomy, whereas zileuton treatment (10 or 100 mg) resulted in reverse effects. Here, we describe for the first time the expression of Rbbp4 mRNA and its increase in tibia after ovariectomy. Zileuton caused downregulation of Rbbp4 in the hippocampus and had an effect on bone healing, changed the expression of genes involved in cross talk between bones and brain, and may be a potent drug for further examination in estrogen deficiency-related dysfunction(s). NEW & NOTEWORTHY Zileuton, a 5-lipoxygenase inhibitor, increased bone volume, callus and cortical volume in osteotomized tibia, and trabecular and cortical volume in femur. Although the expression of Sema3a (positively regulating bone mass) in brain was downregulated and Sema4d (negatively regulating bone mass) was upregulated in tibia callus after ovariectomy, zileuton could counteract these effects. Rbbp4 (involved in age-related memory loss) was increased in tibia callus after ovariectomy.

Effect of the lipoxygenase-inhibitors baicalein and zileuton on the vertebra in ovariectomized rats

Osteoporosis is one of the most common diseases worldwide. In osteoporosis, vertebral fractures represent a major burden. Lipoxygenase (LOX) inhibitors such as baicalein and zileuton may represent a promising therapeutic option owing to their antioxidative effects and suppression of various inflammatory processes in muscle and bone. The effect of these LOX inhibitors on the spine was studied in osteopenic rats. Female Sprague-Dawley rats were divided two times into five groups: four groups each were ovariectomized (OVX) and one control group was non-ovariectomized (NON-OVX). Eight weeks after ovariectomy, three concentrations of baicalein (1mg/kg body weight [BW], 10mg/kgBW, and 100mg/kgBW) were administered subcutaneously daily in three OVX groups for 4weeks. Similarly, zileuton was administered in three concentrations via food for 5weeks. In vivo computed tomography (pQCT) of the spine was performed before the treatments and at the end of the experiment. Lumbar vertebrae were subjected to a compression test, micro-CT, and ashing analyses. After baicalein treatment, cortical bone mineral density (BMD) was improved; trabecular connectivity and trabecular BMD were diminished at high dose. After zileuton treatment, the total BMD, anorganic weight, trabecular nodes, and trabecular area were improved. The in vivo stress-strain index was increased and alkaline phosphatase activity in serum was enhanced after both treatments. A dose-dependent effect was not clearly observed after both treatments. The treatments using baicalein for 4 and zileuton for 5weeks were not sufficient to change the biomechanical properties and bone volume fraction (BV/TV). Overall, baicalein improved the cortical bone parameters whereas zileuton had a favorable effect on the trabecular structure. Moreover, both treatments increased the bone formation rate. Longer trials, a combination of both LOX inhibitors, and their effect at the cellular and molecular levels should be investigated in further studies.

Comparison of parathyroid hormone and strontium ranelate in combination with whole-body vibration in a rat model of osteoporosis

We investigated the combinatorial effects of whole-body vertical vibration (WBVV) with the primarily osteoanabolic parathyroid hormone (PTH) and the mainly antiresorptive strontium ranelate (SR) in a rat model of osteoporosis. Ovariectomies were performed on 76 three-month-old Sprague-Dawley rats (OVX, n = 76; NON-OVX, n = 12). After 8 weeks, the ovariectomized rats were divided into 6 groups. One group (OVX + PTH) received daily injections of PTH (40 µg/kg body weight/day) for 6 weeks. Another group (OVX + SR) was fed SR-supplemented chow (600 mg/kg body weight/day). Three groups (OVX + VIB, OVX + PTH + VIB, and OVX + SR + VIB) were treated with WBVV twice a day at 70 Hz for 15 min. Two groups (OVX + PTH + VIB, OVX + SR + VIB) were treated additionally with PTH and SR, respectively. The rats were killed at 14 weeks post-ovariectomy. The lumbar vertebrae and femora were removed for biomechanical and morphological assessment. PTH produced statistically significant improvements in biomechanical and structural properties, including bone mineral density (BMD) and trabecular bone quality. In contrast, SR treatment exerted mild effects, with significant effects in cortical thickness only. SR produced no significant improvement in biomechanical properties. WBVV as a single or an adjunctive therapy produced no significant improvements. In conclusion, vibration therapy administered as a single or dual treatment had no significant impact on bones affected by osteoporosis. PTH considerably improved bone quality in osteoporosis cases and is superior to treatment with SR.

The Effect of Vibration Treatments Combined with Teriparatide or Strontium Ranelate on Bone Healing and Muscle in Ovariectomized Rats

The aim of the present study was to study the effect of combined therapy of teriparatide (PTH) or strontium ranelate (SR) with whole-body vibration (WBV) on bone healing and muscle properties in an osteopenic rat model. Seventy-two rats (3 months old) were bilaterally ovariectomized (Ovx), and 12 rats were left intact (Non-Ovx). After 8 weeks, bilateral transverse osteotomy was performed at the tibia metaphysis in all rats. Thereafter, Ovx rats were divided into six groups (n = 12): (1) Ovx-no treatment, (2) Ovx + vibration (Vib), (3) SR, (4) SR + Vib, (5) PTH, and (6) PTH + Vib. PTH (40 μg/kg BW sc. 5×/week) and SR (613 mg/kg BW in food daily) were applied on the day of ovariectomy, vibration treatments 5 days later (vertical, 70 Hz, 0.5 mm, 2×/day for 15 min) for up to 6 weeks. In the WBV + SR group, the callus density, trabecular number, and Alp and Oc gene expression were decreased compared to SR alone. In the WBV + PTH group, the cortical and callus widths, biomechanical properties, Opg gene expression, and Opg/Rankl ratio were increased; the cortical and callus densities were decreased compared to PTH alone. A case of non-bridging was found in both vibrated groups. Vibration alone did not change the bone parameters; PTH possessed a stronger effect than SR therapy. In muscles, combined therapies improved the fiber size of Ovx rats. WBV could be applied alone or in combination with anti-osteoporosis drug therapy to improve muscle tissue. However, in patients with fractures, anti-osteoporosis treatments and the application of vibration could have an adverse effect on bone healing.

In Vivo siRNA Delivery Using JC Virus-like Particles Decreases the Expression of RANKL in Rats

Bone remodeling requires a precise balance between formation and resorption. This complex process involves numerous factors that orchestrate a multitude of biochemical events. Among these factors are hormones, growth factors, vitamins, cytokines, and, most notably, osteoprotegerin (OPG) and the receptor activator for nuclear factor-kappaB ligand (RANKL). Inflammatory cytokines play a major role in shifting the RANKL/OPG balance toward excessive RANKL, resulting in osteoclastogenesis, which in turn initiates bone resorption, which is frequently associated with osteoporosis. Rebalancing RANKL/OPG levels may be achieved through either upregulation of OPG or through transient silencing of RANKL by means of RNA interference. Here, we describe the utilization of a viral capsid-based delivery system for in vivo and in vitro RNAi using synthetic small interfering RNA (siRNA) molecules in rat osteoblasts. Polyoma JC virus-derived virus-like particles are capable of delivering siRNAs to target RANKL in osteoblast cells both in vitro and in a rat in vivo system. Expression levels were monitored using quantitative real-time polymerase reaction and enzyme-linked immunosorbent assay after single and repeated injections over a 14-day period. Our data indicate that this is an efficient and safe route for in vivo delivery of gene modulatory tools to study important molecular factors in a rat osteoporosis model.

Validation of a standardized mapping system of the hip joint for radial MRA sequencing

OBJECTIVE

Intraarticular gadolinium-enhanced magnetic resonance arthrography (MRA) is commonly applied to characterize morphological disorders of the hip. However, the reproducibility of retrieving anatomic landmarks on MRA scans and their correlation with intraarticular pathologies is unknown. A precise mapping system for the exact localization of hip pathomorphologies with radial MRA sequences is lacking. Therefore, the purpose of the study was the establishment and validation of a reproducible mapping system for radial sequences of hip MRA.

MATERIALS AND METHODS

Sixty-nine consecutive intraarticular gadolinium-enhanced hip MRAs were evaluated. Radial sequencing consisted of 14 cuts orientated along the axis of the femoral neck. Three orthopedic surgeons read the radial sequences independently. Each MRI was read twice with a minimum interval of 7 days from the first reading. The intra- and inter-observer reliability of the mapping procedure was determined.

RESULTS

A clockwise system for hip MRA was established. The teardrop figure served to determine the 6 o'clock position of the acetabulum; the center of the greater trochanter served to determine the 12 o'clock position of the femoral head-neck junction. The intra- and inter-observer ICCs to retrieve the correct 6/12 o'clock positions were 0.906-0.996 and 0.978-0.988, respectively.

CONCLUSIONS

The established mapping system for radial sequences of hip joint MRA is reproducible and easy to perform.