The C1q-ApoE complex: A new hallmark pathology of viral hepatitis and nonalcoholic fatty liver disease

We recently identified a high-affinity C1q-ApoE complex in human artery atherosclerotic intima lesions and in human amyloid plaques of Alzheimer's Disease brains defining a common pathogenetic pathway of two diverse diseases, i.e. atherosclerosis and dementia. C1q is the initiating and controlling protein of the classical complement cascade (CCC), which occupies a key role in multiple acute and chronic inflammatory tissue responses. C1q is largely produced by myeloid cells including Kupffer cells (KCs) and subsequently secreted into the circulation as an inactive preprotein. Its binding partner, Apolipoprotein E (ApoE), is produced by KCs and hepatocytes and it is also secreted into the circulation, where it regulates essential steps of lipid transport. In addition to its major source, ApoE can be produced by non-liver cells including immune cells and multiple other cells depending on local tissue contexts. To initiate the CCC cascade, C1q must be activated by molecules as varied as oxidized lipids, amyloid fibrils, and immune complexes. However, ApoE is mute towards inactive C1q but binds at high-affinity to its activated form. Specifically, our studies revealed that ApoE is a CCC-specific checkpoint inhibitor via the formation of the C1q-ApoE complex. We proposed that it may arise in multiple if not all CCC-associated diseases and that its presence indicates ongoing CCC activity. Here, we turned to the liver to examine C1q-ApoE complexes in human B- and C-viral hepatitis and nonalcoholic fatty liver disease (NAFLD). In addition, we used multidrug-resistance-2 gene-knockout (Mdr2-KO) mice as a model for inflammatory liver disease and hepatocellular carcinoma (HCC) pathogenesis. In normal murine and human livers, KCs were the major C1q-producing cell type while hepatocytes were the primary ApoE-forming cell type though the C1q-ApoE complex was rare or nonexistent. However, significant numbers of C1q-ApoE complexes formed in both Mdr2-KO, human viral hepatitis, and NAFLD around portal triads where immune cells had infiltrated the liver. Additionally, high numbers of C1q-ApoE complexes emerged in human livers in areas of extracellular lipid droplets across the entire liver parenchyma in NAFLD-affected patients. Thus, the C1q-ApoE complex is a new pathological hallmark of viral hepatitis B and C and NAFLD.

Targeted Hsp70 fluorescence molecular endoscopy detects dysplasia in Barrett's esophagus

PURPOSE

The incidence of esophageal adenocarcinoma (EAC) has been increasing for decades without significant improvements in treatment. Barrett's esophagus (BE) is best established risk factor for EAC, but current surveillance with random biopsies cannot predict progression to cancer in most BE patients due to the low sensitivity and specificity of high-definition white light endoscopy.

METHODS

Here, we evaluated the membrane-bound highly specific Hsp70-specific contrast agent Tumor-Penetrating Peptide (Hsp70-TPP) in guided fluorescence molecular endoscopy biopsy.

RESULTS

Hsp70 was significantly overexpressed as determined by IHC in dysplasia and EAC compared with non-dysplastic BE in patient samples (n = 12) and in high-grade dysplastic lesions in a transgenic (L2-IL1b) mouse model of BE. In time-lapse microscopy, Hsp70-TPP was rapidly taken up and internalized  by human BE dysplastic patient-derived organoids. Flexible fluorescence endoscopy of the BE mouse model allowed a specific detection of Hsp70-TPP-Cy5.5 that corresponded closely with the degree of dysplasia but not BE. Ex vivo application of Hsp70-TPP-Cy5.5 to freshly resected whole human EAC specimens revealed a high (> 4) tumor-to-background ratio and a specific detection of previously undetected tumor infiltrations.

CONCLUSION

In summary, these findings suggest that Hsp70-targeted imaging using fluorescently labeled TPP peptide may improve tumor surveillance in BE patients.

[Barrett Esophagus - Update of clinical management and therapy options]

PATHOGENESIS

Adenocarcinomas of the esophagus are very similar to those of the stomach and most likely develop in the gastric cardia, from where proliferating cells expand into the esophagus and form benign Barrett's mucosa. An additional genomic instability leads to the clonal evolution of certain cells, which can lead to the development of adenocarcinoma.

RISK FACTORS

A clear definition of factors is urgently needed for better risk stratification and the establishment of preventive strategies. Current prediction models, which include overweight, diet or tobacco consumption, have not yet been able to establish themselves in clinical application.

DIAGNOSTICS AND MONITORING

Current guidelines exist for diagnostics and monitoring. The diagnosis of Barrett's esophagus is performed histopathologically from 4-quadrant biopsies. In addition, macroscopically conspicuous areas of the Barrett mucosa should be biopsies. The detection of neoplastic areas can be improved by using chromoendoscopy in combination with magnification endoscopy and staining techniques (methylene blue or acetic acid).

THERAPY

The curatively intended endoscopic resection is the standard therapy for dysplastic Barrett's metaplasia, mucosal (T1a m) and superficial submucosal (T1a sm1) adenocarcinoma. Here, cap and ligature resection as well as endoscopic submucosal dissection (ESD) represent the recommended resection techniques and, in combination with radiofrequency ablation, the therapy according to guidelines.