Clinical and Pathological Correlation in Concomitant Celiac Disease and Eosinophilic Esophagitis Suggests Separate Etiologies.

Introduction. Recently, an increased risk of celiac disease or eosinophilic esophagitis has been postulated among patients with either of these disorders, prompting some to suggest a common underlying mechanism, whereas others maintain that their co-existence is coincidental. Methods. We compared clinical and pathological features of 29 patients meeting criteria for both celiac disease and eosinophilic esophagitis to 26 celiac disease and 26 eosinophilic esophagitis controls to determine whether any distinguished study patients from controls. Results. Eight (28%) study patients presented with symptoms of both celiac disease and eosinophilic esophagitis, whereas 14 (48%) had celiac disease symptoms only and 5 had (17%) esophageal symptoms only. Study patients had similar autoimmune and atopic conditions seen in both control groups. Histological severity of disease, including Marsh II-III duodenal histology (study specimens: 87%; controls: 89%), mean peak esophageal eosinophil counts (study specimens: 55/400x field; controls: 80/400X field, P = .1), and presence of eosinophil microabscesses, scale crust, and subepithelial fibrosis were also similar to controls. Gluten-free diet resolved celiac disease-related symptoms (19 of 20, 95%) and histology (10 of 12, 83%), but not esophageal symptoms or eosinophilia in most study patients. Conclusion. Patients with concomitant celiac disease and eosinophilic esophagitis lack distinguishing features compared to controls with celiac disease or eosinophilic esophagitis alone. The occurrence of both disorders is likely coincidental in most cases.

Liver allograft findings of donation after cardiac death versus brain death in recipients with hepatitis C related cirrhosis: a matched histologic comparison.

As the demand for organ transplantation increases, utilization of liver allografts of donation after cardiac death (DCD) is becoming increasingly necessary. Although the clinical outcomes of DCD allografts have been well described, the histologic features are not well characterized. Liver biopsies (n = 131) from age-matched DCD (n = 60) and donation after brain death (DBD; n = 71) recipients with hepatitis C virus were compared. Histologic features were studied in a blinded fashion, subgrouped into time 0, 0-6 months, and >6 months. In time 0 biopsies, more DCD cases had zone 3 (43.8 vs 29%) and bridging necrosis (19 vs 0%), albeit not statistically significant. At 0-6 months, more DCD cases had portal edema (p = 0.01). Pericholangitis (30.4% vs 18.8%) and acute cholestasis (21.7% vs 12.5%) were more common in DCD, but not statistically significant. At >6 months, pericholangitis (19% vs 4.5%) persisted in DCD, although not statistically significant. Overall, both groups had similar bile duct injury, portal inflammation, and fibrosis. Postoperative biliary complications were more common in DCD (19% vs 0%). Three-year and 10-year graft survival and patient outcomes were similar in both cohorts. Biliary alterations were more prevalent in the 0-6 month time period DCD biopsies, reflecting increased vulnerability of this group to biliary complications in the early post-orthotopic liver transplant (OLT) period. This finding may suggest poor graft perfusion despite comparable cold ischemia times. However, these features improved and DCD recipients have similar graft and overall survival compared to DBD recipients, indicating that carefully selected DCD liver allografts are a viable option for transplantation.

Apobec1 complementation factor overexpression promotes hepatic steatosis, fibrosis, and hepatocellular cancer.

The RNA-binding protein Apobec1 complementation factor (A1CF) regulates posttranscriptional ApoB mRNA editing, but the range of RNA targets and the long-term effect of altered A1CF expression on liver function are unknown. Here we studied hepatocyte-specific A1cf-transgenic (A1cf+/Tg), A1cf+/Tg Apobec1-/-, and A1cf-/- mice fed chow or high-fat/high-fructose diets using RNA-Seq, RNA CLIP-Seq, and tissue microarrays from human hepatocellular cancer (HCC). A1cf+/Tg mice exhibited increased hepatic proliferation and steatosis, with increased lipogenic gene expression (Mogat1, Mogat2, Cidea, Cd36) associated with shifts in polysomal RNA distribution. Aged A1cf+/Tg mice developed spontaneous fibrosis, dysplasia, and HCC, and this development was accelerated on a high-fat/high-fructose diet and was independent of Apobec1. RNA-Seq revealed increased expression of mRNAs involved in oxidative stress (Gstm3, Gpx3, Cbr3), inflammatory response (Il19, Cxcl14, Tnfα, Ly6c), extracellular matrix organization (Mmp2, Col1a1, Col4a1), and proliferation (Kif20a, Mcm2, Mcm4, Mcm6), and a subset of mRNAs (including Sox4, Sox9, Cdh1) were identified in RNA CLIP-Seq. Increased A1CF expression in human HCC correlated with advanced fibrosis and with reduced survival in a subset with nonalcoholic fatty liver disease. In conclusion, we show that hepatic A1CF overexpression selectively alters polysomal distribution and mRNA expression, promoting lipogenic, proliferative, and inflammatory pathways leading to HCC.

Recurrent Autoimmune Hepatitis and De Novo Autoimmune Hepatitis in the Liver Allograft.

OBJECTIVES: Autoimmune hepatitis (AIH) is a form of severe hepatitis that can recur after orthotopic liver transplant (OLT). Presentation of AIH in patients with OLT who do not have a history of AIH is called de novo AIH (DNAIH). We evaluated the clinicopathologic characteristics of AIH and DNAIH. METHODS: Clinicopathologic and outcome measures of 11 patients with recurrent AIH (RAIH) and 22 with DNAIH identified between 2000 and 2017 were compared. RESULTS: Both cohorts showed female predominance. The mean clinical follow-up was 13 and 7.8 years in the in the RAIH and DNAIH groups, respectively (P = .1). Moderate portal inflammation was more common in patients with RAIH (64% vs 27%, P = .043). A trend was observed for more cases of DNAIH showing severe inflammation (36% vs 9%, P = .09) and submassive necrosis compared with RAIH (23% vs 0%, P = .086). A trend for more advanced fibrosis was also noted in the RAIH group (27% vs 5%, P = .059). Three patients with RAIH lost their grafts because of RAIH. Five-year disease-specific graft survival (GS) (P = .012) and overall GS (P = .015) were worse in patients with RAIH. Complement component 4d immunohistochemistry was positive in 2 patients with RAIH and 3 with DNAIH but showed no correlation with GS or other parameters. CONCLUSIONS: RAIH seems to have a more aggressive clinical course than DNAIH and warrants closer clinical follow-up and aggressive treatment.

Reproducibility of AJCC Criteria for Classifying Deeply Invasive Colon Cancers Is Suboptimal for Consistent Cancer Staging.

The eighth edition of the American Joint Committee on Cancer (AJCC) Staging Manual attempts to address ambiguity in the pT category assignment for colon cancer from prior editions. Despite modifications, the distinction between the pT3 and pT4a categories continues to be a source of diagnostic confusion. In this study, we assessed interobserver agreement among pathologists from different institutions in the application of AJCC eighth edition criteria for categorizing deeply invasive colonic adenocarcinomas. We identified morphologic patterns that produce diagnostic confusion. We assessed 47 colon cancers that closely approached the serosal surface. Six pathologists with interest in gastrointestinal pathology and 4 focused in other subspecialties classified each case as pT3 or pT4a, based on examination of low-magnification and high-magnification images of the most deeply invasive area. Interobserver agreement was assessed using Fleiss' κ. Cases displayed 3 morphologic patterns at the advancing tumor edge, namely, (1) continuous invasion through an inflammatory focus, (2) pushing border, and (3) infiltrative glands and cell clusters with serosal reaction. Gastrointestinal pathologists achieved slight (κ=0.21) or moderate (κ=0.46) and (κ=0.51) agreement in each category, whereas agreement among nongastrointestinal pathologist was fair (0.31) and (0.39), or moderate (0.57) for each category, respectively. In 10 (21%) cases, the distinction between pT3 and pT4a would have changed the overall clinical stage. We conclude that histologic criteria for serosal penetration is a persistent source of diagnostic ambiguity for gastrointestinal and general pathologists in the pT categorization of colon cancers. Clarification of these criteria will help ensure uniform reporting of pathologic and clinical stage.

Primary sclerosing cholangitis associated colitis: Characterization of clinical, histologic features, and their associations with liver transplantation.

BACKGROUND: Primary sclerosing cholangitis (PSC) associated inflammatory bowel disease (IBD) is a unique form of IBD (PSC-IBD) with distinct clinical and histologic features from ulcerative colitis (UC) and Crohn disease (CD). In patients with PSC and IBD, the severity of the two disease processes may depend on each other. AIM: To study the histologic and clinical features of PSC patients with and without IBD. METHODS: We assessed specimens from patients with UC (n = 28), CD (n = 10), PSC and UC (PSC-UC; n = 26); PSC and CD (PSC-CD; n = 6); and PSC and no IBD (PSC-no IBD; n = 4) between years 1999-2013. PSC-IBD patients were matched to IBD patients without PSC by age and colitis duration. Clinical data including age, gender, age at IBD and PSC diagnoses, IBD duration, treatment, follow-up, orthotopic liver transplantation (OLT) were noted. RESULTS: PSC-UC patients had more isolated right-sided disease (P = 0.03), and less active inflammation in left colon, rectum (P = 0.03 and P = 0.0006), and overall (P = 0.0005) compared to UC. They required less steroids (P = 0.01) and fewer colectomies (P = 0.03) than UC patients. The PSC-CD patients had more ileitis and less rectal involvement compared to PSC-UC and CD. No PSC-CD patients required OLT compared to 38% of PSC-UC (P = 0.1). PSC-IBD (PSC-UC and PSC-CD) patients with OLT had severe disease in the left colon and rectum (P = 0.04). CONCLUSION: PSC-UC represents a distinct form of IBD. The different disease phenotype in PSC-IBD patients with OLT may support liver-gut axis interaction, however warrants clinical attention and further research.

Cryptogenic cirrhosis: Old and new perspectives in the era of molecular and genomic medicine.

Cryptogenic cirrhosis (CC) is defined as cirrhosis of unknown etiology despite extensive clinical, laboratory and pathologic work-up, and constitutes approximately 5-10% of all cirrhosis cases. Histologic examination can provide important clues and help identify the potential etiology of CC. Most CC cases can still be classified into four histologic patterns: hepatitic, steatotic, biliary, and patternless (bland). The use of genetic testing has significantly improved diagnostic ability and treatment, especially in pediatric patients with acute and chronic liver diseases. More recently, whole exome sequencing has been used for identifying genetic alterations that lead to a diagnosis in adults with liver disease of unknown etiology. Recent advances in genomic analysis has allowed the unraveling of the underlying etiology in a subset of CC cases, and also helped identify new disorders. Providing a diagnosis for these patients has several important implications for treatment, possible genetic counseling, and transplant eligibility. However, detailed clinical and histologic characterization of the patients still remains an important part of the CC work-up, since clinicopathologic and genomic correlation is crucial in making a diagnosis, or in some cases, discovery of a new entity. This article summarizes the main histologic findings that can be observed in CC cases, potential causes of CC, and recent advances in the field.

Clinical, Histologic, and Immunophenotypic Features of Serrated Polyps in Patients With Inflammatory Bowel Disease.

BACKGROUND: Colorectal serrated polyps (SP), which include hyperplastic polyps (HP), sessile serrated adenomas/polyps (SSA/P), and traditional serrated adenomas, are not uncommon and have been implicated to play a role in the pathogenesis in a subset of sporadic colorectal carcinomas; however, their significance in patients with prolonged inflammatory bowel disease (IBD) remains unclear. METHODS: We retrospectively studied the clinicopathologic features, BRAF and ß-catenin immunohistochemistry staining patterns in 36 SPs from 28 patients with IBD compared with 40 SPs in patients without IBD. RESULTS: Eleven SSA/Ps and 25 HPs from IBD and site-matched controls were included. SSA/Ps in the study group were slightly more commonly seen in males (55% vs. 41%, P = 0.7) and older patients (55.2 vs. 47.8 years, P = 0.2) compared to patients with HP. They were moderately larger (7.13 mm vs. 4.83 mm, P = 0.14) and more likely located on the right (63.6% vs. 32%, P = 0.46). Smaller percentage of SSA/Ps showed BRAF staining compared to controls (55.6% vs. 73.3%, P = 0.41) and HPs showed similar features (52.0% vs. 54.2%, P = 1). ß-catenin was negative in all cases. During follow-up, only one patient in the SSA/P group developed carcinoma 42 months after at the same site and two developed adenoma-like low-grade dysplasia but no patients with HPs had such findings. CONCLUSIONS: Our findings show that SPs in IBD share similar clinicodemographic and immunophenotypical features with sporadic SPs. However, patients with SSA/Ps may have a slight increase in risk of developing dysplasia compared to patients with HPs in IBD.

Frequent GNAQ and GNA14 Mutations in Hepatic Small Vessel Neoplasm.

Hepatic small vessel neoplasm (HSVN) is a recently described infiltrative vascular neoplasm of the liver, composed of small vessels. Although the infiltrative nature can mimic angiosarcoma, HSVN are thought to be benign or low-grade neoplasms because they lack cytologic atypia and increased proliferation. To characterize the molecular pathogenesis of HSVN, we performed both targeted panel sequencing and exome sequencing on 18 benign or low-grade vascular neoplasms in the liver including 8 HSVN, 6 classic cavernous hemangioma (CH), and 4 variant lesions (VL) with overlapping features between HSVN and CH. All 18 lesions had simple genomes without copy number alterations. In total, 75% (6/8) of HSVN demonstrated known activating hotspot mutations in GNAQ (2/8, p.Q209H) or GNA14 (4/8, p.Q205L), and the remaining 2 had the same missense mutation in GNAQ, p.G48L, which has not been previously described. 25% (1/4) of VL had a hotspot GNAQ p.Q209H mutation and another VL had a GNAQ p.G48L mutation. Known pathogenic mutations were not identified in any of the 6 CH. These data suggest that HSVN share a similar molecular biology to several other vascular lesions (congenital hemangioma, tufted angioma, anastomosing hemangioma, lobular capillary hemangioma, and kaposiform hemangioendothelioma) recently reported to have GNAQ, GNA11, or GNA14 mutations.

Unique causes of esophageal inflammation: a histopathologic perspective.

Gastroenterologists frequently perform endoscopic esophageal mucosal biopsies for pathologic diagnosis in patients experiencing symptoms of esophagitis. The more common causes of esophagitis diagnosed on esophageal mucosal biopsy include reflux esophagitis, eosinophilic esophagitis, and infectious esophagitis caused by Candida albicans, herpes simplex virus, and/or cytomegalovirus. However, there are several causes of esophagitis seen less frequently by pathologists that are very important to recognize. We discuss unique types of esophageal inflammation, including acute bacterial esophagitis, esophageal manifestations of dermatologic diseases, medication-induced esophageal injury, and sloughing esophagitis; and we review their clinical and histopathologic features.

The microscopic anatomy of the esophagus including the individual layers, specialized tissues, and unique components and their responses to injury.

The esophagus, a straight tube that connects the pharynx to the stomach, has the complex architecture common to the rest of the gastrointestinal tract with special differences that relate to its function as a conduit of ingested substances. For instance, it has submucosal glands that are unique and have a specific protective function. It has a squamous lining that exists nowhere else in the gut except the anus and it has a different submucosal nerve plexus when compared to the stomach and intestines. All of the layers of the esophageal wall and the specialized structures including blood and lymphatic vessels and nerves have specific responses to injury. The esophagus also has unique features such as patches of gastric mucosa called inlet patches at the very proximal part and it has a special sphincter mechanism at the most distal aspect. This review covers the normal microscopic anatomy of the esophagus and the patterns of reaction to stress and injury of each layer and each special structure.

The impact of diet-induced hepatic steatosis in a murine model of hepatic ischemia/reperfusion injury.

The prevalence of obesity-associated nonalcoholic fatty liver disease has significantly increased over the past decade, and end-stage liver disease secondary to nonalcoholic steatohepatitis has become 1 of the most common indications for liver transplantation. This both increases the demand for organs and decreases the availability of donor livers deemed suitable for transplantation. Although in the past many steatotic livers were discarded due to concerns over enhanced susceptibility to ischemia/reperfusion injury (IRI) and organ failure, the discrepancy between supply and demand has resulted in increasing use of expanded criteria donor organs including steatotic livers. However, it remains controversial whether steatotic livers can be safely used for transplantation and how best to improve the performance of steatotic grafts. We aimed to evaluate the impact of diet-induced hepatic steatosis in a murine model of IRI. Using a diet of high trans-fat, fructose, and cholesterol (HTF-C) and a diet high in saturated fats, sucrose, and cholesterol (Western diet), we were able to establish models of mixed macrovesicular and microvesicular steatosis (HTF-C) and microvesicular steatosis (Western). We found that the presence of hepatic steatosis, whether it is predominantly macrovesicular or microvesicular, significantly worsens IRI as measured by plasma alanine aminotransferase levels and inflammatory cytokine concentration, and histological evaluation for necrosis. Additionally, we report on a novel finding in which hepatic IRI in the setting of steatosis results in the induction of the necroptosis factors, receptor interacting protein kinase (RIPK) 3, RIPK1, and mixed-lineage kinase domain-like. These data lay the groundwork for additional experimentation to test potential therapeutic approaches to limit IRI in steatotic livers by using a genetically tractable system. Liver Transplantation 24 908-921 2018 AASLD.

Differentiation of Hepatocellular Carcinoma from Other Hepatic Malignancies in Patients at Risk: Diagnostic Performance of the Liver Imaging Reporting and Data System Version 2014.

Purpose To evaluate the diagnostic performance and interrater reliability of the Liver Imaging Reporting and Data System (LI-RADS) version 2014 in differentiating hepatocellular carcinoma (HCC) from non-HCC malignancy in a population of patients at risk for HCC. Materials and Methods This retrospective HIPAA-compliant institutional review board-approved study was exempt from informed consent. A total of 178 pathology-proven malignant liver masses were identified in 178 patients at risk for HCC but without established extrahepatic malignancy from August 2012 through August 2015. Two readers blinded to pathology findings and clinical follow-up data independently evaluated a liver protocol magnetic resonance or computed tomography study for each lesion and assigned LI-RADS categories, scoring all major and most ancillary features. Statistical analyses included the independent samples t test, x2 test, Fisher exact test, and Cohen k. Results This study included 136 HCCs and 42 non-HCC malignancies. Specificity and positive predictive value of an HCC imaging diagnosis (LR-5 or LR-5V) were 69.0% and 90.5%, respectively, for reader 1 (R1) and 88.3% and 95.5%, respectively, for reader 2 (R2). Tumor in vein was a common finding in patients with non-HCC malignancies (R1, 10 of 42 [23.8%]; R2, five of 42 [11.9%]). Exclusion of the LR-5V pathway improved specificity and positive predictive value for HCC to 83.3% and 92.9%, respectively, for R1 (six fewer false-positive findings) and 92.3% and 96.4%, respectively, for R2 (one fewer false-positive finding). Among masses with arterial phase hyperenhancement, the rim pattern was more common among non-HCC malignancies than among HCCs for both readers (R1: 24 of 36 [66.7%] vs 13 of 124, [10.5%], P < .001; R2: 27 of 35 [77.1%] vs 21 of 123 [17.1%], P < .001) (k = 0.76). Exclusion of rim arterial phase hyperenhancement as a means of satisfying LR-5 criteria also improved specificity and positive predictive value for HCC (R1, two fewer false-positive findings). Conclusion Modification of the algorithmic role of tumor in vein and rim arterial phase hyperenhancement improves the diagnostic performance of LI-RADS version 2014 in differentiating HCC from non-HCC malignancy. © RSNA, 2017 Online supplemental material is available for this article.

Genomic regions associated with susceptibility to Barrett's esophagus and esophageal adenocarcinoma in African Americans: The cross BETRNet admixture study.

BACKGROUND: Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) are far more prevalent in European Americans than in African Americans. Hypothesizing that this racial disparity in prevalence might represent a genetic susceptibility, we used an admixture mapping approach to interrogate disease association with genomic differences between European and African ancestry. METHODS: Formalin fixed paraffin embedded samples were identified from 54 African Americans with BE or EAC through review of surgical pathology databases at participating Barrett's Esophagus Translational Research Network (BETRNet) institutions. DNA was extracted from normal tissue, and genotyped on the Illumina OmniQuad SNP chip. Case-only admixture mapping analysis was performed on the data from both all 54 cases and also on a subset of 28 cases with high genotyping quality. Haplotype phases were inferred with Beagle 3.3.2, and local African and European ancestries were inferred with SABER plus. Disease association was tested by estimating and testing excess European ancestry and contrasting it to excess African ancestry. RESULTS: Both datasets, the 54 cases and the 28 cases, identified two admixture regions. An association of excess European ancestry on chromosome 11p reached a 5% genome-wide significance threshold, corresponding to -log10(P) = 4.28. A second peak on chromosome 8q reached -log10(P) = 2.73. The converse analysis examining excess African ancestry found no genetic regions with significant excess African ancestry associated with BE and EAC. On average, the regions on chromosomes 8q and 11p showed excess European ancestry of 15% and 20%, respectively. CONCLUSIONS: Chromosomal regions on 11p15 and 8q22-24 are associated with excess European ancestry in African Americans with BE and EAC. Because GWAS have not reported any variants in these two regions, low frequency and/or rare disease associated variants that confer susceptibility to developing BE and EAC may be driving the observed European ancestry association evidence.

How does it feel to be a pathology resident? Results of a survey on experiences and job satisfaction during pathology residency.

Residents' career choices and professional motivation can be affected from perception of their role and recognition within a medical team as well as their educational and workplace experiences. To evaluate pathology trainees' perceptions of their pathology residency, we conducted a 42-item survey via a web-based link questioning respondents' personal and institutional background, workplace, training conditions, and job satisfaction level. For the 208 residents from different European countries who responded, personal expectations in terms of quality of life (53%) and scientific excitement (52%) were the most common reasons why they chose and enjoy pathology. Sixty-six percent were satisfied about their relationship with other people working in their department, although excessive time spent on gross examination appeared less satisfactory. A set residency training program (core curriculum), a set annual scientific curriculum, and a residency program director existed in the program of 58, 60, and 69% respondents, respectively. Most respondents (76%) considered that pathologists have a direct and high impact on patient management, but only 32% agreed that pathologists cooperate with clinicians/surgeons adequately. Most (95%) found that patients barely know what pathologists do. Only 22% considered pathology and pathologists to be adequately positioned in their country's health care system. Almost 84% were happy to have chosen pathology, describing it as "puzzle solving," "a different fascinating world," and "challenging while being crucial for patient management." More than two thirds (72%) considered pathology and pathologists to face a bright future. However, a noticeable number of respondents commented on the need for better physical working conditions, a better organized training program, more interaction with experienced pathologists, and deeper knowledge on molecular pathology.

Tumor budding in intestinal-type gastric adenocarcinoma is associated with nodal metastasis and recurrence.

Gastric adenocarcinoma (GAC) is a common cause of cancer-related death worldwide. GAC can be classified as intestinal or diffuse. Intestinal-type cancers are common and reported to have a better prognosis compared to diffuse cancers. Studies have shown the presence and amount of tumor budding in intestinal carcinomas of the colon and esophagus to predict nodal metastasis and recurrence. Our aim is to determine if tumor budding in intestinal-type GAC correlates with prognostic features. One hundred four patients treated with primary surgical excision between 1999 and 2013 were identified. Histologic type (intestinal, diffuse, or mixed), tumor grade, T-stage, and lymph node status were evaluated. Tumor bud scores were assigned to all intestinal-type cancers using methods previously described for colorectal adenocarcinoma. Scores of <1 were designated as low and ≥1 as high. Tumor characteristics were as follows: 52 intestinal (50%), 36 diffuse (35%), and 16 mixed (15%). Of the 52 cases with intestinal histology, 4 were well (8%), 28 were moderately (54%), and 20 were poorly differentiated (38%). Thirty-three (63%) of the intestinal tumors had high tumor bud scores. Cases with high scores were associated with higher T-stage, N-stage, and grade (P<.001, P<.001, and P=.002). These also had a higher likelihood of recurrence (P=.007). In our cohort, high tumor bud scores in intestinal-type GAC have higher T-stage, N-stage, grade, and likelihood of recurrence. Assessment of tumor budding may guide clinical management in a subset of patients.

Targeting the mitochondrial pyruvate carrier attenuates fibrosis in a mouse model of nonalcoholic steatohepatitis.

Diseases of the liver related to metabolic syndrome have emerged as the most common and undertreated hepatic ailments. The cause of nonalcoholic fatty liver disease is the aberrant accumulation of lipid in hepatocytes, though the mechanisms whereby this leads to hepatocyte dysfunction, death, and hepatic fibrosis are still unclear. Insulin-sensitizing thiazolidinediones have shown efficacy in treating nonalcoholic steatohepatitis (NASH), but their widespread use is constrained by dose-limiting side effects thought to be due to activation of the peroxisome proliferator-activated receptor γ. We sought to determine whether a next-generation thiazolidinedione with markedly diminished ability to activate peroxisome proliferator-activated receptor γ (MSDC-0602) would retain its efficacy for treating NASH in a rodent model. We also determined whether some or all of these beneficial effects would be mediated through an inhibitory interaction with the mitochondrial pyruvate carrier 2 (MPC2), which was recently identified as a mitochondrial binding site for thiazolidinediones, including MSDC-0602. We found that MSDC-0602 prevented and reversed liver fibrosis and suppressed expression of markers of stellate cell activation in livers of mice fed a diet rich in trans-fatty acids, fructose, and cholesterol. Moreover, mice with liver-specific deletion of MPC2 were protected from development of NASH on this diet. Finally, MSDC-0602 directly reduced hepatic stellate cell activation in vitro, and MSDC-0602 treatment or hepatocyte MPC2 deletion also limited stellate cell activation indirectly by affecting secretion of exosomes from hepatocytes. CONCLUSION: Collectively, these data demonstrate the effectiveness of MSDC-0602 for attenuating NASH in a rodent model and suggest that targeting hepatic MPC2 may be an effective strategy for pharmacologic development. (Hepatology 2017;65:1543-1556).

Lymphoid Aggregates Remodel Lymphatic Collecting Vessels that Serve Mesenteric Lymph Nodes in Crohn Disease.

Early pathological descriptions of Crohn disease (CD) argued for a potential defect in lymph transport; however, this concept has not been thoroughly investigated. In mice, poor healing in response to infection-induced tissue damage can cause hyperpermeable lymphatic collecting vessels in mesenteric adipose tissue that impair antigen and immune cell access to mesenteric lymph nodes (LNs), which normally sustain appropriate immunity. To investigate whether analogous changes might occur in human intestinal disease, we established a three-dimensional imaging approach to characterize the lymphatic vasculature in mesenteric tissue from controls or patients with CD. In CD specimens, B-cell-rich aggregates resembling tertiary lymphoid organs (TLOs) impinged on lymphatic collecting vessels that enter and exit LNs. In areas of creeping fat, which characterizes inflammation-affected areas of the bowel in CD, we observed B cells and apparent innate lymphoid cells that had invaded the lymphatic vessel wall, suggesting these cells may be mediators of lymphatic remodeling. Although TLOs have been described in many chronic inflammatory states, their anatomical relationship to preestablished LNs has never been revealed. Our data indicate that, at least in the CD-affected mesentery, TLOs are positioned along collecting lymphatic vessels in a manner expected to affect delivery of lymph to LNs.