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Cryopreservation of Human Mesenchymal Stem Cells for Clinical Applications: Current Methods and Challenges

Yong KW, Wan Safwani WK, Xu F, Wan Abas WA, Choi JR, Pingguan-Murphy B

Biopreserv Biobank, 2015 Aug;13(4):231-9.
PMID: 26280501 DOI: 10.1089/bio.2014.0104

Mesenchymal stem cells (MSCs) hold many advantages over embryonic stem cells (ESCs) and other somatic cells in clinical applications. MSCs are multipotent cells with strong immunosuppressive properties. They can be harvested from various locations in the human body (e.g., bone marrow and adipose tissues). Cryopreservation represents an efficient method for the preservation and pooling of MSCs, to obtain the cell counts required for clinical applications, such as cell-based therapies and regenerative medicine. Upon cryopreservation, it is important to preserve MSCs functional properties including immunomodulatory properties and multilineage differentiation ability. Further, a biosafety evaluation of cryopreserved MSCs is essential prior to their clinical applications. However, the existing cryopreservation methods for MSCs are associated with notable limitations, leading to a need for new or improved methods to be established for a more efficient application of cryopreserved MSCs in stem cell-based therapies. We review the important parameters for cryopreservation of MSCs and the existing cryopreservation methods for MSCs. Further, we also discuss the challenges to be addressed in order to preserve MSCs effectively for clinical applications.
Risk Stratification in Pediatric Acute Respiratory Distress Syndrome: A Multicenter Observational Study

Wong JJ, Phan HP, Phumeetham S, Ong JSM, Chor YK, Qian S, et al.

Crit Care Med, 2017 Jul 26.
PMID: 28749854 DOI: 10.1097/CCM.0000000000002623

OBJECTIVES: The Pediatric Acute Lung Injury Consensus Conference developed a pediatric specific definition for acute respiratory distress syndrome (PARDS). In this definition, severity of lung disease is stratified into mild, moderate, and severe groups. We aim to describe the epidemiology of patients with PARDS across Asia and evaluate whether the Pediatric Acute Lung Injury Consensus Conference risk stratification accurately predicts outcome in PARDS.
DESIGN: A multicenter, retrospective, descriptive cohort study.
SETTING: Ten multidisciplinary PICUs in Asia.
PATIENTS: All mechanically ventilated children meeting the Pediatric Acute Lung Injury Consensus Conference criteria for PARDS between 2009 and 2015.
INTERVENTIONS: None.
MEASUREMENTS AND MAIN RESULTS: Data on epidemiology, ventilation, adjunct therapies, and clinical outcomes were collected. Patients were followed for 100 days post diagnosis of PARDS. A total of 373 patients were included. There were 89 (23.9%), 149 (39.9%), and 135 (36.2%) patients with mild, moderate, and severe PARDS, respectively. The most common risk factor for PARDS was pneumonia/lower respiratory tract infection (309 [82.8%]). Higher category of severity of PARDS was associated with lower ventilator-free days (22 [17-25], 16 [0-23], 6 [0-19]; p < 0.001 for mild, moderate, and severe, respectively) and PICU free days (19 [11-24], 15 [0-22], 5 [0-20]; p < 0.001 for mild, moderate, and severe, respectively). Overall PICU mortality for PARDS was 113 of 373 (30.3%), and 100-day mortality was 126 of 317 (39.7%). After adjusting for site, presence of comorbidities and severity of illness in the multivariate Cox proportional hazard regression model, patients with moderate (hazard ratio, 1.88 [95% CI, 1.03-3.45]; p = 0.039) and severe PARDS (hazard ratio, 3.18 [95% CI, 1.68, 6.02]; p < 0.001) had higher risk of mortality compared with those with mild PARDS.
CONCLUSIONS: Mortality from PARDS is high in Asia. The Pediatric Acute Lung Injury Consensus Conference definition of PARDS is a useful tool for risk stratification.
Fulltext Comparative Analysis of Pediatric COVID-19 Infection in Southeast Asia, South Asia, Japan, and China

Wong JJM, Abbas Q, Chuah SL, Malisie RF, Pon KM, Katsuta T, et al.

Am J Trop Med Hyg, 2021 Jun 15;105(2):413-420.
PMID: 34129517 DOI: 10.4269/ajtmh.21-0299

There is a scarcity of data regarding coronavirus disease 2019 (COVID-19) infection in children from southeast and south Asia. This study aims to identify risk factors for severe COVID-19 disease among children in the region. This is an observational study of children with COVID-19 infection in hospitals contributing data to the Pediatric Acute and Critical Care COVID-19 Registry of Asia. Laboratory-confirmed COVID-19 cases were included in this registry. The primary outcome was severity of COVID-19 infection as defined by the World Health Organization (WHO) (mild, moderate, severe, or critical). Epidemiology, clinical and laboratory features, and outcomes of children with COVID-19 are described. Univariate and multivariable logistic regression models were used to identify risk factors for severe/critical disease. A total of 260 COVID-19 cases from eight hospitals across seven countries (China, Japan, Singapore, Malaysia, Indonesia, India, and Pakistan) were included. The common clinical manifestations were similar across countries: fever (64%), cough (39%), and coryza (23%). Approximately 40% of children were asymptomatic, and overall mortality was 2.3%, with all deaths reported from India and Pakistan. Using the multivariable model, the infant age group, presence of comorbidities, and cough on presentation were associated with severe/critical COVID-19. This epidemiological study of pediatric COVID-19 infection demonstrated similar clinical presentations of COVID-19 in children across Asia. Risk factors for severe disease in children were age younger than 12 months, presence of comorbidities, and cough at presentation. Further studies are needed to determine whether differences in mortality are the result of genetic factors, cultural practices, or environmental exposures.
Vale Professor Xiaoxian Liu

Xu F, Binns C, Low WY

Asia Pac J Public Health, 2020 5 16;32(2-3):134-135.
PMID: 32410510 DOI: 10.1177/1010539520915009
Ethyl cinnamate suppresses tumor growth through anti-angiogenesis by attenuating VEGFR2 signal pathway in colorectal cancer

Wang S, Yang J, Kuang X, Li H, Du H, Wu Y, et al.

J Ethnopharmacol, 2024 May 23;326:117913.
PMID: 38360380 DOI: 10.1016/j.jep.2024.117913

ETHNOPHARMACOLOGICAL RELEVANCE: Kaempferia galanga Linn. is an aromatic medicinal herb with extensively applied in India, China, Malaysia and other South Asia countries for thousands of years. It has been mentioned to treat abdominal tumors. Ethyl cinnamate (EC), one of the main chemical constituents of the rhizome of K. galanga, exhibited nematocidal, sedative and vasorelaxant activities. However, its anti-angiogenic activity, and anti-tumor effect have not been investigated.
AIM OF THE STUDY: To investigate the anti-angiogenic mechanism of EC and its anti-tumor effect by suppressing angiogenesis.
MATERIALS AND METHODS: The in vitro anti-angiogenic effect was evaluated using HUVECs model induced by VEGF and zebrafish model in vivo. The influence of the EC on phosphorylation of VEGFR2 and its downstream signaling pathways were evaluated by western blotting assay. Molecule docking technology was conducted to explore the interaction between EC and VEGFR2. SPR assay was used for detecting the binding affinity between EC and VEGFR2. To further investigate the molecular mechanism of EC on anti-angiogenesis, VEGFR2 knockdown in HUVECs and examined the influence of the EC. Anti-tumor activity of EC was evaluated using colony formation assay and apoptosis assay. The inhibitory effect of EC on tumor growth was explored using HT29 colon cancer xenograft model.
RESULTS: EC obviously inhibited proliferation, migration, invasion and tube formation of VEGF-induced HUVECs. EC also induced apoptosis of HUVECs. Moreover, it inhibited the development of vessel formation in zebrafish. Further investigations demonstrated that EC could suppress the phosphorylation of VEGFR2, and its downstream signaling pathways were altered in VEGF-induced HUVECs. EC formed a hydrogen bond to bind with the ATP binding site of the VEGFR2, and EC-VEGFR2 interaction was shown in SPR assay. The suppressive effect of EC on angiogenesis was abrogated after VEGFR2 knockdown in HUVECs. EC inhibited the colon cancer cells colony formation and induced apoptosis. In addition, EC suppressed tumor growth in colon cancer xenograft model, and no detectable hepatotoxicity and nephrotoxicity. In addition, it inhibited the phosphorylation of VEGFR2, and its downstream signal pathways in tumor.
CONCLUSIONS: EC could inhibit tumor growth in colon cancer by suppressing angiogenesis via VEGFR2 signaling pathway, and suggested EC as a promising candidate for colon cancer treatment.
Fulltext Paracrine Effects of Adipose-Derived Stem Cells on Matrix Stiffness-Induced Cardiac Myofibroblast Differentiation via Angiotensin II Type 1 Receptor and Smad7

Yong KW, Li Y, Liu F, Bin Gao, Lu TJ, Wan Abas WA, et al.

Sci Rep, 2016 10 05;6:33067.
PMID: 27703175 DOI: 10.1038/srep33067

Human mesenchymal stem cells (hMSCs) hold great promise in cardiac fibrosis therapy, due to their potential ability of inhibiting cardiac myofibroblast differentiation (a hallmark of cardiac fibrosis). However, the mechanism involved in their effects remains elusive. To explore this, it is necessary to develop an in vitro cardiac fibrosis model that incorporates pore size and native tissue-mimicking matrix stiffness, which may regulate cardiac myofibroblast differentiation. In the present study, collagen coated polyacrylamide hydrogel substrates were fabricated, in which the pore size was adjusted without altering the matrix stiffness. Stiffness is shown to regulate cardiac myofibroblast differentiation independently of pore size. Substrate at a stiffness of 30 kPa, which mimics the stiffness of native fibrotic cardiac tissue, was found to induce cardiac myofibroblast differentiation to create in vitro cardiac fibrosis model. Conditioned medium of hMSCs was applied to the model to determine its role and inhibitory mechanism on cardiac myofibroblast differentiation. It was found that hMSCs secrete hepatocyte growth factor (HGF) to inhibit cardiac myofibroblast differentiation via downregulation of angiotensin II type 1 receptor (AT1R) and upregulation of Smad7. These findings would aid in establishment of the therapeutic use of hMSCs in cardiac fibrosis therapy in future.
Fulltext Effects of tai chi on postural balance and quality of life among the elderly with gait disorders: A systematic review

Xu F, Soh KG, Chan YM, Bai XR, Qi F, Deng N

PLoS One, 2023;18(9):e0287035.
PMID: 37768953 DOI: 10.1371/journal.pone.0287035

BACKGROUND: Tai Chi is good for improving the physical fitness of older adults. But few studies have reported the effects of Tai Chi on the postural balance and quality of life of older adults with gait disorders.
OBJECTIVE: This review aimed to assess the influence of tai chi on postural stability and quality of life in older adults with abnormal gait.
METHOD: According to the literature retrieval principles, the works published from the inception date to May 2023 were retrieved, including the following databases: PubMed, Scopus, Web of Science, China National Knowledge Infrastructure, EBSCOhost, and Google Scholar. Subsequently, literature screening and quality assessment were performed.
RESULTS: A total of 16 randomized controlled trials were included in this study, Tai Chi intervention can affect populations with Parkinson's disease (PD), no exercise, mild cognitive impairment (MCI), chronic stroke, sedentary, fear of falling, or history of falling. Postural instability is associated with balance, gait, the Unified Parkinson's Disease Rating Scale Motor Subscale 3 (UPDRS III), mobility, lower body strength, and falls. Only two articles looked at quality of life. The Yang style is the most commonly used in the intervention. Nonetheless, most studies were performed on female participants, hence, more research on older male populations is needed.
CONCLUSION: Tai Chi intervention benefits postural balance in patients with gait disorders. 12 weeks is the most common intervention period for patients with gait disorders. The frequency of intervention is seven articles twice a week, and the intervention time is about 60 minutes. The Tai Chi intervention methods in this study involve Yang Style, Sun Style, Taoist Tai Chi, and Health Qigong Tai Chi, but the Yang Style Tai Chi intervention is the most widely used.
RpoS differentially affects the general stress response and biofilm formation in the endophytic Serratia plymuthica G3

Liu X, Wu Y, Chen Y, Xu F, Halliday N, Gao K, et al.

Res. Microbiol., 2016 Apr;167(3):168-77.
PMID: 26671319 DOI: 10.1016/j.resmic.2015.11.003

The σ(S) subunit RpoS of RNA polymerase functions as a master regulator of the general stress response in Escherichia coli and related bacteria. RpoS has been reported to modulate biocontrol properties in the rhizobacterium Serratia plymuthica IC1270. However, the role of RpoS in the stress response and biofilm formation in S. plymuthica remains largely unknown. Here we studied the role of RpoS from an endophytic S. plymuthica G3 in regulating these phenotypes. Mutational analysis demonstrated that RpoS positively regulates the global stress response to acid or alkaline stresses, oxidative stress, hyperosmolarity, heat shock and carbon starvation, in addition to proteolytic and chitinolytic activities. Interestingly, rpoS mutations resulted in significantly enhanced swimming motility, biofilm formation and production of the plant auxin indole-3-acetic acid (IAA), which may contribute to competitive colonization and environmental fitness for survival. These findings provide further insight into the strain-specific role of RpoS in the endophytic strain G3 of S. plymuthica, where it confers resistance to general stresses encountered within the plant environment. The heterogeneous functionality of RpoS in rhizosphere and endophytic S. plymuthica populations may provide a selective advantage for better adaptation to various physiological and environmental stresses.
Glutamate application maintains quality and antioxidant capacity of fresh-cut carrots by modulating GABA shunt, phenylpropanoid and ROS metabolism

Zhang J, Zhao J, Zuo X, You W, Ru X, Xu F, et al.

Food Chem, 2024 Jun 15;443:138545.
PMID: 38306904 DOI: 10.1016/j.foodchem.2024.138545

The effects of exogenous glutamate treatment on the quality attributes, γ-aminobutyric acid (GABA) shunt, phenylpropanoid pathway, and antioxidant capacity of fresh-cut carrots were investigated. Results showed that glutamate treatment suppressed the increases in lightness and whiteness values, inhibited the degradation of total carotenoids and maintained better flavor and taste in fresh-cut carrots. Moreover, glutamate treatment rapidly promoted the activities of glutamate decarboxylase and GABA transaminase, thus improving the GABA content. It also significantly enhanced the activities of phenylalanine ammonia-lyase, cinnamate-4-hydroxylase, and 4-coumarate coenzyme A ligase and promoted the accumulation of total phenolics as well as the main individual phenolic compounds, including chlorogenic and caffeic acid. In addition, glutamate application activated the reactive oxygen system-related enzyme including peroxidase, superoxide dismutase, ascorbate peroxidase, and catalase activities to maintain higher antioxidant capacity in fresh-cut carrots. These results demonstrated that exogenous glutamate treatment maintained better nutritional quality and alleviated color deterioration by accelerating the accumulation of GABA and phenolics and enhancing the antioxidant capacity in fresh-cut carrots.
CmCML11 interacts with CmCAMTA5 to enhance γ-aminobutyric acid (GABA) accumulation by regulating GABA shunt in fresh-cut cantaloupe

You W, Zhang J, Ru X, Xu F, Wu Z, Jin P, et al.

Plant Physiol Biochem, 2024 Jan;206:108217.
PMID: 38039581 DOI: 10.1016/j.plaphy.2023.108217

The effect of calcium chloride (CaCl2) treatment on γ-aminobutyric acid (GABA) accumulation in fresh-cut cantaloupe and the involved mechanisms were investigated. The result showed that 1% (w/v) CaCl2 treatment increased GABA content and activities of glutamate decarboxylase (GAD) and succinate semialdehyde dehydrogenase (SSADH), while decreased glutamate (Glu) content and GABA transaminase (GABA-T) activities in fresh-cut cantaloupe. CmCML11 and CmCAMTA5 expressions of CaCl2-treated fruit increased by 187.4% and 165.6% than control fruit in the initial 6 h. Besides, expressions of GABA shunt genes, including CmGAD1, CmGAD2, CmGABA-T and CmSSADH were also up-regulated by CaCl2 treatment during early storage. Moreover, acting as a transcriptional activator, CmCAMTA5 could bind to the CG-box in promoters of CmGAD1, CmGABA-T and CmSSADH and activate their transcription. Furthermore, the interaction between CmCML11 and CmCAMTA5 could enhance the transcriptional activation on GABA shunt genes which were regulated by CmCAMTA5. Collectively, our findings revealed that CaCl2 treatment promoted GABA accumulation in fresh-cut cantaloupe via the combined effect of CmCML11 and CmCAMTA5 in the regulation of expressions of CmGAD1, CmGABA-T, and CmSSADH in GABA shunt.
Exogenous chlorogenic acid inhibits quality deterioration in fresh-cut potato slices

You W, Wang C, Zhang J, Ru X, Xu F, Wu Z, et al.

Food Chem, 2024 Jul 15;446:138866.
PMID: 38430769 DOI: 10.1016/j.foodchem.2024.138866

Fresh-cut potatoes are prone to surface browning and physiological degradation. Chlorogenic acid (CGA), a natural phenolic antioxidant, has demonstrated preservative properties in various postharvest products. However, the underlying mechanisms of its application on maintaining quality remain unclear. Therefore, the effect of exogenous CGA treatment on quality deterioration of potato slices and the mechanisms involved were investigated. Results revealed CGA treatment retarded the browning coloration, suppressed microbial growth and inhibited the declines in starch, and ascorbic acid contents in potato slices. Meanwhile, the treatment activated the phenylpropanoid pathway but decreased the activities of phenolic decomposition-related enzymes such as polyphenol oxidase (PPO) and tyrosinase and downregulated StPPO expression. Moreover, the treated slices exhibited reduced accumulation of reactive oxygen species and increased activity of antioxidant enzymes. Additionally, they displayed enhanced 2,2-diphenyl-1-picrylhydrazyl radicals scavenging capacity and higher ATP levels. Therefore, these findings indicated that CGA treatment was effective for quality maintenance and antioxidant capacity enhancement in fresh-cut potatoes, thereby providing potential strategies for the preservation and processing of fresh-cut produce.

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