Pericyte stem cells induce Ly6G+ cell accumulation and immunotherapy resistance in pancreatic cancer.

We report the identification of a cell population that shares pericyte, stromal and stemness features, does not harbor the KrasG12D mutation and drives tumoral growth in vitro and in vivo. We term these cells pericyte stem cells (PeSCs) and define them as CD45- EPCAM- CD29+ CD106+ CD24+ CD44+ cells. We perform studies with p48-Cre;KrasG12D (KC), pdx1-Cre;KrasG12D ;Ink4a/Arffl/fl (KIC) and pdx1-Cre;KrasG12D ;p53R172H (KPC) and tumor tissues from PDAC and chronic pancreatitis patients. We also perform single-cell RNAseq analysis and reveal a unique signature of PeSC. Under steady-state conditions, PeSCs are barely detectable in the pancreas but present in the neoplastic microenvironment both in humans and mice. The coinjection of PeSCs and tumor epithelial cells leads to increased tumor growth, differentiation of Ly6G+ myeloid-derived suppressor cells, and a decreased amount of F4/80+ macrophages and CD11c+ dendritic cells. This population induces resistance to anti-PD-1 immunotherapy when coinjected with epithelial tumor cells. Our data reveal the existence of a cell population that instructs immunosuppressive myeloid cell responses to bypass PD-1 targeting and thus suggest potential new approaches for overcoming resistance to immunotherapy in clinical settings.

The Effect of Perioperative Dexamethasone on Postoperative Complications After Pancreaticoduodenectomy: A Multicenter Randomized Controlled Trial.

OBJECTIVE: To evaluate the effect of perioperative dexamethasone on postoperative complications after pancreaticoduodenectomy. BACKGROUND: The glucocorticoid dexamethasone has been shown to improve postoperative outcomes in surgical patients, but its effects on postoperative complications after pancreaticoduodenectomy are unclear. METHODS: This multicenter, double-blind, randomized controlled trial was conducted in four Chinese high-volume pancreatic centers. Adults undergoing elective pancreaticoduodenectomy were randomized to receive either 0.2 mg/kg dexamethasone or a saline placebo as an intravenous bolus within 5 minutes after anesthesia induction. The primary outcome was the Comprehensive Complication Index (CCI) score within 30 days after the operation, analyzed using the modified intention-to-treat principle. RESULTS: Among 428 patients for eligibility, 300 participants were randomized and 265 were included in the modified intention-to-treat analyses. One hundred thirty-four patients received dexamethasone and 131 patients received a placebo. The mean (SD) CCI score was 14.0 (17.5) in the dexamethasone group and 17.9 (20.3) in the placebo group (mean difference: -3.8; 95% CI: -8.4 to 0.7; P = 0.100). The incidence of major complications (Clavien-Dindo grade ≥III; 12.7% vs 16.0%, risk ratio: 0.79; 95% CI: 0.44 to 1.43; P = 0.439) and postoperative pancreatic fistula (25.4% vs 31.3%, risk ratio: 0.81; 95% CI: 0.55 to 1.19; P = 0.286) were not significantly different between the two groups. In the stratum of participants with a main pancreatic duct ≤3 mm (n = 202), the CCI score was significantly lower in the dexamethasone group (mean difference: -6.4; 95% CI: -11.2 to -1.6; P = 0.009). CONCLUSIONS: Perioperative dexamethasone did not significantly reduce postoperative complications within 30 days after pancreaticoduodenectomy.

LIPH contributes to glycolytic phenotype in pancreatic ductal adenocarcinoma by activating LPA/LPAR axis and maintaining ALDOA stability.

BACKGROUND: LIPH, a membrane-associated phosphatidic acid-selective phospholipase A1a, can produce LPA (Lysophosphatidic acid) from PA (Phosphatidic acid) on the outer leaflet of the plasma membrane. It is well known that LIPH dysfunction contributes to lipid metabolism disorder. Previous study shows that LIPH was found to be a potential gene related to poor prognosis with pancreatic ductal adenocarcinoma (PDAC). However, the biological functions of LIPH in PDAC remain unclear. METHODS: Cell viability assays were used to evaluate whether LIPH affected cell proliferation. RNA sequencing and immunoprecipitation showed that LIPH participates in tumor glycolysis by stimulating LPA/LPAR axis and maintaining aldolase A (ALDOA) stability in the cytosol. Subcutaneous, orthotopic xenograft models and patient-derived xenograft PDAC model were used to evaluate a newly developed Gemcitabine-based therapy. RESULTS: LIPH was significantly upregulated in PDAC and was related to later pathological stage and poor prognosis. LIPH downregulation in PDAC cells inhibited colony formation and proliferation. Mechanistically, LIPH triggered PI3K/AKT/HIF1A signaling via LPA/LPAR axis. LIPH also promoted glycolysis and de novo synthesis of glycerolipids by maintaining ALDOA stability in the cytosol. Xenograft models show that PDAC with high LIPH expression levels was sensitive to gemcitabine/ki16425/aldometanib therapy without causing discernible side effects. CONCLUSION: LIPH directly bridges PDAC cells and tumor microenvironment to facilitate aberrant aerobic glycolysis via activating LPA/LPAR axis and maintaining ALDOA stability, which provides an actionable gemcitabine-based combination therapy with limited side effects.

Stromal protein ßig-h3 reprogrammes tumour microenvironment in pancreatic cancer.

OBJECTIVE: Pancreatic cancer is associated with an abundant stromal reaction leading to immune escape and tumour growth. This massive stroma drives the immune escape in the tumour. We aimed to study the impact of ßig-h3 stromal protein in the modulation of the antitumoural immune response in pancreatic cancer. DESIGN: We performed studies with p48-Cre;KrasG12D, pdx1-Cre;KrasG12D;Ink4a/Arffl/fl, pdx1-Cre;KrasG12D; p53R172H mice and tumour tissues from patients with pancreatic ductal adenocarcinoma (PDA). Some transgenic mice were given injections of anti-ßig-h3, anti-CD8, anti-PD1 depleting antibodies. Tumour growth as well as modifications in the activation of local immune cells were analysed by flow cytometry, immunohistochemistry and immunofluorescence. Tissue stiffness was measured by atomic force microscopy. RESULTS: We identified ßig-h3 stromal-derived protein as a key actor of the immune paracrine interaction mechanism that drives pancreatic cancer. We found that ßig-h3 is highly produced by cancer-associated fibroblasts in the stroma of human and mouse. This protein acts directly on tumour-specific CD8+ T cells and F4/80 macrophages. Depleting ßig-h3 in vivo reduced tumour growth by enhancing the number of activated CD8+ T cell within the tumour and subsequent apoptotic tumour cells. Furthermore, we found that targeting ßig-h3 in established lesions released the tissue tension and functionally reprogrammed F4/80 macrophages in the tumour microenvironment. CONCLUSIONS: Our data indicate that targeting stromal extracellular matrix protein ßig-h3 improves the antitumoural response and consequently reduces tumour weight. Our findings present ßig-h3 as a novel immunological target in pancreatic cancer.

A Genetic Predictive Model Estimating the Risk of Developing Adolescent Idiopathic Scoliosis.

BACKGROUND: Previous GWASs have revealed several susceptible variants associated with adolescent idiopathic scoliosis (AIS). Risk prediction based on these variants can potentially improve disease prognosis. We aimed to evaluate the combined effects of genetic factors on the development of AIS and to further develop a genetic predictive model. METHODS: A total of 914 AIS patients and 1441 normal controls were included in the discovery stage, which was followed by the replication stage composed of 871 patients and 1239 controls. Genotyping assay was performed to analyze 10 previously reported susceptible variants, including rs678741 of LBX1, rs241215 of AJAP1, rs13398147 of PAX3, rs16934784 of BNC2, rs2050157 of GPR126, rs2180439 of PAX1, rs4940576 of BCL2, rs7593846 of MEIS1, rs7633294 of MAGI1 and rs9810566 of TNIK. Logistic regression analysis was performed to generate a risk predictive model. The predicted risk score was calculated for each participant in the replication stage. RESULTS: The association of the 10 variants with AIS was successfully validated. The established model could explain approximately 7.9% of the overall variance. In the replication stage, patients were found to have a remarkably higher risk score as compared to the controls (44.2 ± 14.4 vs. 33.9 ± 12.5, p <0.001). There was a remarkably higher proportion of the risk score i.e. >40 in the patients than in the controls (59% vs. 28.9%, p <0.001). CONCLUSION: Risk predictive model based on the previously reported genetic variants has a remarkable discriminative power. More clinical and genetic factors need to be studied, to further improve the proba-bility to predict the onset of AIS.

Internal Hernia Following Robotic Assisted Pancreaticoduodenectomy.

BACKGROUND Robotic assisted pancreaticoduodenectomy (RPD) is reported to be safe and feasible. Internal hernia (IH) after RPD is a serious but rarely reported complication. MATERIAL AND METHODS We retrospectively reviewed data of 231 patients who underwent RPD from October 2010 to December 2016. The incidence, symptoms, time of presentation, and outcome were investigated. RESULTS Five patients (2.6%) were diagnosed with IH. Significant correlation (P<0.001) between IH and transverse mesocolon defect was confirmed. In patients without defect closure, the incidence of IH was 62.5%, while patients who received defect closure experienced no IH. The median time between initial surgery and occurrence of IH was 76 days. The main symptoms were abdominal pain, nausea, and vomiting. All patients received abdominal computed tomography (CT) and were suspected to have IH according to imaging and symptoms. All patients underwent reoperation (2 laparoscopic and 3 open surgery). The median length of hospital stay was 13 days. No patient experienced a relapse after treatment. CONCLUSIONS Abdominal pain, nausea, and vomiting were common symptoms in our study patients who underwent RPD. IH should be suspected if there is a positive finding on CT. Timely reoperation is necaAbdominal pain, nausea, and vomiting were common symptoms in our study patients who underwent RPD. IH should be suspected if there is a positive finding on CT. Timely reoperation is necessary because IH may cause intestinal ischemia. Meticulous closure of the mesenteric defect is vital to avoid IH.essary because IH may cause intestinal ischemia. Meticulous closure of the mesenteric defect is vital to avoid IH.

Robot-assisted laparoscopic versus open middle pancreatectomy: short-term results of a randomized controlled trial.

OBJECTIVE: This first prospective randomized controlled trial was performed to compare short-term outcomes of robot-assisted laparoscopic middle pancreatectomy (RA-MP) with open middle pancreatectomy (OMP). BACKGROUND: RA-MP is a novel minimally invasive surgical technique for benign or borderline tumors in the pancreatic neck or body. Its short-term effectiveness and safety remain unknown, compared to OMP. METHODS: Patients eligible for MP from August 2011 to November 2015 were randomized into the RA-MP or OMP group. The primary endpoint was length of hospital stay (LOS). Secondary endpoints were intraoperative parameters, and postoperative and recovery variables. RESULTS: A total of 100 patients were included into the study to analyze primary and secondary endpoints. Demographic characteristics and pathological parameters were similar in both groups. Furthermore, LOS was significantly shorter (15.6 vs. 21.7 days, P = 0.002), median operative time was reduced (160 vs. 193 min, P = 0.002), median blood loss was lower (50 vs. 200 mL, P < 0.001), rate of clinical postoperative pancreatic fistula (POPF) was lower (18 vs. 36.0 %, P = 0.043), nutritional status recovery was better, off-bed return to activity was expedited (3.1 vs. 4.6 days, P < 0.001), and resumption of bowel movement was faster (3.5 vs. 5.0 days, P < 0.001) in the RA-MP group, compared to the OMP group. CONCLUSION: RA-MP was associated with significantly shorter LOS, reduced operative time, blood loss and clinical POPF rate, and expedited postoperative recovery, compared to OMP.

Robotic Enucleation for Benign or Borderline Tumours of the Pancreas: A Retrospective Analysis and Comparison from a High-Volume Centre in Asia.

BACKGROUND: Enucleation is increasingly performed for benign or borderline tumours of the pancreas because it is a parenchyma-sparing and less invasive procedure compared to conventional pancreatectomy, which reduces the risk of exocrine and endocrine insufficiency. This study retrospectively evaluated and compared the pre-, intra-, and post-operative clinical characteristics after open and robotic approaches for pancreatic enucleation. METHODS: Fifty-six cases of enucleation for benign or borderline tumours of the pancreas treated from March 2010 to July 2015 were identified by a retrospective search. These included 25 patients who underwent an open approach and 31 patients who underwent a robotic approach. The clinical characteristics were extracted and compared. RESULTS: The two groups had a similar location and pathology of the tumour. The robotic group had a significantly shorter operation time and significantly less blood loss than the open group. The rates of clinical pancreatic fistula (PF) formation and major complications were similar. The robotic approach could be applied for a tumour on the right side of the pancreas without increasing the incidence of clinical PF or other major complications. The patients with clinical PF had a significantly shorter distance between the lesion and the main pancreatic duct (MPD). CONCLUSION: Robotic enucleation appears to be a feasible and safe approach for benign or borderline tumours of the pancreas and was associated with similarly favourable surgical outcomes as the open approach. Identifying and avoiding the MPD is an important step during enucleation.

Robot-Assisted Middle Pancreatectomy for Elderly Patients: Our Initial Experience.

BACKGROUND: The aim of this study was to evaluate the indications, safety, feasibility, and short- and long-term outcomes for elderly patients who underwent robot-assisted middle pancreatectomies (MPs). MATERIAL AND METHODS: Ten patients (≥60 years) underwent robot-assisted middle pancreatectomies from 2012 to 2015. The perioperative data, including tumor size, operating time, rate of postoperative pancreatic fistula (POPF), postoperative morbidity, and other parameters, were analyzed. We collected and analyzed the follow-up information. RESULTS: The mean age of patients was 64.30 years (range, 60-73 years). The average tumor size was 2.61 cm. The 10 cases were all benign or low-grade malignant lesions. The mean operating time was 175.00 min. The mean blood loss was 113.00 ml with no blood transfusion needed. Postoperative fistulas developed in 5 patients; there were 2 Grade A fistulas and 3 grade B fistulas. There were 3 patients who underwent postoperative complications, including 2 Grade 1 or 2 complications and 1 Grade 3 complication. No reoperation and postoperative mortality occurred. The mean hospital stay was 19.91 days. After a median follow-up of 23 months, new onset of diabetes mellitus developed in 1 patient and none suffered from deterioration of previously diagnosed diabetes or exocrine insufficiency, and no tumor recurrence happened. CONCLUSIONS: Robot-assisted middle pancreatectomy was safe and feasible for elderly people. It had low risk of exocrine or endocrine dysfunction and benefited patients' long-term outcomes. Incidence of POPF was relatively high but we could prevent it from resulting in bad outcomes by scientific perioperative care and systemic treatment.

Outcomes of robotic surgery for pancreatic ductal adenocarcinoma.

BACKGROUND: To explore the effectiveness, safety, and efficacy of the robot-assisted surgery in the radical resection of pancreatic ductal adenocarcinoma (PDAC). METHODS: The clinical data of 72 patients with PDAC who underwent radical resection using the da Vinci Surgical System from April 2010 to December 2014 were retrospectively analyzed. RESULTS: Among these 72 patients, three were converted to conventional laparotomy due to the vascular invasion or due to the difficulties in tissue isolation from the surrounding organs. Among 39 patients who underwent the pancreatoduodenectomy, the average operative time was 395.3±118.8 min, and the mean intra-operative blood loss was 447.3±269.9 mL. Among 31 patients who underwent the distal pancreatectomy (DP), the average operative time was 185.5±74.1 min, and the mean intra-operative blood loss was 267.1±305.3 mL. In two patients who received the middle pancreatectomy (MP), the average operative time was 225 min and mean intra-operative blood loss was 100 mL. Among all the 72 patients, an average of 4.2±2.6 lymph nodes were dissected, with an average hospital stay of 22.6±10.7 days. Complications were observed in 18 patients, which included pancreatic fistula (n=11), bile leak (n=5), anastomotic bleeding (n=2), pancreatic fistula complicated with portal vein thrombosis (n=1), and anastomotic bleeding complicated with acute renal failure (n=1). Except that one patient died due to post-operative bleeding and acute renal failure, all the other patients were cured after conservative treatment. These 72 patients were followed for 1-45 (15.6±5.8) months, during which 10 patients died. Eleven patients suffered from recurrence or metastasis, among which 6 had local recurrence, 4 had liver metastasis, and 1 had ascites accompnaied with incision site tumor metastasis. CONCLUSIONS: Radical resection of PDAC by robotic surgical system is safe and feasible. It has less surgical trauma and enables faster post-operative recovery, and therefore can achieve the lymph node dissection scope and tumor resection margin required by the standards of radical resection for pancreatic cancer. Nevertheless, its long-term efficacy requires further validation.

Genetic Variants can Predict the Outcome of Brace Treatment in Patients With Adolescent Idiopathic Scoliosis.

STUDY DESIGN: A genetic case-control study. OBJECTIVES: To investigate the association between AIS progression-associated SNPs reported by GWAS studies and the effectiveness of brace treatment. SUMMARY OF BACKGROUND DATA: Bracing is the most effective conservative method to treat adolescent idiopathic scoliosis (AIS). Several factors have been reported to be associated with bracing failure in AIS patients. Genetic markers associated with AIS have potential prognostic value. METHODS: A retrospective cohort of AIS patients undergoing brace treatment was enrolled in this study and divided into success and failure groups based on treatment outcome. Clinical characteristics of AIS patients were documented. Candidate SNPs were selected from previous GWAS studies of AIS, which were known to be associated with curve progression and validated across diverse populations. Genotype and allele frequencies between the success and failure groups were compared using chi-square analysis. RESULTS: A total of 259 female AIS patients were included in this study, 30.5% of the well-braced patients had curve progression exceeding 5° and 69.5% of the patients undergo an improvement or progression of less than 5°. Allele C of rs10738445 (BNC2) could significantly add to the risk of bracing failure, with odds ratio of 1.59. No significant association with bracing outcomes was found for rs12946942 (SOX9/KCNJ2), rs1978060 (TBX1), rs1017861 (CHD7), and rs35333564 (MIR4300HG). CONCLUSIONS: SNP rs10738445 were significantly associated with brace treatment effectiveness. The other four SNPs were not significantly associated with the outcome of bracing. More SNPs and predictors should be included in future study to develop a more accurate predictive model for clinical application.

Magnetic resonance imaging tracing of superparamagnetic iron oxide nanoparticle-labeled mesenchymal stromal cells for repairing spinal cord injury.

ABSTRACT: Mesenchymal stromal cell transplantation Is an effective and promising approach for treating various systemic and diffuse diseases. However, the biological characteristics of transplanted mesenchymal stromal cells in humans remain unclear, including cell viability, distribution, migration, and fate. Conventional cell tracing methods cannot be used in the clinic. The use of superparamagnetic iron oxide nanoparticles as contrast agents allows for the observation of transplanted cells using magnetic resonance imaging. In 2016, the National Medical Products Administration of China approved a new superparamagnetic iron oxide nanoparticle, Ruicun, for use as a contrast agent in clinical trials.In the present study, an acute hemi-transection spinal cord injury model was established in beagle dogs. The injury was then treated by transplantation of Ruicun-labeled mesenchymal stromal cells. The results indicated that Ruicun-labeled mesenchymal stromal cells repaired damaged spinal cord fibers and partially restored neurological function in animals with acute spinal cord injury. T2*-weighted imaging revealed low signal areas on both sides of the injured spinal cord. The results of quantitative susceptibility mapping with ultrashort echo time sequences indicated that Ruicun-labeled mesenchymal stromal cells persisted stably within the injured spinal cord for over 4 weeks. These findings suggest that magnetic resonance imaging has the potential to effectively track the migration of Ruicun-labeled mesenchymal stromal cells and assess their ability to repair spinal cord injury.

Higher Baseline Serum Myokine of FSTL1 May Serve as a Potential Predictive Biomarker for Successful Brace Treatment in Girls With Adolescent Idiopathic Scoliosis.

STUDY DESIGN: A retrospective case-control study. OBJECTIVE: This study aimed to investigate whether myokine, which is related to exercise and muscle mass, could serve as a biomarker for predicting bracing outcomes. SUMMARY OF BACKGROUND DATA: Several risk factors have been documented to be associated with bracing failure in patients with adolescent idiopathic scoliosis (AIS). However, serum biomarkers have not been extensively explored. PATIENTS AND METHODS: Skeletally immature females with AIS, without previous histories of bracing or surgery, were included. Peripheral blood was collected at the time of the bracing prescription. Baseline serum concentrations of 8 myokines [apelin, fractalkine, brain-derived neurotrophic factor, erythropoietin, osteonectin, fatty-acid-binding protein 3, follistatin-like 1 (FSTL1), and musclin] were measured by multiplex assays. Patients were followed up until weaned from bracing and then designated as a "failure" (defined as Cobb angle progression >5°) or "success." A logistic regression analysis was performed that accounted for serum myokines and skeletal maturity. RESULTS: We included 117 patients, with 27 in the failure group. Patients in the failure group had lower initial Risser sign and lower baseline serum levels of myokines, including FSTL1 (2217.3 ± 617.0 vs . 1369.3 ± 704.9, P = 0.002), apelin [116.5 (12.0, 335.9) vs . 83.5 (10.5, 221.1), P = 0.016], fractalkine (979.6 ± 457.8 vs . 743.8 ± 456.1, P = 0.020), and musclin [211.3 (16.3, 370.3) vs . 67.8 (15.5, 325.6), P = 0.049]. Following adjusted analysis, serum FSTL1 [odds ratio = 10.460; (2.213-49.453)] was determined to be predictive of bracing effectiveness. CONCLUSION: Patients who failed AIS bracing had significantly lower mean baseline levels of FSTL1 than those who achieved success. FSTL1 may serve as a biomarker that can inform outcomes after bracing.

Differential Gene Expression Profiles and Pathways Highlight the Role of Osteoimmunology in Neurofibromatosis Type 1-Related Dystrophic Scoliosis With Osteopenia.

STUDY DESIGN: Microarray approach and integrated gene network analysis. OBJECTIVE: To explore the differential genetic expression profile, Gene Ontology terms, and Kyoto Encyclopedia of Genes and Genomes pathways in human trabecular bone (HTB)-derived cells of dystrophic scoliosis secondary to neurofibromatosis type 1 (DS-NF1) and compare these to normal controls. SUMMARY OF BACKGROUND DATA: The pathogenesis of DS-NF1 and the accompanying generalized osteopenia remain unclear. We hypothesized that HTBs may play a significant role in the etiology and pathogenesis of DS-NF1. MATERIALS AND METHODS: Microarray analysis was used to identify differentially expressed genes of HTBs from patients with DS-NF1 compared with those from healthy individuals. Functional and pathway enrichment analysis were implemented through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway database. Then, the "search tool for the retrieval of interacting genes/proteins" database, Cytoscape, and "Molecular Complex Detection" were applied to construct the protein-protein interaction (PPI) network and screen hub genes. Pathway enrichment analysis was further performed for hub genes and gene clusters identified through module analysis. Six potential crucial genes were selected for validation by reverse transcription polymerase chain reaction. RESULTS: Bioinformatic analysis revealed that there are 401 previously unrecognized differentially expressed genes (238 up and 163 downregulated genes) in HTBs from patients with DS-NF1, and they were mainly enriched in terms of immune response, type-I interferon (IFN) signaling, TNF signaling pathway and etinoic acid inducible gene I-like receptor signaling pathway. Five hub genes, including signal transducer and activator of transcription 1, 2'-5'-oligoadenylate synthetase-like, IFN induced with helicase C domain 1, IFN regulatory factor 7, and MX dynamin-like GTPase 1 were identified through PPI network, which were mainly enriched in terms of Jak-STAT and etinoic acid inducible gene I-like receptor signaling pathway. An independently dysregulated protein cluster containing CCL2, CXCL1, CXCL3, CX3CL1, TLR1 , and CXCL12 was also identified through the PPI network. This indicated that the upper abnormally expressed genes may play essential roles in DS-NF1 pathogenesis and accompanied osteopenia. CONCLUSION: Six key genes were identified in the progression of DS-NF1-related osteopenia. Immune response might play a key role in the progression of osteopenia, whereas a CXCL12 -mediated osteogenic effect might play a protective role.

Genetic insight into the putative causal proteins and druggable targets of osteoporosis: a large-scale proteome-wide mendelian randomization study.

Background: Osteoporosis is a major causative factor of the global burden of disease and disability, characterized by low bone mineral density (BMD) and high risks of fracture. We aimed to identify putative causal proteins and druggable targets of osteoporosis. Methods: This study utilized the largest GWAS summary statistics on plasma proteins and estimated heel BMD (eBMD) to identify causal proteins of osteoporosis by mendelian randomization (MR) analysis. Different GWAS datasets were used to validate the results. Multiple sensitivity analyses were conducted to evaluate the robustness of primary MR findings. We have also performed an enrichment analysis for the identified causal proteins and evaluated their druggability. Results: After Bonferroni correction, 67 proteins were identified to be causally associated with estimated BMD (eBMD) (p < 4 × 10-5). We further replicated 38 of the 67 proteins to be associated with total body BMD, lumbar spine BMD, femoral neck BMD as well as fractures, such as RSPO3, IDUA, SMOC2, and LRP4. The findings were supported by sensitivity analyses. Enrichment analysis identified multiple Gene Ontology items, including collagen-containing extracellular matrix (GO:0062023, p = 1.6 × 10-10), collagen binding (GO:0005518, p = 8.6 × 10-5), and extracellular matrix structural constituent (GO:0005201, p = 2.7 × 10-5). Conclusion: The study identified novel putative causal proteins for osteoporosis which may serve as potential early screening biomarkers and druggable targets. Furthermore, the role of plasma proteins involved in collagen binding and extracellular matrix in the development of osteoporosis was highlighted. Further studies are warranted to validate our findings and investigate the underlying mechanism.

A Genetic Variant of FAM46A is Associated With the Development of Adolescent Idiopathic Scoliosis in the Chinese Population.

STUDY DESIGN: A genetic case-control study. OBJECTIVE: To replicate recently reported genetic loci associated with adolescent idiopathic scoliosis (AIS) in the Chinese Han population, and to determine the relationship between gene expression and the clinical features of the patients. SUMMARY OF BACKGROUND DATA: A recent study conducted in the Japanese population identified several novel susceptible loci, which might provide new insights into the etiology of AIS. However, the association of these genes with AIS in other populations remains unclear. MATERIALS AND METHODS: A total of 1210 AIS and 2500 healthy controls were recruited for the genotyping of 12 susceptibility loci. Paraspinal muscles used for gene expression analysis were obtained from 36 AIS and 36 patients with congenital scoliosis. The difference regarding genotype and allele frequency between patients and controls was analyzed by χ 2 analysis. The t test was performed to compare the target gene expression level between controls and AIS patients. Correlation analysis was performed between gene expression and phenotypic data, including Cobb angle, bone mineral density, lean mass, height, and body mass index. RESULTS: Four SNPs, including rs141903557, rs2467146, rs658839, and rs482012, were successfully validated. Allele C of rs141903557, allele A of rs2467146, allele G of rs658839, and allele T of single nucleotide polymorphism rs482012 showed significantly higher frequency in patients. Allele C of rs141903557, allele A of rs2467146, allele G of rs658839, and allele T of rs482012 could notably increase the risk of AIS patients, with an odds ratio of 1.49, 1.16, 1.11, and 1.25, respectively. Moreover, tissue expression of FAM46A was significantly lower in AIS patients as compared with controls. Moreover, FAM46A expression was remarkably correlated with bone mineral density of patients. CONCLUSION: Four SNPs were successfully validated as novel susceptibility loci associated with AIS in the Chinese population. Moreover, FAM46A expression was associated with the phenotype of AIS patients.

More Prevalent and Severe Low Bone-Mineral Density in Boys with Severe Adolescent Idiopathic Scoliosis Than Girls: A Retrospective Study of 798 Surgical Patients.

INTRODUCTION: A total of 0.1-0.8% of AIS patients progress to severe stages without clear mechanisms, and AIS girls are more prone to curve progression than boys. Recent studies suggest that AIS girls have systemic and persistent low bone-mineral density (BMD), which has been shown to be a significant prognostic factor of curve progression in AIS. The present study aimed to (a) investigate the prevalence of low BMD in patients with severe AIS and (b) assess the sexual dimorphism and independent risk factors of low BMD in severe AIS patients. MATERIALS AND METHODS: A total of 798 patients (140 boys vs. 658 girls) with AIS who reached surgical threshold (Cobb ≥ 40°) were recruited. BMD were assessed using BMD Z-scores from dual-energy X-ray absorptiometry (DXA). Demographic, clinical, and laboratory values of the subjects were collected from their medical records. Logistic regression analysis was performed to identify independent risk factors of low BMD. RESULTS: The overall prevalence of BMD Z-score ≤ -2 and ≤ -1 were 8.1% and 37.5%, respectively. AIS boys had significantly lower BMD Z-scores (-1.2 ± 0.96 vs. -0.57 ± 0.92) and higher prevalence of low BMD (Z-score ≤ -2: 22.1% vs. 5.2%, p < 0.001; Z-score ≤ -1: 59.3% vs. 32.8%, p < 0.001) than girls. Sex, BMI, serum alkaline phosphatase, and potassium were independent factors of low BMD in the severe AIS patients. CONCLUSIONS: The present large cohort of surgical AIS patients revealed that low BMD is more prevalent and severe in boys than in girls with severe curves. Low BMD may serve as a more valuable predictive factor for curve progression to the surgical threshold in boys than girls with AIS.

Stiffness-induced cancer-associated fibroblasts are responsible for immunosuppression in a platelet-derived growth factor ligand-dependent manner.

Pancreatic ductal adenocarcinoma (PDAC) is associated with a vast stromal reaction that arises mainly from cancer-associated fibroblasts (CAFs) and promotes both immune escape and tumor growth. Here, we used a mouse model with deletion of the activin A receptor ALK4 in the context of the KrasG12D mutation, which strongly drives collagen deposition that leads to tissue stiffness. By ligand-receptor analysis of single-cell RNA-sequencing data, we identified that, in stiff conditions, neoplastic ductal cells instructed CAFs through sustained platelet-derived growth factor (PDGF) signaling. Tumor-associated tissue rigidity resulted in the emergence of stiffness-induced CAFs (siCAFs) in vitro and in vivo. Similar results were confirmed in human data. siCAFs were able to strongly inhibit CD8+ T-cell responses in vitro and in vivo, promoting local immunosuppression. More importantly, targeting PDGF signaling led to diminished siCAF and reduced tumor growth. Our data show for the first time that early paracrine signaling leads to profound changes in tissue mechanics, impacting immune responses and tumor progression. Our study highlights that PDGF ligand neutralization can normalize the tissue architecture independent of the genetic background, indicating that finely tuned stromal therapy may open new therapeutic avenues in pancreatic cancer.

ßig-h3-structured collagen alters macrophage phenotype and function in pancreatic cancer.

Macrophages play an important role in immune and matrix regulation during pancreatic adenocarcinoma (PDAC). Collagen deposition massively contributes to the physical and functional changes of the tissue during pathogenesis. We investigated the impact of thick collagen fibers on the phenotype and function of macrophages. We recently demonstrated that the extracellular protein ßig-h3/TGFßi (Transforming growth factor-ß-induced protein) plays an important role in modulating the stiffness of the pancreatic stroma. By using atomic force microscopy, we show that ßig-h3 binds to type I collagen and establishes thicker fibers. Macrophages cultured on ßig-h3-structured collagen layers display a different morphology and a pro-tumoral M2 phenotype and function compared to those cultured on non-structured collagen layers. In vivo injection of those instructed CD206+CD163+ macrophages was able to suppress T cell responses. These results reveal for the first time that the collagen structure impacts the phenotype and function of macrophages by potentiating their immunosuppressive features.

Dipeptidyl peptidase-4 is associated with myogenesis in patients with adolescent idiopathic scoliosis possibly via mediation of insulin sensitivity.

BACKGROUND: Abnormal metabolic features have been previously described in adolescent idiopathic scoliosis (AIS) patients. As an important regulator involved in energy metabolism, DPP-4 activity was reported to be remarkably decreased in osteoblasts of AIS patients. To date, there was still a lack of knowledge concerning the role of DPP-4 in the myogenesis of AIS. METHODS: Circulation DPP-4 level was assessed in the serum of 80 AIS girls and 50 healthy controls by ELISA. Myoblasts were purified from muscle specimens of AIS patients and LDH controls, and then treated with metabolic effectors including glucose and insulin. CCK-8 assay was used to assess the cell viability and myotube fusion index was calculated to evaluate myogenesis ability. Gene expressions of downstream signals of DPP-4 were evaluated by RT-qPCR and Western blot respectively. RESULTS: AIS girls had remarkably down-expressed DPP-4 in both serum level (0.76 fold) and tissue (0.68 fold) level. Treatment with metabolic effectors led to significantly increased DPP-4 expression in the control cells, while there was no increase of DPP-4 in AIS cells. CCK-8 assay showed that the proliferation rate of control cells was significantly increased after being treated. Remarkably higher fusion index was also observed in the treated control cells. By contrast, the fusion index and cell proliferation rate were comparable between the treated and the untreated AIS cells. CONCLUSIONS: Our study suggested a potential role of DPP-4 in abnormal metabolic condition of AIS patients. Compared with control cells, AIS myoblasts presented obviously impaired sensitivity to the treatment of glucose and insulin. Aberrant DPP-4 expression could lead to impaired insulin sensitivity in myoblasts and further influence the cell viability during myogenesis. The molecular mechanism connecting DPP-4 and insulin-related signaling in AIS is worthy of further investigation.