Mitochondrial transcription factor A in RORγt+ lymphocytes regulate small intestine homeostasis and metabolism

RORγt+ lymphocytes, including interleukin 17 (IL-17)-producing gamma delta T (γδT17) cells, T helper 17 (Th17) cells, and group 3 innate lymphoid cells (ILC3s), are important immune regulators. Compared to Th17 cells and ILC3s, γδT17 cell metabolism and its role in tissue homeostasis remains poorly understood. Here, we report that the tissue milieu shapes splenic and intestinal γδT17 cell gene signatures. Conditional deletion of mitochondrial transcription factor A (Tfam) in RORγt+ lymphocytes significantly affects systemic γδT17 cell maintenance and reduces ILC3s without affecting Th17 cells in the gut. In vivo deletion of Tfam in RORγt+ lymphocytes, especially in γδT17 cells, results in small intestine tissue remodeling and increases small intestine length by enhancing the type 2 immune responses in mice. Moreover, these mice show dysregulation of the small intestine transcriptome and metabolism with less body weight but enhanced anti-helminth immunity. IL-22, a cytokine produced by RORγt+ lymphocytes inhibits IL-13-induced tuft cell differentiation in vitro, and suppresses the tuft cell-type 2 immune circuit and small intestine lengthening in vivo, highlighting its key role in gut tissue remodeling.

Endoscopic ultrasound-guided biopsy in chronic liver disease: a randomized comparison of 19-G FNA and 22-G FNB needles

Background and study aims  Endoscopic ultrasound-guided liver biopsy uses a 19-gauge (G) needle for parenchymal liver biopsies. We evaluated tissue yields with a 22G fine-needle biopsy (FNB) versus 19G FNA fine-needle aspirate (FNA) device. Patients and methods  Biopsies were obtained from 20 patients using the 19G FNA and 22G FNB randomizing each in a cross-over fashion with a blinded outcome assessor. Tissue adequacy for histologic evaluation was the primary outcome, or the proportion of specimens obtaining pathologic diagnosis (portal structures ≥ 5 or length of the longest piece ≥ 15 mm). Additional secondary outcomes included portal and centrilobular inflammation/fibrosis, length of the longest piece, aggregate specimen length, and small (< 5 mm), medium (5 - 8 mm) and large (> 8 mm) fragments. Results were compared in a per needle basis. Patients with cirrhosis were excluded. Results  Eighty biopsies (40 each 19G FNA and 22G FNB) were obtained. Tissue adequacy was greater for the 19G FNA (88 %) versus 22G FNB (68 %), ( P  = 0.03). There was no difference in total portal structures for the 19G FNA (7.4) and 22G FNB (6.1), ( P  = 0.28). There was no difference in pre-processing outcomes. After processing, length of the longest piece was higher for the 19G FNA (9.1 mm) versus 22G FNB (6.6 mm), ( P  = 0.02). More total post-processing small fragments 29.9 versus 20.7, ( P  = 0.01) and fewer large fragments 1.0 versus 0.4 for the 22G FNB ( P  = 0.01) were detected. Conclusions  Tissue adequacy was higher for the 19G FNA versus 22G FNB needle. The 22G FNB needle produced samples more prone to fragmentation during specimen processing.

A prospective pilot comparison of wet and dry heparinized suction for EUS-guided liver biopsy (with videos)

BACKGROUND AND AIMS

As EUS-guided liver biopsy sampling (EUS-LB) becomes more widely used, further studies have investigated ways to improve tissue yields. Use of a heparin-primed needle may lead to less clotting of blood within the needle, improve tissue recovery, and decrease fragmentation. The purpose of this study was to prospectively evaluate wet suction using a heparin-primed needle for EUS-LB.

METHODS

This was a prospective crossover study evaluating wet suction for EUS-LB in parenchymal liver disease. The primary outcome was specimen adequacy, defined by an aggregate specimen length ≥15 mm and ≥5 complete portal tracts (CPTs). Secondary outcomes included number of CPTs, length of the longest piece, aggregate specimen length, and number of small (≤4 mm), medium (5-8 mm), and large (≥9 mm) fragments. Adverse events were tracked at 7 and 30 days.

RESULTS

One hundred twenty biopsy specimens were collected from 40 participants (3 specimens per patient). Specimen adequacy occurred in 39 wet heparin (98%), 37 dry heparin (93%), and 30 dry needle biopsy samples (80%; 95% confidence interval [CI], .14-.18; P = .01). There was no difference between dry needle techniques. Length of the longest piece was 8.9 mm for wet heparin and 5.8 mm for dry techniques (95% CI, .33-1.53; P = .003). Aggregate specimen length was 49.2 mm for wet heparin and 23.9 mm for dry heparin (95% CI, -46.34 to 44.94; P = .003). Mean CPT count was 7.0 for wet heparin versus 4.0 for dry (95% CI, .74-6.26; P = .01). There were more medium (2.0 vs 1.0; 95% CI, .06-1.24; P = .03) and large (1.0 versus 0.0; 95% CI, .33-1.53; P = .003) fragments with wet suction with no difference in small fragments between groups.

CONCLUSIONS

The use of wet suction EUS-LB demonstrated improved tissue adequacy compared with dry needle techniques. (Clinical trial registration number: NCT03103997.).

Restriction of IL-22-producing T cell responses and differential regulation of regulatory T cell compartments by zinc finger transcription factor Ikaros

Proper immune responses are needed to control pathogen infection at mucosal surfaces. IL-22-producing CD4(+) T cells play an important role in controlling bacterial infection in the gut; however, transcriptional regulation of these cells remains elusive. In this study, we show that mice with targeted deletion of the fourth DNA-binding zinc finger of the transcription factor Ikaros had increased IL-22-producing, but not IL-17-producing, CD4(+) T cells in the gut. Adoptive transfer of CD4(+) T cells from these Ikaros-mutant mice conferred enhanced mucosal immunity against Citrobacter rodentium infection. Despite an intact in vivo thymic-derived regulatory T cell (Treg) compartment in these Ikaros-mutant mice, TGF-β, a cytokine well known for induction of Tregs, failed to induce Foxp3 expression in Ikaros-mutant CD4(+) T cells in vitro and, instead, promoted IL-22. Aberrant upregulation of IL-21 in CD4(+) T cells expressing mutant Ikaros was responsible, at least in part, for the enhanced IL-22 expression in a Stat3-dependent manner. Genetic analysis using compound mutations further demonstrated that the aryl hydrocarbon receptor, but not RORγt, was required for aberrant IL-22 expression by Ikaros-mutant CD4(+) T cells, whereas forced expression of Foxp3 was sufficient to inhibit this aberrant cytokine production. Together, our data identified new functions for Ikaros in maintaining mucosal immune homeostasis by restricting IL-22 production by CD4(+) T cells.

Immunohistochemical stains of proliferating cell nuclear antigen, insulin-like growth factor 2 and clusterin help distinguish malignant from benign liver nodular lesions

AIMS

To explore the immunohistochemical utility of proliferating cell nuclear antigen (PCNA), insulin-like growth factor 2 (IGF2) and clusterin in the distinction between malignant and benign liver nodular lesions.

METHODS

Immunohistochemical stains for PCNA, IGF2 and clusterin were performed on 284 liver nodular lesions, including 33 hepatocellular adenomas (HCA), 40 focal nodular hyperplasias (FNH), 77 large regenerative nodules (LRN) and 134 hepatocellular carcinomas (HCC).

RESULTS

Strong and diffuse nuclear PCNA immunoreactivity was observed in 103 (77%) HCCs but in only 2 (6%) HCAs. None of the FNH and LRN cases showed a strong and diffuse staining pattern. All HCAs, 95% of FNHs and 92% of LRNs showed cytoplasmic IGF2 expression, with a strong staining observed in 70% of HCAs, 20% of FNHs and 30% of LRNs. This was in marked contrast to that observed in HCCs, where 66% of HCCs demonstrated a weak and focal/patchy immunostaining pattern and another 25% showed no detectable IGF2 immunoreactivity. In comparison with their adjacent non-lesional hepatocytes, 75% of HCCs showed decreased IGF2 expression. However, decreased IGF2 expression was not evident in HCAs, FNHs and LRNs. Cytoplasmic staining for clusterin was seen in both benign and malignant nodular lesions. However, an enhanced and exaggerated pericanalicular staining pattern was observed in 75% of HCCs, which was not demonstrated in HCAs, FNHs and LRNs.

CONCLUSIONS

PCNA, IGF2 and clusterin show unique immunostaining characteristics in HCCs, which can be useful adjuncts to other currently available markers to aid in the distinction of HCC from benign liver nodular lesions.

Iron deposition surrounding the hepatic veins of cirrhotic patients on MRI

PURPOSE

To provide the first description of a pattern of iron deposition surrounding the hepatic veins in patients with alcoholic cirrhosis and postulate the reason for these findings.

MATERIALS AND METHODS

Two institutions' teaching files were searched for abdominal MRI studies between January 2003 and April 2009 which showed iron deposition within the liver surrounding the hepatic veins. MRI exams were reviewed by two radiologists for iron deposition and signs of portal hypertension. Liver explant pathology reports were also reviewed.

RESULTS

Four patients with alcoholic cirrhosis demonstrated perihepatic vein low signal intensity on T1 gradient echo images correlating with iron overload confirmed at histopathologic evaluation of explanted livers.

CONCLUSION

This is the first described uncommon distribution of iron deposition surrounding the hepatic veins. This pattern is well seen on in-phase T1 gradient echo sequences because of the T2* effects in this sequence.

Lack of HER2 overexpression and amplification in small intestinal adenocarcinoma

HER2 overexpression and amplification have been studied as a therapeutic and prognostic target in a number of human cancers, including esophageal, gastric, and colorectal adenocarcinomas. However, HER2 status has not been well investigated in primary small intestinal adenocarcinoma, probably because of its rarity. In this study, we conducted immunohistochemical analysis and fluorescence in situ hybridization (FISH) for HER2 on 49 primary nonampullar small intestinal adenocarcinomas. The results showed a complete lack of HER2 protein expression in 47 cases (96%) by immunohistochemical analysis. Only 2 cases (4%) showed a 1+ staining pattern. No tumors exhibited 2+ or 3+ HER2 immunoreactivity. By FISH, none of the tumors, including those with 1+ HER2 immunoreactivity, exhibited HER2 gene amplification. These observations demonstrate that HER2 protein overexpression and gene amplification are infrequent events, if they occur at all, in small intestinal adenocarcinoma. Thus, routine immunohistochemical and/or FISH testing for HER2 for potential targeted anti-HER2 therapy may not be beneficial for patients with primary small intestinal adenocarcinoma.

Expression of mucins, SIMA, villin, and CDX2 in small-intestinal adenocarcinoma

Expression of gastrointestinal biomarkers MUC1, MUC2, MUC5AC, small-intestinal mucin antigen (SIMA), villin, and CDX2 has been studied in colorectal adenocarcinoma (CRC). Little is known, however, about their expression in small-intestinal adenocarcinoma (SIA). We immunohistochemically compared 30 SIAs with 48 CRCs for the expression of these biomarkers. The results showed that all 6 proteins were variably expressed in SIA, but the frequencies of expression were significantly lower than those for CRC with the exception of MUC1. Specifically, positive staining for MUC1, MUC2, MUC5AC, SIMA, villin, and CDX2 was observed in 16 (53%), 17 (57%), 12 (40%), 15 (50%), 20 (67%), and 18 (60%) of SIAs and 25 (52%), 43 (90%), 39 (81%), 45 (94%), 47 (98%), and 47 (98%) of CRCs, respectively. In addition, SIAs more frequently exhibited a focal staining pattern for MUC2, MUC5AC, SIMA, and villin, whereas more diffuse immunoreactivity was evident in CRCs. Focal staining for MUC1 and diffuse staining for CDX2 were common for SIAs and CRCs. Furthermore, poorly differentiated SIAs tended to express MUC1 more frequently when compared with well- and moderately differentiated SIAs. These observations further support the notion that SIA is immunophenotypically distinct from CRC despite their morphologic similarity.

Immunohistochemical investigation of tumorigenic pathways in small intestinal adenocarcinoma: a comparison with colorectal adenocarcinoma

Small intestinal adenocarcinoma is an uncommon neoplasm morphologically similar to or indistinguishable from colorectal adenocarcinoma. Although much has been learned about genetic pathways critical to colorectal tumorigenesis, little is known about molecular alterations involved in the development of small intestinal adenocarcinoma. In this study, we immunohistochemically compared non-ampullary small intestinal adenocarcinomas with sporadic colorectal adenocarcinomas for the expression of several proteins known to serve pivotal roles in colorectal tumorigenesis. These included adenomatous polyposis coli and beta-catenin involved in the Wnt signaling pathway, and DNA mismatch repair enzymes hMLH1, hMSH2 and hMSH6 involved in the microsatellite instability pathway. The expression of two important tumor suppressors, p53 and RB, was also examined. The results show that complete loss of adenomatous polyposis coli immunoreactivity, presumably resulting from its gene mutations, was observed in eight of 26 (31%) small intestinal adenocarcinomas and 36 of 51 (71%) colorectal adenocarcinomas (P = 0.0008). Nuclear localization of beta-catenin, an indirect evidence of deregulated Wnt signaling pathway, was observed in 5 (19%) small intestinal adenocarcinomas and 36 (71%) colorectal adenocarcinomas (P<0.0001). Total lack of nuclear staining for one or more of the DNA mismatch repair enzymes occurred in a similar low frequency in both small intestinal and colorectal adenocarcinomas, seen in two of 25 (8%) and 10 of 47 (21%) cases, respectively (P = 0.1958). The frequencies of aberrant p53 and RB expression were also similar between small intestinal and colorectal adenocarcinomas. These observations indicate that defects in the Wnt and microsatellite instability pathways occur in over 90% of colorectal adenocarcinomas, but in only 40% of small intestinal adenocarcinomas. Small intestinal tumorigenesis appears to follow a distinct, yet unidentified, molecular pathway(s) from its colorectal counterpart despite their morphologic similarity.

Identification of a unique gene expression signature that differentiates hepatocellular adenoma from well-differentiated hepatocellular carcinoma

It is often difficult to distinguish hepatocellular adenoma (HCA) from well-differentiated hepatocellular carcinoma (WDHCC) when limited tissue from a needle biopsy is evaluated. The aim of this study was to identify gene expression patterns that can distinguish HCA from WDHCC, with the ultimate goal of discovering novel diagnostic markers. Gene expression profile analysis was performed using Affymetrix U133Plus2 GeneChip microarrays on RNA isolated from frozen tissue of 6 HCA and 8 WDHCC specimens. Statistical analysis of microarray data identified 63 genes whose expression levels were significantly different between HCA and WDHCC. These included 57 genes overexpressed by HCA and 6 overexpressed by WDHCC. Eight genes were chosen for further analysis by quantitative RT-PCR on RNA derived from archived, paraffin-embedded tissue blocks of an independent validation set comprising 9 HCAs and 9 HCCs. Seven of the 8 genes demonstrated average expression differences between HCA and HCC that were concordant with the microarray findings, and their expression pattern correctly classified the 18 tumors into HCA and HCC using unsupervised clustering analysis. Furthermore, immunohistochemical staining performed on a third, independent set of 27 HCAs and 33 HCCs confirmed the expression differences at protein levels for 5 of the genes. Taken together, our data demonstrate significant molecular differences between HCA and WDHCC, despite their morphologic similarity. More importantly, we have identified a unique set of genes whose expression pattern can discriminate between these two types of hepatocellular neoplasms, suggesting the possibility of future development of ancillary molecular and immunohistochemical diagnostic methods.

Differential Expression of α-Methylacyl Coenzyme A Racemase in Adenocarcinomas of the Small and Large Intestines

Alpha-methylacyl coenzyme A racemase (AMACR), a novel immunomarker for prostatic adenocarcinoma, has recently been shown to be expressed in a number of malignancies including colorectal adenocarcinoma. In the current study, 59 surgically resected primary small intestinal adenocarcinomas (34 ampullary and 25 non-ampullary) were immunohistochemically examined for AMACR expression and compared with 66 colorectal adenocarcinomas (including 24 secondary tumors involving the small intestine by direct extension or metastasis). The results show that no AMACR immunoreactivity was detected in normal-appearing small and large intestinal mucosa. While 41 of 66 (62%) colorectal adenocarcinomas exhibited a variable degree of cytoplasmic staining, only 1 of 25 (4%) non-ampullary and 2 of 34 (6%) ampullary small intestinal adenocarcinomas showed positive AMACR immunoreactivity (P < 0.0001). Interestingly, AMACR appeared to be less frequently expressed in mucinous or poorly differentiated colorectal adenocarcinomas when compared with non-mucinous or better-differentiated counterparts, suggesting an association with microsatellite instability status. These results extend our previous observations that small intestinal adenocarcinomas differ markedly from colorectal adenocarcinomas despite their morphologic similarity. The different AMACR expression patterns may not only provide an additional diagnostic tool in the distinction between adenocarcinomas of the small and large intestinal origins but may also shed light on further understanding of intestinal tumorigenesis.

Alteration of Cytokeratin 7 and Cytokeratin 20 Expression Profile Is Uniquely Associated With Tumorigenesis of Primary Adenocarcinoma of the Small Intestine

Twenty-four cases of primary nonampullary small intestinal adenocarcinoma were immunohistochemically examined for the expression of cytokeratin (CK) 7 and CK20 and compared with 23 colorectal adenocarcinomas secondarily involving the small intestine by direct extension or metastasis. While normal small intestinal mucosa was diffusely positive for CK20 and completely negative for CK7 expression, all small intestinal adenocarcinomas (24 of 24) showed a variable degree of CK7 expression. Specifically, the CK7 staining pattern was diffuse in 13 cases (54%) and focal in the remaining cases. Sixteen small intestinal adenocarcinomas (67%) coexpressed CK7 and CK20, and 8 (33%) completely lost CK20 immunoreactivity when compared with adjacent non-neoplastic small intestinal mucosa. In the latter cases, the loss of CK20 immunoreactivity with a reciprocal emergence of CK7 expression was evident. This was in contrast to secondary colorectal adenocarcinomas where 22 cases (96%) expressed CK20, among which only 1 case showed focal CK7 expression. The remaining 1 case was negative for both CK7 and CK20. Interestingly, adenomatous epithelium associated with small intestinal adenocarcinomas identified in 18 cases also exhibited CK7 positivity with a sharp transition from CK7-negative normal-appearing epithelium. Taken together, these observations delineate an alteration of CK7 and CK20 expression profile that occurs early in small intestinal tumorigenesis. This unique pattern may be of diagnostic value in distinguishing primary small intestinal adenocarcinoma from secondary colorectal adenocarcinoma.