Comparison of clinicopathological features and survival analysis between esophageal neuroendocrine carcinoma and esophageal squamous cell carcinoma based on the SEER database, alongside nomogram analysis for esophageal neuroendocrine carcinoma.

Background: Esophageal neuroendocrine carcinoma (ENEC) is a rare subtype of esophageal cancer (EC). It presents distinctive clinical and pathological features in comparison to esophageal squamous cell carcinoma (ESCC). To better elucidate the disparities between the two and establish a prognostic prediction model for ENEC, we conducted this study. Methods: Data of ENEC and ESCC patients (1975 to 2016) were extracted from the Surveillance, Epidemiology and End Results (SEER) database. Patients with a confirmed pathological diagnosis of ENEC and ESCC were enrolled in the study. The Chi-square test was employed to compare categorical variables, and the median survival time was analyzed using the Kaplan-Meier curve. Training and validation groups were randomly assigned at a ratio of 7:3. Factors with a significance level of <0.05 in the multifactor regression model as well as age were integrated into the nomogram model. Concordance index (C-index), calibration curves, and decision curve analyses (DCA) were generated for model validation. Results: This study encompassed a total of 737 ENEC patients and 29,420 ESCC. Compared to ESCC, ENEC patients had higher probability of liver metastasis (13.8% vs. 1.9%, P<0.001), poor differentiation (68.0% vs. 37.1%, P<0.001), and late SEER stage (52.8% vs. 26.9%, P<0.001). Patients who received either surgery, radiotherapy (RT), or chemotherapy had a significantly longer disease-specific survival (DSS) and overall survival (OS) (all P<0.001). After propensity score matching (PSM), ENEC patients were associated with shorter DSS (7.0 months vs. not reached, P<0.0001) and OS (7.0 vs. 12.0 months, P<0.0001) compared to ESCC. Race, SEER stage, surgery, RT, and chemotherapy were identified as predictors of DSS and were incorporated into the nomogram model together with age. The validation of the model using C-index (0.751 and 0.706, respectively) and calibration curves reflected the better discrimination power of the model. In addition, DCA supported the favorable potential clinical effect of the predictive model. Lastly, a risk classification based on the nomogram also verified the reliability of the model. Conclusions: ENEC and ESCC exhibit distinct clinicopathological features. Patients with ENEC experience significantly poorer survival outcomes compared to those with ESCC. Surgical intervention, radiation therapy, and chemotherapy significantly improve OS and DSS for ENEC patients. The nomogram prediction model, constructed based on age, race, stage, and treatment regimen, demonstrates accurate and effective predictive capabilities for prognostic factors in ENEC patients.

Zoledronic acid enhances the efficacy of immunotherapy in non-small cell lung cancer.

BACKGROUND: Only a minority of patients benefit from immune checkpoint inhibitors (ICIs) therapy, although they have become the standard of care for patients of non-small cell lung cancer (NSCLC) without driver mutations. Zoledronic acid (ZA) enhances the anti-tumor efficacy of endocrine therapy, chemotherapy and targeted therapy. However, little is known about the effect of ZA on the clinical outcomes of ICIs, or its possible mechanisms. METHODS: Patients with advanced NSCLC treated with ICIs alone or in combination with ZA were recruited. The clinical efficacy was compared between the two cohorts. We used an LL2 mouse model to confirm the combined effects of ZA with ICIs. Immune cell populations and cytokines in the tumor microenvironment and circulation were assayed and analyzed. RESULTS: The median PFS for the patients treated with and without ZA was 5.4 months and 2.8 months, respectively. The combination group showed a higher rate of disease control. In the mouse LL2 lung cancer model, tumor growth was significantly inhibited in mice treated with the combination treatment. More CD8 + IFN-γ + T cells and γδ T cells, and fewer CD11b cells were found in the circulation and TILs in the combination group. Anti-tumor cytokines INF-γ and IL-18 were elevated in the sera after combination therapy. CONCLUSION: Our study provides preclinical and clinical evidence to show that ZA could improve the therapeutic effects of ICIs. This effect was likely related to the activation of immune cells and elevated cytokines, which provided a new way to improve the effect of ICIs therapy, and is worth exploring further.

Immunotherapy for a POLE Mutation Advanced Non-Small-Cell Lung Cancer Patient.

Currently, the predictive role of POLE mutations for immunotherapy is under intense investigation. The POLE gene encodes one of the four subunits of DNA polymerase important for DNA replication and repair. POLE mutations are related to other favorable predicative factors such as high expression of PD-L1, high TMB, and infiltration of CD8+ cells in the tumor microenvironment. No formal clinical trials studied the efficacy of immunotherapy in lung patients harboring POLE mutation, and only few cases were mentioned in the literature. Moreover, lung cancer patients are prone to brain metastasis, which is notorious for the unresponsiveness to chemotherapy. The efficacy of immunotherapy for brain metastasis is still controversial. Here, we described a case of a POLEmt non-small-cell lung cancer (NSCLC) patient with brain metastasis who was treated with immunotherapy. His brain lesions disappeared after treatment. Our report strongly supported the benefit of immune-combined therapy for advanced NSCLC patients with POLE mutation, even with brain metastasis.

Neoantigen: A Promising Target for the Immunotherapy of Colorectal Cancer.

At present, there are various treatment strategies for colorectal cancer, including surgery, chemotherapy, radiotherapy, and targeted therapy. In recent years, with the continuous development of immunotherapy, immune checkpoint inhibitors (ICIs) can significantly improve the treatment of advanced colorectal cancer patients with high levels of microsatellite instability. In addition to ICIs, neoantigens, as a class of tumor-specific antigens (TSA), are regarded as new immunotherapy targets for many cancer species and are being explored for antitumor therapy. Immunotherapy strategies based on neoantigens include tumor vaccines and adoptive cell therapy (ACT). These methods aim to eliminate tumor cells by enhancing the immune response of host T-cells to neoantigens. In addition, for MSS colorectal cancer, such "cold tumors" with low mutation rates and stable microsatellites are not sensitive to ICIs, whereas neoantigens could provide a promising immunotherapeutic avenue. In this review, we summarized the current status of colorectal cancer neoantigen prediction and current clinical trials of neoantigens and discussed the difficulties and limitations of neoantigens-based therapies for the treatment of CRC.

Toxicities of Immunotherapy for Small Cell Lung Cancer.

Small cell lung cancer (SCLC), composing 15-20% of lung cancer, is a fatal disease with extremely poor prognosis. In the past two decades, etoposide platinum doublet chemotherapy remained the only choice of therapy, with disappointing overall survival ≤1 year for the metastatic disease. Novel treatments including immunotherapy are urgently needed and extensively explored. Recently, in two phase III trials, atezolizumab and durvalumab were shown to bring survival benefit to patients. While immunotherapy brings better outcome, it is accompanied by adverse events different from traditional treatments. Although these immune-related adverse events (irAEs) are generally mild and can be managed, some irAEs (myocarditis, pneumonitis) may be severe and even life-threatening. Accompanying with the increasing application of immunotherapy in clinical practice, the irAEs should not be overlooked. In this review, the irAEs profile in clinical trials of immunotherapy for SCLC will be summarized, also its unique features compared with irAEs in other malignancies will be explored. This review may be helpful for the appropriate clinical use of immunotherapy for SCLC.

Inferior outcome of bone metastasis in non-small-cell-lung-cancer patients treated with epidermal growth factor receptor inhibitors.

BACKGROUND: Targeted therapy has been established as the standard-of-care for patients with advanced non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations. Among patients with advanced lung cancer, 30-40% have bone metastases (BoM) at first diagnosis. However, little is known on the clinical characteristics and prognostic factors of BoM in patients with NSCLC harboring EGFR mutations. METHODS: Treatment-naive patients with advanced NSCLC harboring EGFR mutations who were prescribed tyrosine kinase inhibitors (TKIs) were screened and enrolled between June 2009 and April 2019 from West China Hospital. Patients were dichotomized according to whether they had BoM. The demographic characteristics, gene mutation status and therapeutic efficacy, including objective response rate (ORR), progression-free survival (PFS) and overall survival (OS), were collected. RESULTS: A cohort of 604 patients were enrolled. The BoM group had worse PFS (11.7 vs. 14.0 months, HR = 0.73, p = 0.00013) and OS (32.8 vs. 46.1 months, HR = 0.54, p < 0.0001) compared with the non-BoM group. No significant differences were observed in disease control rate (p = 0.407) or ORR (p = 0.537) between the two groups. The metastatic sites in the two groups exhibited obvious differences. In multivariate analysis, BoM was found to be an independent factor of worse prognosis. CONCLUSION: BoM was identified as an independent inferior prognostic factor for EGFR-TKI treatment, and may have complex biological implications.

Major pathological response after neoadjuvant immunotherapy in esophageal spindle cell carcinoma: A case report.

Esophageal spindle cell carcinoma (ESpCC) is a rare subtype of esophageal carcinoma, accounting for 1% of all esophageal malignancies. The clinical outcome is unknown due to the lack of treatment options. Here, we present the case of a 60-year-old male with initially unresectable ESpCC, in which platinum-based concurrent chemoradiotherapy was unsuccessful. He was subsequently treated with neoadjuvant immunotherapy and after surgery achieved a complete pathological response; therefore, neoadjuvant immunotherapy might be a novel option for ESpCC patients.

Pulmonary Lymphoepithelioma-Like Carcinoma Treated with Immunotherapy or Chemotherapy: A Single Institute Experience.

BACKGROUND: Lymphoepithelioma-like carcinoma (LELC) is a rare malignant tumor of the lung. It is related to EB virus infection. Epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) are rarely found in this disease, while high level programmed cell death ligand 1 (PD-L1) expression is observed. Here a series of patients with advanced LELC treated with immunotherapy were summarized. METHODS: This retrospective, observational study was conducted in patients who were pathologically confirmed, metastatic or recurrent LELC patients. Patients were prescribed with either chemotherapy or immunotherapy, according to treating physicians' discretion. RESULTS: A total of 27 patients were included in our study, 10 with immunotherapy (ICI group) and 17 with chemotherapy (Chemo group). The objective response rates (ORR) of the two groups were 80.0% and 70.5% (p=0.678), and disease control rates (DCR) were 100% and 88.2% (p=0.516). However, the response depth was better in the ICI group. Although the cohort of patients in the ICI group was in a disadvantageous state (both up-front and salvage), the progression-free survival (PFS) was much longer (15.0 and 7.9 m, p=0.005). The 1-year PFS rate in the ICI group was also much higher (40% and 5.9%, p=0.047). CONCLUSION: This study implicated the high efficiency of ICI therapy in this disease.

Novel applications of platelet concentrates in tissue regeneration (Review).

Numerous studies have explored the suitability of biocompatible materials in regenerative medicine. Platelet concentrates are derived from centrifuged blood and are named according to their biological characteristics, such as platelet-rich plasma, platelet-rich fibrin and concentrated growth factor. Platelet concentrates have gained considerable attention in soft and hard tissue engineering. Indeed, multiple components of autologous platelet concentrates, such as growth factors, fibrin matrix and platelets, serve essential roles in wound healing. Current studies are focused on cutting-edge strategies to meet the requirements for tissue restoration by improving the properties of autologous platelet concentrates. In the present review, applications of platelet concentrates for tissue engineering are discussed, presenting a selection of recent advances and novel protocols. In addition, several aspects of these strategies, such as the advantages of lyophilized platelet concentrates and the combination of platelet concentrates with biomaterials, stem cells or drugs are discussed. The present review aims to summarize novel strategies using platelet concentrates to improve the outcomes of wound healing.

Imaging Pattern of Diffuse Intrapulmonary Metastases in Lung Cancer Was Associated with Poor Prognosis to Epidermal Growth Factor Receptor Inhibitors.

BACKGROUND: Epidermal growth factor receptor (EGFR) mutations are more frequently seen in miliary intrapulmonary metastases than EGFR wild-type non-small cell lung cancer (NSCLC). Also, small-scale retrospective studies showed that patients harboring EGFR mutation with miliary pulmonary metastases had a worse prognosis. This study aimed to explore the impact of imaging patterns on the outcomes of EGFR tyrosine kinase inhibitor (TKI) treatment. METHODS: A cohort of treatment-naive NSCLC patients harboring EGFR mutation with intrapulmonary metastases who were prescribed with TKI were enrolled. The demographic feature, clinical outcome, and CT imaging of each patient were reviewed and analyzed. RESULTS: A cohort of 174 patients were enrolled. Five intrapulmonary patterns of imaging were recognized: solid nodular, ground-glass nodular, miliary, multiple uniform nodular, and not otherwise specified. Among them, miliary and multiple uniform nodular patterns had similar poor prognosis, and, therefore, were combined as diffuse group. A worse PFS (9.0 mon, 95% CI: 8.0-10.0 mon) was observed compared with the rest (non-diffuse group, 13.3 mon, 95% CI: 10.2-16.4 mon, p<0.001, HR=0.49). The objective response rates (ORR) between the two groups were 76.8% and 84.1%, respectively, with no significant difference (p = 0.474). The OS of the diffuse and the non-diffuse group were 25.6 mon (95% CI 21.9-29.3 mon) and 35.0 mon (95% CI: 27.5-42.5, p = 0.01, HR= 0.59). Organs like bone (p=0.167), liver (p=0.513), and adrenal gland (p=0.375) were involved in similar frequencies in both groups. However, brain (p=0.070) and leptomeningeal (p=0.078) metastases were less common in the non-diffuse group with marginally statistical significance. The 2 groups contained similar missense mutations, and gene amplification was more common in the non-diffuse group. CONCLUSION: Patients with diffuse intrapulmonary metastases had inferior outcomes after TKI treatment. More aggressive treatments might be warranted for these patients.

The Ways of Isolating Neoantigen-Specific T Cells.

Immunotherapy has revolutionized the standard of care for a range of malignancies. Accumulating evidence suggests that the success of immunotherapy is likely attributable to neoantigen-specific T cells. Thus, adoptive cell therapy with these neoantigen-specific T cells is highly promising. This strategy has proven to successfully elicit tumor regression or even complete remission in metastatic cancer patients. However, a fundamental challenge is to effectively identify and isolate neoantigen-specific T cells or their T cell receptors (TCRs), from either tumor-infiltrating lymphocytes (TILs) or peripheral blood lymphocytes (PBLs), and many methods have been developed to this end. In this review, we focus on the current proposed strategies for identifying and isolating neoantigen-specific T cells.

Immune Checkpoint Inhibitor-Associated Cardiotoxicity: Current Understanding on Its Mechanism, Diagnosis and Management.

Immune checkpoint inhibitors (ICIs) that target cytotoxic T lymphocyte antigen 4, programmed cell death-1, and PD-ligand 1 have revolutionized cancer treatment, achieving unprecedented efficacy in multiple malignancies. ICIs are increasingly being used in early cancer settings and in combination with various other types of therapies, including targeted therapy, radiotherapy, and chemotherapy. However, despite the excellent therapeutic effect of ICIs, these medications typically result in a broad spectrum of toxicity reactions, termed immune-related adverse events (irAEs). Of all irAEs, cardiotoxicity, uncommon but with high mortality, has not been well recognized. Herein, based on previous published reports and current evidence, we summarize the incidence, diagnosis, clinical manifestations, underlying mechanisms, treatments, and outcomes of ICI-associated cardiotoxicity and discuss possible management strategies. A better understanding of these characteristics is critical to managing patients with ICI-associated cardiotoxicity.

Safety and Efficacy of Therapeutic Cancer Vaccines Alone or in Combination With Immune Checkpoint Inhibitors in Cancer Treatment.

Therapeutic cancer vaccines have proven to seldom induce dramatic clinical response when used alone, and therefore, they are being studied in combination with additional treatment modalities to achieve optimal treatment activities. Growing preclinical data show that combining vaccines and immune checkpoint inhibitors (ICIs) can prime intensified immunogenicity and modulate immunosuppressive tumor microenvironment. Herein, we focus on the safety and efficacy of approved and promising cancer vaccines alone or combined with ICIs in the treatment of several malignancies. Generally, the majority of clinical trials support the concept of synergy that combination therapy of vaccines and ICIs holds maximized potential to improve clinical outcomes. Importantly, the combination has acceptable safety and minimal additional toxicity compared with single-agent vaccines or ICIs. Additionally, the potential strategies of combining personalized tumor vaccines with ICIs will become priority option and future direction of vaccine development and application and the urgent need to develop effective biomarkers to screen appropriate patient populations and predict response to combination therapy.

PD-1 Inhibitors in the Advanced Esophageal Cancer.

Esophageal cancer (EC) is a lethal disease, and ranks 7th in incidence and 6th in mortality worldwide. Patients are treated with surgery and/or chemoradiotherapy for a curative intent, but for those with advanced diseases systemic chemotherapy and targeted therapy are the mainstay treatment with poor prognosis. For the patients with squamous cell carcinoma and those progressed after chemotherapy, treatment option is even fewer, and effective treatment modalities are urgently needed. Preclinical and clinical studies have found the PD-1/PD-L1 inhibitors activate T lymphocytes, inhibit cancer growth, and improve survival in cancer patients. Multiple PD-1/PD-L1 inhibitors have been approved for the management of a variety of cancers. Interestingly, a large of proportion of EC patients have tumors with PD-L1 expression and high tumor mutation burden. Trials have been performed to evaluate the efficacy and safety of the PD-1/PD-L1 inhibitors in EC patients. This review will summarize the current progress in this field, especially the toxicities associated with these agents.

Impaired Liver Function Implied Shorter Progression Free Survival for EGFR Tyrosine Kinase Inhibitors

Background: Epithelial growth factor receptor tyrosine kinase inhibitor (EGFR TKI) revolutionize the standard of care for advanced non-small cell lung cancer (NSCLC) harboring sensitive EGFR mutation. Liver toxicity is the dose-limiting factor for TKI but its importance is largely overlooked. Here the relationship between the elevation of transaminase and progression-free survival (PFS) was explored. Methods: This was a retrospective study where patients with advanced NSCLC were screened. And those treatment-naïve and with sensitive EGFR mutation who were prescribed with EGFR TKI were enrolled. The highest level of transaminase (alanine aminotransferase, ALT, and aspartate transaminase, AST) during the treatment course was recorded. Results: Totally 208 patients were recruited, and most of them (48.6%) took gefitinib. The whole cohort achieved a median PFS of 11.2 months (95%CI: 10.0-12.3 m). 73 (35.1%) patients had elevated transaminase and most was attributed to gefitinib (n=43, 42.5%). Specifically, ALT was elevated in 65 patients (31.3%) while AST in 24 patients (11.5%). Again, gefitinib was associated with more cases of ALT (40.6%) and AST (17.8%) elevation. The elevation of AST was not related to PFS (P=0.259, HR=0.751, 95%CI: 0.464-1.214). Interestingly, those with normal ALT level had a longer PFS (12.6m, 95%CI: 10.6-14.5 m) than those with elevated ALT (9.5m 95%CI: 7.9-11.0 m, P=0.025, HR=0.682, 95%CI: 0.488-0.953). The inverse relationship was confirmed in the COX regression analysis (P=0.047). Conclusion: This study revealed the side effects of elevated ALT was inversely related to the PFS of EGFR TKI treatment. The liver impairment by TKI should not be overlooked.

A Case-control Study Supporting the Use of Liquid Biopsy in the Targeted Therapy for Lung Cancer

Backgrounds: Targeted therapy for lung cancer depends on the genetic testing. Liquid biopsy provides a valuable source for the genetic testing. However, direct evidence was lacking for whether liquid biopsy could guide the targeted therapy. Methods: In this retrospective study, the admitted patients from Jan 2015 to Feb 2016 were screened through a pre-established database. Patients with metastatic, pathologically-confirmed, and treatment naïve non-small cell lung cancer who were prescribed with epithelial growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) from the guidance of liquid biopsy were enrolled (Liquid group). The mutation status in tumors was not mandatory. During the same period, patients medicated with TKI based on tumor samples were included in the Control group. They were enrolled in an age-, gender-, performance-, smoking-, and histology-matched manner. Results: We screened 536 patients and enrolled 26 patients in the Liquid group. Another 26 patients were enrolled in a 1:1 ratio in the Control group. In the Liquid group, a high consistence (84.6%) in EGFR mutation status between liquid and tumor was observed. The best response was partial response in 19 patients (73.1 %), and followed by stable disease in 6 patients (23.1 %). The median progression-free survival was 10.0 months (95%CI: 4.2-15.8 months). In the Control group, a similar disease control rate (88.4%, P=0.603) and comparable PFS (8.6 months, 95% CI: 7.6-10.4 months, P=0.714, HR=0.657, 95% CI: 0.309-1.396) was found. In the Liquid group, 3 of 4 patients with discordant results between tumor and liquid biopsy showed treatment responses favoring the liquid biopsy. Conclusion: This study provided direct evidence supporting the liquid biopsy for guiding the targeted therapy for lung cancer.

Conventional real-time PCR-based detection of T790M using tumor tissue or blood in patients with EGFR TKI-resistant NSCLC.

Blood biopsy has many advantages over tissue biopsy for diagnosing acquired T790M mutation in patients with non-small-cell lung cancer, such as being less risky and painful. New techniques with high sensitivity (eg, droplet digital PCR) show promising results during blood biopsy, but the positive rates of identification are still quite unclear. Whether there are other factors, except technology, affecting the results of blood biopsy is unclear. In this study, we used conventional amplification refractory mutation system to detect tumor tissue or blood for T790M mutation in patients clinically resistant to tyrosine kinase inhibitors. A total of 45 patients treated at West China Hospital between 2014 and 2016 were analyzed. The positive rate of T790M mutation was 70.8% based on tissue biopsy and 37.5% based on blood biopsy. Of the 24 patients whose epidermal growth factor receptor gene was genotyped through tissue and blood biopsy, 10 (41.7%) were concordant for T790M mutation status (κ=0.006). Of the 17 patients positive for T790M by tissue biopsy, 7 (41.2%) were positive for T790M by blood biopsy, and 3 of these 7 were only weakly positive. Of the 7 patients negative for T790M by tissue biopsy, 2 (28.6%) were positive by blood biopsy. Our T790M detection rate is higher than that reported by other studies using digital droplet PCR. These results suggest that other factors (eg, clinical features), intrinsically connected with circulating tumor DNA level, also affect the results of blood biopsy, and thus cannot be controlled through technological optimization.

Bone metastasis from lung cancer identified by genetic profiling.

Cancer metastasis remains responsible for the vast majority of cases of cancer-related morbidity and mortality. Metastasis, by its definition, is the spread of cancer from the primary site to the distant tissues. Advancing the scientific and clinical understanding of cancer metastasis is a high priority. The prerequisite requirement for pathological consistency may be compromised during metastasis. The present study reports the case of a cancer patient with different pathological types. The patient presented with pain in the neck and right hip, as well as weight loss. He underwent whole-body positron emission tomography-computed tomography, which identified a mass in the lung and abnormal metabolism of the bone. Biopsies of the ilium and lung were performed and he was shown to have lung adenocarcinoma and bone squamous carcinoma. The morphology and immunohistochemical patterns were completely different, while each lesion harbored an identical genetic profile. The bone lesion was identified to be a metastasis from the lung cancer. The patient was prescribed an epithelial growth factor receptor inhibitor, which resulted in a partial response in the lung mass and alleviation of the patient's bone pain. Through this case study, we advocate the importance of using genetic testing in addition to pathological assessment.

Enhanced osteogenesis and angiogenesis by mesoporous hydroxyapatite microspheres-derived simvastatin sustained release system for superior bone regeneration.

Biomaterials with both excellent osteogenic and angiogenic activities are desirable to repair massive bone defects. In this study, simvastatin with both osteogenic and angiogenic activities was incorporated into the mesoporous hydroxyapatite microspheres (MHMs) synthesized through a microwave-assisted hydrothermal method using fructose 1,6-bisphosphate trisodium salt (FBP) as an organic phosphorous source. The effects of the simvastatin-loaded MHMs (S-MHMs) on the osteogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs) and angiogenesis in EA.hy926 cells were investigated. The results showed that the S-MHMs not only enhanced the expression of osteogenic markers in rBMSCs but also promoted the migration and tube formation of EA.hy926 cells. Furthermore, the S-MHMs were incorporated into collagen matrix to construct a novel S-MHMs/collagen composite scaffold. With the aid of MHMs, the water-insoluble simvastatin was homogenously incorporated into the hydrophilic collagen matrix and presented a sustained release profile. In vivo experiments showed that the S-MHMs/collagen scaffolds enhanced the bone regeneration and neovascularization simultaneously. These results demonstrated that the water-insoluble simvastatin could be incorporated into the MHMs and maintained its biological activities, more importantly, the S-MHMs/collagen scaffolds fabricated in this study are of immense potential in bone defect repair by enhancing osteogenesis and angiogenesis simultaneously.

Synergistic effects of dimethyloxallyl glycine and recombinant human bone morphogenetic protein-2 on repair of critical-sized bone defects in rats.

In bone remodeling, osteogenesis is closely coupled to angiogenesis. Bone tissue engineering using multifunctional bioactive materials is a promising technique which has the ability to simultaneously stimulate osteogenesis and angiogenesis for repair of bone defects. We developed mesoporous bioactive glass (MBG)-doped poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) composite scaffolds as delivery vehicle. Two bioactive molecules, dimethyloxalylglycine (DMOG), a small-molecule angiogenic drug, and recombinant human bone morphogenetic protein-2 (rhBMP-2), an osteoinductive growth factor, were co-incorporated into the scaffold. The synergistic effects of DMOG and rhBMP-2 released in the composite scaffolds on osteogenic and angiogenic differentiation of hBMSCs were investigated using real-time quantitative polymerase chain reaction and western blotting. Moreover, in vivo studies were conducted to observe bone regeneration and vascular formation of critical-sized bone defects in rats using micro-computed tomography, histological analyses, Microfil® perfusion, fluorescence labeling, and immunohistochemical analysis. The results showed that DMOG and rhBMP-2 released in the MBG-PHBHHx scaffolds did exert synergistic effects on the osteogenic and angiogenic differentiation of hBMSCs. Moreover, DMOG and rhBMP-2 produced significant increases in newly-formed bone and neovascularization of calvarial bone defects in rats. It is concluded that the co-delivery strategy of both rhBMP-2 and DMOG can significantly improve the critical-sized bone regeneration.