TNF-α is upregulated in T2DM patients with fracture and promotes the apoptosis of osteoblast cells in vitro in the presence of high glucose

TNF-α-licensed exosome-integrated titaniumaccelerated T2D osseointegration by promoting autophagy-regulated M2 macrophage polarization

Type 2 diabetes (T2D) is on a notable rise worldwide, which leads to unfavorable outcomes during implant treatments. Surface modification of implants and exosome treatment have been utilized to enhance osseointegration. However, there has been insufficient approach to improve adverse osseointegration in T2D conditions. In this study, we successfully loaded TNF-α-treated mesenchymal stem cell (MSC)-derived exosomes onto micro/nano-network titanium (Ti) surfaces. TNF-α-licensed exosome-integrated titanium (TNF-exo-Ti) effectively enhanced M2 macrophage polarization in hyperglycemic conditions, with increased secretion of anti-inflammatory cytokines and decreased secretion of pro-inflammatory cytokines. In addition, TNF-exo-Ti pretreated macrophage further enhanced angiogenesis and osteogenesis of endothelial cells and bone marrow MSCs. More importantly, TNF-exo-Ti markedly promoted osseointegration in T2D mice. Mechanistically, TNF-exo-Ti activated macrophage autophagy to promote M2 polarization through inhibition of the PI3K/AKT/mTOR pathway, which could be abolished by PI3K agonist. Thus, this study established TNF-α-licensed exosome-immobilized titanium surfaces that could rectify macrophage immune states and accelerate osseointegration in T2D conditions.

Polychlorinated biphenyls exposure and type 2 diabetes: Molecular mechanism that causes insulin resistance and islet damage

Polychlorinated biphenyls (PCBs) are typical persistent organic pollutants that have been associated with type 2 diabetes (T2DM) in cohort studies. This review aims to comprehensively assess the molecular mechanisms of PCBs-induced T2DM. Recent progress has been made in the research of PCBs in liver tissue, adipose tissue, and other tissues. By influencing the function of nuclear receptors, such as the aryl hydrocarbon receptor (AhR), pregnancy X receptor (PXR), and peroxisome proliferator activated receptor γ (PPARγ), as well as the inflammatory response, PCBs disrupt the balance of hepatic glucose and lipid metabolism. This is associated with insulin resistance (IR) in the target organ of insulin. Through androgen receptor (AR), estrogen receptor α/β (ERα/β), and pancreato-duodenal-homeobox gene-1 (PDX-1), PCBs affect the secretion of insulin and increase blood glucose. Thus, this review is a discussion on the relationship between PCBs exposure and the pathogenesis of T2DM. It is hoped to provide basic concepts for diabetes research and disease treatment.

Biochanin A abrogates osteoclastogenesis in type 2 diabetic osteoporosis via regulating ROS/MAPK signaling pathway based on integrating molecular docking and experimental validation

BACKGROUND

There are accumulating type 2 diabetes patients who have osteoporosis simultaneously. More effective therapeutic strategies should be discovered. Biochanin A (BCA) has been indicated that can play a role in improving metabolic disorders of type 2 diabetes and preventing osteoporosis. But whether BCA can treat type 2 diabetic osteoporosis has not been studied.

PURPOSE

To investigate if the BCA can protect against type 2 diabetic osteoporosis and clarify the mechanism.

METHODS

Micro-CT and histology assays were performed to detect the trabecular bone and analyze the bone histomorphology effect of BCA. CCK-8 assay was performed to detect the toxicity of BCA. TRAcP staining, immunofluorescence and hydroxyapatite resorption assay were used to observe osteoclasts differentiation and resorptive activity. Molecular docking provided evidence about BCA regulating the MAPK axis via prediction by the algorithm. QRT-PCR and Western Blotting were utilized to detect the expression of osteoclastogenesis-related markers and MAPK signaling pathway.

RESULTS

Accumulation of bone volume after BCA treatment could be found based on the 3D reconstruction. Besides, there were fewer osteoclasts in db/db mice treated with BCA than db/db mice treated with saline. In vitro, we found that BCA hadn't toxicity in osteoclasts precursor, but also inhibited differentiation of osteoclasts. Further, we found that BCA suppresses osteoclastogenesis via ROS/MAPK signaling pathway.

CONCLUSION

BCA can prevent type 2 diabetic osteoporosis by restricting osteoclast differentiation via ROS/MAPK signaling pathway.

Application of machine learning algorithms to predict osteoporosis in postmenopausal women with type 2 diabetes mellitus

PURPOSE

The screening and diagnosis of osteoporosis in patients with type 2 diabetes mellitus (T2DM) based on bone mineral density remains challenging because of the limited availability and accessibility of dual-energy X-ray absorptiometry. We aimed to develop and validate models to predict the risk of osteoporosis in postmenopausal women with T2DM based on machine learning (ML) algorithms.

METHODS

This retrospective study included 303 postmenopausal women with T2DM. To develop prediction models for osteoporosis, we applied nine ML algorithms combined with demographic, clinical, and laboratory data. The least absolute shrinkage and selection operator were used to perform feature selection. We used the bootstrap resampling technique for model training and validation. To test the performance of the models, we calculated indices including the area under the receiver operating characteristic curve (AUROC), accuracy, sensitivity, specificity, positive predictive value, negative predictive value, F1 score, calibration curve, and decision curve analysis. Furthermore, we conducted fivefold cross-validation for parameter optimization and model validation. Feature importance was assessed using the SHapley additive explanation (SHAP).

RESULTS

We identified 10 independent predictors as the most valuable features. An AUROC of 0.616-1.000 was observed for nine ML algorithms. The extreme gradient boosting (XGBoost) model exhibited the best performance, outperforming conventional risk assessment tools and registering 0.993 in the training set, 0.798 in the validation set, and 0.786 in the test set for fivefold cross-validation. Using SHAP, we found that the explanatory variables contributed to the model and their relationship with osteoporosis occurrence. Furthermore, we developed a user-friendly tool for calculating the risk of osteoporosis.

CONCLUSIONS

With the integration of demographic and clinical risk factors, ML algorithms can accurately predict osteoporosis. The XGBoost model showed ideal performance. With the incorporation of these models in the clinic, patients may benefit from early osteoporosis diagnosis and treatment.

Reduced Bone Regeneration in Rats With Type 2 Diabetes Mellitus as a Result of Impaired Stromal Cell and Osteoblast Function-A Computer Modeling Study

Bone has the fascinating ability to self-regenerate. However, under certain conditions, such as type 2 diabetes mellitus (T2DM), this ability is impaired. T2DM is a chronic metabolic disease known by the presence of elevated blood glucose levels that is associated with reduced bone regeneration capability, high fracture risk, and eventual non-union risk after a fracture. Several mechanical and biological factors relevant to bone regeneration have been shown to be affected in a diabetic environment. However, whether impaired bone regeneration in T2DM can be explained due to mechanical or biological alterations remains unknown. To elucidate the relevance of either one, the aim of this study was to investigate the relative contribution of T2DM-related alterations on either cellular activity or mechanical stimuli driving bone regeneration. A previously validated in silico computer modeling approach that was capable of explaining bone regeneration in uneventful conditions of healing was further developed to investigate bone regeneration in T2DM. Aspects analyzed included the presence of mesenchymal stromal cells (MSCs), cellular migration, proliferation, differentiation, apoptosis, and cellular mechanosensitivity. To further verify the computer model findings against in vivo data, an experimental setup was replicated, in which regeneration was compared in healthy and diabetic after a rat femur bone osteotomy stabilized with plate fixation. We found that mechanical alterations had little effect on the reduced bone regeneration in T2DM and that alterations in MSC proliferation, MSC migration, and osteoblast differentiation had the highest effect. In silico predictions of regenerated bone in T2DM matched qualitatively and quantitatively those from ex vivo μCT at 12 weeks post-surgery when reduced cellular activities reported in previous in vitro and in vivo studies were included in the model. The presented findings here could have clinical implications in the treatment of bone fractures in patients with T2DM. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Expression of TNF-α and IL-1β in Peripheral Blood of Patients with T2DM Retinopathy

Aims

The expression and clinical significance of tumor necrosis factor-α (INF-α) and interleukin 1-β (IL-1β) in retinal cells of patients with type 2 diabetes (T2DM) retinopathy were detected by flow cytometry.

Materials and Methods

Fifty patients with T2DM who attended our ophthalmology clinic between May 2021 and May 2022 were selected as the observation group. Another 50 healthy individuals who were examined at our hospital during the same period were selected as the comparison group. Tear film rupture time (BUT), fluorescein staining (FL), basal tear secretion (Schirmer I) test, and conjunctival impression cytology (CIC) were detected in both groups, and the expression of TNF-α and IL-1β in retinal cells was observed by immunohistochemical staining.

Results

The levels of IL13 and TNF-α in the two groups were not exactly the same. The serum levels of IL13 and TNF-α in the observation group were significantly higher than those in the control group, and there was a statistically significant difference (P < 0.05). TNF-α and IL-1B expressions in the observation group were positively correlated with the fluorescence staining, and the expression of TNF-α and IL-1β in the observation group was significantly negatively correlated with the BUT test and Schirmer I test.

Conclusion

Serums TNF-α and IL-1β are significantly elevated in patients with T2DM retinopathy and gradually increase with disease progression. Combined detection of serums TNF-α and IL-1β can help determine the severity of the disease and assess the prognosis.

Bone mass and microarchitecture in T2DM patients and corticosteroids therapy: the Bushehr Elderly Health program

Purpose

Our study examined whether T2DM and glucocorticoids treatment affect bone quality and quantity that are measured by Bone Mineral Density (BMD) and Trabecular Bone Score (TBS).

Materials & methods

Participants in this study were 2294 women and men aged over 60 years who participated in stage II of the Bushehr Elderly Health (BEH) program. Patients with T2DM and those who received glucocorticoids were included. BMD was detected using the DXA method and the TBS of L1-L4 was evaluated by TBS iNsight® software. To evaluate the correlation between TBS and BMD levels with diabetes and taking corticosteroids sex-specific multivariable linear regression models were appplied.

Results

TBS and BMD were not significantly different in those who had received glucocorticoids versus those who did not.T2DM revealed a significant association with both BMD and TBS in men (beta = 0.12, p < 0.001 and beta = 0.063, p = 0.03, respectively). BMD values were significantly higher in diabetic women (beta = 0.073, p < 0.01). BMI had a significant association with both TBS and BMD but in an opposite direction, in women and men (BMD: beta = -0.22, -0.24, and regarding TBS: beta = 0.37, 0.25, all p-values < 0.001).

Conclusion

Our findings showed that T2DM had major effects on BMD in both men and women. However, T2DM only affects TBS in men. Furthermore, neither BMD nor TBS were affected by GC intake in men or women.Based on the variable importance of covariates, BMI was the most influential factor on both BMD and TBS, although in opposite directions, in both sexes.

Involvement of the TNF-α/SATB2 axis in the induced apoptosis and inhibited autophagy of osteoblasts by the antipsychotic Risperidone

BACKGROUND

Risperidone, an atypical antipsychotic, impedes serotonin and dopamine receptor systems. Meanwhile, tumor necrosis factor-α (TNF-α) is known to participate in regulating osteoblast functions. Consequently, the current study aimed to investigate whether the influences of Risperidone on osteoblast functions are associated with TNF-α and special AT-rich sequence-binding protein (SATB2).

METHODS

Firstly, we searched the DGIdb, MEM and GeneCards databases to identify the critical factors involved in the effects of Risperidone on osteoblasts, as well as their interactions. Afterwards, osteoblast cell line MC3T3-E1 was transduced with lentivirus carrying si-TNF-α, si-SATB2 or both and subsequently treated with Risperidone. Various abilities including differentiation, autophagy and apoptosis of osteoblasts were examined after different treatments. Finally, animal experiments were performed with Risperidone alone or together with lentivirus to verify the function of Risperidone in vivo and the mechanism.

RESULTS

It was found that Risperidone might promote TNF-α expression, thereby inhibiting the expression of SATB2 to affect the autophagy and apoptosis in osteoblasts. Furthermore, as shown by our experimental findings, Risperidone treatment inhibited the differentiation and autophagy, and promoted the apoptosis of osteoblasts, as evidenced by elevated levels of OPG, p62, cleaved PARP1, cleaved caspase-3, cleaved caspase-8, and cleaved caspase-9, and reduced levels of LC3 II/I, Beclin1, collagen I, and RANKL. In addition, Risperidone was also found to elevate the expression of TNF-α to down-regulate SATB2, thereby inhibiting the differentiation and autophagy and enhancing the apoptosis of osteoblasts in vitro and in vivo.

CONCLUSIONS

Collectively, our findings indicated that Risperidone affects the differentiation of osteoblasts by inhibiting autophagy and enhancing apoptosis via TNF-α-mediated down-regulation of SATB2.

Diabetic wound healing in soft and hard oral tissues

There is significant interest in understanding the cellular mechanisms responsible for expedited healing response in various oral tissues and how they are impacted by systemic diseases. Depending upon the types of oral tissue, wound healing may occur by predominantly re-eptihelialization, by re-epithelialization with substantial new connective tissue formation, or by a a combination of both plus new bone formation. As a result, the cells involved differ and are impacted by systemic diaseses in various ways. Diabetes mellitus is a prevalent metabolic disorder that impairs barrier function and healing responses throughout the human body. In the oral cavity, diabetes is a known risk factor for exacerbated periodontal disease and delayed wound healing, which includes both soft and hard tissue components. Here, we review the mechanisms of diabetic oral wound healing, particularly on impaired keratinocyte proliferation and migration, altered level of inflammation, and reduced formation of new connective tissue and bone. In particular, diabetes inhibits the expression of mitogenic growth factors whereas that of pro-inflammatory cytokines is elevated through epigenetic mechanisms. Moreover, hyperglycemia and oxidative stress induced by diabetes prevents the expansion of mesengenic cells that are involved in both soft and hard tissue oral wounds. A better understanding of how diabetes influences the healing processes is crucial for the prevention and treatment of diabetes-associated oral complications.

HspB4/αA-Crystallin Modulates Neuroinflammation in the Retina via the Stress-Specific Inflammatory Pathways

PURPOSE

We have previously demonstrated that HspB4/αA-crystallin, a molecular chaperone, plays an important intrinsic neuroprotective role during diabetes, by its phosphorylation on residue 148. We also reported that HspB4/αA-crystallin is highly expressed by glial cells. There is a growing interest in the potential causative role of low-grade inflammation in diabetic retinopathy pathophysiology and retinal Müller glial cells' (MGCs') participation in the inflammatory response. MGCs indeed play a central role in retinal homeostasis via secreting various cytokines and other mediators. Hence, this study was carried out to delineate and understand the regulatory function of HspB4/αA-crystallin in the inflammatory response associated with metabolic stresses.

METHODS

Primary MGCs were isolated from knockout HspB4/αA-crystallin mice. These primary cells were then transfected with plasmids encoding either wild-type (WT), phosphomimetic (T148D), or non-phosphorylatable mutants (T148A) of HspB4/αA-crystallin. The cells were exposed to multiple metabolic stresses including serum starvation (SS) or high glucose with TNF-alpha (HG + T) before being further evaluated for the expression of inflammatory markers by qPCR. The total protein expression along with subcellular localization of NF-kB and the NLRP3 component was assessed by Western blot.

RESULTS

Elevated levels of IL-6, IL-1β, MCP-1, and IL-18 in SS were significantly diminished in MGCs overexpressing WT and further in T148D as compared to EV. The HG + T-induced increase in these inflammatory markers was also dampened by WT and even more significantly by T148D overexpression, whereas T148A was ineffective in either stress. Further analysis revealed that overexpression of WT or the T148D, also led to a significant reduction of Nlrp3, Asc, and caspase-1 transcript expression in serum-deprived MGCs and nearly abolished the NF-kB induction in HG + T diabetes-like stress. This mechanistic effect was further evaluated at the protein level and confirmed the stress-dependent regulation of NLRP3 and NF-kB by αA-crystallin.

CONCLUSIONS

The data gathered in this study demonstrate the central regulatory role of HspB4/αA-crystallin and its modulation by phosphorylation on T148 in retinal MGCs. For the first time, this study demonstrates that HspB4/αA-crystallin can dampen the stress-induced expression of pro-inflammatory cytokines through the modulation of multiple key inflammatory pathways, therefore, suggesting its potential as a therapeutic target for the modulation of chronic neuroinflammation.

Progranulin promotes bone fracture healing via TNFR pathways in mice with type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) significantly increases bone fragility and fracture risk. Progranulin (PGRN) promotes bone fracture healing in both physiological and type 1 diabetic conditions. The present study aimed to investigate the role of PGRN in T2DM bone fracture healing. MKR mice (with an FVB/N genetic background) were used as the T2DM model. Drill-hole and Bonnarens and Einhorn models were used to investigate the role of PGRN in T2DM fracture healing in vivo. Primary bone marrow cells were isolated for molecular and signaling studies, and reverse transcription-polymerase chain reaction, immunohistochemical staining, and western blotting were performed to assess PGRN effects in vitro. PGRN mRNA and protein expression were upregulated in the T2DM model. Local administration of recombinant PGRN effectively promoted T2DM bone fracture healing in vivo. Additionally, PGRN could induce anabolic metabolism during endochondral ossification through the TNFR2-Akt and Erk1/2 pathways. Furthermore, PGRN showed anti-inflammatory activity in the T2DM bone regeneration process. These findings suggest that local administration of exogenous PGRN may be an alternative strategy to support bone regeneration in patients with T2DM. Additionally, PGRN might hold therapeutic potential for other TNFR-related metabolic disorders.

Impact of Type 2 Diabetes Mellitus and Antidiabetic Medications on Bone Metabolism

PURPOSE OF REVIEW

This review focuses on the complex interactions between hyperglycemia and bone fragility and the effects of antidiabetic medications on bone metabolism.

RECENT FINDINGS

Type 2 diabetes (T2D) is associated with increased risk of bone fracture even in those with increased or normal bone mineral density (BMD). The pathophysiology of diabetic bone disease is not completely understood, but it is thought to be multifactorial and associated with complex cross talk among factors such as AGEs, IGF-1, enteric hormones, and pro-inflammatory cytokines. Treatment for T2D may have an impact on bone metabolism. Diabetic bone disease should be considered a serious complication of long-standing T2D.

Impact of diabetes mellitus simulations on bone cell behavior through in vitro models

Diabetes mellitus (DM) is related to impaired bone healing and an increased risk of bone fractures. While it is recognized that osteogenic differentiation and the function of osteoblasts are suppressed in DM, the influence of DM on osteoclasts is still unclear. Hyperglycemia and inflammatory environment are the hallmark of DM that causes dysregulation of various pro-inflammatory cytokines and alternated gene expression in periodontal ligament cells, osteoblasts, osteocytes, osteoclasts, and osteoclast precursors. A methodological review on conceptual and practical implications of in vitro study models is used for DM simulation on bone cells. Several major databases were screened to find literature related to the study objective. Published literature within last 20 years that used in vitro DM-simulated models to study how DM affects the cellular behavior of bone cells were selected for this review. Studies utilizing high glucose and serum acquired from diabetic animals are the mainly used methods to simulate the diabetic condition. The combination with various simulating factors such as lipopolysaccharide (LPS), hydrogen peroxide (H₂O₂), and advanced glycation end products (AGEs) have been reported in diabetic situations in vitro, as well. Through screening procedure, it was evident DM-simulated conditions exerted negative impact on bone-related cells. However, inconsistent results were found among different reported studies, which could be due to variation in culture conditions, concentrations of the stimulating factors and cell lineage, etc. This manuscript has concisely reviewed currently existing DM-simulated in vitro models and provides valuable insights of detailed components in simulating DM conditions in vitro. Studies using DM-simulated microenvironment revealed that in vitro simulation negatively impacted periodontal ligament cells, osteoblasts, osteocytes, osteoclasts, and osteoclast precursors. Contrarily, studies also indicated beneficial influence on bone-related cells when such conditions are reversed.

Identification of key candidate genes and pathways revealing the protective effect of liraglutide on diabetic cardiac muscle by integrated bioinformatics analysis

Background

Diabetes mellitus is becoming a significant health problem with the International Diabetes Federation (IDF) expecting a startling 642 million diabetes patients by 2040. Liraglutide, a glucagon-like peptide-1 (GLP-1) analog, is reported to protect against diabetic cardiomyopathy by binding to the receptor, GLP-1R. However, the underlying mechanism has yet to be clarified. This study aimed to investigate the underlying mechanisms and the effects of liraglutide on diabetic patient's cardiac muscles.

Methods

GSE102194 genetic expression profiles were extracted from the Gene Expression Omnibus (GEO) database. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) enrichment analyses were carried out. Next, Cytoscape software was used to construct the protein-protein interaction (PPI) network of the differentially expressed genes (DEGs). DEGs were mapped onto a protein-protein interaction (PPI) network that comprised 249 nodes and 776 edges.

Results

A total of 520 DEGs were discovered, including 159 down-regulated genes and 361 up-regulated genes. DEGs that were upregulated were notably enriched in biological processes (BP) such as muscle system process, muscle system process, muscle structure development and anatomical structure morphogenesis while DEGs that were downregulated were rich in detection of chemical stimulus and neurological system process. KEGG pathway analysis showed the up-regulated DEGs were enriched in adrenergic signaling for cardiomyocytes, dopaminergic synapse, and circadian entrainment, while the down-regulated DEGs were enriched for factory transduction in 249 of the 520 tested samples. The modular analysis identified 4 modules that participated in some pathways associated with cardiac muscle contraction, hypertrophic cardiomyopathy (HCM), and MAPK signaling pathway.

Conclusions

Our data showed that Glp-1 could decrease the protein expression of p38, JNK, ERK1/2, and MARS proteins induced by high glucose (22 mM, 72 h). This study highlights the potential physiological processes that take place in diabetic cardiac muscles exposed to liraglutide. Our findings elucidated the regulatory network in diabetic cardiomyopathy and might provide a novel diagnostic and therapeutic target for diabetic cardiomyopathy.

Surface-Anchored Graphene Oxide Nanosheets on Cell-Scale Micropatterned Poly(d,l-lactide-co-caprolactone) Conduits Promote Peripheral Nerve Regeneration

Regeneration and functional recovery of peripheral nerves remain formidable due to the inefficient physical and chemical cues in the available nerve guidance conduits (NGCs). Introducing micropatterns and bioactive substances into the inner wall of NGCs can effectively regulate the behavior of Schwann cells, the elongation of axons, and the phenotype of macrophages, thereby aiding the regeneration of injured nerve. In this study, linear micropatterns with ridges and grooves of 3/3, 5/5, 10/10, and 30/30 μm were created on poly(d,l-lactide-co-caprolactone) (PLCL) films following with surface aminolysis and electrostatic adsorption of graphene oxide (GO) nanosheets. The GO-modified micropatterns could significantly accelerate the collective migration of Schwann cells (SCs) and migration of SCs from their spheroids in vitro. Moreover, the SCs migrated directionally along the stripes with a fastest rate on the 3/3-GO film that had the largest cell adhesion force. The neurites of N2a cells were oriented along the micropatterns, and the macrophages tended to differentiate into the M2 type on the 3/3-GO film judged by the higher expression of Arg 1 and IL-10. The systematic histological and functional assessments of the regenerated nerves at 4 and 8 weeks post-surgery in vivo confirmed that the 3/3-GO NGCs had better performance to promote the nerve regeneration, and the CMAP, NCV, wet weight of gastrocnemius muscle, positive S100β and NF200 area percentages, and average myelinated axon diameter were more close to those of the autograft group at 8 weeks. This type of NGCs thus has a great potential for nerve regeneration.

RNA-Seq analysis of the pathogenesis of STZ-induced male diabetic mouse liver

OBJECTIVE

Diabetes mellitus (DM) is a chronic disease characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both. The liver is a key organ involved in glucose metabolism, and the major target proteins' changes in the pathogenesis are still unknown.

METHODS

A diabetic mouse model was induced by intraperitoneal injection of streptozotocin (STZ) solution and the RNA-Seq analysis was used to evaluate the transcription differences in the livers of diabetic mice of this study. And then, the differentially expressed genes were validated between a normal mouse group (n = 6) and a diabetic mouse group (n = 6) using quantitative real-time PCR (qRT-PCR) and Western blotting analysis. In addition, we also constructed protein-protein interacting (PPI) networks of up-regulated and down-regulated genes.

RESULTS

Transcriptome sequencing analysis revealed 370 up-regulated differentially expressed genes and 281 down-regulated differentially expressed genes in the diabetes model. The gene ontology (GO) analysis and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis results showed that the differentially expressed genes were mainly involved in immunity, enzyme activity, metabolism, and steroid synthesis. PPI analysis results indicated that the main 15 core differential proteins (Cyp51a1, Acsl4, Ugt1a1, Stat1, Gsta2, Cbr1, Aldh1a1, Fasn, Ces1, Camk2b, Tap1, Egr1, Sqle, Lpin1, Fabp5) were involved in the pathogenesis of diabetes. The qRT-PCR results showed that expression changes of four genes (Acsl4, Stat1, Gsta2, Fabp5) were in different directions from those of RNA-Seq. Western blotting results indicated that Sqle expression change at the protein level was in opposition direction from qRT-PCR, and we speculated that Sqle may be involved in the post-transcriptional modification process.

CONCLUSIONS

Our data speculated that the pathogenesis of diabetes may be mediated mainly through steroid biosynthesis, metabolic processes, and immune responses. Further researches on these pathways may provide new targets for the prevention and treatment of diabetes.

The Bones of Children With Obesity

Excess adiposity in childhood may affect bone development, ultimately leading to bone frailty. Previous reports showing an increased rate of extremity fractures in children with obesity support this fear. On the other hand, there is also evidence suggesting that bone mineral content is higher in obese children than in normal weight peers. Both adipocytes and osteoblasts derive from multipotent mesenchymal stem cells (MSCs) and obesity drives the differentiation of MSCs toward adipocytes at the expense of osteoblast differentiation. Furthermore, adipocytes in bone marrow microenvironment release a number of pro-inflammatory and immunomodulatory molecules that up-regulate formation and activation of osteoclasts, thus favoring bone frailty. On the other hand, body adiposity represents a mechanical load, which is beneficial for bone accrual. In this frame, bone quality, and structure result from the balance of inflammatory and mechanical stimuli. Diet, physical activity and the hormonal milieu at puberty play a pivotal role on this balance. In this review, we will address the question whether the bone of obese children and adolescents is unhealthy in comparison with normal-weight peers and discuss mechanisms underlying the differences in bone quality and structure. We anticipate that many biases and confounders affect the clinical studies conducted so far and preclude us from achieving robust conclusions. Sample-size, lack of adequate controls, heterogeneity of study designs are the major drawbacks of the existing reports. Due to the increased body size of children with obesity, dual energy absorptiometry might overestimate bone mineral density in these individuals. Magnetic resonance imaging, peripheral quantitative CT (pQCT) scanning and high-resolution pQCT are promising techniques for the accurate estimate of bone mineral content in obese children. Moreover, no longitudinal study on the risk of incident osteoporosis in early adulthood of children and adolescents with obesity is available. Finally, we will address emerging dietary issues (i.e., the likely benefits for the bone health of polyunsaturated fatty acids and polyphenols) since an healthy diet (i.e., the Mediterranean diet) with balanced intake of certain nutrients associated with physical activity remain the cornerstones for achieving an adequate bone accrual in young individuals regardless of their adiposity degree.

Therapeutic effect of percutaneous kyphoplasty combined with anti-osteoporosis drug on postmenopausal women with osteoporotic vertebral compression fracture and analysis of postoperative bone cement leakage risk factors: a retrospective cohort study

Background

The purpose of this study is to explore the therapeutic effect of percutaneous kyphoplasty (PKP) combined with anti-osteoporosis drug, zoledronic acid, on postmenopausal women with osteoporotic vertebral compression fracture (OVCF) and to perform an analysis of postoperative bone cement leakage risk factors.

Methods

A total of 112 OVCF patients, according to therapeutic regimens, were divided into control group (n = 52, treated with PKP) and observation group (n = 60, treated with PKP and zoledronic acid injection).

Results

Postoperative tumor necrosis factor-α and interleukin-6 levels were significantly decreased in the two groups, compared with those before treatment (both P < 0.05); bone mineral density (BMD), serum bone gla protein (BGP), and vertebral height ratio of injured vertebrae were significantly increased, and procollagen type I N-terminal propeptide (PINP), Cobb angle, visual analogue scale/score (VAS), and Oswestry disability index (ODI) were significantly decreased compared with those before treatment (all P < 0.05). There were significantly higher changes in difference value of BMD, PINP, BGP, vertebral height ratio of injured vertebrae, Cobb angle, VAS, and ODI levels and significantly better therapeutic effect in the observation group than those in the control group (all P < 0.05). Multivariate logistic regression analysis showed that the use of zoledronic acid, vertebral height ratio of injured vertebrae, and ODI were independent factors affecting the therapeutic effect, and that the dosage of bone cement, and peripheral vertebrae wall damage were independent risk factors causing postoperative bone cement leakage. There were no significant differences in postoperative bone cement leakage rate between the two groups.

Conclusions

Peripheral vertebrae wall damage and the dosage of bone cement are independent risk factors causing bone cement leakage in OVCF patients treated with PKP. PKP combined with zoledronic acid has an improvement effect on the condition of postmenopausal women with OVCF and reduces the inflammation and pain in patients, which is beneficial to clinical treatment.

Role of Long Non-Coding RNA (LncRNA) LINC-PINT Downregulation in Cardiomyopathy and Retinopathy Progression Among Patients with Type 2 Diabetes

Background

Despite the acknowledgement that LncRNA LINC-PINT may inhibit tumor cell invasion in human cancers, it is not yet determined when it comes to diabetes and its related complications.

Material/Methods

There were 244 patients with T2D and 126 healthy volunteers were admitted to People’s Hospital of Xinjiang Uygur Autonomous Region Hospital. Fasting blood (5 mL) was obtained from the patients and controls a day after admission. The diabetes patients’ fasting blood was extracted once every 6 months during follow-up. The total RNA was extracted and then used for detecting the expression of LINC-PINT.

Results

A comparison was made in this study, where LINC-PINT did not experience significant downregulation level in the majority of those suffering diabetes complications when in contrast to healthy controls, while LINC-PINT expression was found in diabetics. The follow-up study showed that LINC-PINT was downregulated in patients who developed cardiomyopathy and retinopathy or both but not in patients who developed other complications. Treatment with high glucose limited the extent of LINC-PINT expression in the ARPE-19 and AC16 cells. While the overexpression of LINC-PINT increased the viability of ARPE-19 and AC16 cells, siRNA-mediated silencing of LINC-PINT elicited the opposite effect.

Conclusions

Hence, we concluded that the overexpression of LINC-PINT may exhibit inhibitory effects on the progression of cardiomyopathy and retinopathy among patients with type 2 diabetes.

The Effect of Type 2 Diabetes on Bone Biomechanics

PURPOSE OF REVIEW

There is ample evidence that patients with type 2 diabetes (T2D) have increased risk of fracture even though they have normal or high bone mineral density. As a result, poor bone quality is suggested to contribute to skeletal fragility in this population. Thus, our goal was to conduct a comprehensive literature review to understand how bone quality components are altered in T2D and their effects on bone biomechanics and fracture risk.

RECENT FINDINGS

T2D does affect bone quality via alterations in bone microarchitecture, organic matrix, and cellular behavior. Further, studies indicate that bone biomechanical properties are generally deteriorated in T2D, but there are few reports in patients. Additional work is needed to better understand molecular and cellular mechanisms that contribute to skeletal fragility in T2D. This knowledge can contribute to the development of improved diagnostic tools and drug targets to for improved quality of life for those with T2D.

Progranulin promotes diabetic fracture healing in mice with type 1 diabetes

Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by insulin deficiency, and patients with diabetes have an increased risk of bone fracture and significantly impaired fracture healing. Proinflammatory cytokine tumor necrosis factor-alpha is significantly upregulated in diabetic fractures and is believed to underlie delayed fracture healing commonly observed in diabetes. Our previous genetic screen for the binding partners of progranulin (PGRN), a growth factor-like molecule that induces chondrogenesis, led to the identification of tumor necrosis factor receptors (TNFRs) as the PGRN-binding receptors. In this study, we employed several in vivo models to ascertain whether PGRN has therapeutic effects in diabetic fracture healing. Here, we report that deletion of PGRN significantly delayed bone fracture healing and aggravated inflammation in the fracture models of mice with T1DM. In contrast, recombinant PGRN effectively promoted diabetic fracture healing by inhibiting inflammation and enhancing chondrogenesis. In addition, both TNFR1 proinflammatory and TNFR2 anti-inflammatory signaling pathways are involved in PGRN-stimulated diabetic fracture healing. Collectively, these findings illuminate a novel understanding concerning the role of PGRN in diabetic fracture healing and may have an application in the development of novel therapeutic intervention strategies for diabetic and other types of impaired fracture healing.

OSTEOPOROSIS AND FRACTURE RISK IN PATIENTS WITH TYPE 2 DIABETES MELLITUS

Type 2 diabetes mellitus (T2DM) is associated with an increased risk of fragility fractures compared to the general population. The pathogenesis of the elevated fracture risk is multifactorial and still largely elusive. In contrast to primary osteoporosis, in T2DM the bone mineral density (BMD) is increased compared to controls, suggesting that specific alterations in bone quality occur in diabetic patients. Even more, the specific increase in BMD observed in these patients impairs at least in part both the classical diagnosis of osteoporosis by dual-energy X-ray absorptiometry (DXA) and the current fracture risk estimation by FRAX (fracture risk assessment tool). Trabecular bone score (TBS) and TBS-adjusted FRAX could improve fracture risk estimation in patients with T2DM but improved tools are needed in the future as well as specific risk stratification criteria. Decreases in the fracture risk of patients with T2DM can be obtained by optimal diabetes control and standard treatment of osteoporosis (most drugs appear to have similar efficacy in patients with T2DM and primary osteoporosis).

Necroptosis occurs in osteoblasts during tumor necrosis factor-α stimulation and caspase-8 inhibition

Necroptosis is a regulated cell death mechanism. However, it is unknown whether necroptosis is involved in the death of tumor necrosis factor-α (TNF-α)-treated osteoblasts. Therefore, we conducted the study with TNF-α, Nec-1 (a specific inhibitor of necroptosis), and Z-IETD-FMK (a specific inhibitor of apoptosis) to determine whether necroptosis plays a role in the death of TNF-α-treated osteoblast cell line MC3T3-E1. Cell viability, cell death, and lactate dehydrogenase (LDH) release were assayed to evaluate cytotoxicity. Specific marker proteins receptor interacting protein kinase (RIPK3) and phosphorylated mixed lineage kinase domain-like protein (p-MLKL) for necroptosis, and cleaved caspase 3 for apoptosis were detected by western blot, and mRNA was measured by quantitative real-time polymerase chain reaction (qRT-PCR). We found that TNF-α inhibited cell proliferation in a dose- and time-dependent manner. Nec-1 plus Z-IETD-FMK restored cell viability and significantly decreased LDH release. In addition, TNF-α alone increased the cell population of AV+PI−, while Z-IETD-FMK caused a shift in the cell population from AV+PI− to AV+PI+. Furthermore, TNF-α significantly increased protein cleaved caspase 3. TNF-α plus Z-IETD-FMK significantly increased the proteins RIPK3 and MLKL phosphorylation in MC3T3-E1 cells, while the changes in mRNA levels of RIPK3, MLKL, and caspase 3 were not consistent with the changes in the corresponding protein expression levels. In conclusion, TNF-α induced preferentially apoptosis in osteoblast cell line and necroptosis played a decisive role when TNF-α-induced death was inhibited by the inhibitor of apoptosis. Combined treatment with Nec-1 and Z-IETD-FMK protected mouse osteoblasts from death induced by TNF-α.

Molecular pathogenesis of fracture nonunion

Fracture nonunion, a serious bone fracture complication, remains a challenge in clinical practice. Although the molecular pathogenesis of nonunion remains unclear, a better understanding may provide better approaches for its prevention, diagnosis and treatment at the molecular level. This review tries to summarise the progress made in studies of the pathogenesis of fracture nonunion. We discuss the evidence supporting the concept that the development of nonunion is related to genetic factors. The importance of several cytokines that regulate fracture healing in the pathogenesis of nonunion, such as tumour necrosis factor-α, interleukin-6, bone morphogenetic proteins, insulin-like growth factors, matrix metalloproteinases and vascular endothelial growth factor, has been proven in vitro, in animals and in humans. Nitric oxide and the Wnt signalling pathway also play important roles in the development of nonunion. We present potential strategies for the prevention, diagnosis and treatment of nonunion, and the interaction between genetic alteration and abnormal cytokine expression warrants further investigation.

The translational potential of this article

A better understanding of nonunion molecular pathogenesis may provide better approaches for its prevention, diagnosis and treatment in clinical practice.

Addressing Stem Cell Therapeutic Approaches in Pathobiology of Diabetes and Its Complications

High morbidity and mortality of diabetes mellitus (DM) throughout the human population is a serious threat which needs to be addressed cautiously. Type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) are most prevalent forms. Disruption in insulin regulation and resistance leads to increased formation and accumulation of advanced end products (AGEs), which further enhance oxidative and nitrosative stress leading to microvascular (retinopathy, neuropathy, and nephropathy) and macrovascular complications. These complications affect the normal function of organ and tissues and may cause life-threatening disorders, if hyperglycemia persists and improperly controlled. Current and traditional treatment procedures are only focused on to regulate the insulin level and do not cure the diabetic complications. Pancreatic transplantation seemed a viable alternative; however, it is limited due to lack of donors. Cell-based therapy such as stem cells is considered as a promising therapeutic agent against DM and diabetic complications owing to their multilineage differentiation and regeneration potential. Previous studies have demonstrated the various impacts of both pluripotent and multipotent stem cells on DM and its micro- and macrovascular complications. Therefore, this review summarizes the potential of stem cells to treat DM and its related complications.

Clinical Fractures Among Older Men With Diabetes Are Mediated by Diabetic Complications

INTRODUCTION

Type 2 diabetes mellitus among older women has been associated with increased bone mineral density, but paradoxically with increased fracture risk. Findings among older men have varied, and potential mechanisms have not been fully elucidated.

METHODS

A retrospective study of male veterans 65 to 99 years of age who received primary care in the Veterans Health Administration from 2000 to 2010, using administrative data from all 146 Veterans Health Administration medical centers linked to Centers for Medicare and Medicaid Services Medicare fee-for-service data. Potential mediating factors of the diabetes-associated risk were evaluated using negative binomial regression models with the outcomes of any clinical fracture and hip fracture.

RESULTS

Of 2,798,309 Veterans included in the cohort, 900,402 (32.3%) had a diagnosis of diabetes. After adjusting for age, race, ethnicity, body mass index, alcohol and tobacco use, rheumatoid arthritis, and corticosteroid use, the risk of any clinical fracture associated with diabetes was 1.22 (95% confidence interval, 1.21 to 1.23) and that of hip fracture was 1.21 (95% confidence interval, 1.19 to 1.23). Significant mediating factors included peripheral neuropathy, cardiovascular disease, and congestive heart failure, with 45.5% of the diabetes-associated fracture risk explained by these diagnoses.

CONCLUSIONS

Older male Veterans with diabetes have a 22% increased risk of incident clinical fracture compared with those without. A significant portion of this risk is explained by diabetes-related comorbidities, specifically peripheral neuropathy and congestive heart failure. Identification of these mediating factors suggests possible mechanisms, as well as potential interventions.

The effect of experimental diabetes and glycaemic control on guided bone regeneration: histology and gene expression analyses

OBJECTIVES

To investigate the effect of experimental diabetes and metabolic control on intramembranous bone healing following guided bone regeneration (GBR).

MATERIAL AND METHODS

Ninety-three Wistar rats were allocated to three experimental groups, healthy (H), uncontrolled diabetes (D) and controlled diabetes (CD). Twenty one days following diabetes induction, a standardised 5-mm defect was created at the mid-portion of each parietal bone. In 75 animals (25H, 25D, 25CD), one defect was treated with an intracranial and extracranial membrane according to the GBR principle, and one defect was left empty (control); five animals per group were then randomly sacrificed at 3, 7, 15, 30 and 60 days and processed for decalcified histology. In 18 animals (6H, 6D, 6CD), both defects were treated according to the GBR principle; three animals from each group were then randomly sacrificed at 7 and 15 days of healing and employed for gene expression analysis.

RESULTS

Application of the GBR therapeutic principle led to significant bone regeneration even in the D group. However, at 15 and 30 days, the osteogenesis process was impaired by uncontrolled diabetes, as shown by the significant reduction in terms of defect closure (38-42%) and newly formed bone (54-61%) compared to the healthy group. The comparison of the D vs. H group at 15 days of healing yielded the largest number of genes with significantly differential expression, among which various genes associated with the ossification process (bmp4, ltbp4, thra and cd276) were identified.

CONCLUSIONS

Uncontrolled diabetes seems to affect early phases of the bone regeneration following GBR. A misregulation of genes and pathways related to cell division, energy production, inflammation and osteogenesis may account for the impaired regeneration process in D rats. Further studies are warranted to optimise the GBR process in this medically compromised patient population.

Fracture Risk Assessment in Patients With Diabetes Mellitus

Diabetes mellitus, both type 1 and type 2 (T2DM), is associated with decreased bone strength as well as increased fracture risk. Bone mineral density is decreased in type 1 diabetes but increased in T2DM, compared with controls. This suggests alterations in bone quality are a major player in the pathogenesis of fragility fractures in patients with diabetes. The link between diabetes and bone appears to be mediated by complex pathways, including the insulin-insulin growth factors system, accumulation of advanced glycation end-products in bone collagen, microangiopathy, and increased bone marrow fat content. Bone fragility in T2DM, which is not reflected by bone mineral density and bone mass reduction, depends on deterioration of bone quality. Also, at least in T2DM, the classical diagnosis of osteoporosis by dual-energy X-ray absorptiometry and the fracture risk estimation by FRAX (fracture risk assessment tool) are only partially useful in assessing fracture risk. Trabecular bone score and trabecular bone score-adjusted FRAX offer an enhanced estimation of fracture risk in these patients. Specific risk stratification criteria are needed in the future. The development of improved methods to assess the material properties of bone to better characterize fracture risk is also a priority. Adequate glycemic control is generally associated with decreased fracture risk, with the exception of specific antidiabetics (thiazolidinediones, canagliflozin) that have been shown to have a detrimental effect. Most currently used antiosteoporotic treatments seem equally effective in diabetic patients as compared with patients without diabetes, but clinical data regarding the reduction in fracture risk specifically in patients with diabetes mellitus are lacking.

Platelet-functionalized three-dimensional poly-ε-caprolactone fibrous scaffold prepared using centrifugal spinning for delivery of growth factors

Bone and cartilage are tissues of a three-dimensional (3D) nature. Therefore, scaffolds for their regeneration should support cell infiltration and growth in all 3 dimensions. To fulfill such a requirement, the materials should possess large, open pores. Centrifugal spinning is a simple method for producing 3D fibrous scaffolds with large and interconnected pores. However, the process of bone regeneration is rather complex and requires additional stimulation by active molecules. In the current study, we introduced a simple composite scaffold based on platelet adhesion to poly-ε-caprolactone 3D fibers. Platelets were used as a natural source of growth factors and cytokines active in the tissue repair process. By immobilization in the fibrous scaffolds, their bioavailability was prolonged. The biological evaluation of the proposed system in the MG-63 model showed improved metabolic activity, proliferation and alkaline phosphatase activity in comparison to nonfunctionalized fibrous scaffold. In addition, the response of cells was dose dependent with improved biocompatibility with increasing platelet concentration. The results demonstrated the suitability of the system for bone tissue.

Potential Role of Chemokines in Fracture Repair

Chemokines are a family of small cytokines that share a typical key structure that is stabilized by disulfide bonds between the cysteine residues at the NH₂-terminal of the protein, and they are secreted by a great variety of cells in several different conditions. Their function is directly dependent on their interactions with their receptors. Chemokines are involved in cell maturation and differentiation, infection, autoimmunity, cancer, and, in general, in any situation where immune components are involved. However, their role in postfracture inflammation and fracture healing is not yet well established. In this article, we will discuss the response of chemokines to bone fracture and their potential roles in postfracture inflammation and healing based on data from our studies and from other previously published studies.

Design, synthesis, and in vivo evaluations of benzyl Nω-nitro-Nα-(9H-pyrido[3,4-b]indole-3-carbonyl)-l-argininate as an apoptosis inducer capable of decreasing the serum concentration of P-selectin

A series of findings suggest that the discovery of in vivo apoptosis inducers for chemotherapy is of clinical importance.