Nano-engineered VEGF-C ameliorates gut lymphatic drainage, portal pressure and ascites in experimental portal hypertension

Background and AimLymphatic vessels (LVs) are crucial for maintaining abdominal fluid homeostasis and immunity. In liver cirrhosis, mesenteric LVs (mLVs) are dilated and dysfunctional. Given an established protective role of VEGF-C in LVs, we hypothesized that VEGF-C treatment could improve functions of mLVs in cirrhosis. MethodIn this study, we developed a nanoformulation comprising LV-specific growth-factor, recombinant human VEGF-C(Cys156Ser) protein(E-VEGF-C) and delivered it orally in rat models of liver cirrhosis to target mLVs. Nanoformulation without VEGF-C served as vehicle. Drainage of mLVs was analyzed using tracer dye. Portal and systemic physiological assessments and computed-tomography were performed to measure portal pressures and ascites. Gene expression of mesenteric lymphatic endothelial cells (LyECs) was studied. Immune cell subsets in mesenteric lymph nodes (MLNs) were quantified by flow-cytometry. Gut bacterial translocation to MLNs was examined using GFP-labelled bacteria. ResultsIn cirrhotic rats, mLVs were dilated and leaky with impaired drainage. Treatment with E-VEGF-C induced proliferation of VEGFR3+ mLVs, reduced their diameter and improved functional drainage. Ascites and portal pressures were significantly reduced in E-VEGF-C treated rats compared to vehicle. At molecular level, E-VEGF-C treatment upregulated the expression of cell adhesion and permeability genes (VCAM1, VE-Cad) in LyECs. In MLNs of E-VEGF-C rats, there was an increased percentage of CD8+CD134+ T-cells and decreased CD25+Treg-cells. Bacterial translocation was also limited to MLNs only in E-VEGF-C treated rats with reduced levels of endotoxins in ascites in comparison to vehicle. ConclusionE-VEGF-C treatment ameliorates mesenteric lymph drainage, portal pressure, and strengthens cytotoxic immune responses in MLNs in experimental cirrhosis. It may thus serve as a promising therapy to manage ascites and portal pressure and reduce gut bacterial translocation in patients with cirrhosis. Lay SummaryA human recombinant pro-lymphangiogenic growth factor, VEGF-C, was encapsulated in nanolipocarriers (E-VEGF-C) and orally delivered in rat models of decompensated liver cirrhosis to facilitate its gut lymphatic vessel uptake. E-VEGF-C administration significantly increased mesenteric lymphatic vessel proliferation and improved lymph drainage, attenuating abdominal ascites and portal pressures in the animal models. E-VEGF-C treatment limits bacterial translocation to MLNs only with reduced gut bacterial load and ascitic endotoxins. E-VEGF-C therapy holds the potential to manage ascites and portal pressure and reduce gut bacterial translocation in patients with decompensated cirrhosis. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=80 SRC="FIGDIR/small/20248815v4_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1f63596org.highwire.dtl.DTLVardef@1381e52org.highwire.dtl.DTLVardef@14ebe05org.highwire.dtl.DTLVardef@9d559a_HPS_FORMAT_FIGEXP M_FIG C_FIG