Omega-9 Modifies Viscoelasticity and Augments Bone Strength and Architecture in a High-Fat Diet-Fed Murine Model

A Multifunctional Therapeutic Strategy Using P7C3 as A Countermeasure Against Bone Loss and Fragility in An Ovariectomized Rat Model of Postmenopausal Osteoporosis

By 2060, an estimated one in four Americans will be elderly. Consequently, the prevalence of osteoporosis and fragility fractures will also increase. Presently, no available intervention definitively prevents or manages osteoporosis. This study explores whether Pool 7 Compound 3 (P7C3) reduces progressive bone loss and fragility following the onset of ovariectomy (OVX)-induced osteoporosis. Results confirm OVX-induced weakened, osteoporotic bone together with a significant gain in adipogenic body weight. Treatment with P7C3 significantly reduced osteoclastic activity, bone marrow adiposity, whole-body weight gain, and preserved bone area, architecture, and mechanical strength. Analyses reveal significantly upregulated platelet derived growth factor-BB and leukemia inhibitory factor, with downregulation of interleukin-1 R6, and receptor activator of nuclear factor kappa-B (RANK). Together, proteomic data suggest the targeting of several key regulators of inflammation, bone, and adipose turnover, via transforming growth factor-beta/SMAD, and Wingless-related integration site/be-catenin signaling pathways. To the best of the knowledge, this is first evidence of an intervention that drives against bone loss via RANK. Metatranscriptomic analyses of the gut microbiota show P7C3 increased Porphyromonadaceae bacterium, Candidatus Melainabacteria, and Ruminococcaceae bacterium abundance, potentially contributing to the favorable inflammatory, and adipo-osteogenic metabolic regulation observed. The results reveal an undiscovered, and multifunctional therapeutic strategy to prevent the pathological progression of OVX-induced bone loss.

Sex-specific effects of Fat-1 transgene on bone material properties, size, and shape in mice

Western diets are becoming increasingly common around the world. Western diets have high omega 6 (ω-6) and omega 3 (ω-3) fatty acids and are linked to bone loss in humans and animals. Dietary fats are not created equal; therefore, it is vital to understand the effects of specific dietary fats on bone. We aimed to determine how altering the endogenous ratios of ω-6:ω-3 fatty acids impacts bone accrual, strength, and fracture toughness. To accomplish this, we used the Fat-1 transgenic mice, which carry a gene responsible for encoding a ω-3 fatty acid desaturase that converts ω-6 to ω-3 fatty acids. Male and female Fat-1 positive mice (Fat-1) and Fat-1 negative littermates (WT) were given either a high-fat diet (HFD) or low-fat diet (LFD) at 4 wk of age for 16 wk. The Fat-1 transgene reduced fracture toughness in males. Additionally, male BMD, measured from DXA, decreased over the diet duration for HFD mice. In males, neither HFD feeding nor the presence of the Fat-1 transgene impacted cortical geometry, trabecular architecture, or whole-bone flexural properties, as detected by main group effects. In females, Fat-1-LFD mice experienced increases in BMD compared to WT-LFD mice; however, cortical area, distal femur trabecular thickness, and cortical stiffness were reduced in Fat-1 mice compared to pooled WT controls. However, reductions in stiffness were caused by a decrease in bone size and were not driven by changes in material properties. Together, these results demonstrate that the endogenous ω-6:ω-3 fatty acid ratio influences bone material properties in a sex-dependent manner. In addition, Fat-1 mediated fatty acid conversion was not able to mitigate the adverse effects of HFD on bone strength and accrual.

Omega-3 PUFAs prevent bone impairment and bone marrow adiposity in mouse model of obesity

Obesity adversely affects bone and fat metabolism in mice and humans. Omega-3 polyunsaturated fatty acids (omega-3 PUFAs) have been shown to improve glucose metabolism and bone homeostasis in obesity. However, the impact of omega-3 PUFAs on bone marrow adipose tissue (BMAT) and bone marrow stromal cell (BMSC) metabolism has not been intensively studied yet. In the present study we demonstrated that omega-3 PUFA supplementation in high fat diet (HFD + F) improved bone parameters, mechanical properties along with decreased BMAT in obese mice when compared to the HFD group. Primary BMSCs isolated from HFD + F mice showed decreased adipocyte and higher osteoblast differentiation with lower senescent phenotype along with decreased osteoclast formation suggesting improved bone marrow microenvironment promoting bone formation in mice. Thus, our study highlights the beneficial effects of omega-3 PUFA-enriched diet on bone and cellular metabolism and its potential use in the treatment of metabolic bone diseases.

Dietary fat differentially modulates the response of bone marrow-derived macrophages to TLR4 and NOD2 agonists

Consumption of diets high in fat has been linked to the development of obesity and related metabolic complications. Such associations originate from the enhanced, chronic, low-grade inflammation mediated by macrophages in response to translocated bacteria, bacterial products, or dietary constituents such as fatty acids (FAs). Nucleotide-binding Oligomerization Domain 2 (NOD2) senses muramyl dipeptide (MDP), a component of bacterial peptidoglycan. The inability to sense peptidoglycan through NOD2 has been demonstrated to lead to dysbiosis, increased bacterial translocation, inflammation and metabolic dysfunction. Currently, it is unknown how consumption of HFDs with different FA compositions might influence NOD2-dependent responses. In this study, we subjected WT mice to a control diet or to HFDs comprised of various ratios of unsaturated to saturated fats and determined the macrophage response to TLR4 and NOD2 agonists. A HFD with equal ratios of saturated and unsaturated fats enhanced subsequent responsiveness of macrophages to LPS but not to MDP. However, a high-unsaturated fat diet (HUFD) or a high-saturated fat diet (HSFD) both decreased the responsiveness to NOD2 agonists compared to that observed in control diet (CD) fed mice. These data suggest that dietary fatty acid composition can influence the subsequent macrophage responsiveness to bacterial products.

A novel multifunctional radioprotective strategy using P7C3 as a countermeasure against ionizing radiation-induced bone loss

Radiotherapy is a critical component of cancer care but can cause osteoporosis and pathological insufficiency fractures in surrounding and otherwise healthy bone. Presently, no effective countermeasure exists, and ionizing radiation-induced bone damage continues to be a substantial source of pain and morbidity. The purpose of this study was to investigate a small molecule aminopropyl carbazole named P7C3 as a novel radioprotective strategy. Our studies revealed that P7C3 repressed ionizing radiation (IR)-induced osteoclastic activity, inhibited adipogenesis, and promoted osteoblastogenesis and mineral deposition in vitro. We also demonstrated that rodents exposed to clinically equivalent hypofractionated levels of IR in vivo develop weakened, osteoporotic bone. However, the administration of P7C3 significantly inhibited osteoclastic activity, lipid formation and bone marrow adiposity and mitigated tissue loss such that bone maintained its area, architecture, and mechanical strength. Our findings revealed significant enhancement of cellular macromolecule metabolic processes, myeloid cell differentiation, and the proteins LRP-4, TAGLN, ILK, and Tollip, with downregulation of GDF-3, SH2B1, and CD200. These proteins are key in favoring osteoblast over adipogenic progenitor differentiation, cell matrix interactions, and shape and motility, facilitating inflammatory resolution, and suppressing osteoclastogenesis, potentially via Wnt/β-catenin signaling. A concern was whether P7C3 afforded similar protection to cancer cells. Preliminarily, and remarkably, at the same protective P7C3 dose, a significant reduction in triple-negative breast cancer and osteosarcoma cell metabolic activity was found in vitro. Together, these results indicate that P7C3 is a previously undiscovered key regulator of adipo-osteogenic progenitor lineage commitment and may serve as a novel multifunctional therapeutic strategy, leaving IR an effective clinical tool while diminishing the risk of adverse post-IR complications. Our data uncover a new approach for the prevention of radiation-induced bone damage, and further work is needed to investigate its ability to selectively drive cancer cell death.

Association between fatty acids intake and bone mineral density in adults aged 20–59: NHANES 2011–2018

Background

Previous studies have investigated the link between fatty acid intake and bone mineral density (BMD), but the results are controversial. This study aims to examine the relationship between fatty acid intake and BMD in adults aged 20–59.

Methods

The association between fatty acid consumption and BMD was analyzed using a weighted multiple linear regression model with National Health and Nutrition Examination Survey data from 2011 to 2018. The linearity relationship and saturation value of the connection between fatty acid consumption and BMD were assessed by fitting a smooth curve and a saturation effect analysis model.

Results

The study included 8,942 subjects. We found a significant positive correlation between the consumption of saturated fatty acids, monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids and BMD. In subgroup analyses that were stratified by gender and race, this association was still shown to be significant. Based on the smooth curve and saturation effect analysis, we found no saturation effect for the three fatty acids and total BMD. However, there was a turning point (20.52 g/d) between MUFAs intake and BMD, and only MUFAs intake >20.52 g/d showed a positive correlation between MUFAs and BMD.

Conclusion

We found that fatty acid intake is beneficial for bone density in adults. Therefore, according to our findings, it is recommended that adults consume moderate amounts of fatty acids to ensure adequate bone mass but not metabolic diseases.

The Effect of Omega-9 on Bone Viscoelasticity and Strength in an Ovariectomized Diet-Fed Murine Model

Few studies have investigated the effect of a monosaturated diet high in ω-9 on osteoporosis. We hypothesized that omega-9 (ω-9) protects ovariectomized (OVX) mice from a decline in bone microarchitecture, tissue loss, and mechanical strength, thereby serving as a modifiable dietary intervention against osteoporotic deterioration. Female C57BL/6J mice were assigned to sham-ovariectomy, ovariectomy, or ovariectomy + estradiol treatment prior to switching their feed to a diet high in ω-9 for 12 weeks. Tibiae were evaluated using DMA, 3-point-bending, histomorphometry, and microCT. A significant decrease in lean mass (p = 0.05), tibial area (p = 0.009), and cross-sectional moment of inertia (p = 0.028) was measured in OVX mice compared to the control. A trend was seen where OVX bone displayed increased elastic modulus, ductility, storage modulus, and loss modulus, suggesting the ω-9 diet paradoxically increased both stiffness and viscosity. This implies beneficial alterations on the macro-structural, and micro-tissue level in OVX bone, potentially decreasing the fracture risk. Supporting this, no significant differences in ultimate, fracture, and yield stresses were measured. A diet high in ω-9 did not prevent microarchitectural deterioration, nevertheless, healthy tibial strength and resistance to fracture was maintained via mechanisms independent of bone structure/shape. Further investigation of ω-9 as a therapeutic in osteoporosis is warranted.