Catheter-directed Intraportal Delivery of Endothelial Cell Therapy for Liver Regeneration: A Feasibility Study in a Large-Animal Model of Cirrhosis

Ultrasound-guided hepatic portal vein injection is not a reproducible technique for delivery of cell therapies to the liver in mice

AIMS

Our aim was to determine if ultrasound-guided HPV injection in mice would provide reproducible and reliable results, as is currently obtained via open laparotomy techniques, and offer a surgical refinement to emulate islet transplantation in humans.

METHODS

Fluorescent-polymer microparticles (20 μm) were injected (27G-needle) into the HPV via open laparotomy (n = 4) or under ultrasound-guidance (n = 4) using an MX550D-transducer with a Vevo3100-scanner (FUJIFILM VisualSonics, Inc.). Mice were culled 24-h post injection; organs were frozen, step sectioned (10 μm-slices) and 10 sections/mouse (50 μm-spacing) were quantified for microparticles in the liver and other organs by fluorescent microscopy.

RESULTS

Murine HPV injection, via open laparotomy-route, resulted in widespread distribution of microparticles in the liver, lungs and spleen; ultrasound-guided injection resulted in reduced microparticle delivery (p < 0.0001) and microparticle clustering in distinct areas of the liver at the site of needle penetration, with very few/no microparticles being seen in lung and spleen tissues, hypothesised to be due to flow into the body cavity: liver median (interquartile range) 4.15 (0.00-4.15) versus 0.00 (0.00-0.00) particle-count mm-2 , respectively.

CONCLUSIONS

Ultrasound-guided injection results in microparticle clustering in the liver, with an overall reduction in microparticle number when compared to open laparotomy HPV injection, and high variability in microparticle-counts detected between mice. Ultrasound-guided injection is not currently a technique that can replace open laparotomy HPV of islet transplantation in mice.

Phenotyping of Macrophages After Radiolabeling and Safety of Intra-arterial Transplantation Assessed by SPECT/CT and MRI

Cell therapy is an integral modality of regenerative medicine. Macrophages are known for their sensitivity to activation stimuli and capability to recruit other immune cells to the sites of injury and healing. In addition, the route of administration can impact engraftment and efficacy of cell therapy, and modern neuro-interventional techniques provide the possibility for selective intra-arterial (IA) delivery to the central nervous system (CNS) with very low risk. The effects of radiolabelling and catheter transport on differentially activated macrophages were evaluated. Furthermore, the safety of selective IA administration of these macrophages to the rabbit brain was assessed by single-photon emission computed tomography/computed tomography (SPECT/CT) and ultra-high-field (9.4 T) magnetic resonance imaging (MRI). Cells were successfully labeled with (111In)In-(oxinate)3 and passed through a microcatheter with preserved phenotype. No cells were retained in the healthy rabbit brain after IA administration, and no adverse events could be observed either 1 h (n = 6) or 24 h (n = 2) after cell administration. The procedure affected both lipopolysaccharide/gamma interferon (LPS/IFNγ) activated cells and interleukin 4 (IL4), interleukin 10 (IL10)/transforming growth factor beta 1 (TGFβ1) activated cells to some degree. The LPS/IFNγ activated cells had a significant increase in their phagocytotic function. Overall, the major impact on the cell phenotypes was due to the radiolabeling and not passage through the catheter. Unstimulated cells were substantially affected by both radiolabeling and catheter administration and are hence not suited for this procedure, while both activated macrophages retained their initial phenotypes. In conclusion, activated macrophages are suitable candidates for targeted IA administration without adverse effects on normal, healthy brain parenchyma.

Developmental angiocrine diversification of endothelial cells for organotypic regeneration

Adult organs are vascularized by specialized blood vessels. In addition to inter-organ vascular heterogeneity, each organ is arborized by structurally and functionally diversified populations of endothelial cells (ECs). The molecular pathways that are induced to orchestrate inter- and intra- organ vascular heterogeneity and zonation are shaped during development and fully specified postnatally. Notably, intra-organ specialization of ECs is associated with induction of angiocrine factors that guide cross-talk between ECs and parenchymal cells, establishing co-zonated vascular regions within each organ. In this review, we describe how microenvironmental tissue-specific biophysical, biochemical, immune, and inflammatory cues dictate the specialization of ECs with zonated functions. We delineate how physiological and biophysical stressors in the developing liver, lung, and kidney vasculature induce specialization of capillary beds. Deciphering mechanisms by which vascular microvasculature diversity is attained could set the stage for treating regenerative disorders and promote healing of organs without provoking fibrosis.

A potent protective effect of baicalein on liver injury by regulating mitochondria-related apoptosis

Liver injury is the early stage of liver disease, which is caused by multiple factors. Baicalein has shown extensive bioactivity. But whether baicalein has a protective effect on liver injury has not been reported thus far. In this study, we aim to investigate the protective effects of baicalein on liver injury induced by oxidative stress. H₂O₂ and CCl₄ were employed to establish liver injury models in vivo and in vitro, respectively. The protective effect of baicalein on oxidative stress-induced liver injury was evaluated by detecting the mitochondrial dynamics, the level of autophagy and apoptosis, the histopathology of liver, the indicators of liver function, and the level of oxidative stress in vitro and in vivo. March5 is the key regulator during liver injury induced by oxidative stress. March5 can ubiquitinate Drp1 and promote Drp1 degradation, then maintain the homeostasis of mitochondrial dynamics, keep the balance of autophagy, and reduce apoptosis. Baicalein is able to effectively reduce liver injury; it can contribute to the expression of March5 by regulating KLF4 during liver injury. These results indicate that baicalein plays a key role in salvaging liver from injury induced by oxidative stress via regulating the KLF4-March5-Drp1 signal pathway.

Molecular determinants of nephron vascular specialization in the kidney

Although kidney parenchymal tissue can be generated in vitro, reconstructing the complex vasculature of the kidney remains a daunting task. The molecular pathways that specify and sustain functional, phenotypic and structural heterogeneity of the kidney vasculature are unknown. Here, we employ high-throughput bulk and single-cell RNA sequencing of the non-lymphatic endothelial cells (ECs) of the kidney to identify the molecular pathways that dictate vascular zonation from embryos to adulthood. We show that the kidney manifests vascular-specific signatures expressing defined transcription factors, ion channels, solute transporters, and angiocrine factors choreographing kidney functions. Notably, the ontology of the glomerulus coincides with induction of unique transcription factors, including Tbx3, Gata5, Prdm1, and Pbx1. Deletion of Tbx3 in ECs results in glomerular hypoplasia, microaneurysms and regressed fenestrations leading to fibrosis in subsets of glomeruli. Deciphering the molecular determinants of kidney vascular signatures lays the foundation for rebuilding nephrons and uncovering the pathogenesis of kidney disorders.

The kidney is vascularized with highly specialized and zonated endothelial cells that are essential for its filtration function. Here, Barry et al. provide a single-cell RNA sequencing analysis of the kidney vasculature that highlights its transcriptional heterogeneity and uncovers pathways important for its development and function.

CD133 + cell infusion in patients with colorectal liver metastases going to be submitted to a major liver resection (CELLCOL): A randomized open label clinical trial

BACKGROUND

Treatment of liver metastases of colorectal carcinoma is surgical resection. However, only 10-15% of the patients in this context will be candidate for curative resection arising other 10-13% after response to neoadyuvant chemotherapy. In order to perform the liver metastases surgery, it is necessary to have a sufficient remnant liver volume (RLV) which allows maintaining an optimal liver function after resection. Studies on liver regeneration have determined that CD133 + stem cells are involved in liver hypertrophy developed after an hepatectomy with encouraging results. As presented in previous studies, CD133 + stem cells can be selected from peripheral blood after stimulation with G-CSF, being able to obtain a large number of them. We propose to treat patients who do not meet criteria for liver metastases surgery because of insufficient RLV (<40%) with CD133 + cells together with portal embolization, in order to achieve enough liver volume which avoids liver failure.

METHODS

/Design: The aim of this study is to evaluate the effectiveness of preoperative PVE plus the administration of CD133 + mobilized from peripheral blood with G-CSF compared to PVE only. SECONDARY AIMS ARE: to compare the grade of hypertrophy, speed and changes in liver function, anatomopathological study of hypertrophied liver, to determine the safety of the treatment and analysis of postoperative morbidity and surveillance.

STUDY DESIGN

Prospective randomized longitudinal phase IIb clinical trial, open, to evaluate the efficacy of portal embolization (PVE) together with the administration of CD133 + cells obtained from peripheral blood versus PVE alone, in patients with hepatic metastasis of colorectal carcinoma (CCRHM).

DISCUSSION

The number of CD133 + obtained from peripheral blood after G -CSF stimulation will be far greater than the number obtained with direct puncture of bone marrow. This will allow a greater intrahepatic infusion, which could have a direct impact on achieving a larger and quicker hypertrophy. Consequently, it will permit the treatment of a larger number of patients with an increase on their survival.

TRIAL REGISTRATION

ClinicalTrials.gov, ID NCT03803241.

Distribution of Connective Tissue in the Male and Female Porcine Liver: Histological Mapping and Recommendations for Sampling

The pig is a large animal model that is often used in experimental medicine. The aim of this study was to assess, in normal pig livers, sexual dimorphism in the normal fraction of hepatic interlobular and intralobular connective tissue (CT) in six hepatic lobes and in three macroscopical regions of interest (ROIs) with different positions relative to the liver vasculature. Using stereological point grids, the fractions of CT were quantified in histological sections stained with aniline blue and nuclear fast red. Samples (415 tissue blocks) were collected from healthy piglets, representing paracaval, paraportal and peripheral ROIs. There was considerable variability in the CT fraction at all sampling levels. In males the mean fraction of interlobular CT was 4.7 ± 2.4% (mean ± SD) and ranged from 0% to 11.4%. In females the mean fraction of the interlobular CT was 3.6 ± 2.2% and ranged from 0% to 12.3%. The mean fraction of intralobular (perisinusoidal summed with pericentral) CT was <0.2% in both sexes. The interlobular CT represented >99.8% of the total hepatic CT and the fractions were highly correlated (Spearman r = 0.998, P <0.05). The smallest CT fraction was observed in the left medial lobe and in the paracaval ROI and the largest CT fraction was detected in the quadrate lobe and in the peripheral ROI. For planning experiments involving the histological quantification of liver fibrosis and requiring comparison between the liver lobes, these data facilitate the power analysis for sample size needed to detect the expected relative increase or decrease in the fraction of CT.

The impact of high hydrostatic pressure (40 MPa and 60 MPa) on the apoptosis rates and functional activity of cryopreserved porcine mesenchymal stem cells

The aim of the present study was to examine the influence of two varied high hydrostatic pressure (HHP) values on the apoptosis (assessing caspase-8, survivin, CAD, Bax, BclxL and BclxS) and functional activity (using cocultures with bovine embryos) of porcine mesenchymal stem cells (pBMSCs). pBMSCs were isolated from porcine bone marrow and cultured in vitro. Before cryopreservation and storage in liquid nitrogen, pBMSCs were subjected to HHP values of 40 MPa and 60 MPa for 1 h at 24°C. After thawing, the cells were analysed for caspase-8 activity and protein expression of survivin, CAD, Bax, BclxL and BclxS. To indirectly test the influence of HHP on the functional activity of pBMSCs, in vitro maturated bovine oocytes were fertilized in vitro, and the obtained embryos were cultured under 4 different conditions: 1. monoculture in SOF medium; 2. coculture with pBMSCs in SOF medium; 3. coculture with pBMSCs subjected to 40 MPa HHP in SOF medium and 4. coculture with pBMSCs subjected to 60 MPa HHP in SOF medium. The quality of the developed blastocysts was analysed by TUNEL assay. HHP did not induce apoptosis in pBMSCs, as no significant difference was noted in the expression of any of the analysed apoptosis- related proteins between pBMSCs subjected to HHP (40 MPa or 60 MPa) and control. The highest number of obtained blastocysts was observed when the embryos were cultured in SOF. A highly significant difference (P<0.005) was noted between embryos cultured in SOF and embryos cultured in the presence of pBMSCs subjected to 60 MPa HHP or untreated pBMSCs. A significant difference (P<0.05) was noted between embryos cultured in SOF and embryos cultured in the presence of pBMSCs subjected to 40 MPa HHP. In conclusion, HHP does not induce apoptosis in pBMSCs. The obtained results of the blastocysts cocultured in vitro with pBMSCs (HHP-treated and untreated cells) imply that coculture with pBMSCs has a negative impact on the developmental rates of blastocysts.