Dong Sik Kim

Spheroid-based three-dimensional liver-on-a-chip to investigate hepatocyte–hepatic stellate cell interactions and flow effects

We have developed a three-dimensional (3D) liver-on-a-chip to investigate the interaction of hepatocytes and hepatic stellate cells (HSCs) in which primary 3D hepatocyte spheroids and HSCs are co-cultured without direct cell-cell contact. Here, we show that the 3D liver chip offers substantial advantages for the formation and harvesting of spheroids. The most important feature of this liver chip is that it enables continuous flow of medium to the cells through osmotic pumping, and thus requires only minimal handling and no external power source. We also demonstrate that flow assists the formation and long-term maintenance of spheroids. Additionally, we quantitatively and qualitatively investigated the paracrine effects of HSCs, demonstrating that HSCs assist in the maintenance of hepatocyte spheroids and play an important role in the formation of tight cell-cell contacts, thereby improving liver-specific function. Spheroids derived from co-cultures exhibited improved albumin and urea secretion rates compared to mono-cultured spheroids after 9 days. Immunostaining for cytochrome P450 revealed that the enzymatic activity of spheroids co-cultured for 8 days was greater than that of mono-cultured spheroids. These results indicate that this system has the potential for further development as a unique model for studying cellular interactions or as a tool that can be incorporated into other models aimed at creating hepatic structure and prolonging hepatocyte function in culture.

Concave microwell based size-controllable hepatosphere as a three-dimensional liver tissue model

We have developed a size-controllable spheroidal hepatosphere and heterosphere model by mono-culturing of primary hepatocytes and by co-culturing primary hepatocytes and hepatic stellate cells (HSCs). We demonstrated that uniform-sized heterospheres, which self-aggregated from primary hepatocytes and HSCs, formed within concave microwell arrays in a rapid and homogeneous manner. The effect of HSCs was quantitatively and qualitatively investigated during spheroid formation, and HSC played an important role in controlling the organization of the spheroidal aggregates and formation of tight cell-cell contacts. An analysis of the metabolic function showed that heterospheres secreted 30% more albumin than hepatospheres on day 8. In contrast, the urea secretion from heterospheres was similar to that of hepatospheres. A quantitative cytochrome P450 assay showed that the enzymatic activity of heterospheres cultured for 9 days was higher as compared with primary hepatospheres. These size-controllable heterospheres could be mass-produced using concave plate and be useful for creating artificial three-dimensional hepatic tissue constructs and regeneration of failed liver.

Microfluidic wet spinning of chitosan-alginate microfibers and encapsulation of HepG2 cells in fibers

The successful encapsulation of human hepatocellular carcinoma (HepG2) cells would greatly assist a broad range of applications in tissue engineering. Due to the harsh conditions during standard chitosan fiber fabrication processes, encapsulation of HepG2 cells in chitosan fibers has been challenging. Here, we describe the successful wet-spinning of chitosan-alginate fibers using a coaxial flow microfluidic chip. We determined the optimal mixing conditions for generating chitosan-alginate fibers, including a 1:5 ratio of 2% (w∕w) water-soluble chitosan (WSC) solution to 2% (w∕w) alginate solution. Ratio including higher than 2% (w∕w) WSC solution increased aggregation throughout the mixture. By suspending cells in the WSC-alginate solution, we successfully fabricated HepG2 cell-laden fibers. The encapsulated HepG2 cells in the chitosan-alginate fibers were more viable than cells encapsulated in pure alginate fibers, suggesting that cross-linked chitosan provides a better environment for HepG2 cells than alginate alone. In addition, we found that the adhesion of HepG2 cells on the chitosan-alginate fiber is much better than that on the alginate fibers.

Chemotherapy-induced Focal Hepatopathy in Patients with Gastrointestinal Malignancy: Gadoxetic Acid–enhanced and Diffusion-weighted MR Imaging with Clinical-Pathologic Correlation

PURPOSE To retrospectively evaluate findings of chemotherapy-induced focal hepatopathy (CIFH) on gadoxetic acid-enhanced magnetic resonance (MR) and diffusion-weighted (DW) images and to determine imaging features that are most helpful in differentiating CIFH from metastasis. MATERIALS AND METHODS This retrospective study was approved by the institutional review board, and informed consent was waived. MR images, including DW images and gadoxetic acid-enhanced images, from 12 patients (four men, eight women; age range, 25-64 years) with 15 CIFHs were reviewed independently and in consensus by two radiologists and were compared with those obtained in 20 control patients (12 men, eight women; age range, 32-84 years) with 30 hepatic metastasis who were matched for tumor size, primary organ, and chemotherapy regimen. Interobserver agreement was assessed with κ statistics, and univariate analysis was performed for comparisons. For quantitative analyses, apparent diffusion coefficients (ADCs) and lesion-to-liver contrast ratios (CRs) were measured. Histopathologic examinations were performed for CIFHs. RESULTS Histopathologic examination revealed that the development of CIFHs was attributable to accentuated manifestations of sinusoidal obstruction syndrome. Interobserver agreement was excellent (κ > 0.85). An ill-defined margin on hepatobiliary phase (HBP) images was the most discriminating independent variable in the differentiation of CIFH from metastasis (odds ratio, 16; P = .009). ADC and CR values in CIFH group were significantly higher than those in metastasis group (P < .001 and P = .041). CONCLUSION CIFH should be considered a mimicker of metastasis in patients with gastrointestinal malignancy during chemotherapy. CIFH can be differentiated from metastasis on the basis of gadoxetic acid-enhanced MR and DW imaging findings; an ill-defined margin on HBP images was especially characteristic.

Implication of lymph node metastasis detected on 18F-FDG PET/CT for surgical planning in patients with peripheral intrahepatic cholangiocarcinoma.

Objectives Intrahepatic cholangiocarcinoma (ICC) is the second most common primary hepatic malignancy after hepatocellular carcinoma. ICC can be divided into 2 types according to their location: peripheral and hilar types. Intense 18F-FDG uptake on PET was reported in peripheral ICC. However, the usefulness of PET/CT in detecting tumors and predicting prognosis in peripheral ICC has not been fully evaluated. In this study, we evaluated the clinical role of 18F-FDG PET/CT to predict the recurrence after the curative resection in patients with surgically indicated peripheral ICC. Methods Eighteen patients with ICC underwent preoperative CT and 18F-FDG PET/CT scans. SUVmax of tumor, tumor to normal liver SUV ratio (TNR), lymph node status evaluated by 18F-FDG PET/CT, tumor and lymph node size measured by CT, vascular invasion confirmed by pathology, and satellite nodules found on CT were compared between 1-year recurrence group and recurrence-free group by chi-square test. Results Of total 23 measurable lymph nodes, 4 nodes were positive and other 19 nodes were negative or equivocal on CT. Among those 23 nodes, 9 nodes were positive and other 14 nodes were negative on 18F-FDG PET/CT. The sensitivity and specificity of CT were 20.0% and 86.4%, and those of 18F-FDG PET/CT were 80.0% and 92.3%. In the comparison between 1-year recurrent and nonrecurrent groups, lymph node metastasis detected on 18F-FDG PET/CT had statistically positive correlation with the 1-year recurrence after surgical resection (P = 0.02). Other factors showed no statistically significant difference between the groups. Conclusion We found that lymph node metastasis detected on 18F-FDG PET/CT correlated positively with 1-year recurrence after surgical resection in patients with peripheral ICC.

Biliary phytobezoar resulting in intestinal obstruction.

Phytobezoar is the most common type of bezoar. It is composed of indigestible vegetable matter and is usually found in the stomach. Biliary phytobezoar is extremely rare and difficult to diagnose preoperatively. The pathogenesis is not clear, and there have been only a few reports of biliary bezoars associated with sphincteric impairment at the ampulla of Vater. Here, we present a report of biliary bezoar that resulted in jejunal obstruction. We were unable to identify the bezoar in the extrahepatic bile duct until it obstructed the small bowel lumen. To our knowledge, this is the first report of small bowel obstruction resulting from migration of a biliary bezoar.

Diagnostic performance of gadoxetic acid (Primovist)-enhanced MR imaging versus CT during hepatic arteriography and portography for small hypervascular hepatocellular carcinoma.

AbstractTo compare the diagnostic performance of gadoxetic acid-enhanced magnetic resonance imaging (MRI) with that of computed tomography (CT) during hepatic arteriography and arterial portography (CT HA/AP) for detecting hepatocellular carcinoma (HCC) from small hypervascular nodules.This retrospective study included 38 patients with 131 hypervascular nodules (⩽2 cm) who had underwent MRI and CT HA/AP within a 2-week interval. Two observers analyzed MRI while other 2 observers analyzed CT HA/AP. Thereafter, MRI observers reviewed the CT HA/AP and magnetic resonance (MR) images again using both modalities. HCC was diagnosed by pathologic or imaging studies according to American Association for the Study of Liver Diseases (AASLD) criteria. Alternative free-response receiver operating characteristic (ROC) analysis was performed on a lesion-by-lesion basis. Diagnostic accuracy (area under the ROC curve [Az]), sensitivity, specificity, and positive and negative predictive values were calculated.The pooled Az was significantly higher for the combined modalities (0.946) than for MRI alone (0.9, P = 0.004), and for MRI than for CT HA/AP alone (0.827, P = 0.0154). Subgroup analysis for HCC ⩽1 cm showed the sensitivity of the combined modalities (79.4%) was significantly higher than for MRI (52.9%) and CT HA/AP alone (50%) (both, P < 0.005). The specificity of the combined modalities was not different from MRI alone (98.8% vs. 97.3%, P = 0.5), but was significantly higher than for CT HA/AP alone (98.8% vs. 92.5%, P = 0.022).Hypervascular HCCs >1 to 2 cm can be diagnosed sufficiently by MRI. The combined modalities increased the diagnostic accuracy of HCCs ⩽1 cm, compared with MRI or CT HA/AP alone.

Usefulness of radioembolization in identifying patients with favorable tumor biology before living donor liver transplantation.

inherent to any observational cohort study, including a small sample size representing HL practice at a single center, potentiating the risk of a type 2 error. In this study, the heart was the primary organ for allocation in all HL recipients, which may not be representative of the national HL experience (8). The effects of bypassing candidates on the wait list are most likely pertinent at the first few match run positions, which we believe justifies our inclusion of only the first five candidates. Confirmation of the findings from this study awaits analysis of national data. In summary, this analysis suggests that liver candidates bypassed by HL dual transplants do not incur a survival disadvantage. Our intention is to highlight the previously unstudied consequences of dual organ transplantation and spur further inquiries into the indications and allocation practices for dual organ transplantation. Guidelines for dual-organ transplantation will ultimately need to be established which provide equipoise to single as well as dual organ candidates.

Effects of splanchnic vasoconstrictors on liver regeneration and survival after 90% rat hepatectomy

Purpose Posthepatectomy liver failure is a serious complication and considered to be caused by increased portal pressure and flow. Splanchnic vasoactive agents and propranolol are known to decrease portal pressure. The aim of this study was to identify optimal candidates with potential for clinical use among somatostatin, terlipressin, and propranolol using rats with 90% hepatectomy. Methods Rats were divided into 5 groups: sham operation (n = 6), control (n = 20), propranolol (n = 20), somatostatin (n = 20), and terlipressin group (n = 20). Seven-day survival rates and portal pressure change were measured, and biochemical, histologic, and molecular analyses were performed. Results Portal pressure was significantly decreased in all 3 treatment groups compared to control. All treatment groups showed a tendency of decreased liver injury markers, and somatostatin showed the most prominent effect at 24 hours postoperatively. Histologic liver injury at 24 hours was significantly decreased in propranolol and terlipressin groups (P = 0.016, respectively) and somatostatin group showed borderline significance (P = 0.056). Hepatocyte proliferation was significantly increased after 24 hours in all treatment groups. Median survival was significantly increased in terlipressin group compared to control group (P < 0.01). Conclusion Terlipressin is considered as the best candidate, while somatostatin has good potential for clinical use, considering their effects on portal pressure and subsequent decrease in liver injury and increase in liver regeneration.

A Case of Simultaneous Resection of Recurrent Combined Hepatocellular Cholangiocarcinoma and Hypovascular Hepatocellular Carcinoma

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. pISSN 2288-8128 eISSN 2383-5001 https://doi.org/10.17998/jlc.17.1.94 대한간암학회지 2017;17:94-99 Case Report