Distinct experiences and care needs of advanced cancer patients with good ECOG performance status: a qualitative phenomenological study

BACKGROUND

Advanced cancer patients with good Eastern Cooperative Oncology Group (ECOG) performance status (score 0-1) are underrepresented in current qualitative reports compared with their dying counterparts.

AIM

To explore the experiences and care needs of advanced cancer patients with good ECOG.

DESIGN

A qualitative phenomenological approach using semi-structured interview was employed. Data was analyzed using the Colaizzi's method.

SETTING/PARTICIPANTS

Purposive sample of terminal solid cancer patients on palliative care aged 18-70 years with a 0-1 ECOG score were recruited from a tertiary general hospital.

RESULTS

Sixteen participants were interviewed. Seven themes were generated from the transcripts, including experiencing no or mild symptoms; independence in self-care, decision-making, and financial capacity; prioritization of cancer growth suppression over symptom management; financial concerns; hope for prognosis and life; reluctance to discuss death and after-death arrangements; and use of complementary and alternative medicine (CAM) and religious coping.

CONCLUSIONS

Advanced cancer patients with good ECOG have distinct experiences and care needs from their dying counterparts. They tend to experience no or mild symptoms, demonstrate a strong sense of independence, and prioritize cancer suppression over symptom management. Financial concerns were common and impact their care-related decision-making. Though being hopeful for their prognosis and life, many are reluctant to discuss death and after-death arrangements. Many Chinese patients use herbal medicine as a CAM modality but need improved awareness of and accessibility to treatment options. Healthcare professionals and policy-makers should recognize their unique experiences and needs when tailoring care strategies and policies.

D-dimer/fibrinogen ratio for the prediction of deep venous thrombosis after traumatic spinal cord injury

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To evaluate the predictive value of D-dimer/fibrinogen (D/F) ratio for deep vein thrombosis (DVT) in patients with traumatic spinal cord injury (SCI).

SETTING

Department of Rehabilitation Medicine Center, West China Hospital, Sichuan University.

METHODS

SCI patients within 24 h of trauma were consecutively enrolled. DVT was diagnosed by DUS examination during hospitalization. Multivariable logistic regression analysis was performed to determine the relationship between D/F ratio and DVT. Stratified logistic regression analysis was performed to identify effect modifiers. The receiver operating characteristic (ROC) curve was conducted to assess the predictive value of D/F ratio.

RESULTS

A total of 284 patients with SCI were included, of whom 106 (37.3%) developed DVT. D/F ratio was positively correlated with DVT (OR 1.17, 95% confidence interval [CI] 1.04-1.31, p = 0.009). Patients in the upper D/F ratio tertile (3.15-18.27) had a higher risk of DVT than patients in the lower tertile (0.08-0.97) after adjustment for potential confounders (OR 6.01, 95% CI 2.24-16.15, p < 0.001). The risk of DVT increased stepwise across D/F ratio tertiles (p for trend = 0.003). The area under the ROC curve (AUC) was 0.758 (95% CI 0.704-0.806). There was a significant interaction between D/F ratio and neurological level of injury (p for interaction = 0.003) and the association between D/F ratio and DVT remained significant only in patients with cervical injury.

CONCLUSIONS

A higher D/F ratio was independently associated with a higher risk of DVT in a dose-dependent manner in patients with cervical SCI.

Effectiveness of robotic-assisted gait training on cardiopulmonary fitness and exercise capacity for incomplete spinal cord injury: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To determine the effects of robotic-assisted gait training on cardiopulmonary fitness and exercise capacity for people with incomplete spinal cord injury.

METHODS

PubMed, Embase, Web of Science, PEDro, CENTRAL and CINAHL were searched from inception until September 4, 2022. Randomized controlled trials that evaluated the effects of robotic-assisted gait training on cardiopulmonary fitness and exercise capacity for individuals with incomplete spinal cord injury were selected. Mean differences (MD) with 95% confidence interval (CI) were calculated. The methodological quality was evaluated by the Cochrane Risk of Bias 2.0 tool. Subgroup analyses were conducted according to the time since injury.

RESULTS

In total 19 studies involving 770 patients were eligible for analysis. Individuals with acute incomplete spinal cord injury in robotic-assisted gait training groups showed significantly greater improvements in 6-minute walking test (MD 53.32; 95% CI 33.49 to 73.15; P < 0.001), lower extremity motor scale (MD 5.22; 95% CI 3.63 to 6.80; P < 0.001) and walking index for spinal cord injury II (MD 3.18; 95% CI 1.34 to 5.02; P < 0.001). Robotic-assisted gait training improved peak oxygen consumption to a greater degree for chronic incomplete spinal cord injury patients (MD 4.90; 95% CI 0.96 to 8.84; P = 0.01).

CONCLUSION

Robot-assisted gait training may be a feasible and effective intervention in terms of cardiopulmonary fitness and exercise capacity for individuals with incomplete spinal cord injury.

Association between neutrophil percentage-to-albumin ratio and pneumonia in patients with traumatic spinal cord injury

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To investigate the association between neutrophil percentage-to-albumin ratio (NPAR) and pneumonia in patients with SCI.

SETTING

Department of Rehabilitation Medicine Center, West China Hospital, Sichuan University.

METHODS

SCI patients admitted to West China Hospital within 24 h of injury were consecutively enrolled. Blood samples were collected on admission. Pneumonia was diagnosed based on chest radiography and clinician records of patient symptoms and laboratory tests. Multivariable logistic regression analysis was performed to determine the relationship between NPAR and pneumonia. Receiver operating characteristic (ROC) curves were generated to assess the predictive value of NPAR.

RESULTS

A total of 264 SCI patients were included, of whom 65 (24.6%) developed pneumonia. NPAR was positively correlated with pneumonia (OR 2.66, 95% CI, 1.06-6.71, p = 0.038). Patients in the upper NPAR tertile (2.35-3.71) had a higher risk of pneumonia than patients in the lower tertile (1.66-2.12) after adjustment for potential confounders (OR 2.55, 95% CI, 1.05-6.19, p = 0.039). The risk of pneumonia increased stepwise across NPAR tertiles (p for trend = 0.031). The optimal cutoff value of NPAR for predicting pneumonia was 2.17 with a sensitivity of 0.82 and a specificity of 0.50. There was a significant interaction between NPAR and neurological level of injury (p for interaction = 0.034), with no significant association between NPAR and pneumonia in patients with cervical SCI.

CONCLUSIONS

A higher NPAR was independently associated with higher risk of pneumonia in a dose-dependent manner in patients with non-cervical SCI.

Lactation time influences the composition of Bifidobacterium and Lactobacillus at species level in human breast milk

Human breast milk is a source of microorganisms for infants that play an important role in building infant gut health and immunity. The bacterial composition in human breast milk is influenced by lactation time. This study aimed to investigate the influence of lactation time on bacteria in breast milk at the genus level and the species levels of Bifidobacterium and Lactobacillus on days 2-4, 8, 14, and 30. Eighteen individuals were recruited and 60 milk samples were collected. The 16S rRNA gene, and the bifidobacterial groEL and lactobacilli groEL genes were used for amplicon sequencing. The results revealed that the alpha diversities of colostrum and transition 1 (day 8) milk were lower than that of transition 2 (day 14) and mature milk. PCoA analysis showed that bacterial composition in colostrum and transition 1 milk differed from transition 2 and mature milk. A lower relative abundance of Blautia was found in colostrum and transition 1 milk compared with mature milk and lower abundances of Ruminococcus, Dorea, and Escherichia-Shigella were found in transition 1 compared with mature milk. Bifidobacterium ruminantium, Limosilactobacillus mucosae, and Ligilactobacillus ruminis were the predominant species across all four lactation stages, while Bifidobacterium bifidum was lower in transition 1, and Bifidobacterium pseudocatenulatum and Bifidobacterium pseudolongum were higher in transition 1 milk. This study indicated that the bacterial composition in colostrum was more similar to that of transition 1 milk, whereas the bacterial community in transition 2 milk was similar to that of mature milk which suggests that bacterial composition in human breast milk shows stage-specific signatures even within a short period at both genus level and Bifidobacterium and Lactobacillus species levels, providing insights into probiotic supplementation for the nursing mother.

Portable fluid circuit device containing printed silicone microvessels as a training aid for arterial microanastomosis

Anastomosis of the microvessels requires high-level skills and extensive basic training. This study was performed to introduce and evaluate an inexpensive laboratory device as a training aid. Micro-tubes of 0.8 mm inner diameter and 0.5/0.8 mm wall thickness mimicking human vein/artery were printed from a silicon-containing hydrogel using three-dimensional printing technology. The hydrogel components are optimized to render the printed tubes biomechanical features resembling the blood vessels of a living organism. These artificial vessels were connected to a pump for fluid flow, simulating the blood circulation. Forty medical interns were assigned to two equal groups. The 20 interns in group A practiced anastomosis using the training aid for a total of 10 hours over 5 days. The 20 interns in group B practiced anastomosis using the traditional gum pieces and silicone tubes. Then, all interns performed anastomosis on rat carotid arteries, and their performance was scored by a team of five experienced maxillofacial surgeons. The average success score and time required for anastomosis were compared between the two groups. The mean success score of group A was significantly higher than that of group B (0.83 ± 0.12 vs 0.64 ± 0.10, P < 0.001). The mean anastomosis time of group A was significantly shorter than that of group B (10.2 ± 1.1 vs 17.2 ± 1.4 minutes, P < 0.001). This training device for vessel microanastomosis is an inexpensive, practical, and effective tool for use in laboratories and also reduces the use of animals.

[Research progress in the role and mechanism of polysaccharides in regulating glucose and lipid metabolism]

Polysaccharides are a group of compounds composed of multiple monosaccharides of the same or different structures combined by glycosidic bonds, and are widely found in animals and plants and in the cell walls of microorganisms. Polysaccharides possess the advantages of high safety and low toxicity. Recent studies revealed that polysaccharides have a wide range of biological activities including immunoregulation, anti-tumor, antiviral, antioxidant activities, and blood glucose-and lipid- lowering effects. The effects of polysaccharides in improving insulin sensitivity and regulating glucose and lipid metabolism have drawn much attention from researchers. Many polysaccharides can reduce blood glucose and blood lipid by repairing pancreatic islet cells, improving insulin resistance, regulating intestinal flora, enhancing antioxidant capacity, and regulating the activities of key enzymes in glucose and lipid metabolism. This reviews examines the role and mechanism of polysaccharides in regulating glucose and lipid metabolism. The mechanisms of polysaccharide in regulating glucose metabolism include repairing islet cells and increasing insulin content, increasing insulin sensitivity and improving insulin resistance, regulating the activity of key enzymes in glucose metabolism, increasing synthesis of liver glycogen, and regulating intestinal flora. Polysaccharides can also regulate glucose metabolism by improving immune regulation and antagonizing glucagon. Polysaccharide also regulate lipid metabolism by regulating lipid absorption, expression of the related genes such as PPAR-α, enzyme activities in lipid metabolism, improving antioxidant capacity, and modulating intestinal flora and signaling pathways.

Comparative evaluation of cardiovascular risks among nine FDA-approved VEGFR-TKIs in patients with solid tumors: a Bayesian network analysis of randomized controlled trials

Purpose

The present meta-analysis study was performed to identify the potential cardiotoxicity risks when using Vascular Endothelial Growth Factor Receptor Tyrosine kinase inhibitors (VEGFR-TKIs) as anticancer drugs in patients with solid tumors.

Methods

Pubmed, Embase, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov databases were searched for the randomized controlled trials. We have included 45 randomized controlled trials (RCTs) associated with nine VEGFR-TKIs Food and Drug Administration (FDA)-approved drugs used to treat patients with solid tumors. To evaluate the trials’ risk of bias, Cochrane Risk of Bias Tool was assessed. A direct comparison was assessed by RevMan5.3 software, calculating the odds ratio (OR) and 95% confidence interval (CI). Heterogeneity was tested by the I² statistic and Chi-square test for P value. Bayesian network meta-analysis was performed using Stata 15.0 and GeMTC 0.14.3 software, calculated OR along with corresponding 95% credible interval (CrI). The model’s convergence was evaluated by the potential scale reduced factor (PSRF). Consistency between direct and indirect comparisons was assessed by the “node-splitting” method.

Results

In this network meta-analysis, a total of 20,027 patients from 45 randomized controlled trials and associated with nine FDA-approved VEGFR-TKIs (axitinib, cabozantinib, lenvatinib, nintedanib, pazopanib, regorafenib, sorafenib, sunitinib, vandetanib), were enrolled. Findings indicated that lenvatinib had the most significant probability of provoking all grades cardiovascular incident and hypertension, followed by vandetanib, cabozantinib, axitinib, pazopanib, sorafenib, sunitinib, regorafenib and nintedanib. The nine agent’s severe cardiovascular and severe hypertension risk was probably similar. The ranking probability of cardiac toxicity shows that vandetanib ranked most likely to have the highest risk for cardiotoxicity among all the VEGFR-TKIs reviewed, followed by pazopanib, axitinib, sorafenib, sunitinib. In contrast, regorafenib and nintedanib did not exhibit an increased risk of cardiac damage.

Conclusions

The association between the nine VEGFR-TKIs with potential cardiotoxicity occurrence was reviewed. Both the regorafenib and nintedanib did not display detectable signs of cardiotoxic damage. In contrast, lenvatinib and vandetanib are ranked to have the most severe cardiotoxicity side impacts. These results may provide information for clinical practice guidelines, implementing strategies in selecting the adequate VEGFR-TKIs, and understanding the cardiovascular toxicity inflicted by the VEGFR-TKIs.

PROSPERO identifier

CRD 42,020,167,307.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-021-03521-w.

Sarcopenia as a Risk Factor for Future Hip Fracture: A Meta-Analysis of Prospective Cohort Studies

OBJECTIVE

Our study aims to determine whether sarcopenia is a predictive factor of future hip fractures.

DESIGN

Systematic review and meta-analysis. Set: We searched for potentially suitable articles in PubMed, Cochrane library, Medline and EMBASE from inception to March 2020. The quality of the research was assessed by the Newcastle-Ottawa Scale (NOS). Finally, a meta-analysis was conducted with the Stata software.

PARTICIPANTS

Older community-dwelling residents.

MEASUREMENTS

Hip fracture due to sarcopenia.

RESULTS

We retrieved 2129 studies through our search strategy, and five studies with 23,359 individuals were analyzed in our pooled analyses. Sarcopenia increases the risk of future hip fractures with a pooled hazard ratio (HR) of 1.42 (95% CI: 1.18-1.71, P <0.001, I2 = 37.7%). In addition, in subgroup analyses based on different definitions of sarcopenia, sarcopenia was associated with the risk of future hip fractures with the Asian Working Group for Sarcopenia (AWGS) criteria with a pooled HR of 2.13(95% CI: 1.33-3.43). When subgroup analyses were conducted by sex, sarcopenia was associated with the risk for future hip fractures in females with pooled HRs of 1.69 (95% CI: 1.18-2.43). Sarcopenia was associated with the risk of future hip fractures in the group with a follow-up period of more than 5 years, with a pooled HR of 1.32 (95% CI: 1.08-1.61), and in the group with a follow-up period of less than 5 years, with a pooled HR of 2.13 (95% CI: 1.33-3.43).

CONCLUSIONS

Sarcopenia could significantly increase the risk of future hip fracture in old people; thus, it is necessary to prevent hip fractures in individuals with sarcopenia.

FULLEROL alleviates myocardial ischemia-reperfusion injury by reducing inflammation and oxidative stress in cardiomyocytes via activating the Nrf2/HO-1 signaling pathway

OBJECTIVE

Myocardial ischemia-reperfusion injury (MIRI) is myocardial tissue injury caused by blood supply returning to myocardial tissue after ischemia or hypoxia. The purpose of this study was to investigate the protective effect of FULLEROL on myocardial tissue in MIRI rats and its mechanism.

MATERIALS AND METHODS

We use rats and ligate their left anterior descending coronary artery to make a MIRI model, and we also subcutaneously injected some MIRI rats with FULLEROL daily for two weeks before modeling. We determined the effects of model building and the therapeutic effect of FULLEROL on MIRI by detecting the changes of myocardial tissue morphology, myocardial injury markers and cardiac function in rats. In addition, we detected the expression changes of inflammatory factors and antioxidative molecules in rat myocardial tissue and serum to determine the effect of FULLEROL on inflammation and oxidative stress in myocardial tissue. Finally, we detected the activity of the Nrf2/HO-1 signaling pathway in rat cardiomyocytes to determine the mechanism of action of FULLEROL.

RESULTS

The structure of myocardial tissue in MIRI rats was remarkably damaged, and the range of myocardial infarction was increased. In addition, the concentrations of creatine kinase and lactate dehydrogenase were increased, and the heart function was reduced, while FULLEROL could reverse these conditions. In addition, FULLEROL was found to reduce the concentration of the inflammatory factors in rat myocardial tissue and serum, and to increase the expression of antioxidative molecules in myocardial tissue. The Nrf2/HO-1 signaling pathway was found to be related to MIRI and FULLEROL could increase the activity of the Nrf2/HO-1 signaling pathway in cardiomyocytes.

CONCLUSIONS

FULLEROL can alleviate MIRI by promoting the activity of the Nrf2/HO-1 signaling pathway to reduce the expression of inflammatory factors in rats and increase the antioxidative capacity of cardiomyocytes.

Protective effects of melatonin on mitochondrial biogenesis and mitochondrial structure and function in the HEK293-APPswe cell model of Alzheimer's disease

OBJECTIVE

The effects and mechanisms of melatonin on Alzheimer's disease (AD) are still not researched thoroughly. 20E2 cells (HEK293-APPswe cells) are a cellular model of AD. The modulation effects of melatonin on the structure and function of mitochondria in 20E2 cells need to be studied.

MATERIALS AND METHODS

The Alzheimer's disease (AD) cell model was assessed for cell viability, expression levels of mitochondrial biogenesis factors (peroxisome proliferator-activated receptor gamma coactivator 1-alpha [PGC-1α], nuclear respiratory factor 1 [NRF1], nuclear respiratory factor 2 [NRF2], mitochondrial transcription factor A [TFAM]), mitochondrial membrane potential, Na+-K+-adenosine triphosphatase (ATPase) and cytochrome C oxidase activity, adenosine triphosphate (ATP) level, mitochondrial DNA/nuclear DNA (mtDNA/nDNA) ratio, and mitochondrial structure with and without melatonin.

RESULTS

Melatonin improved 20E2 cell viability, expression of mitochondrial biogenesis factors (PGC-1α, NRF1, NRF2, TFAM), mitochondrial membrane potential, Na+-K+-ATPase, and cytochrome C oxidase activity, ATP level, mtDNA/nDNA ratio, mitochondrial structure, and decreased amyloidogenic amyloid precursor protein processing.

CONCLUSIONS

Mitochondrial biogenesis disorder is associated with the pathogenesis of AD through PGC-1α-NRF-TFAM pathway, and melatonin improves the mitochondrial structure and function by enhancing mitochondrial biogenesis and decreasing amyloidogenic APP processing in Alzheimer's disease.

Characterization of a P18 protein in the S1 segment of the novel duck reovirus genome

Novel duck reovirus (NDRV), the prototype strain of avian orthoreoviruses, continues to circulate among ducks. Analysis of its genome suggested that a putative second open reading frame in the S1 segment encodes a 162-amino acid nonstructural protein with size of 18 kDa, provisionally designated P18. This protein is different from the 17 kDa nonstructural protein encoded in the same open reading frame in other avian orthoreoviruses, which is designated P17 and consists of 146 amino acids. There is no corresponding protein in Muscovy duck reovirus. Antibodies raised to the purified recombinant protein reacted with viral P18 both in vitro and in vivo. In cells, P18 was located predominantly in the nucleus at 6-12 h post-infection, with negligible levels in the cytoplasm. However, the protein accumulated both in the nucleus and cytoplasm at 24 to 36 h post-infection. Immunohistochemistry indicated that P18 strongly accumulates in spleen tissues of infected ducklings. Collectively, the data provide the direct experimental evidence that P18 is expressed by novel duck reovirus both in vivo and in vitro. Keywords: duck reovirus; expression; characterization; novel P18 protein.

Sequential treatment by polidocanol and radiofrequency ablation of large benign partially cystic thyroid nodules with solid components: Efficacy and safety

PURPOSE

The purpose of this study was to retrospectively evaluate the efficacy and safety of a sequential treatment including percutaneous polidocanol sclerotherapy and radiofrequency ablation (RFA) in terms of volume reduction and complication rate in large, benign, partially cystic thyroid nodules with solid components.

MATERIALS AND METHOD

From April 2017 to April 2019, 46 patients with 47 large benign partially cystic thyroid nodules underwent sequential treatment. There were 14 men and 32 women with a mean age of 49.9±11.5 (SD) years (range: 18-75 years). The volume of initial nodules was 12.7±12.3 (SD) mL (range: 2.16-75.62mL). Volume reduction after percutaneous polidocanol sclerotherapy and further RFA was evaluated respectively. Patients had clinical and ultrasound evaluations at a follow-up time of 12.1±5.3 (SD) months (range: 1.5-23.9 months). Technical success and complications were accessed retrospectively.

RESULTS

After unsatisfying results with polidocanol sclerotherapy alone the 46 patients with 47 large benign partially cystic thyroid nodules had further RFA. Mean volume reduction of 47 nodules was 90.5±11.3 (SD) % (range: 43.9-99.3%) one month after RFA, 94.9±6.2 (SD) % (range: 66.9-99.5%) three months after RFA, and 95.8±5.5 (SD) % (range: 71.0-99.8%) six months after RFA. No recurrence or nodule enlargement after RFA was observed at the last follow-up. The complication rate of RFA was 12.5% (8/46 patients), with minor complications only.

CONCLUSIONS

The sequential treatment regimen, including percutaneous polidocanol sclerotherapy and RFA, is an appropriate and safe treatment strategy for large benign partially cystic thyroid nodules with solid components.

Discovery and identification of fatigue-related biomarkers in human saliva

OBJECTIVE

To identify stable and specific biomarkers/biomarker combinations for fatigue assessment and establish a discriminant model.

PATIENTS AND METHODS

Saliva was collected and electroencephalogram analysis was performed for 47 emergency physicians while awake and after continuoutas duty for 18-24 h. Physicians were divided into the fatigue and non-fatigue groups. Protein spectra of completely quantified saliva specimens were identified before and after long working hours using mass spectrometry. Data were analyzed through Proteome Discoverer software combined with SEQUEST to search protein databases. Proteins were characterized by collision-induced dissociation spectra. A global internal standard (GIS) was added to each group of samples and labeled by tandem mass tags m/z 131.1. All data were compared with GIS, and data between groups were further compared. Qualitative and quantitative data on proteins were exported for fatigue-related proteomic analysis, and a fatigue assessment model was established.

RESULTS

We identified 767 salivary proteins in the fatigue group. The correct rates of the discriminant function of the non-fatigue and fatigue groups were 97.1% and 91.7%, respectively (the total correct rate was 95.7%).

CONCLUSIONS

We identified 30 fatigue-related protein markers from saliva. We also established a fatigue assessment model for emergency physicians using salivary biomarkers.

Measurement of the cosmic ray proton spectrum from 40 GeV to 100 TeV with the DAMPE satellite

The precise measurement of the spectrum of protons, the most abundant component of the cosmic radiation, is necessary to understand the source and acceleration of cosmic rays in the Milky Way. This work reports the measurement of the cosmic ray proton fluxes with kinetic energies from 40 GeV to 100 TeV, with 2 ¹/₂ years of data recorded by the DArk Matter Particle Explorer (DAMPE). This is the first time that an experiment directly measures the cosmic ray protons up to ~100 TeV with high statistics. The measured spectrum confirms the spectral hardening at ~300 GeV found by previous experiments and reveals a softening at ~13.6 TeV, with the spectral index changing from ~2.60 to ~2.85. Our result suggests the existence of a new spectral feature of cosmic rays at energies lower than the so-called knee and sheds new light on the origin of Galactic cosmic rays.

Integrating transcriptome-wide association study and mRNA expression profiling identifies novel genes associated with bone mineral density

To scan novel candidate genes associated with osteoporosis, a two-stage transcriptome-wide association study (TWAS) of bone mineral density (BMD) was conducted. The BMD-associated genes identified by TWAS were then compared with the gene expression profiling of BMD in bone cells, B cells, and mesenchymal stem cells. We identified multiple candidate genes and gene ontology (GO) terms associated with BMD.

INTRODUCTION

Osteoporosis (OP) is a metabolic bone disease characterized by decrease in BMD. Our objective is to scan novel candidate genes associated with OP.

METHODS

A transcriptome-wide association study (TWAS) was performed by integrating the genome-wide association study (GWAS) summary of bone mineral density (BMD) with two pre-computed mRNA expression weights of peripheral blood and muscle skeleton. Then, another independent GWAS data of BMD was used to verify the discovery results. The BMD-associated genes identified between discovery and replicate TWAS were further subjected to gene ontology (GO) analysis implemented by DAVID. Finally, the BMD-associated genes and GO terms were further compared with the mRNA expression profiling results of BMD to detect the common genes and GO terms shared by both DNA-level TWAS and mRNA expression profile analysis.

RESULTS

TWAS identified 95 common genes with permutation P value < 0.05 for peripheral blood and muscle skeleton, such as TMTC4 in muscle skeleton and DDX17 in peripheral blood. Further comparing the genes detected by discovery-replicate TWAS with the differentially expressed genes identified by mRNA expression profiling of OP patients found 18 overlapped genes, such as MUL1 in muscle skeleton and SPTBN1 in peripheral blood. GO analysis of the genes identified by discovery-replicate TWAS detected 12 BMD-associated GO terms, such as negative regulation of cell growth and regulation of glycogen catabolic process. Further comparing the GO results of discovery-replicate TWAS and mRNA expression profiles found 6 overlapped GO terms, such as membrane and cell adhesion.

CONCLUSION

Our study identified multiple candidate genes and GO terms for BMD, providing novel clues for understanding the genetic mechanism of OP.