Yock Young Dan

Yock Young Dan


Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 October 2020 in Gastroenterology
Verified
Journal Article
Open access
MRMuhammad Nadzim Bin Ramli
Muhammad Nadzim Bin Ramli
YLYee Siang Lim
Yee Siang Lim
CKChwee Tat Koe
Chwee Tat Koe
DDDeniz Demircioglu
Deniz Demircioglu
WTWeiquan Tng
Weiquan Tng
YCYun-Shen Chan
Yun-Shen Chan
There are few in vitro models for studying the 3-dimensional interactions among different liver cell types during organogenesis or disease development. We aimed to generate hepatic organoids that comprise different parenchymal liver cell types and have structural features of the liver, using human pluripotent stem cells. We cultured H1 human embryonic stem cells (WA-01, passage 27-40) and induced pluripotent stem cells (GM23338) with a series of chemically defined and serum-free media to induce formation of posterior foregut cells, which were differentiated in 3-dimensions into hepatic endoderm spheroids and stepwise into hepatoblast spheroids. Hepatoblast spheroids were re-seeded in a high-throughput format and induced to form hepatic organoids; development of functional bile canaliculi was imaged live. Levels of albumin and apolipoprotein B were measured in cell culture supernatants using an ELISA. Levels of gamma glutamyl transferase (GGT) and alkaline phosphatase (ALP) were measured in cholangiocytes. Organoids were incubated with troglitazone for varying periods and bile transport and accumulation were visualized by live-imaging microscopy. Organoids were incubated with oleic and palmitic acid and formation of lipid droplets was visualized by staining. We compared gene expression profiles of organoids incubated with free fatty acids or without. We also compared gene expression profiles between liver tissue samples from patients with nonalcoholic steatohepatitis (NASH) vs without. We quantified hepatocyte and cholangiocyte populations in organoids using immunostaining and flow cytometry; cholangiocyte proliferation of cholangiocytes was measured. We compared the bile canaliculi network in the organoids incubated with vs without free fatty acids by live imaging. Cells in organoids differentiated into hepatocytes and cholangiocytes, based on the expression of albumin and cytokeratin-7. Hepatocytes were functional, based on secretion of albumin and apolipoprotein B and cytochrome P450 activity; cholangiocytes were functional, based on GGT and ALP activity and proliferative responses to secretin. The organoids organized a functional bile canaliculi system, which was disrupted by cholestasis-inducing drugs such as troglitazone. Organoids incubated with free fatty acids had gene expression signatures similar to those of liver tissues from patients with NASH. Incubation of organoids with free fatty acid-enriched media resulted in structural changes associated with non-alcoholic fatty liver disease, such as decay of bile canaliculi network and ductular reactions. We developed a hepatic organoid platform with human cells that can be used to model complex liver diseases, including NASH.

8 April 2008 in Journal of Gastroenterology and Hepatology
Verified
Journal Article
Closed access
PDF file
YDYock Young Dan
Yock Young Dan
GYGeorge Cheng Yeoh
George Cheng Yeoh

1 January 2022 in Metabolism
Verified
Journal Article
Open access
ETEunice Xiang-Xuan Tan
Eunice Xiang-Xuan Tan
JLJonathan Wei-Jie Lee
Jonathan Wei-Jie Lee
NJNur Halisah Jumat
Nur Halisah Jumat
WCWah-Kheong Chan
Wah-Kheong Chan
STSombat Treeprasertsuk
Sombat Treeprasertsuk
YDYock Young Dan
Yock Young Dan
A significant proportion of the non-alcoholic fatty liver disease (NAFLD) population is non-obese. Prior studies reporting the severity of NAFLD amongst non-obese patients were heterogenous. Our study, using data from the largest biopsy-proven NAFLD international registry within Asia, aims to characterize the demographic, metabolic and histological differences between non-obese and obese NAFLD patients. 1812 biopsy-proven NAFLD patients across nine countries in Asia assessed between 2006 and 2019 were pooled into a curated clinical registry. Demographic, metabolic and histological differences between non-obese and obese NAFLD patients were evaluated. The performance of Fibrosis-4 index for liver fibrosis (FIB-4) and NAFLD fibrosis score (NFS) to identify advanced liver disease across the varying obesity subgroups was compared. A random forest analysis was performed to identify novel predictors of fibrosis and steatohepatitis in non-obese patients. One-fifth (21.6%) of NAFLD patients were non-obese. Non-obese NAFLD patients had lower proportions of NASH (50.5% vs 56.5%, p = 0.033) and advanced fibrosis (14.0% vs 18.7%, p = 0.033). Metabolic syndrome in non-obese individuals was associated with NASH (OR 1.59, 95% CI 1.01-2.54, p = 0.047) and advanced fibrosis (OR 1.88, 95% CI 0.99-3.54, p = 0.051). FIB-4 performed better than the NFS score (AUROC 81.5% vs 73.7%, p < 0.001) when classifying patients with F2-4 fibrosis amongst non-obese NAFLD patients. Haemoglobin, GGT, waist circumference and cholesterol are additional variables found on random forest analysis useful for identifying non-obese NAFLD patients with advanced liver disease. A substantial proportion of non-obese NAFLD patients has NASH or advanced fibrosis. FIB-4, compared to NFS better identifies non-obese NAFLD patients with advanced liver disease. Serum GGT, cholesterol, haemoglobin and waist circumference, which are neither components of NFS nor FIB-4, are important biomarkers for advanced liver disease in non-obese patients.

1 March 2024 in Journal of Clinical Oncology
Verified
Journal Article
Closed access
DHDaniel Huang
Daniel Huang
JHJoseph K Hoang
Joseph K Hoang
RKRubayet Kamal
Rubayet Kamal
Pei Chien TsaiPei Chien Tsai
Pei Chien Tsai
HTHidenori Toyoda
Hidenori Toyoda
Mindie H. NguyenMindie H. Nguyen
Mindie H. Nguyen
PURPOSE: There are limited data on antiviral treatment utilization and its impact on long-term outcomes of hepatitis B virus (HBV)– and hepatitis C virus (HCV)–related hepatocellular carcinoma (HCC) after hepatic resection. We aimed to determine the utilization and impact of antivirals in HBV- and HCV-related HCC. METHODS: This cohort study included 1,906 participants (1,054 HBV-related HCC and 852 HCV-related HCC) from 12 international sites. All participants had HBV- or HCV-related HCC and underwent curative surgical resection. The primary outcome was the utilization of antiviral therapy, and the secondary outcome was long-term overall survival (OS). RESULTS: The mean (±standard deviation [SD]) age was 62.1 (±11.3) years, 74% were male, and 84% were Asian. A total of 47% of the total cohort received antiviral therapy during a mean (±SD) follow-up of 5.0 (±4.3) years. The overall antiviral utilization for participants with HBV-related HCC was 57% and declined over time, from 65% before 2010, to 60% from 2010 to 2015, to 47% beyond 2015, P < .0001. The overall utilization of antivirals for HCV-related HCC was 35% and increased over time, from 24% before 2015 to 74% from 2015 and beyond, P < .0001. The 10-year OS was lower in untreated participants for both HBV (58% v 61%) and HCV participants (38% v 82%; both P < .0001). On multivariable Cox regression analysis adjusted for relevant confounders, antiviral therapy initiated before or within 6 months of HCC diagnosis was independently associated with lower mortality in both HBV- (adjusted hazard ratio [aHR], 0.60 [95% CI, 0.43 to 0.83]; P = .002) and HCV-related HCC (aHR, 0.18 [95% CI, 0.11 to 0.31]; P < .0001). CONCLUSION: Antiviral therapy is associated with long-term survival in people with HBV- or HCV-related HCC who undergo curative resection but is severely underutilized.

29 September 2022 in Annals of Hepatology
Verified
Journal Article
Open access
MMMark Muthiah
Mark Muthiah
CNCheng Han Ng
Cheng Han Ng
KCKai En Chan
Kai En Chan
CFClarissa Elysia Fu
Clarissa Elysia Fu
WLWen Hui Lim
Wen Hui Lim
MNMazen Noureddin
Mazen Noureddin
Type 2 Diabetes Mellitus (T2DM) is comorbidity commonly presenting with fatty liver. A recently proposed definition of "metabolic associated fatty liver disease" (MAFLD) is thought to replace non-alcoholic fatty liver disease (NAFLD). Yet, despite the significant prevalence of T2DM among fatty liver, there remains limited evidence on the impact of the change in the definition of T2DM. The current study uses data from the United States National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018. Survival analysis was conducted with a cox regression and sub-distribution hazard ratio for competing risk events. 6727 patients had a diagnosis of T2DM. 4982 individuals with T2DM had MAFLD and 2032 were MAFLD(+)/NAFLD(-), while 2950 patients were MAFLD(+)/NAFLD(+). The new definition increased fatty liver diagnosis by 68.89%. Patients who were classified as MAFLD(+)/NAFLD(-) were at a higher risk of major adverse cardiovascular events, advanced fibrosis, all-cause and cardiovascular-related mortality compared to MAFLD(+)/NAFLD(+). In MAFLD(+)/NAFLD(-), viral hepatitis significantly increases the odds of advanced fibrosis (OR: 6.77, CI: 3.92 to 11.7, p < 0.001) and all-cause mortality (HR: 1.75, CI: 1.29 to 2.40, p < 0.001). The identification and treatment of NAFLD in patients with T2DM is a major concern and the premature change to MAFLD results in an over-diagnosis of fatty liver, exaggerated mortality, and morbidity in patients with T2DM. The definition of MAFLD causes further heterogeneity in fatty liver disease/NAFLD.

14 May 2015 in Journal of Gastroenterology and Hepatology
Verified
Journal Article
Closed access
PDF file
JLJaymie Siqi Lin
Jaymie Siqi Lin
LZLei Zhou
Lei Zhou
ASAntony Sagayaraj
Antony Sagayaraj
NJNur Halisah Bte Jumat
Nur Halisah Bte Jumat
MCMahesh Choolani
Mahesh Choolani
YDYock Young Dan
Yock Young Dan