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.

Nontargeted Metabolomic Analysis of Plasma Metabolite Changes in Patients with Adolescent Idiopathic Scoliosis.

OBJECTIVE: Adolescent idiopathic scoliosis (AIS) is a relatively common spinal rotation deformity, and the pathogenesis of AIS is accompanied by metabolic dysfunction and changes in biochemical factors. In this study, plasma metabolite changes in AIS patients were analyzed based on nontargeted metabolomics to provide new insights for clarifying functional metabolic abnormalities in AIS patients. METHODS: Clinical indexes and blood samples were collected from 12 healthy subjects and 16 AIS patients. Metabolomics was used to analyze the changes in metabolites in plasma samples. The correlation between plasma metabolites and clinical indexes was analyzed by the Spearman rank correlation coefficient. RESULTS: Analysis of clinical data showed that the body weight, body mass index (BMI), and bone mineral density (BMD) index of the AIS group significantly decreased, while the blood phosphorus and Cobb angles increased significantly. Metabolomic analysis showed significant changes in 72 differential metabolites in the plasma of the AIS group, mainly including organooxygen compounds, carboxylic acids and derivatives, fatty acyls, steroids and steroid derivatives, and keto acids and derivatives. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway showed that arginine biosynthesis, D-glutamine and D-glutamate metabolism, alanine, aspartate and glutamate metabolism, and citrate cycle (TCA cycle) were significantly enriched in the AIS and healthy groups. Spearman rank correlation coefficient analysis showed that the plasma metabolites C00026 (oxoglutarate), C00062 (L-arginine, arginine), C01042 (N-acetylaspartate), and C00158 (citrate) were significantly correlated with clinical indexes in AIS patients. In the healthy group, the plasma metabolites C00122 (fumarate), C00025 (glutamate and L-glutamic acid) and C00149 (malate, L-malic acid) were significantly correlated with clinical indexes, while C00624 (N-acetylglutamate) was not significantly correlated with the clinical indexes. CONCLUSION: The occurrence of AIS led to changes in clinical indexes and plasma metabolites. Plasma biomarkers and functional metabolic pathways were correlated with clinical indexes, which might provide new insights for the diagnosis and treatment of AIS.

Plasma proteomics analysis of adolescent idiopathic scoliosis patients revealed by Quadrupole-Orbitrap mass spectrometry.

OBJECTIVE: We aim to investigate the changes of plasma proteome among mild, severe adolescent idiopathic scoliosis (AIS) patients and healthy controls. METHODS: In this retrospective study, there were 84 individuals including 56 confirmed AIS patients (27 follow-up AIS patients and 29 surgical AIS patients) and another 28 healthy teenagers. Plasma samples were obtained and Quadrupole-Orbitrap Mass Spectrometer was performed to identify proteins in AIS patients and control group. T-test and ANOVA were performed to screen for differential proteins. GO and KEGG pathway, Pearson's correlation analysis and PLS model were applied to identify enriched proteins, investigate correlation between proteins and Cobb angles. ELISA was performed to further verify the quantitative proteomics results. RESULTS: A total of 349 proteins were identified, among which 55 protein levels changed significantly in AIS group, compared with control group. Post hoc test indicated 36 proteins were significantly different between surgical and control group, 35 proteins between follow-up and control group. Fibronectin, fibrinogen and calmodulin were statistically different among three groups through mass spectrometry and were positively correlated with the Cobb angle. CONCLUSIONS: We performed the proteomic study and revealed that fibronectin, fibrinogen and calmodulin might not only be considered as biomarkers for AIS but could be correlated with curve severity.

Immunodeficiency, Centromeric Region Instability, and Facial Anomalies Syndrome (ICF) in a Boy with Variable Clinical and Immunological Presentations.

Immunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome is a rare primary immunodeficiency disorder characterized by recurrent infections and low immunoglobulin levels due to variable combined immunodeficiency, and centromeric region instability, and facial dysmorphism. We describe a 12-year-old boy with recurrent respiratory tract infections, facial anomalies, scoliosis, and psychomotor retardation. He had recurrent pneumonia with low serum IgG and IgM levels during infancy and preschool age. Later at the age of 10, he developed recurrent ear infections. An IgA and IgM deficiency was found accompanied by a normal B-cell and T-cell count as well as an impaired candida-induced T-cell proliferation. Further evaluations revealed a missense mutation in the DNMT3B gene on chromosome 20. Chromosomal analysis showed a sunburst multi-radial feature on chromosome 1, which is a hallmark of ICF syndrome. The genetic mutation and chromosomal abnormality along with clinical findings are compatible with the diagnosis of ICF syndrome. To the best of our knowledge, this is the first time that scoliosis is observed in an ICF patient. The additional variable clinical symptoms in the case were the presence of spastic gait as well as hypogammaglobulinemia with immunoglobulin isotype switch at different ages.

Impact of Preoperative Anemia on Outcomes After Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis.

OBJECTIVE: The aim of this study was to investigate the relationship of preoperative anemia and outcomes after posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS). METHODS: A retrospective cohort study was performed using the American College of Surgeons National Surgical Quality Improvement Program-Pediatric database from 2016 to 2018. All pediatric patients (age 10-18 years) with AIS undergoing PSF were identified. Two cohorts were categorized into anemic and nonanemic cohorts based on age-based and sex-based criteria for anemia. Thirty-day outcomes and readmission rates were evaluated. RESULTS: A total of 4929 patients were identified, of whom 592 (12.0%) were found to have preoperative anemia. The anemic cohort had a greater prevalence of comorbidities and longer operative times. Compared with the nonanemic cohort, the anemic cohort experienced significantly higher rates of perioperative bleed/transfusion (nonanemic, 67.4% vs. anemic, 73.5%; P = 0.004) and required a greater total amount of blood transfused (nonanemic, 283.2 ± 265.5 mL vs. anemic, 386.7 ± 342.6 mL; P < 0.001). The anemic cohort experienced significantly longer hospital stays (nonanemic, 3.8 ± 2.2 days vs. anemic, 4.2 ± 3.9 days; P = 0.001), yet discharge disposition (P = 0.58), 30-day complication rates (P = 0.79) and unplanned reoperation rates (P = 0.90) were similar between cohorts. On multivariate analysis, anemia was found to be an independent predictor of perioperative bleed/transfusion (odds ratio, 1.36; 95% confidence interval, 1.12-1.66; P = 0.002) as well as a longer length of hospital stay (relative risk, 0.46; 95% confidence interval, 0.25-0.67; P < 0.001) but was not an independent predictor for postoperative complications (P = 0.85). CONCLUSIONS: Our study suggests that preoperative anemia may be a risk factor for a greater perioperative bleed/transfusion event and slightly longer length of stay; however, it was not associated with greater 30-day complication and readmission rates in patients with AIS undergoing PSF.

Altered Circulating Cell-free Mitochondrial DNA of Patients with Congenital Scoliosis.

STUDY DESIGN: Case-control study. OBJECTIVE: The aim of this study was to estimate the relationship between circulating cell-free DNA (ccf DNA) and clinical parameters of patients with congenital scoliosis (CS). SUMMARY OF BACKGROUND DATA: CS is a complex spinal deformity characteristic of congenital vertebral malformations. Although numerous studies have centered on the etiology of CS, the cause of CS remains unclear. Previously, we reported that circulating cell-free DNA (ccf DNA) is altered in adolescent idiopathic scoliosis (AIS). However, the relationship between ccf DNA and the clinical parameters of patients with CS remains unclear. METHODS: The plasma of peripheral blood from 35 patients with CS and 32 age-matched controls was collected for ccf DNA analysis. Quantitative PCR was used to detect ccf n-DNA and ccf mt-DNA levels, and correlation analyses between ccf n-DNA and ccf mt-DNA levels were conducted. Receiver-operating characteristic (ROC) curves were used to analyze the sensitivity and specificity of ccf n-DNA and ccf mt-DNA levels to different characteristics. RESULTS: The plasma ccf mt-DNA levels of both ND1 and CYTC were significantly decreased in patients with CS compared with levels in controls both in total and by sex, whereas the plasma ccf n-DNA levels showed no significant difference. There is no difference in both ccf mt-DNA and ccf n-DNA between S-SDV and M-SDV according to The International Consortium for Vertebral Anomalies and Scoliosis (ICVAS) classification. The ROC curve analyses showed a reliable sensitivity and specificity of CS predicted by ccf mt-DNA levels in total but failed to distinguish different ICVAS types. CONCLUSION: Significantly decreased plasma ccf mt-DNA levels were observed in patients with CS compared with those in controls. Although this finding has limited significance for clinical practice, it indicates that ccf mt-DNA may predict the onset or development of CS. Further studies should focus on the role of ccf mt-DNA in embryo development and whether ccf mt-DNAs could be considered as a marker for prenatal screening in development disorder like CS.Level of Evidence: 4.

Dysregulated Bone Metabolism Is Related to High Expression of miR-151a-3p in Severe Adolescent Idiopathic Scoliosis.

Adolescent idiopathic scoliosis (AIS) is a common complex disease, and bone homeostasis plays an important role in its pathogenesis. Recent advances in epigenetic research show that dysregulated miRNAs may participate in the development of orthopedic diseases and AIS. The aim of this study was to detect differentially expressed miRNAs in severe AIS and elucidate the mechanism of miRNA deregulation in the pathogenesis of AIS. In the present study, miRNA expression profiles were detected in severe and mild AIS patients as well as healthy controls by miRNA sequencing. Candidate miRNAs were validated in a larger cohort. Primary osteoblasts from severe AIS patients were extracted and isolated to determine the effect of the candidate miRNAs on bone metabolism. Finally, we determined the methylation level in primary osteoblasts from severe AIS patients. The result showed that miR-151a-3p was overexpressed in severe AIS patients. Reduced GREM1 expression was observed in primary osteoblasts from severe AIS patients. miR-151a-3p directly inhibited GREM1 in primary osteoblasts. Relatively lower methylation levels were detected in primary osteoblasts from severe AIS patients. In conclusion, our study revealed that plasma miR-151a-3p levels may serve as a biomarker for severe AIS. Overexpression of miR-151a-3p may interrupt bone homeostasis via inhibiting GREM1 expression. Our result may provide a new biomarker for the early detection of AIS and increase our understanding of the pathogenesis of AIS.

Association between Bone Turnover Markers, Leptin, and Nutritional Status in Girls with Adolescent Idiopathic Scoliosis (AIS).

The link between scoliotic deformity and bone metabolism in adolescent idiopathic scoliosis (AIS) has not been well researched. Moreover, the data concerning the cross-talk between fat tissue content/hormonal activity and bone markers in this group of patients are lacking. The aim of the study was to assess whether there exists a significant relationship between the severity of AIS and bone turnover markers and leptin levels. The study group was consisted of 77 AIS girls, aged 14.7 ± 2.17 years. Scoliotic curve severity assessed by Cobb's angle was categorized as mild (10-19°), moderate (20-39°), or severe (≥40°). Corrected height, weight, and waist and hip circumferences were measured and body mass index (BMI), corrected height Z-score, BMI Z-score, and waist/height ratio (WHtR) were calculated for the entire group. Body composition parameters: fat mass (FAT), fat-free mass (FFM), and predicted muscle mass (PMM) were determined using a bioelectrical impedance analyzer. Bone turnover markers (osteocalcin (OC) and amino terminal of collagen cross-links (NTx) and leptin levels were assessed in serum. Multiple regression analysis showed that, OC, NTx (negatively with p < 0.05), and leptin (positively with p < 0.01) were significantly associated with curve severity in AIS girls. Moreover, Cobb's angle was positively correlated with W/HtR (p < 0.01) and FAT (p < 0.05). One-way analysis of variance (ANOVA) revealed significant differences in leptin (p < 0.05 vs. mild only), OC (p < 0.05 vs. mild and moderate), and W/HtR (p < 0.01 and p < 0.05 vs. mild and moderate, respectively) between the three AIS severity subgroups. OC was significantly lower in the severe AIS subgroup, while leptin and W/HtR were significantly higher. Significant correlations between leptin and anthropometrical parameters as BMI z-score and W/HtR were shown. Leptin level correlated also significantly with BMI z score (p < 0.001), W/HtR (p < 0.0001), and body composition parameters (p < 0.000001). Moreover, there was a significant negative correlation between NTx and leptin level (p < 0.05). Bone metabolism in AIS girls seems to be altered and significantly related to the scoliotic curve severity. Leptin may be a crucial link in the cross-talk between bone turnover and body composition in this group of patients. Further studies concerning interrelationship between nutritional status and bone metabolism in patients with AIS are warranted.

Chromium Metal Ion Release During Instrumented Spinal Surgery in Children: The Effects of Electrosurgery.

STUDY DESIGN: Prospective 2-year study with operative sampling and in-vitro analysis of chromium ions following spinal surgery in children. OBJECTIVES: To measure metal ion levels at preoperative, intraoperative, and postoperative times to determine patterns of metal ion release during instrumented spinal surgery. SUMMARY OF BACKGROUND DATA: Raised serum metal ion levels are reported following instrumented spinal fusion in adolescent idiopathic scoliosis. The authors noted raised chromium levels in patients receiving implants that did not contain chromium. This prompted further work to establish the source. The electrosurgery tips used were discovered to contain 17% chromium. METHODS: Chromium, cobalt, and titanium levels were measured before, during, and after surgery in serum and local intraoperative fluid samples in 11 children undergoing posterior instrumentation for scoliosis. Administered drugs, cell-saver fluids, and intraoperative fluids, both local and intravenous, were investigated to exclude these as sources of chromium ions. An in-vitro study was also performed to elucidate sources of intraoperative chromium ions. RESULTS: High chromium levels were detected in all samples from the wound irrigation fluid prior to insertion of metal implants. Immediate postoperative chromium serum ion levels were also elevated and returned to baseline by day 30. In-vitro sampling of fluids from test models using electrosurgery revealed high levels of chromium ions CONCLUSION.: This finding of high chromium metal ion concentrations in intraoperative and early postoperative samples provides evidence of chromium release during the dissection phase of spinal surgery. This challenges existing beliefs that metal ion release occurs solely due to implants and now implicates the electrosurgery electrode tips as a source of raised chromium ion levels. Thorough irrigation of the operative site after the dissection phase of surgery to both dilute and reduce the intraoperative chromium ion load is suggested. Alternative electrosurgery electrode tips or other methods to coagulate during surgery could be considered. LEVEL OF EVIDENCE: 2.

Prevalence of 25-OH-Vitamin D and Calcium Deficiency in Adolescent Idiopathic Scoliosis.

Several etiologies have been proposed as a basis and evolution theory for the development of adolescent idiopathic scoliosis, but limited data were published until now that link vitamin D and calcium deficiency to this condition. The present study aims to evaluate the relationship between 25-OH-Vitamin D, total calcium, and the following data: Cobb angle, age, and patient sex. The seasonal variation for vitamin D will also be taken into consideration. A total of 101 patients with a mean age of 11.61 ± 2.33 years had vitamin D and calcium levels tested. The mean Cobb angle was 26.21o ± 12.37. The level of vitamin D was, on average, 24 ng/mL ± 9.64. Calcium values were within the normal range, with an average of 9.82 mg/dL ± 0.42. The male group showed lower levels of vitamin D compared to the female group (19.6 vs. 25.45 ng/mL) (p = 0.02). Seasonal variations showed significant differences for vitamin D (p=.0001). Vitamin D level was positively correlated with the calcium level (p=0.01, r=0.973), but also with the patient's age (p <0.001, r=0.158). The Cobb angle was negatively correlated with serum vitamin D levels (p<0.01, r=-0.472). Patients included in this study had low vitamin D levels, significant differences being observed between boys and girls, boys being more affected. The positive correlation between vitamin D and calcium, together with the negative correlation with the Cobb angle, is yet another proof that patients with idiopathic scoliosis should be investigated regularly for these pathologies.

Estrogen Receptors (ESRs) Mutations in Adolescent Idiopathic Scoliosis: A Cross-Sectional Study.

BACKGROUND Adolescent idiopathic scoliosis (AIS) is the most common spinal deformity, but its etiology is unclear. Multiple genetic mutations have been reported to be associated with AIS. MATERIAL AND METHODS We enrolled a cohort of 113 surgically treated AIS patients with available parental subjects from the Peking Union Medical College Hospital. We performed whole-exome sequencing in 10 trio families and whole-genome sequencing in 103 singleton patients. Luciferase assay was used to detect the functional alterations of candidate ESR1 and ESR2 variants. RESULTS Using a de novo strategy, a missense variant in ESR1 (c.868A>G) was selected as a candidate gene for AIS. The main Cobb angle of this patient was 41° (T6-T10). Another potential pathogenic variant in ESR2 (c.236T>C) was identified. The main curve of the patient was 45° at T10-L3. The transactivation capacities of the mutated ESR1 and ESR2 protein were both significantly decreased (p=0.026 and 0.014, respectively). CONCLUSIONS Potential pathogenic variants in ESR1 and ESR2 were identified in 113 AIS patients, suggesting that genetic mutations in ESR1/2 were associated with the risk of AIS.

A comparative study of fibrinogen measurement using TEG® functional fibrinogen and Clauss in adolescents undergoing scoliosis surgery.

INTRODUCTION: Thromboelastography (TEG®) functional fibrinogen (FF) test is a point-of-care test for fibrinogen measurement and is preferred for its rapid turnaround time. This study was designed to compare TEG® functional fibrinogen level (FLEV) with classic Clauss fibrinogen in patients undergoing scoliosis surgery and to evaluate the concordance between the two methods. METHODS: Patients in this study were part of a larger study evaluating the effect of fibrinogen concentrate (FC) supplementation on perioperative blood loss in scoliosis surgery. Paired samples for TEG® FF and Clauss fibrinogen assays were taken from 40 patients at three different timepoints perioperatively. The agreement between FLEV and Clauss was assessed, and the possibility of using FLEV measurements to predict Clauss fibrinogen was explored. RESULTS: One hundred and seventeen paired samples from 39 patients were finally analyzed. Pearson correlation test confirmed positive linear correlations between FLEV and Clauss at all three timepoints (r = .70, .67, and .66 at baseline, before FC administration, and after FC administration, respectively; P < .001 for all) and together for all measures (r = .76, P < .001), while Bland-Altman plots showed FLEV significantly overestimated Clauss constantly. Optimum diagnostic values of FLEV at 4.27 and 3.77 g/L were generated to predict normal fibrinogen as Clauss ≥ 3.0 g/L (AUROC 0.941, 95% CI: 0.891-0.991) and critical intraoperative hypofibrinogenemia as Clauss ≤ 2.0g/L (AUROC 0.894, 95% CI: 0.838-0.950), respectively. CONCLUSIONS: In adolescents undergoing scoliosis surgery, FLEV correlated linearly with Clauss fibrinogen. Though FLEV overestimates Clauss constantly, FLEV values are able to predict hypofibrinogenemia and normal fibrinogen with both AUROC > 0.85.

Leptin in adolescent idiopathic scoliosis - A meta-analysis.

To compare the serum levels of leptin and soluble leptin receptor (sOB-R) with adolescent idiopathic scoliosis (AIS) girls and controls through meta-analysis. The MEDLINE via PubMed, Cochrane, Scopus, and EMBASE database, from the earliest available date of indexing between January 2010 and January 2019, were searched for comparative studies evaluating serum levels of leptin and sOB-R in AIS girls. Two authors performed the data extraction independently. Any discrepancies were resolved by a consensus. Six comparative studies were identified. There was no statistically significant difference in terms of leptin between AIS girls and control [p = 0.19, WMD = -2.06 (-5.14, 1.03) ng/mL]. However, the sOB-R level was significantly higher [p < 0.00001, WMD = 2.85 (1.81, 3.88) ng/mL] and the free leptin index was significantly lower [p = 0.0006, WMD = -0.12 (-0.19, -0.05)] in AIS girls than those of healthy control girls. The body mass index was significantly lower in AIS girls [p = 0.03, WMD = -1.53 (-2.95, -0.12) kg/m2]. The current meta-analysis showed that the level of sOB-R is higher in AIS patients than controls, while the concentration of leptin remains unchanged in AIS patients. Further well-designed studies would be necessary to substantiate our results.

Comparison of the Coagulation Profile of Adolescent Idiopathic Scoliosis Patients Undergoing Posterior Spinal Fusion With and Without Tranexamic Acid.

STUDY DESIGN: Prospective, observational cohort study. OBJECTIVE: To improve the understanding of coagulation and bleeding mechanisms during spinal deformity surgery. SUMMARY OF BACKGROUND DATA: Fibrinolysis is the mechanism of bleeding for adolescent idiopathic scoliosis undergoing posterior spinal fusion. Antifibrinolytics have become popular; however, literature to support their use remains mixed. The mechanism of action has not been demonstrated. METHODS: The coagulation profile of 88 adolescent idiopathic scoliosis patients undergoing posterior spinal fusion was analyzed. Standard coagulation laboratory investigations and thromboelastograms were drawn hourly through the case. Fifty-eight patients received no antifibrinolytic, whereas 30 patients received tranexamic acid by standardized protocol. The coagulation parameters, estimated blood loss, and transfusion requirements were compared in the two groups. RESULTS: The two cohorts had no differences in demographic or surgical characteristics. Mean age was 13.6 years, 83% were female, a mean of 11.1 levels were fused, and the mean duration of surgery was 209 minutes. The tranexamic acid cohort did not demonstrate a decrease in blood loss. The transfusion rate, however, dropped from 47% in the non-tranexamic acid cohort to 23% in the tranexamic acid cohort (p = .03). Standard coagulation parameters did not differ between the groups. Fibrinolysis was diminished in the tranexamic acid cohort as measured by a Fibrinolysis score (mean maximum value 2.0 without tranexamic acid vs. 0.7 with tranexamic acid, p < .0001) and the lysis percent at 30 minutes by thromboelastogram (elevated to 3.9% without tranexamic acid vs. 1.2% with tranexamic acid at the 3-hour mark, p = .05). CONCLUSIONS: This study provides confirmation of antifibrinolytic activity during posterior spinal fusion for adolescent idiopathic scoliosis. The presented data of fibrinolysis are proposed as standard measurements for future work on controlling blood loss during scoliosis surgery. LEVEL OF EVIDENCE: Level 2, prospective comparative study.

Changes in circulating cell-free nuclear DNA and mitochondrial DNA of patients with adolescent idiopathic scoliosis.

BACKGROUND: Adolescent idiopathic scoliosis (AIS) which characterized by complex three-dimensional deformity of spine has been difficult to cure because of the unknown etiopathology and uncertainty of progression. Nowadays, circulating cell-free (ccf) DNA was found to be a potential biomarker for several benign and malignant diseases. However, whether ccf DNA can be a biomarker for AIS has not been reported yet. In this study, we investigate the circulating cell-free nuclear DNA (ccf n-DNA) and mitochondrial DNA (ccf mt-DNA) concentrations in the plasma of patients with AIS and controls (CT), and the changed plasma ccf n-DNA and ccf mt-DNA levels and their association with clinical parameters were assessed. METHODS: The plasma of peripheral blood from 69 AIS patients and 21 age-matched CT was collected for ccf DNA analysis. Quantitative PCR was used to detect ccf n-DNA and ccf mt-DNA levels, and correlation analyses between the ccf n-DNA and ccf mt-DNA levels and clinical characteristics were conducted. Receiver operator curves (ROC) were used to analyze the sensitivity and specificity of ccf n-DNA and ccf mt-DNA levels to different characteristics. RESULTS: The plasma ccf n-DNA levels of both GAPDH and ACTB were significantly decreased in AIS patients compared with those in controls, while the plasma ccf mt-DNA levels did not changed. According to sex-related analyses, the ccf n-DNA levels in male CT-M was higher than that in female CT and male AIS, but the ccf n-DNA levels in female AIS was not significantly changed when compared with male AIS or female CT. However, the concentration of ccf mt-DNA in female AIS increased significantly when compared with male AIS. Surprisingly, Lenke type-related analyses suggested that Lenke type 1 patients had lower ccf n-DNA levels, whereas Lenke type 5 patients had higher ccf mt-DNA levels compared with those of controls. However, a lower sensitivity and specificity of AIS predicted by ccf n-DNA or ccf mt-DNA levels was observed, whether in total, by sex, or by Lenke type. CONCLUSION: Although with no/little predictive accuracy of AIS/progressed AIS by ccf DNA levels, significantly changed plasma ccf DNA levels were observed in AIS patients compared with those in controls.

Abnormal lacuno-canalicular network and negative correlation between serum osteocalcin and Cobb angle indicate abnormal osteocyte function in adolescent idiopathic scoliosis.

Adolescent idiopathic scoliosis (AIS) is a prevalent spinal deformity occurring during peripubertal growth period that affects 1-4% of adolescents globally without clear etiopathogenetic mechanism. Low bone mineral density is an independent and significant prognostic factor for curve progression. Currently, the cause underlying low bone mass in AIS remains elusive. Osteocytes play an important role in bone metabolism and mineral homeostasis, but its role in AIS has not been studied. In the present study, iliac bone tissues were harvested from 21 patients with AIS (mean age of 14.3 ± 2.20 yr old) with a mean Cobb angle of 55.6 ± 10.61° and 13 non-AIS controls (mean age of 16.5 ± 4.79 yr old) intraoperatively. Acid-etched scanning electron microscopy (SEM) images of AIS demonstrated abnormal osteocytes that were more rounded and cobblestone-like in shape and were aligned in irregular clusters with shorter and disorganized canaliculi. Further quantitative analysis with FITC-Imaris technique showed a significant reduction in the canalicular number and length as well as an increase in lacunar volume and area in AIS. SEM with energy-dispersive X-ray spectroscopy analysis demonstrated a lower calcium-to-phosphorus ratio at the perilacunar/canalicular region. Moreover, microindentaion results revealed lower values of Vickers hardness and elastic modulus in AIS when compared with controls. In addition, in the parallel study of 99 AIS (27 with severe Cobb angle of 65.8 ± 14.1° and 72 with mild Cobb angle of 26.6 ± 9.1°) with different curve severity, the serum osteocalcin level was found to be significantly and negatively associated with the Cobb angle. In summary, the findings in this series of studies demonstrated the potential link of abnormal osteocyte lacuno-canalicular network structure and function to the observed abnormal bone mineralization in AIS, which may shed light on etiopathogenesis of AIS.-Chen, H., Zhang, J., Wang, Y., Cheuk, K.-Y., Hung, A. L. H., Lam, T.-P., Qiu, Y., Feng, J. Q., Lee, W. Y. W., Cheng, J. C. Y. Abnormal lacuno-canalicular network and negative correlation between serum osteocalcin and Cobb angle indicate abnormal osteocyte function in adolescent idiopathic scoliosis.

Coagulative function assessed preoperatively via the clot formation and lysis assay as a prognostic factor for blood loss in adolescents undergoing posterior spinal fusion for idiopathic scoliosis.

BACKGROUND: Posterior spinal fusion for adolescent idiopathic scoliosis is a complex surgery often associated with clinically significant blood loss leading to perioperative blood transfusion. Knowledge of risk factors for blood loss and transfusion stems mostly from retrospective studies. AIM: We sought to prospectively investigate putative prognostic factors for intraoperative blood loss and perioperative blood transfusion in adolescent idiopathic scoliosis patients undergoing posterior spine fusion, including clinical characteristics, surgical factors, and preoperative assessment of overall coagulative and fibrinolytic functions in plasma using the clot formation and lysis (CloFAL) assay. METHODS: Following Internal Review Board approval, adolescents 10 to <21 years old with idiopathic scoliosis undergoing posterior spine fusion were enrolled preoperatively in a single-institutional prospective cohort and biobanking study. Clinical data were collected on patient characteristics, surgical approach, perioperative management, intraoperative estimated blood loss, and blood transfusion through hospital discharge. Coagulative and fibrinolytic functions in plasma were measured on preoperative samples by CloFAL assay (Coagulation Index and modified Fibrinolytic Index). Univariate linear regression and multivariable linear regression were performed to identify predictors of weight-indexed intraoperative estimated blood loss EBL (EBL/kg). RESULTS: The final study population included 74 patients. Median age was 14.8 years (SD = 2.2). After adjustment for other putative prognostic factors via multivariable linear regression, coagulative function as determined preoperatively by CloFAL Coagulation Index was an independent predictor of intraoperative (EBL)/kg. Specifically, each 10% increase in CloFAL CI was associated with 3% decrease in the geometric mean of EBL/kg (OR 0.97, 95%CI 0.94-0.99, P = .01). CONCLUSION: In adolescents undergoing posterior spinal fusion for idiopathic scoliosis, increased coagulative function measured preoperatively using the CloFAL assay is independently associated with decreased intraoperative blood loss. Future studies should expand upon these investigations of plasma coagulative and fibrinolytic capacities in combination with clinical factors, to guide precise preventive strategies against blood loss and blood transfusion in this patient population.

Predictors for blood loss in pediatric patients younger than 10 years old undergoing primary posterior hemivertebra resection: a retrospective study.

BACKGROUND: Blood loss during hemivertebra resection may be substantial. Few studies have examined the risk factors of blood loss undergoing hemivertebra resection, especially those in patients under 10 years old. METHODS: Patients under 10 years old diagnosed with congenital scoliosis and hemivertebra were retrospectively included from January 2014 to October 2017. They all had primary posterior hemivertebra resection at Peking Union Medical College Hospital. Perioperative information was collected and multivariable linear logistic regression was performed to determine the independent risk factors of blood loss. RESULTS: One hundred three patients were included. The mean total blood loss was 346 + 178 ml. The percentage of total blood loss to the EBV was 27.0 + 13.3%. Multivariable linear logistic regression indicated that preoperative total Cobb angle (P = 0.046) and the number of fused levels (P < 0.001) were independent risk factors of total blood loss. Preoperative platelet count and preoperative coagulation function were not associated with blood loss in patients undergoing hemivertebra resection. CONCLUSIONS: Preoperative total Cobb angle and the number of fused levels determined the blood loss for patients undergoing hemivertebra resection.

Hemoglobin Levels Pre- and Posttreatment as a Surrogate for Disease Severity in Early-Onset Scoliosis.

STUDY DESIGN: Prospective cohort. OBJECTIVE: To compare preoperative hemoglobin levels to postoperative hemoglobin levels in patients with early-onset scoliosis (EOS). SUMMARY OF BACKGROUND DATA: Elevated hemoglobin (Hgb) may be a marker for preoperative hypoxia in patients with EOS and thoracic insufficiency syndrome (TIS). The changes in Hgb level after treatment may be a surrogate marker for improved oxygenation. METHODS: Because normal levels of Hgb vary with patient age, Hgb z scores were calculated by dividing age-adjusted mean Hgb levels by the age-adjusted standard deviation. Elevated Hgb was defined by a hemoglobin z score >1. Patients with a baseline Hgb value measured before initial implantation with at least one follow-up measurement, at 6, 12, or 18 months, were included in longitudinal analysis. Change in Hgb z score as well as change in curve magnitude over time was assessed using piecewise linear mixed modeling for patients with elevated Hgb and those without. RESULTS: Two hundred sixty-seven patients with EOS were treated surgically over the study period. Average age at initial implantation was 6.8 years. Forty-eight (18%; 95% confidence interval = 13.7%, 23.2%) subjects had an elevated Hgb (z score > 1) level before implantation procedure. Hgb levels decreased in subjects with elevated Hgb from implantation to 6 months (p < .001) with no change in Hgb from 6 to 12 months (p = .46) or from 12 to 18 months (p = .59), but an overall decrease from preoperative to 18 months (p < .001). There was no change in Hgb levels for subjects without elevated Hgb from implantation to 6 months (p = .94), from 6 to 12 months (p = .61), or from 12 to 18 months (p = .78). CONCLUSIONS: In some patients with EOS and TIS, there appears to be significant positive impact on oxygenation from distraction instrumentation as evidenced by a meaningful proxy measurement: improvement in abnormal preoperative Hgb levels after surgery. LEVEL OF EVIDENCE: III.

Differential proteome analysis in adolescent idiopathic scoliosis patients with thoracolumbar/lumbar curvatures.

BACKGROUND: Although the pathogenesis of adolescent idiopathic scoliosis (AIS) remains unclear, there are little evidences of the pathogenesis in patients with thoracolumbar/lumbar AIS. The purpose of this study was to identify proteins or proteomes that may be causally related to the pathogenesis of AIS with structured thoracolumbar/lumbar curvature using two-dimensional fluorescence difference gel electrophoresis (2D-DIGE). METHODS: A total of 20 control volunteers and 61 AIS in patients with thoracolumbar/lumbar curvature were included. First, the plasma samples of each five AIS with pure thoracolumbar/lumbar curvature and control samples were subjected to 2D-DIGE analysis. Protein spots that were expressed differently by the AIS and control groups were selected and identified by nanoscale liquid chromatography-tandem mass spectrometry (nanoLC-MS/MS) analysis. To characterize the differently-expressed proteins in AIS patients, we performed functional pathway analysis using the Protein ANalysis THrough Evolutionary Relationships (PANTHER) system. Additionally, the proteins were compared between control and AIS using western blotting. Lastly, prospectively collected 15 control and 41 AIS with thoracolumbar/lumbar curvature samples were compared to the differentially expressed proteins. RESULTS: A total of 3862 ± 137 spots were detected, of which 11 spots met the criteria when compared with controls. Nine proteins were identified by nanoLC-MS/MS. Functional analysis showed the association of the proteins in AIS patients with blood coagulation using the PANTHER system. Of the proteins, vitamin D binding protein (DBP) significantly correlated with Cobb angle in thoracolumbar/lumbar curvatures. DBP expression of the prospectively collected AIS samples were significantly higher than those of controls (P < 0.05). CONCLUSIONS: This study suggests that DBP and several coagulation-related proteins may play a role in the pathogenesis of AIS. DBP appears to be a marker of severity of AIS with thoracolumbar/lumbar curvature.