Trabecular Micro Research Articles

REMOVED: MiR-539-3p inhibits osteoblast activity and bone formation in vivo via targeting LRP-6

X-linked hypophosphatemia (XLH), the most common form of inherited rickets, is characterized by renal phosphate (Pi) wasting, abnormal vitamin D metabolism and defective bone mineralization. It is caused by an inactivation mutation in PHEX gene. Other factors, such as microRNA (miRNA), which regulates biological functions by interfering with specific mRNA translation, also contribute in controlling disease pathogenesis. Recent studies indicate the role of miRNAs in osteoblast functions. The main objective of this study is to identify novel miRNAs, regulated by Phex in osteoblast cells, and to determine whether miR-539-3p, a known tumor suppressor, aids in osteogenesis. MiRNA expression patterns in control and siPhex treated cells were analyzed by miRNA microarray profiling and quantitative RT-PCR. Effect of miR-539-3p on osteoblast differentiation was achieved by transfection with miR-539-3p and anti-miR in mouse calvarial osteoblasts. MiR-539-3p targets were identified by Luciferase reporter gene assay. LRP-6, Wnt3, Beta catenin, p-beta catenin, GSK3β and Lef-1 protein levels were determined by Western blotting. To investigate the function of miR-539-3p in vivo, animal groups were divided into; sham+PBS (ovary intact), ovariectomized (Ovx)+miC, Ovx+miR and Ovx+anti-miR. Chemically modified oligonucleotide miR and anti-miR were injected at 5ug/animal dose via a subcutaneously injection into mice. In PHEX silenced mice calvarial osteoblast cells, miR-539-3p was up-regulated as analyzed by miRNA array profiling and qRT-PCR analysis. Over-expression of miR-539-3p inhibited osteoblast differentiation, whereas inhibition of miR-539-3p function promoted expression of osteoblast-specific genes and alkaline phosphatase (ALP) activity. Target prediction analysis tools and experimental validation by luciferase 3ⲠUTR reporter assay identified LRP-6 as a direct target of miR-539-3p. Over-expression of miR-539-3p led to LRP-6 repression and inhibition of Wnt-Beta catenin signaling. Furthermore, miR-539-3p silencing led to increased bone formation and improved trabecular micro architecture in Ovx mice. Although miR-539-3p is known to be a tumor repressor, we identified a second complementary function of miR-539-3p where it inhibits LRP-6-mediated osteogenesis. Our findings suggest that pharmacological inhibition of miR-539-3p by anti-miR-539-3p could represent a therapeutic strategy for enhancing bone formation in vivo.

Refractive outcomes of toric intraocular lens in combined trabecular micro bypass stent implantation and cataract surgery in glaucomatous eyes.

To evaluate the impact of trabecular micro bypass stents (iStent Inject) on refractive outcomes with toric intraocular lens (IOL) in glaucomatous eyes. We identified glaucomatous eyes receiving a toric IOL between October 2017 and December 2020. Eyes with iStent implantation were included in the study group and eyes undergoing isolated phacoemulsification served as controls. Corrected and uncorrected visual acuity, manifest refraction, intraocular pressure (IOP), and number of hypotensive drugs three months after surgery were evaluated. 26 eyes comprised the study group and 41 eyes the control group. Mean postoperative refractive cylinder was 0.26D in the control and 0.11D in the iStent group, with 63% and 85% of eyes with a cylinder of 0 and 85% and 92% of eyes with a cylinder ≤ 0.5D respectively. The mean absolute difference between target and outcome spherical equivalent was 0.26D in the control and 0.22D in the iStent group, with all eyes within 0.75D of target. LogMar uncorrected postoperative vision in eyes targeted for emmetropia was 0.04 in the control and 0.03 in the iStent group. There was a statistically significant reduction in IOP and number of hypotensive drugs in both groups, with a mean decrease in IOP of 8.6% in the control and 15.7% in the iStent group. The number of hypotensive drugs dropped from 1.63 ± 0.80 to 1.34 ± 0.91 in the control group and from 2.12 ± 0.65 to 0.44 ± 0.71 in the iStent group. Toric IOLs provide predictable refractive outcomes in glaucomatous eyes undergoing combined phacoemulsification with iStent implantation, reducing postoperative spectacle dependence.

Effectiveness of two trabecular micro bypass stents in open angle glaucoma

Micro-invasive glaucoma surgical implantation of trabecular micro- bypass stents, previously shown to be safe and effective for open-angle glaucoma (OAG) subjects during cataract surgery, was considered for evaluation as a sole procedure. Objectives:The aim of this study was to evaluate the safety and intraocular pressure (IOP)-lowering efficacy after ab interno implantation of two Glaukos Trabecular Micro-Bypass iStent inject second generation devices in subjects with OAG. Methods: 99 patients with OAG on at least two topical ocular hypotensive medications who required additional IOP lowering to control glaucoma disease underwent implantation of two GTS400 stents in a standalone procedure. Patients were qualified if they presented with preoperative mean IOP between 22 and 38 mmHg after medication washout. Postoperatively, subjects were assessed at Day 1, Months 1, 3, 6, 7, 9, and 12. IOP, medication use and safety were assessed at each visit. Results: Sixty-six percent of subjects achieved IOP B18 mmHg at 12 months without medication, and 81% of subjects achieved Month 12 IOP B 18 mmHg with either a single medication or no medication. Mean baseline washout IOP values decreased by 10.2 mmHg or 39.7% from 26.3 (SD 3.5) mmHg to 15.7 (SD 3.7) mmHg at Month 12. Mean IOP at 12 months was 14.7 (SD 3.1) mmHg in subjects not using ocular hypotensive medications. Reduction from preoperative medication burden was achieved in 86.9% of patients, including 15.2% with reduction of one medication and 71.7% with reduction of two or more medications. Postoperative complications occurred at a low rate and resolved without persistent effects. Conclusion: In this series, implantation of two trabecular micro-bypass second generation stents in subjects with OAG resulted in IOP and medication reduction and favorable safety outcome

A Prospective Randomized Trial Comparing Hydrus and iStent Microinvasive Glaucoma Surgery Implants for Standalone Treatment of Open-Angle Glaucoma: The COMPARE Study

To compare the efficacy of different microinvasive glaucoma surgery (MIGS) devices for reducing intraocular pressure (IOP) and medications in open-angle glaucoma (OAG). Prospective, multicenter, randomized clinical trial. One hundred fifty-two eyes from 152 patients aged 45 to 84 years with OAG, Shaffer angle grade III-IV, best-corrected visual acuity (BCVA) 20/30 or better, and IOP 23 to 39 mmHg after washout of all hypotensive medications. Eyes with secondary glaucoma other than pseudoexfoliative or pigmentary glaucoma, angle closure, previous incisional glaucoma surgery, or any significant ocular pathology other than glaucoma were excluded. Study eyes were randomized 1:1 to standalone MIGS consisting of either 1 Hydrus Microstent (Ivantis, Inc, Irvine, CA) or 2 iStent Trabecular Micro Bypass devices (Glaukos Inc, San Clemente, CA). Follow-up was performed 1 day, 1 week, and 1, 3, 6, and 12 months postoperatively. Within-group and between-group differences in IOP and medications at 12 months and complete surgical success defined as freedom from repeat glaucoma surgery, IOP 18 mmHg or less, and no glaucoma medications. Safety measures included the frequency of surgical complications, changes in visual acuity, slit-lamp findings, and adverse events. Study groups were well matched for baseline demographics, glaucoma status, medication use, and baseline IOP. Twelve-month follow-up was completed in 148 of 152 randomized subjects (97.3%). At 12 months, the Hydrus had a greater rate of complete surgical success (P < 0.001) and reduced medication use (difference= -0.6 medications, P= 0.004). More Hydrus subjects were medication free at 12 months (difference= 22.6% P= 0.0057). Secondary glaucoma surgery was performed in 2 eyes in the 2-iStent group (3.9%) and in none of the Hydrus eyes. Two eyes in the Hydrus group and 1 in the 2-iStent group had BCVA loss of ≥2 lines. Standalone MIGS in OAG with the Hydrus resulted in a higher surgical success rate andfewermedications compared with the 2-iStent procedure. The 2 MIGS devices have similar safety profiles.

Cost-effectiveness analysis of iStent trabecular micro-bypass stent for patients with open-angle glaucoma in Colombia

Objective: To estimate the cost-effectiveness of trabecular micro bypass stent vs laser trabeculoplasty or medications only, for patients with open-angle glaucoma in a setting of the Colombian System Health.Methods: This is a cost-effectiveness analysis that based its assumptions in external data sources, used to extrapolate the quality-of-life related to health, survival, and costs. A Markov model, with stages from 0 (ocular hypertension without glaucoma) to 5 and bilateral blindness, was developed inclusive of Colombians older than 40 years in 2018, from a societal perspective, comparing trabecular micro-bypass stents vs laser trabeculoplasty, timolol + dorzolamide + brimonidine, timolol + dorzolamide + latanoprost, or timolol + dorzolamide + brimatoprost, in terms of clinical and economic outcomes over a lifetime horizon. Both costs and health outcomes had an annual rate discount of 5%. Health outcomes were evaluated in terms of QALYs related with loss of visual acuity. Trabecular micro-bypass costs include the joint use of timolol, and the costs of laser trabeculoplasty include the combined use of timolol + dorzolamide.Results: Trabecular micro-bypass stents were estimated to have 127,971 more discounted QALYs vs laser trabeculoplasty; 405,982 vs timolol + dorzolamide + brimonidine; and 378,287 vs timolol + dorzolamide + latanoprost or timolol + dorzolamide + brimatoprost. Cumulative costs with trabecular micro-bypass stents at 40 years was $13,252,318 lower than laser trabeculoplasty; $6,403,534, lower than timolol + dorzolamide + brimonidine; $22,311,064, lower than timolol + dorzolamide + latanoprost; and $29,156,113 lower than timolol + dorzolamide + brimatoprost.Conclusions: The trabecular micro-bypass stent is a highly cost-saving strategy due to more QALYs related to a lower rate of the population with loss of visual acuity in the long-term, and because the costs associated with additional medications and complications are lower with trabecular micro-bypass stents.

Osteogenic activity of natural diterpenoids isolated from Cupressus sempervirens fruits in calvarial derived osteoblast cells via differentiation and mineralization

The aim of the present study was to investigate the antiosteoporotic activity of four structurally related diterpenoids: sugiol (1), trans-communic acid (2), 15-acetoxy imbricatolic acid (3) and imbricatolic acid (4). Their osteogenic effect was evaluated by using validated models including alkaline phosphatase (ALP) assay, mineralization assay and expression of osteogenic genes-bone morphogenetic protein-2 (BMP-2) and osteoblast transcription factor (RUNX2) – in primary calvarial cultures harvested from neonatal mice. Among them, compound 1 at a dose of 1.0mg/kg body weight exhibited significant osteoprotective effects and did not show uterine estrogenicity at the same dose. Additionally, compound 1 treatment led to improved biomechanical properties as exhibited by increased power, energy and stiffness in femoral bones compared to untreated Ovx animals. Since osteoporotic compression fracture correlates with the mechanical characteristics of trabecular bone, so that it could effectively reduce the risk of this type of fracture by improving trabecular micro architecture in postmenopausal women. Therefore, our findings proposed that diterpenoids may be useful new chemical agents in the treatment of diseases associated with bone loss.

Ethanolic extract of Coelogyne cristata Lindley (Orchidaceae) and its compound coelogin promote osteoprotective activity in ovariectomized estrogen deficient mice

Coelogyne cristata Lindley (CC) family Orchidaceae is an Indian medicinal plant used for the treatment of fractured bones in folk-tradition of Kumaon region, Uttarakhand, India. In continuation of our drug discovery program, feeding of ethanolic extract to ovariectomized estrogen deficient mice led to significant restoration of trabecular micro architecture in both femoral and tibial bones, better bone quality and also devoid of any uterine estrogenicity. Subsequently, coelogin, a pure compound was isolated from ethyl acetate fraction of C. cristata and evaluated in in vitro osteoblast cell cultures. Treatment of coelogin to osteoblasts led to enhanced ALP activity (a marker of osteoblast differentiation), mineral nodule formation and mRNA levels of osteogenic markers like BMP-2, Type 1 Collagen and RUNX-2. Based on these results, we propose that ethanolic extract of C. cristata and its pure compound coelogin have potential in the management of post menopausal osteoporosis.

Liuwei Dihuang Wan, A Traditional Chinese Medicinal Formula, Protects Against Osteoporosis

The treatment and prevention of osteoporosis involve great challenges. Liuwei Dihuang Wan (LW), a classic Chinese medicinal formula, has been widely used for clinically treating ‘kidney deficiency’ in Asia, however, its potency in osteogenesis remains unknown. The purpose of this study is to systemically investigate the effects of LW on ovariectomy-induced osteoporosis in rats. A total of forty-eight 7-month-old female Wistar rats were used and randomly divided into sham-operated group and three ovariectomized (OVX, model) groups: OVX with vehicle; OVX with LW; OVX with nilestriol. Daily oral administration began 4 weeks after the surgery and lasted for 24 weeks. The bone mineral density (BMD), bone mineral content (BMC), uterine index, blood mineral levels and biochemical markers were examined in LW orally treated rats. The trabecular bone micro architecture was also evaluated by MicroCT. Results showed that LW treatment significantly enhanced BMD, BMC, and blood antioxidant enzymes activities, decreased blood Ca and P levels compared to the model group. LW prevented total BMD decrease in the femur induced by OVX, which was accompanied by a significant decrease in skeletal remodeling, as was evidenced by the decreased levels of the bone turnover markers, such as alkaline phosphatase (ALP). Treated rats showed significantly improved mineral content in ashed femurs compared to untreated animals. The treatment could also enhance the bone strength and prevent the deterioration of trabecular micro architecture. This experiment demonstrates that the administration of LW to ovariectomized rats reverses bone loss and prevents osteoporosis. The present study indicated that LW might be a potential alternative medicine for the prevention and treatment of osteoporosis.

2E17 ヒト大腿骨における力学負荷と骨梁構造についてのリモデリングシミュレーションによる検討(GS5-2:硬組織のバイオメカニクス(2))

2E17 ヒト大腿骨における力学負荷と骨梁構造についてのリモデリングシミュレーションによる検討(GS5-2:硬組織のバイオメカニクス(2))

Shape based Monte Carlo code for light transport in complex heterogeneous Tissues

A Monte Carlo code for the calculation of light transport in heterogeneous scattering media is presented together with its validation. Triangle meshes are used to define the interfaces between different materials, in contrast with techniques based on individual volume elements. This approach allows to address realistic problems in a flexible way. A hierarchical spatial organisation enables a fast photon-surface intersection test. The application of the new environment to evaluate the impact of the trabecular structure of bone on its optical properties is demonstrated. A model of the trabecular micro structure recovered from microCT data was used to compute light distribution within tissue. Time-resolved curves across a spherical bone volume were computed. The work presented enables simulation of radiative transport in complex reality-based models of tissue and serves as a powerful, generic tool to study the effect of heterogeneity in the field of biomedical optics.

Spatially isotropic 3-D magnetic resonance imaging of the trabecular bone structure of the calcaneus

Isotroiic imaging of the three dimensional trabecular micro structure is feasable but limited by partial volume effects. Currently, the GRE sequence is preferable because it yiels a clearer visualization of the trabecular structure. SE sequences, however, are less artifact prone and could be developed into multiecho sequences. Hence, they may have greater potential for further improvement of the spatial resolution.