Tie2 Expressing Monocytes in the Spleen of Patients with Primary Myelofibrosis

Recipient Hepatic Tumor-Associated Immunologic Infiltrates Predict Outcomes After Liver Transplantation for Hepatocellular Carcinoma

Background

Transplantation of the liver entails a state of altered recipient immunologic competence. There are only scarce data concerning the impact of host immunologic factors on the outcome of liver transplant recipients in the context of hepatocellular carcinoma (HCC).

Material/Methods

Our study focused on evaluating the presence of tumor necrosis and frequency levels of angiopoietins and monocytes/macrophages subtypes in the host liver prior to liver transplantation (LTX) and their association with recurrence, graft rejection, survival, and clinical prognosis after LTX. Formation of tumor necrosis and tissue densities of angiopoietins and cellular immunologic infiltrates – CD68⁺ and CD163⁺ macrophages (TAMs) and TIE2-expressing monocytes (TEMs) – were quantified in recipient HCC specimens. The densities were then matched with clinicopathologic variables and patient survival after LTX (n=88). Some patients were treated prior to LTX by neoadjuvant transarterial chemoembolization (TACE, n=55).

Results

Recipient hepatic infiltration with TEMs and CD68⁺ TAMs was associated with decreased 1-, 3-, and 5-year survival, as well as metastatic and recurrent HCC after LTX (all p<0.05). TEMs and infiltrating monocytes/macrophages were associated with angiopoietin expression, metastatic, and recurrent HCC (all p<0.05). Furthermore, hepatic angiopoietin-2 expression was associated with graft rejection after LTX (p<0.05). After TACE and LTX, formation of tumor necrosis was associated with an increased presence of monocytes/macrophages and a reduced incidence of recurrent HCC in the graft (all p<0.05).

Conclusions

Infiltrating monocytes/macrophages subsets and related angiopoietin axis are associated with worse survival, tumor recurrence, and clinical outcome after LTX for HCC.

Experimental murine acute lung injury induces increase of pulmonary TIE2-expressing macrophages

Background

Breakdown of the alveolo-capillary wall is pathognomonic for Acute Lung Injury (ALI). Angiopoietins, vascular-specific growth factors, are linked to endothelial barrier dysfunction, and elevated Angiopoietin-2 (ANG2) levels are associated with poor outcome of ALI patients. Specialized immune cells, referred to as ‘TIE2-expressing monocytes and macrophages’ (TEM), were shown to specifically respond to ANG2 binding. However, their involvement in acute inflammatory processes is so far completely undescribed. Thus, our aim was to assess the dynamics of TEMs in a murine model of ALI.

Results

Intratracheal instillation of LPS induced a robust pulmonary pro-inflammatory response with endothelial barrier dysfunction and significantly enhanced ANG2 expression. The percentage number of TEMs, assessed by FACS analysis, was more than trebled compared to controls, with TEM count in lungs reaching more than 40% of all macrophages. Such distinct dynamic was absent in all other analyzed compartments (alveolar space, spleen, blood). Incubation of the monocytic cell line THP-1 with LPS or TNF-α resulted in a dose-dependent, significant upregulation of TIE2, suggesting that not recruitment from extra-pulmonary compartments but TIE2 upregulation in resident macrophages accounts for increased lung TEM frequencies.

Conclusions

For the first time, our data provide evidence that the activity of TEMs changes at sites of acute inflammation.

Electronic supplementary material

The online version of this article (10.1186/s12950-018-0188-5) contains supplementary material, which is available to authorized users.