Peripheral blood T-cell receptor repertoire as a predictor of clinical outcomes in gastrointestinal cancer patients treated with PD-1 inhibitor

BACKGROUND

Identifying valid biomarkers for patient selection impressively promotes the success of anti-PD-1 therapy. However, the unmet need for biomarkers in gastrointestinal (GI) cancers remains significant. We aimed to explore the predictive value of the circulating T-cell receptor (TCR) repertoire for clinical outcomes in GI cancers who received anti-PD-1 therapy.

METHODS

137 pre- and 79 post-treated peripheral blood samples were included. The TCR repertoire was evaluated by sequencing of complementarity-determining region 3 (CDR3) in the TRB gene. The Shannon index was used to measure the diversity of the TCR repertoire, and Morisita's overlap index was used to determine TCR repertoire similarities between pre- and post-treated samples.

RESULTS

Among all enrolled patients, 76 received anti-PD-1 monotherapy and 61 received anti-PD-1 combination therapy. In the anti-PD-1 monotherapy cohort, patients with higher baseline TCR diversity exhibited a significantly higher disease control rate (77.8% vs. 47.2%; hazard ratio [HR] 3.92; 95% confidence interval [CI] 1.14-13.48; P = 0.030) and a longer progression-free survival (PFS) (median: 6.47 months vs. 2.77 months; HR 2.10; 95% CI 1.16-3.79; P = 0.014) and overall survival (OS) (median: NA vs. 8.97 months; HR 3.53; 95% CI 1.49-8.38; P = 0.004) than those with lower diversity. Moreover, patients with a higher TCR repertoire similarity still showed a superior PFS (4.43 months vs. 1.84 months; HR 13.98; 95% CI 4.37-44.68; P < 0.001) and OS (13.40 months vs. 6.12 months; HR 2.93; 95% CI 1.22-7.03; P = 0.016) even in the cohort with lower baseline diversity. However, neither biomarker showed predictive value in the anti-PD-1 combination therapy cohort. Interestingly, the combination of TCR diversity and PD-L1 expression can facilitate patient stratification in a pooled cohort.

CONCLUSION

The circulating TCR repertoire can serve as a predictor of clinical outcomes in anti-PD-1 therapy in GI cancers.

Effect of substituting wet corn gluten feed and corn stover for alfalfa hay in total mixed ration silage on lactation performance in dairy cows

Wet corn gluten feed (WCGF) is a high moisture feed containing rapidly digestible, non-forage fiber and protein. The objective of this study was to investigate the effect of substituting WCGF and corn stover for alfalfa hay in total mixed ration (TMR) silage on lactation performance and nitrogen balance in dairy cows. Nine multiparous Holstein dairy cows (BW = 532 ± 28.9 kg and day in milk = 136 ± 5.6 d; mean ± SD) were used in a replicated 3 × 3 Latin square design with 21-d periods (14 d of diet adaption and 7 d of sample collection). Groups were balanced for parity, day in milk, and milk production and consumed one of three treatment diets during each period. The treatment diets were fed as TMR and contained similar concentrate mixtures and corn silage but different proportions of roughage and WCGF. The three treatments were: (1) 0% WCGF, 0% corn stover, and 22.1% alfalfa hay (0% WCGF); (2) 6.9% WCGF, 3.4% corn stover, and 11.8% alfalfa hay (7% WCGF); and (3) 13.3% WCGF, 4.9% corn stover, and 3.9% alfalfa hay (13.3% WCGF). Compared to the 0% WCGF diet, the cows fed the 7% and 13.3% WCGF diets had a higher milk yield and concentration of milk fat, protein, lactose, and total solids. Effective degradability of DM was higher in the cows fed the 7% and 13.3% WCGF diets than it was with the 0% WCGF diet. Cows fed the 13.3% WCGF had a higher CP effective degradability and a lower rumen undegraded protein than cows fed the 0% WCGF diet. The concentration of ruminal volatile fatty acids and ammonia-N was higher in cows fed the 7% and 13.3% WCGF diets than cows fed the 0% WCGF diet. The fecal N was lower in cows fed the 7% and 13.3% WCGF diets than it was in cows fed the 0% WCGF diet. Milk N secretion and milk N as a percent of N intake were higher in cows fed the 13.3% WCGF diet than cows fed the 0% and 7% WCGF diets. In conclusion, it appears that feeding a TMR silage containing WCGF and corn stover in combination, replacing a portion of alfalfa hay, may improve lactation performance and nitrogen utilization for lactating dairy cows.

Plasma metabolic differences in cows affected by inactive ovaries or normal ovarian function post partum

Anestrus is essential to an unsuccessful pregnancy in dairy cows. One of the many factors that influences anestrus is the inactive ovary. To characterize in detail the plasma metabolic pro- file, anestrus cows suffering from inactive ovaries were compared with those with natural estrus. The Holstein cows 60 to 90 day postpartum in an intensive dairy farm were assigned into inactive ovaries groups (IO, n=20) and natural estrus group (CON, n=22) according to estrus signs and rectal palpation of ovaries. Plasma samples from two groups of cows were collected from the tail vein to screen differential metabolites using gas chromatography/mass spectrometry (GC/MS) techniques and multivariate statistical analysis and pathways. The results showed that 106 compounds were screened by GC/MS and 14 compounds in the IO group were decreased by analyzing important variables in the projection values and p values of MSA.Through pathway analysis, 14 compounds, mainly associated with carbohydrate metabolism and amino acid meta- bolism, were identified to results in IO, which may seriously affect follicular growth. Metabolo- mics profiling, together with MSA and pathway analysis, showed that follicular growth and development in dairy cows is related to carbohydrate and amino acid metabolism by a single or multiple pathway(s).

Value added immunoregulatory polysaccharides of Hericium erinaceus and their effect on the gut microbiota

Hericium erinaceus polysaccharides (HEPs) were isolated from the fruiting bodies of H. erinaceus with 53.36 % total carbohydrates and 32.56 % uronic acid. To examine whether HEPs can alter the diversity and the abundance of gut microbiota, adult mice and middle-aged and old mice were fed with HEPs for 28 days. Based on the result of 16S sequencing of gut microbiota it was found that the relative abundances of Lachnospiraceae and Akkermansiaceae significantly increased, while the relative abundance of Rikenellaceae and Bacteroidaceae appeared to decrease. Bacterial solutions from different murine intestinal segments and feces were collected to ferment HEPs in vitro. It was found that HEPs remarkably promoted the production of NO, IL-6, IL-10, INF-γ and TNF-α. Moreover, HEPs significantly increased phosphorylation of signaling molecules, indicating that the immunomodulatory activity was completed via NF-кB, MAPK and PI3K/Akt pathways. Collectively, HEPs have potential to be developed as functional ingredients or foods to promote health.

Subclinical ketosis risk prediction in dairy cows based on prepartum metabolic indices

ABSTRACT Ketosis can seriously impair cow performance. This study detected changes in prepartum blood metabolic parameters for predicting postpartum ketosis occurrence in dairy cows. Body condition score (BCS) was assessed before and after delivery. Blood samples of 63 cows were collected from 10 days before calving to 10 days after calving to measure metabolic parameters including β-hydroxybutyric acid (BHBA), non-esterified fatty acid (NEFA), glucose (GLU), total bilirubin (TBIL), direct bilirubin (DBIL), indirect bilirubin (IBIL), total protein (TP), albumin (ALB), globulin (GLO), alanine aminotransferase (ALT), and aspartate aminotransferase (AST). There was a postpartum subclinical ketosis incidence of 42.25%. Compared with prepartum, plasma, levels of BHBA, AST, and NEFA significantly increased postpartum, and prepartum AST (R=0.57) and NEFA (R=0.45) showed a significant positive correlation with ketosis postpartum. Plasma GLU level significantly decreased postpartum and was significantly negatively correlated with ketosis (R=-0.21). Receiver operating characteristic curve analysis revealed prepartum BSC < 2.88, and prepartum plasma AST > 68.0 U/L, GLU < 3.97mmol/L, NEFA > 0.27mmol/L, and BHBA > 0.43mmol/L, indicating a high risk of subclinical ketosis postpartum. These levels can be used as risk indicators to predict the occurrence of subclinical ketosis in postpartum cows.

Effects of blood pathological changes before TAI on pregnancy of dairy cows with anestrus and estrus

ABSTRACT The objective of this study was to investigate the influence of plasma pathological changes before timed artificial insemination (TAI) on pregnancy of cows. The contents of estrogen (E2), progesterone (P4), glucose (Glu), selenium (Se), brain-derived neurotrophic factor (BDNF), and histamine (HIS) in plasma of 48 Holstein cows were measured before TAI. According to the estrus detection, the cows were divided into estrus (E) and anestrus (A) groups. After pregnancy testing at 28 d after TAI, two groups of E and A were divided into positive pregnancy of E group (EP+), negative pregnancy of E group (EP-), positive pregnancy of A group (AP+), and negative pregnancy of A group (AP-). The contents of E2, P4, Glu, Se, BDNF and hIS significantly differed among the four groups (P<0.01). The ROC analysis was used to determine the risk of negative pregnancy test (-) after TAI was increased when plasma E2 was less than 46.45 pmol/L in cows before TAI. The changes in E2, P4,hIS, Glu, and BDNF in the blood of natural estrus and natural anestrus cows affected the pregnancy after TAI. the level of E2 in plasma may be used to assess the risk of negative pregnancy after TAI.

Chlorogenic acid ameliorates obesity by preventing energy balance shift in high-fat diet induced obese mice

BACKGROUND

Chlorogenic acid is a type of phenolic acid found in many plants. Chlorogenic acid has an anti-obesity effect with an unclear mechanism. The present study aimed to investigate the regulatory effect of chlorogenic acid on energy balance in high-fat diet (HFD) induced obese C57BL/6J mice administrated 100 mg kg^-1 chlorogenic acid for 13 weeks.

RESULTS

The consumption of chlorogenic acid ameliorated HFD induced obesity. Chlorogenic acid did not change the physical activity but significantly decreased food intake and increased body temperature, thermal dissipation and brown adipose tissue activity. Moreover, chlorogenic acid improved glucose tolerance but had a moderate impact on other blood indices. Additionally, chlorogenic acid failed to restore the microbiota change associated with HFD induced obesity, but modified the gut bacterial composition in a unique way.

CONCLUSION

Supplementation with chlorogenic acid can improve HFD induced obesity and associated glucose intolerance mainly via regulating food intake and energy expenditure. © 2020 Society of Chemical Industry.

Lactobacillus paracasei ameliorates cognitive impairment in high-fat induced obese mice via insulin signaling and neuroinflammation pathways

Long-term consumption of a high-fat diet (HFD) can cause glucose and lipid metabolism disorders, damage the brain and nervous system and result in cognitive impairment.

On-Site Fluorination for Enhancing Utilization of Lithium in a Lithium-Sulfur Full Battery

The rechargeability of the lithium anode in lithium-sulfur (Li-S) batteries is an issue for this type of battery. In this work, we demonstrate a Li-S full battery comprising a protected anode scaffold and a Li₂S cathode. The stabilized performance is attained by an on-site fluorination strategy, using BiF₃ for the interfacial coating of the anode. Unlike previously reported LiF protective coating derived from the vapor/solution depositions, BiF₃ nanocrystals would be lithiated on-site to the anode surface and server as the protective layer. The chemically inertial Li₃Bi alloy can provide additional ion-conductive paths and stitch the LiF to form a seamless protective layer, thereby suppressing the dendrite propagation and parasitic reactions effectively. With the designed anode structures and compositions, the high-loading full battery (8.05 mg cm^-2) can achieve an exceptional utilization of both sulfur (898 mAh g_S^-1) and lithium (1533 mAh g_Li^-1) over 200 cycles, marking a step toward cyclable Li metal batteries at a high capacity.

[Identification of a novel mutation of SOX10 gene and analysis of the phenotype]

Objective: To explore the clinical features and pathogenic mechanisms of a special syndrome with congenital sensorineural hearing loss, albinism, heterochromia iridis, nystagmus and myelin dysplasia. Methods: Detailed medical history, systematic audiology tests, ophthalmic and neurological examinations were carried out to analyze the clinical features of the child, and further molecular genetic tests including chromosome karyotype analysis, and deafness gene screening were conducted. Results: A new de novo heterozygous mutation (c.336G>T/p.Met112Ile) was detected in the child, while both his parents were demonstrated to be wild-type and symptom free. The analysis of clinical features indicated the diagnosis of PCW syndrome. Conclusion: This study identified a new mutation of SOX10 gene, which enriched the mutation spectrum of this gene. And the analysis of clinical characteristics of this patient also expanded the phenotype of this gene. This study provided a reference for clinical diagnosis and genetic diagnosis of PCW syndrome.

Outcomes associated with modern treatment paradigms in connective tissue disease (CTD)-associated pulmonary arterial hypertension (PAH): a meta-analysis of randomized controlled trials (RCTs)

Background

CTD-PAH has historically represented a PAH subtype with poor prognosis. New therapies, as well as combination therapy approaches targeting multiple pathways have been approved for PAH based on RCTs. CTD-PAH patients comprise a subgroup of the RCT populations and efficacy analyses are based on subgroup analyses which can be less reliable than the overall analysis. We conducted a meta-analysis of RCTs of approved PAH therapies to evaluate outcomes of patients with CTD-PAH.

Purpose

To use meta-analysis to determine response to treatment in patients with CTD-PAH.

Methods

The PubMed and EMBASE databases were searched for English-only articles published between January 1, 2000 and November 25, 2019. Inclusion criteria were multicenter RCTs that enrolled adults with WHO group 1 pulmonary hypertension (PAH); enrollment in 2000 or later; long-term clinical morbidity and/or mortality event or 6-minute walk distance (6MWD) as an efficacy endpoint reported for ≥30 patients with CTD-PAH; and evaluation of a US Food and Drug Administration-approved PAH therapy. The primary outcomes were treatment effect as measured by the study time to first morbidity or morality event and change in 6MWD from baseline to between 3–6 months, per the data provided in each article. Results from individual studies were combined using a random-effects model for overall study population (PAH patients) and the subgroup of CTD-PAH patients.

Results

Ten RCTs (N=4329 PAH patients; n=1263 (29%) with CTD-PAH) met inclusion criteria and were included in the meta-analysis. At baseline, PAH patients had a mean age of 50 years, approximately 78% were female, and approximately 58% had functional class III or IV disease. These characteristics were balanced between treatment and control groups. Baseline 6MWD was 356 m for the overall population and 337 m for patients with CTD-PAH. Five RCTs (N=3172; n=941 with CTD-PAH [30%]) reported hazard ratios (HRs) for time to a morbidity or mortality event by drug treatment and PAH etiology: overall population HR=0.63 (95% confidence interval [CI], 0.56–0.72; P&lt;0.001); CTD-PAH population HR=0.64 (95% CI, 0.51–0.80; P&lt;0.001) (Figure). Nine RCTs reported mean change with drug treatment from baseline to 3 to 6 months in 6MWD for PAH and CTD patients: 33.9 m (95% CI, 21.9–45.9; P&lt;0.001) in the overall population; 20.2 m (95% CI, 10.8–29.7; P&lt;0.001) in CTD-PAH patients.

Conclusions

The improvement in 6MWD in patients with CTD-PAH is smaller than in those with other types of PAH, perhaps reflecting comorbidities and CTD-induced mobility constraints, independent of their cardiopulmonary capacity. Data from long term clinical morbidity/mortality endpoint studies in this large group of patients with CTD-PAH demonstrate that these patients derive significant benefit from currently available PAH therapies which, in many patients, comprised the addition of a drug targeting a second or third pathway involved in the pathophysiology of PAH.

Treatment effect on morbidity/mortality

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Actelion Pharmaceuticals US, Inc.

Characteristics and clinical course of the first 500 patients (pts) from SPHERE (SelexiPag: tHe usErs dRug rEgistry) receiving selexipag in real-world clinical practice

Background

SPHERE is a US, multicentre, prospective registry collecting real-world data from pts with pulmonary arterial hypertension (PAH) treated with selexipag, a selective oral IP prostacyclin receptor agonist.

Methods

SPHERE (planned N=800) included newly initiated (NI, receiving selexipag ≤60 days) and previously initiated (PI) pts. We describe disease characteristics, selexipag dose and clinical course of the first 500 pts and risk assessment based on REVEAL 2.0 risk calculator and COMPERA risk assessment strategy.

Results

Disease characteristics at initiation were: 75.0% female, median age 61.0 years, idiopathic etiology (49.2%) or associated with connective tissue disease (26.4%). Pts were mostly WHO functional class (FC) II (31.0%) or III (49.6%) (unknown for 9.2%). Median time from PAH diagnosis to selexipag initiation was 3.4 years. Of the first 500 pts enrolled, 138 (28%) were NI and 362 (72%) were PI; characteristics were consistent between NI and PI.

Risk classification at initiation differed depending on method used: with REVEAL 2.0, low/intermediate/high risk were 41.8%/29.6%/28.6% (38.4%/26.1%/35.5% for NI and 43.1%/30.9%/26.0% for PI, respectively) and with COMPERA were 22.0%/67.2%/9.6% (13.8%/73.2%/10.9% for NI and 25.1%/64.9%/9.1% for PI), respectively. Note, missing variables in real-world registry data may affect risk assessment.

In both cohorts, median individualised maintenance dose was 1200 μg twice daily (NI 1000 μg, PI 1200 μg); median time to individualised maintenance dose was 8.1 weeks. Median treatment duration was 21.7 months (17.7 months NI, 25.8 months PI). Overall, 32.4% of pts discontinued selexipag (46.4% NI, 27.1% PI), most commonly (22.8%) for adverse events (AEs) (34.8% NI, 18.2% PI). Of note, disease progression is classified as an AE. No selexipag-related deaths were reported.

At 18 months, WHO FC improved/remained stable in the majority of pts (205/235, 87%; improved, 24%; stable, 63%), but worsened in 12.8% of pts. At 18 months, the majority of pts had improved/stable risk by REVEAL 2.0 (265/334, 79% [improved, 22%; stable, 57%]) and by COMPERA (255/316, 81% [improved, 23%; stable, 58%]). This was consistent for NI and PI.

For both risk assessment tools higher risk was associated with increased risk of death. With REVEAL 2.0, risk of death was 2.9 and 9.3 times higher for intermediate and high risk, respectively vs low risk. Similarly with COMPERA, risk of death was 3.2 and 11.4 times higher in intermediate and high risk, respectively vs low risk.

Conclusions

Of the first 500 pts in SPHERE, the vast majority were prevalent PAH cases in FC II or III. Around one-quarter of pts had improved FC and/or risk; the majority of pts remained stable risk. Higher risk was associated with increased mortality risk. Over 50% of pts completed 18 months of selexipag. Discontinuations were most commonly for AEs and/or PAH progression.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Actelion Pharmaceuticals US, Inc.

CXCR7 in cardiomyocytes prevents cardiac dysfunction after myocardial infarction

Background

Beta blockers and angiotensin II receptor blockers take effect through G protein-coupled receptors (GPCRs) and their protective roles in heart failure are partially attributable to beta-arrestin biased agonism. CXCR7, a chemokine receptor, is beta-arrestin biased receptor and one of the most expressing GPCRs in the heart. CXCL12 is a common ligand of CXCR4 and CXCR7 and is known to ameliorate myocardial infarction (MI), reportedly through CXCR4 dependent mechanisms. However, the role of another receptor, CXCR7 and its downstream target including beta-arrestin is not fully elucidated in MI.

Purpose

The aim of this study is to uncover the role of CXCR7 in cardiomyocytes after MI.

Methods

First, we quantified CXCR7 mRNA expressions in neonate rat cardiomyocytes (NRCM) in a dish by qRT-PCR. NRCMs were treated with CXCR7 agonist: TC14012 and phosphorylation of extracellular signal regulated kinase (ERK) was measured as readout of the downstream of CXCR7, with immunoblotting. Second, MI was induced by left anterior descending artery (LAD) ligation in male 12-week-old mice. We explored spatial expressions of CXCR7 by qRT-PCR in infarct, peri-infarct and remote zones of wild-type MI mice. Finally, we developed cardiomyocyte-specific CXCR7 knockout mice (cKO) by the Cre/loxP system and analyzed CXCR7 expression in cKO by qRT-PCR. LAD ligation was also performed in cKO and littermate controls (Ctl). Heart weight (HW) was measured and systolic function was examined by echocardiography 4 weeks after ligation. Phosphorylated ERK was evaluated with immunoblotting one-day after ligation.

Results

First, we found that CXCR7 expression was significantly higher in NRCM than neonatal rat fibroblasts (NRFB) and ERK was phosphorylated by CXCR7 stimulation in NRCM. Second, CXCR7 expression was higher in infarct and peri-infarct zones than remote zones. Finally, cardiomyocyte-specific knockout of CXCR7 resulted in 78±21% reduction of CXCR7 expression in the whole heart. HW and left ventricular area was significantly greater (HW: Ctl 190.7±18.4, cKO 220.3±26.4 mg) and fractional area change of left ventricle was significantly lower in cKO than those in Ctl 4 weeks after MI (LV FAC: Ctl 20.6±4.9%, cKO 13.9±5.4%), indicating that loss of CXCR7 in cardiomyocytes caused left ventricle enlargement and systolic dysfunction. One day after MI of Ctl heart, ERK was more phosphorylated in peri-infarct zone than remote zone. However, this ERK phosphorylation in peri-infarct zone was reduced in cKO MI heart.

Conclusion

We revealed that CXCR7 is expressed in cardiomyocytes and deletion of this chemokine receptor in cardiomyocytes resulted in ventricle enlargement and systolic dysfunction possibly through ERK phosphorylation in peri-infarct zone. Therefore, CXCR7 in cardiomyocytes could prevent cardiac dysfunction after myocardial infarction, which may be another pathway of CXCL12 dependent-protective effect.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): JSPS KAKENHI

Impact of macrophage infiltration in patients with st-segment elevation myocardial infarction caused by plaque erosion: an in vivo optical coherence tomography study

Background

Chronic inflammatory infiltration is a common process for atherosclerosis development. However, autopsy studies reveal that incidence rate of inflammatory infiltrates are less abundant in plaque erosion compared with plaque rupture.

Purpose

Studies performed by optical coherence tomography (OCT) have allowed to establish the severity of plaque inflammation by assessing macrophage infiltration (MØI). In this study, we aimed at assessing the impaction of MØI in plaque erosion among patients with STEMI by using OCT.

Methods

A total of 1561 patients with ST-segment elevation myocardial infarctions (STEMI) who underwent OCT imaging were enrolled in this study. According to the exclusion criteria, 312 patients with STEMI exhibiting plaque erosion were classified as MØI or no MØI.

Results

163 (52.2%) patients had MØI at the site of plaque erosion, whereas 149 (47.8%) patients had no evidence of MØI and patients of MØI group were significantly older (P=0.015). The result of angiography showed the prevalence of multi-vessel disease appeared more frequency (P=0.021) and diameter stenosis% were higher (P=0.031) in MØI group. OCT results showed the minimum fibrous-cap thickness was thinner (P&lt;0.001) and the maximum lipid arc was larger (P=0.005) in MØI group. Some patients underwent imaging follow-up at 1 year. There was no significant difference in the culprit plaque morphology progress among two groups (Figure 1A-1D).

Conclusions

This study demonstrated that plaque inflammation can increase culprit lesion severity and plaque vulnerability in patients with STEMI caused by plaque erosion.

Figure 1

Funding Acknowledgement

Type of funding source: None

In vitro probiotic screening and evaluation of space-induced mutant Lactobacillus plantarum

Space mutation is an efficient tool in microbial breeding. The aim of the present study was to screen out space-induced mutants of Lactobacillus plantarum with potent probiotic properties. The wild-type Lactobacillus plantarum GS18 was subjected to 31 days and 18.5 hr of space flight, in which 13 isolates were selected for analysis. These mutants were assayed for milk fermentation performance, low pH resistance, bile salt tolerance, hydrophobicity, and antimicrobial activity. The 16S rDNA sequencing was applied to identify the stain and compare it with the wild type. Results showed that the isolate L. plantarum SS18-50 had the strongest probiotic properties with no mutation in 16S rRNA sequence compared to the wild type. Specifically, L. plantarum SS18-50 had good milk fermentation performance. The viscosity of fermented milk, acid tolerance, and bile salt tolerance were increased by approximately 10%, 8%, and 9%, respectively (p < .05). The antibacterial activity (Escherichia Coli, Salmonella Typhimurium, and Listeria Monocytogenes) was also increased significantly compared to the wild type (p < .05). This study indicates that L. plantarum SS18-50 has the great potential to serve as a probiotic for dairy products.

[Establishment of Mathematical Models for Skeletal Age Determination of Extremitas Sternalis of Clavicle in Shanxi Adolescents]

Objective To develop mathematical models for skeletal age determination with multiple statistic method based on the correlation between age and the growth of the epiphysis of extremitas sternalis of clavicle in Shanxi adolescents. Methods The 562 Shanxi sternoclavicular joint samples （454 cases of modelling, 108 cases of external verification） were scanned by the thin-section computed tomography. After volume rendering was obtained, indicators such as area of epiphysis, area of metaphysis, longest diameter of epiphysis and longest diameter of metaphysis of both extremitas sternalis of clavicle were collected. Indicators such as the ratio of area of epiphysis to area of metaphysis, and the ratio of longest diameter of epiphysis to longest diameter of metaphysis of both sides were calculated. Then multiple linear regression and random forest discriminant models were used to build mathematical models for age determination of adolescents. Results The obtained indicators exhibited a strong correlation with age （r>0.85）. The multiple linear regression model for males and females （all 4 indicators entering the model） based on the ratio of longest diameter of epiphysis to longest diameter of metaphysis and the ratio of area of epiphysis to area of metaphysis had an internal validation accuracy rate （±1.0 year） of over 92% and 108 cases had an external validation accuracy rate of over 70% （±1.0 year）. The out of bag error rates of random forest discriminant models were less than 2% for people over 18.0 years old （≥18.0 years old） and under 18.0 years old. The external validation accuracy rates of the 108 cases were over 80%. Conclusion The regression and discriminant models established in this study have certain reliability and accuracy and can be used in age determination of Shanxi adolescents.