Intraoperative contrast-enhanced ultrasound has an outcome-relevant impact on surgery of primary and metastatic liver lesions

PURPOSE

Complete resection of the affected tissue remains the best curative treatment option for liver-derived tumors and colorectal liver metastases. In addition to preoperative cross-sectional imaging, contrast-enhanced intraoperative ultrasound (CE-IOUS) plays a crucial role in the detection and localization of all liver lesions. However, its exact role is unclear. This study was designed to evaluate the clinical and oncological impact of using CE-IOUS in the surgical treatment of these diseases.

MATERIALS AND METHODS

Over the three-year study period, 206 patients with primary liver tumors and hepatic metastases were enrolled in this prospective, monocentric study to evaluate the impact of CE-IOUS in liver surgery. Secondary outcomes included comparing the sensitivity and specificity of CE-IOUS with existing preoperative imaging modalities and identifying preoperative parameters that could predict a strategic impact of CE-IOUS. In addition, the oncological significance of CE-IOUS was evaluated using a case-cohort design with a minimum follow-up of 18 months.

RESULTS

CE-IOUS findings led to a change in surgical strategy in 34% of cases (n=70/206). The accuracy in cases with a major change could be confirmed histopathologically in 71.4% of cases (n=25/35). The impact could not be predicted using parameters assumed to be clinically relevant. An oncological benefit of a CE-IOUS adapted surgical approach was demonstrated in patients suffering from HCC and colorectal liver metastases.

CONCLUSION

CE-IOUS may significantly increase R0 resection rates and should therefore be used routinely as an additional staging method, especially in complex liver surgery.

Immune profile of patients with peritoneal carcinomatosis selected for CRS-HIPEC therapy

Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is a treatment option for peritoneal carcinomatosis (PC) from colorectal cancer (CRC), which is otherwise a terminal stage of disease. Nevertheless, survival outcomes are only marginally superior to other treatments. This fact highlights the need for better strategies to control intra-abdominal disease recurrence after CRS-HIPEC, including the complementary use of immunotherapies. The aim of this study was therefore to investigate the immune phenotype of T cells in patients with PC. Fifty three patients with CRC (34 patients with PC and 19 patients without PC) were enrolled in a prospective study (clinicaltrials.gov: NCT04108936). Peripheral blood and omental fat were collected to isolate peripheral blood mononuclear cells (PBMCs) and adipose tissue mononuclear cells (ATMCs). These cells were analysed by flow cytometry using a panel focused upon T cell memory differentiation and exhaustion markers. We found a more naïve profile for CD8+ T cells in peripheral blood and intra-abdominal fat of PC patients compared to comparator group (CG) patients. Furthermore, there was an over-representation of CD4+ T cells expressing inhibitory receptors in adipose tissue of PC patients, but not in blood. Our description of intraperitoneal T cell subsets gives us a better understanding of how peritoneal carcinomatosis shapes local immune responses.

Immunomodulation of Natural Killer Cell Function by Ribavirin Involves TYK-2 Activation and Subsequent Increased IFN-γ Secretion in the Context of In Vitro Hepatitis E Virus Infection

Hepatitis E virus (HEV) is a major cause of acute hepatitis globally. Chronic and fulminant courses are observed especially in immunocompromised transplant recipients since administration of ribavirin (RBV) does not always lead to a sustained virologic response. By in vitro stimulation of NK cells through hepatoma cell lines inoculated with a full-length HEV and treatment with RBV, we analyzed the viral replication and cell response to further elucidate the mechanism of action of RBV on immune cells, especially NK cells, in the context of HEV infection. Co-culture of HEV-infected hepatoma cells with PBMCs and treatment with RBV both resulted in a decrease in viral replication, which in combination showed an additive effect. An analysis of NK cell functions after stimulation revealed evidence of reduced cytotoxicity by decreased TRAIL and CD107a degranulation. Simultaneously, IFN-ɣ production was significantly increased through the IL-12R pathway. Although there was no direct effect on the IL-12R subunits, downstream events starting with TYK-2 and subsequently pSTAT4 were upregulated. In conclusion, we showed that RBV has an immunomodulatory effect on the IL-12R pathway of NK cells via TYK-2. This subsequently leads to an enhanced IFN-ɣ response and thus, to an additive antiviral effect in the context of an in vitro HEV infection.

Covid19 vaccination-associated portal vein thrombosis-An interdisciplinary clinical challenge

Despite one of the largest vaccination campaigns in human history, the COVID-19 pandemic has not been yet defeated. More than 10 billion doses of COVID-19 vaccine have been administered worldwide. AstraZeneca's Vaxzevria (ChAdOx1 nCoV-19 / AZD1222) was approved as the first viral vector-based vaccine in the EU on 29 January 2021. Thromboembolic events are a rare complication of vaccination with ChAdOx1 nCoV-19 in the context of, now known as vaccine-induced immune thrombotic thrombocytopenia (VITT), with an incidence of 1.5-3 in 100,000 vaccinations. VITT is clinically as well as pathophysiologically comparable to heparin-induced thrombocytopenia. Illustrated by a fulminant patient case, a multidisciplinary step-by-step guideline was developed for the recognition, diagnosis, and management of patients with severe acute portosplanchic venous thrombosis with mesenteric ischemia due to vaccine-induced immunogenic thrombotic thrombocytopenia.

Development of a Flow Cytometry Assay to Predict Immune Checkpoint Blockade-Related Complications

Treatment of advanced melanoma with combined immune checkpoint inhibitor (ICI) therapy is complicated in up to 50% of cases by immune-related adverse events (irAE) that commonly include hepatitis, colitis and skin reactions. We previously reported that pre-therapy expansion of cytomegalovirus (CMV)-reactive CD4⁺ effector memory T cells (T_EM) predicts ICI-related hepatitis in a subset of patients with Stage IV melanoma given αPD-1 and αCTLA-4. Here, we develop and validate a 10-color flow cytometry panel for reliably quantifying CD4⁺ T_EM cells and other biomarkers of irAE risk in peripheral blood samples. Compared to previous methods, our new panel performs equally well in measuring CD4⁺ T_EM cells (agreement = 98%) and is superior in resolving CD4⁺ CD197⁺ CD45RA^- central memory T cells (T_CM) from CD4⁺ CD197⁺ CD45RA⁺ naive T cells (T_naive). It also enables us to precisely quantify CD14⁺ monocytes (CV = 6.6%). Our new “monocyte and T cell” (MoT) assay predicts immune-related hepatitis with a positive predictive value (PPV) of 83% and negative predictive value (NPV) of 80%. Our essential improvements open the possibility of sharing our predictive methods with other clinical centers. Furthermore, condensing measurements of monocyte and memory T cell subsets into a single assay simplifies our workflows and facilitates computational analyses.

Virus-specific memory T cell responses unmasked by immune checkpoint blockade cause hepatitis

Treatment of advanced melanoma with combined PD-1/CTLA-4 blockade commonly causes serious immune-mediated complications. Here, we identify a subset of patients predisposed to immune checkpoint blockade-related hepatitis who are distinguished by chronic expansion of effector memory CD4⁺ T cells (T_EM cells). Pre-therapy CD4⁺ T_EM cell expansion occurs primarily during autumn or winter in patients with metastatic disease and high cytomegalovirus (CMV)-specific serum antibody titres. These clinical features implicate metastasis-dependent, compartmentalised CMV reactivation as the cause of CD4⁺ T_EM expansion. Pre-therapy CD4⁺ T_EM expansion predicts hepatitis in CMV-seropositive patients, opening possibilities for avoidance or prevention. 3 of 4 patients with pre-treatment CD4⁺ T_EM expansion who received αPD-1 monotherapy instead of αPD-1/αCTLA-4 therapy remained hepatitis-free. 4 of 4 patients with baseline CD4⁺ T_EM expansion given prophylactic valganciclovir and αPD-1/αCTLA-4 therapy remained hepatitis-free. Our findings exemplify how pathogen exposure can shape clinical reactions after cancer therapy and how this insight leads to therapeutic innovations.

In vivo detection of breast cancer liver metastases in humanized tumour mice using tumour specific contrast agent BR55®

OBJECTIVE

To investigate the diagnostic accuracy of high-resolution ultrasound (HRU) for the detection of hepatic metastases of breast cancer in a humanized tumour mouse (HTM) using clinical standard technology. In addition, the efficiency of standard contrast-enhanced ultrasound (CEUS) [microbubbles of sulphur hexafluoride] and CEUS using a novel VEGFR2-targeted contrast agent [BR55®] was examined.

METHODS

A total of 14 HTM were sonographically examined twice. In addition to a human immune system, the animals developed hepatic tumour lesions after intrahepatic injection of BT-474 breast cancer cells. Digital cine loops from the arterial phase (15-35 sec), the portal venous phase (35-90 sec) and the late phase (3-15 min) of the entire liver were analysed. Data were correlated to histopathology.

RESULTS

After 9 months, half of the mice (7/14) revealed the development of hepatic breast cancer metastases. The detection limit was 1 mm tumour diameter. In particular, the use of targeted contrast media reduced the needed tumour diameter and helped to precisely classify tumour tissue. In 93% (13/14), the findings of ultrasound could be approved by histological examination by the pathologist.

CONCLUSIONS

This study in HTM demonstrated the high feasibility of tumour specific contrast media and standard HRU contrast agents to detect early liver metastases.

High-Resolution Ultrasound Including Contrast-Enhanced Ultrasound (CEUS) for the Detection of Gas Formation during Aspergillus Fumigatus Infection in Mice

PURPOSE

A. fumigatus infections represent a major threat for patients with a suppressed immune system. Early diagnosis is of importance for a favorable outcome but appears to be difficult due to limited diagnostic procedures. Here we investigated the sensitivity of high-resolution ultrasound (HRU) for the detection of A. fumigatus infection in the liver.

MATERIALS AND METHODS

BALB/c mice were intravenously infected with A. fumigatus and monitored by HRU, Doppler sonography (CCDS), contrast-enhanced ultrasound (CEUS), and real-time strain color-coded elastography (CCE) using a multi-frequency probe (6 - 15 MHz). Contrast media bolus injection of sulfur-hexafluoride micro-bubbles was applied and digital cine-loops from the arterial phase, as well as the portal venous phase up to the late phase of the whole liver were analyzed. All data were correlated to the histopathological findings.

RESULTS

Using HRU and CEUS, a sonic shadow was detected in all infected animals. All Aspergillus-infected nodes from 3 - 6 mm in the liver showed a shadow with rim enhancement and no intranodal enhancement when using CEUS. A. fumigatus infection was confirmed by CFU assessment and histopathological analysis. Granulomas were not associated with shadowing on B-mode. In contrast, granulomas with a diameter above 5 mm and a higher stiffness in CCE generated particularly an arterial rim enhancement and portal venous washout without contrast media uptake in the late phase. In addition, CEUS was able to define dynamic capillary microvascularization of infected liver areas.

CONCLUSION

Liver lesions associated with A. fumigatus infection can be detected in mice when combined with CEUS and CCE in vivo.

Reduktive Enthalogenierung von (Cl, Br)RP–CH2–PR(Cl, Br) mit Fe2(CO)9– Bildung von Komplexen mit gespannten Diphosphirangerüsten und bifunktionellen Phosphidobrücken (µ2-PR)2CH2 / Reductive Dehalogenation of (Cl, Br)RP–CH2—PR(Cl, Br) with Fe2(CO)9– Formation of Complexes with Strained Diphosphirane Skeletons and Bifunctional Phosphido Bridges (μ2-PR)2CH2

Reductive dehalogenation of the bifunctional methylene bridged halogenphosphines XRP-CH2—PRX (X = Cl, Br; R = iPr, tBu, 2,4,6-R′3C6H2 (R′ = Me, iPr, tBu), N(SiMe3)2 and 2,6,4-tBu2MeC6H2—O) with diironenneacarbonyl affords phosphido complexes with strained RP—CH2—PR backbones, Fe2(CO)6[(μ2-PR)2CH2] (8a-8g). X-Ray structural analyses of the 2,4,6-iPr3C6H2 (8d) and 2,6,4-tBu2MeC6H2—O derivatives (8g) reveal that the Fe2P2C skeletons have remarkably small P—C—P angles (83,7(4)° (8d), 78,6(1)° (8g)).

The dehalogenation of XRP—CH2—PRX with Fe,(CO)9 is preceded by the formation of iron carbonyl complexes (RXP—CH2—PRX)[Fe(CO)4]n (n = 1, 2). For derivatives with bulky substituents R complex formation proceeds diastereoselectively. In case of 3 b the diastereoisomers could be separated and a crystallographic examination of the racemic form showed that the P—C—P backbone possesses C2 symmetry with an approximately trans conformation of the P—C—P fragment. The P-atoms occupy the equatorial position within the Fe(CO)4P units.

The chloro-phosphido bridged complex Fe2(CO)6(μ2-Cl)(µ2-PR—CH2—PRCl—Fe(CO)4) (4a), formed by oxidative addition of a P—Cl bond to Fe(0), or diphosphiranes and their complexes [(RP)2CH2][Fe(CO)4]n (n = 0-2; 5-7) have been isolated as intermediates of the XRP-CH2—PRX dehalogenation. The diphosphiranes 5 were synthesized independently by reduction of the halogenphosphines XRP—CH2—PRX with lithium or magnesium. An X-ray examination of 4a showed that it contains a μ2-PR—CH2—PRCl backbone which bridges Fe2(CO)6(μ2-Cl) and Fe(CO)4 units, the P—C—P angle being remarkably large, 127,3(1)°.

Cyclometallierung und Entalkylierung eines zweizähnigen Chlorphosphans mit Fe2(CO)9/Cyclometallation and Dealkylation of a Bidentate Chlorophosphine by Fe2(CO)9

Treatment of the bifunctional chlorophosphine R2P-CH2-PRCl (R = tBu) with diironenneacarbonyl affords the binuclear complex Fe2(CO)6[μ2,η3-P (tBu )-CH2-P(tBu)-CMe2-CH2] (2) by oxidative addition reaction and metallation of one of the tBu groups within the tBu2P - CH2 unit. At elevated temperatures 2 eliminates isobutene, the phosphido complex Fe2(CO)6[(μ2-P(tBu))2CH2] (3) being formed. The crystal structure of 2 (space group P1̄ with a = 8.663(3), b = 10.849(4), c = 14.618(6) Å, α = 103.02(2), β = 96.32(3), γ = 112.77(2)°, Z = 2) reveals a binuclear complex with a P(tBu) - CH2- P(tBu) - CMe2- CH2 ligand backbone spanning the Fe - Fe bond via a phosphido (μ2-P(tBu)(CH2)) and a phosphinoalkyl (μ2-P(tBu)-CMe2-CH2) bridge. A strained, four-membered P2CFe ring is formed through coordination of the P - C - P donor set to Fe(2).