Vitelline Vein Research Articles

The biodistribution of polystyrene nanoparticles administered intravenously in the chicken embryo

Nanoplastics can cause severe malformations in chicken embryos. To improve our understanding of the toxicity of nanoplastics to embryos, we have studied their biodistribution in living chicken embryos. We injected the embryos in the vitelline vein at stages 18–19. We injected polystyrene nanoparticles (PS-NPs) tagged with europium- or fluorescence. Their biodistribution was tracked using inductively-coupled plasma mass spectrometry on tissue lysates, paraffin histology, and vibratome sections analysed by machine learning algorithms. PS-NPs were found at high levels in the heart, liver and kidneys. Furthermore, PS-NPs crossed the endocardium of the heart at sites of epithelial-mesenchymal transformation; they also crossed the liver endothelium. Finally, we detected PS-NPs in the allantoic fluid, consistent with their being excreted by the kidneys. Our study shows the power of the chicken embryo model for analysing the biodistribution of nanoplastics in embryos. Such experiments are difficult or impossible in mammalian embryos. These findings are a major advance in our understanding of the biodistribution and tissue-specific accumulation of PS-NPs in developing animals.

In utero pulse injection of isotopic amino acids quantifies protein turnover rates during murine fetal development

Protein translational control is critical for ensuring that the fetus develops correctly and that necessary organsand tissues are formed and functional. We developed an in utero method to quantify tissue-specific protein dynamics by monitoring amino acid incorporation into the proteome after pulse injection. Fetuses of pregnant mice were injected with isotopically labeled lysine and arginine via the vitelline vein at various embyonic days, and organs and tissues were harvested. By analyzing the nascent proteome, unique signatures of each tissue were identified by hierarchical clustering. In addition, the quantified proteome-wide turnover rates were calculated between 3.81E-5 and 0.424 h-1. We observed similar protein turnover profiles for analyzed organs (e.g., liver vs. brain); however, their distributions of turnover rates vary significantly. The translational kinetic profiles of developing organs displayed differentially expressed protein pathways and synthesis rates, which correlated with known physiological changes during mouse development.

Left Atrial Ligation in the Avian Embryo as a Model for Altered Hemodynamic Loading During Early Vascular Development.

Due to its four-chambered mature ventricular configuration, ease of culture, imaging access, and efficiency, the avian embryo is a preferred vertebrate animal model for studying cardiovascular development. Studies aiming to understand the normal development and congenital heart defect prognosis widely adopt this model. Microscopic surgical techniques are introduced to alter the normal mechanical loading patterns at a specific embryonic time point and track the downstream molecular and genetic cascade. The most common mechanical interventions are left vitelline vein ligation, conotruncal banding, and left atrial ligation (LAL), modulating the intramural vascular pressure and wall shear stress due to blood flow. LAL, particularly if performed in ovo, is the most challenging intervention, with very small sample yields due to the extremely fine sequential microsurgical operations. Despite its high risk, in ovo LAL is very valuable scientifically as it mimics hypoplastic left heart syndrome (HLHS) pathogenesis. HLHS is a clinically relevant, complex congenital heart disease observed in human newborns. A detailed protocol for in ovo LAL is documented in this paper. Briefly, fertilized avian embryos were incubated at 37.5 °C and 60% constant humidity typically until they reached Hamburger-Hamilton (HH) stages 20 to 21. The egg shells were cracked open, and the outer and inner membranes were removed. The embryo was gently rotated to expose the left atrial bulb of the common atrium. Pre-assembled micro-knots from 10-0 nylon sutures were gently positioned and tied around the left atrial bud. Finally, the embryo was returned to its original position, and LAL was completed. Normal and LAL-instrumented ventricles demonstrated statistically significant differences in tissue compaction. An efficient LAL model generation pipeline would contribute to studies focusing on synchronized mechanical and genetic manipulation during the embryonic development of cardiovascular components. Likewise, this model will provide a perturbed cell source for tissue culture research and vascular biology.

In utero delivery of miRNA induces epigenetic alterations and corrects pulmonary pathology in congenital diaphragmatic hernia

Structural fetal diseases, such as congenital diaphragmatic hernia (CDH) can be diagnosed prenatally. Neonates with CDH are healthy in utero as gas exchange is managed by the placenta, but impaired lung function results in critical illness from the time a baby takes its first breath. MicroRNA (miR) 200b and its downstream targets in the TGF-β pathway are critically involved in lung branching morphogenesis. Here, we characterize the expression of miR200b and the TGF-β pathway at different gestational times using a rat model of CDH. Fetal rats with CDH are deficient in miR200b at gestational day 18. We demonstrate that novel polymeric nanoparticles loaded with miR200b, delivered in utero via vitelline vein injection to fetal rats with CDH results in changes in the TGF-β pathway as measured by qRT-PCR; these epigenetic changes improve lung size and lung morphology, and lead to favorable pulmonary vascular remodeling on histology. This is the first demonstration of in utero epigenetic therapy to improve lung growth and development in a pre-clinical model. With refinement, this technique could be applied to fetal cases of CDH or other forms of impaired lung development in a minimally invasive fashion.

Portal Vein Variations, Clinical Correlation, and Embryological Explanation: A Review Article.

Portal vein(PV) is a large vein that collects blood from the abdominal part of gall bladder, pancreas, alimentary tract, and spleen and transports to the liver. One of the parts of the extraembryonic venous system, the vitelline veins, is where PV starts.In about five weeks of gestation, a venous plexus is formed, and variations in this plexus lead to portal variance.Thejunction of superior mesenteric and splenic veins is typically where the vein begins to network. There are five types of branching patterns of the right PV: conventional branching, trifurcation branching, early branching, separate segment 7 branching, and separate segment 6 branching.To perform pancreatic, duodenal, and liver surgeries, knowledge of variations in PV formation is important.For surgical and interventional operations to be accurate, it is crucial to understand the architecture of the PV and its anomalies. As distinct regions of the brain connect with one another, portal architecture is frequently observed in imaging investigations. Portal hypertension is characterized as an increase in blood pressure in the portal venous system (PVS) in the context of severe liver disease, such as cirrhosis. Non-invasive methods for examining the anatomy and anomalies of the PV include ultrasound, computed tomography (CT), and magnetic resonance (MR). There are many abnormalities of PVS that have been discussed in the articles such as Congenital PV Absence; PV Branches Congenitally Grow in Structure; Hypoplasia, Atresia, and Stenosis of the PV; and Portosystemic Shunts.

Nanoplastics causes extensive congenital malformations during embryonic development by passively targeting neural crest cells

Nanomaterials are widespread in the human environment as pollutants, and are being actively developed for use in human medicine. We have investigated how the size and dose of polystyrene nanoparticles affects malformations in chicken embryos, and have characterized the mechanisms by which they interfere with normal development. We find that nanoplastics can cross the embryonic gut wall. When injected into the vitelline vein, nanoplastics become distributed in the circulation to multiple organs. We find that the exposure of embryos to polystyrene nanoparticles produces malformations that are far more serious and extensive than has been previously reported. These malformations include major congenital heart defects that impair cardiac function. We show that the mechanism of toxicity is the selective binding of polystyrene nanoplastics nanoparticles to neural crest cells, leading to the death and impaired migration of those cells. Consistent with our new model, most of the malformations seen in this study are in organs that depend for their normal development on neural crest cells. These results are a matter of concern given the large and growing burden of nanoplastics in the environment. Our findings suggest that nanoplastics may pose a health risk to the developing embryo.

Sustained Engraftment in Fanconi Anemia (FA) Mice Using in Utero Hematopoietic Cell Transplantation (IUHCT)

Introduction FA is the most common inherited bone marrow failure syndrome caused by a mutation in one of 23 genes involved in DNA repair; the disease manifests as hematologic abnormalities by age seven with near uniform bone marrow failure in adult patients. The gold standard therapy is bone marrow transplantation (BMT), which portends best outcomes when performed at a young age from Human Leukocyte Antigen (HLA)-matched sibling donors. However, due to the underlying pathophysiology of the disease, FA patients are especially sensitive to the chemoradiation conditioning regimens used with BMT, leading to high short-term morbidity and an increased long-term cancer risk. Due to these challenges of conventional BMT in FA, IUHCT is an attractive non-myeloablative and non-immunosuppressive option capable of inducing donor-specific tolerance when in utero testing has identified pathogenic FA mutations. Here we analyzed whether non-conditioned IUHCT confers fetal engraftment as a potential therapy in the FA mouse disease model. Methods Fanconi anemia type C homozygous mice (Fancc-/-) underwent IUHCT on gestation day 14 (E14) via vitelline vein injections of 1x107 T-cell depleted bone marrow cells from green fluorescent protein (GFP)-expressing congenic donor mice. Littermate wild-type mice served as controls. Donor cell engraftment in peripheral blood and bone marrow was assessed by flow cytometry. To confirm long-term donor HSC engraftment, we performed primary and secondary transplantation of an equivalent number of BM mononuclear cells from either Fancc -/- or wild-type mice that had undergone IUHCT. Statistical analysis was performed via Welch's t-test. P values <0.05 were considered statistically significant; for graphical purposes ***p<0.001; **p<0.002; *p<0.033; nonsignificant, ns. Results Fancc-/- homozygous mice had significantly higher donor GFP+ cell engraftment than wild-type controls at one, three, and six months post-transplantation (Figure 1). This higher engraftment was maintained across cell types in peripheral blood including CD3+ T cells (0.7% vs 3.4%), B220+ B cells (1.2% vs 6.9%), GR1+ granulocytes (1.7% vs 10.6%), and CD11B+ myeloid cells (1.9% vs 11.5%). Analysis of the bone marrow of these mice at 6 months post-transplant similarly showed a trend toward increased donor cell engraftment of progenitor cell populations including LSK, HSPC, LTHSC, STHSC, MPP2, MPP3, MPP4, CLP, CMP, GMP, and MEP cells in Fancc -/- recipients compared to wild-type mice. At all timepoints after primary and secondary transplants, recipient mice engrafted with BM mononuclear cells from prenatally transplanted Fancc -/- mice had higher peripheral blood GFP+ chimerism than those engrafted with BM mononuclear cells from prenatally transplanted wild-type mice (Figure 2). Conclusion Fancc-/- homozygous mice have higher sustained donor cell engraftment compared with wild-type littermates, indicating successful engraftment and possible early selection for wild-type donor cells in this preclinical model. These initial studies support the potential of IUHCT as a therapy for FA and highlight the need for additional studies to identify approaches to enhance donor cell engraftment to more clinically relevant levels. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Umbilical cord vessels other than the umbilical arteries and vein: a histological study of midterm human fetuses.

At birth, the umbilical cord contains various types of thin vessels that are near and outside the umbilicus and separate from the umbilical arteries and vein. These vessels are regarded as the remnant "vitelline vessels" and are often called "umbilical vessels", although this terminology could lead to confusion with the true umbilical arteries and vein. No study has yet comprehensively examined these vessels using histological sections. Our examination of these vessels in 25 midterm fetuses (gestational age: 10-16 weeks) led to five major findings: (i) all specimens had umbilical branches of the inferior epigastric artery; (ii) 5 specimens had vitelline vein remnants; (iii) 4 specimens had a thin artery originating from the left hepatic artery that ran along the umbilical vein; (iv) 2 specimens had a so-called "para-umbilical vein" that was along the umbilical vein and reached the umbilicus; and (v) all specimens had lymphatic vessels originating from the umbilicus that ran caudally along the umbilical artery. The pelvic vein tributaries were well developed along the intra-abdominal umbilical artery, but did not reach the umbilicus. The lymphatic vessel was distinguished from the veins by an intraluminar cluster of lymphocytes attaching to the endothelium. The arterial branch in the umbilical cord did not accompany veins and lymphatic vessels, in contrast to the mother artery in the rectus abdominis. All these thin vessels seemed to be obliterated when the fibrous umbilical ring grew during late-term. The para-umbilical collateral vein in adults might develop outside the fibrous umbilical ring after birth.

Topographical relationships of the yolk sac remnant and vitelline vessels with the midgut loop in the extra-embryonic coelom of human embryos.

The yolk sac is supplied by the vitelline artery and vein (VA, VV), which run through the yolk stalk in combination with the omphaloenteric duct. Moreover, the VV takes a free posterior course outside the midgut mesentery containing the secondarily-developed superior mesenteric vein (SMV). However, the regression process of these structures has not been demonstrated photographically. The present study evaluated serial histological sections from 20 embryos of stages 15–19 or crown-rump length (CRL) 7.5–20 mm. All specimens carried the SMV as sequential tissue slits. However, an omphaloenteric duct with epithelia continuous with the midgut loop was not observed. In smaller embryos (CRL <13 mm) the VA extended distally or anteriorly from the midgut apex in the extra-embryonic coelom, whereas in larger embryos (CRL 16–20 mm) the artery was absent from the distal side of the apex. The entire course or part of the VV outside the mesentery was always seen, but four larger embryos lacked the venous terminal near the duodenum. A vacuole-like remnant of the yolk sac was present in all smaller embryos (CRL <10 mm), but was absent from 7 of the 11 larger embryos. The size of the remnant was equal to the thickness of the VA or VV, with the remnant being sandwiched between the VA and VV. Moreover, the regressing yolk sac often communicated with or opened to the VV. Consequently, the yolk sac regressed first, followed by the regression of the VA until 6 weeks. The yolk stalk was clearly observed until 5 weeks.

Anatomy of the vitelline vein remnant in human embryos and fetuses.

To demonstrate the entire course of the human vitelline vein (VV) in specimens after degeneration of the yolk sac. Sagittal and horizontal histological sections from 8 embryos and 19 fetuses (gestational age approximately 6-12weeks; crown-rump length 11-61mm) were examined. Two types of VV remnants were observed: a long VV on the right superior side of the mesentery of the jejunum (VV1) and a short VV on the left inferior side of the mesentery (VV2). The VV1, observed in 12 specimens, was 20-30 microns in diameter and ran dorsally between the right liver lobe and the jejunum, subsequently merging with an initial superior mesenteric vein on the pancreatic head immediately below the superior portion of the duodenum. The VV2, observed in four specimens, passed dorsally between loops of the ileum on the left side of the mesentery of the ileum and connected to the mesentery. Many of the VVs did not originate from the umbilical cord but suddenly started in the sack of physiological herniation. At 10-12weeks, after herniation, the VVs originated from the umbilicus and were involved by the expanding greater omentum. The right-sided and left-sided VVs seemed to correspond to right and left VV remnants, respectively, and both took an upstream course outside the mesentery of the jejunum and ileum. The right VV upstream portion was likely to disappear later than the left one, but the timing of degeneration varied greatly among individuals, depending on the topographical relationship between the right liver lobe and the jejunum.

Persistent aneurysmal vitelline vein with thrombus successfully managed with anticoagulation

Failure of the vitelline veins to regress as expected during embryonic development may lead to long-term consequences for neonatal patients. This case report describes a full-term infant born with a persistent vitelline vein, after prenatal ultrasound at 32 weeks suggested the presence of multiple venous system malformations. Postnatal imaging, including ultrasound and contrast computerized tomography (CT), confirmed a thrombus within the persistent vitelline vein, in addition to several hepatic embolic infarcts. Persistent aneurysmal vitelline vein with a thrombus is a rare diagnosis that has been previously managed with surgical interventions. This case demonstrates the multi-disciplinary decision to proceed with conservative medical management, and the subsequent resolution of both the thrombus and persistent vitelline vein with anticoagulation alone. • Previous case reports of persistent vitelline vein with thrombus suggest prompt surgical management • Our case showed resolution of vitelline vein thrombus and hepatic infarcts with anticoagulation alone. • Our case suggests the possiblity of conservative medical management in place of surgical management.

In Utero Injections of Nanoparticle Encapsulated Myelin Oligodendrocyte Glycoprotein Peptides Prevent Experimental Autoimmune Encephalopathy Via Central Tolerance

IntroductionIn utero hematopoietic cell transplantation (IUHCT) of allogenic bone marrow mononuclear cells (MNC) results in successful engraftment across immune barriers. This is secondary to immune tolerance that is acquired due to the presence of donor cells in the thymus prior to E17. We have demonstrated that immune tolerance to specific proteins is possible by injecting nanoparticle encapsulated peptides which are taken up by dendritic cells and presented in the thymus.The aim of this study is to show that in utero injections of nanoparticle encapsulated antigen can produce tolerance to that antigen. We demonstrate this by preventing the autoimmune disease Experimental Autoimmune Encephalopathy (EAE, the mouse equivalent of multiple sclerosis) by injecting NPs loaded with the peptide Myelin Oligodendrocyte Glycoprotein (35-55) (MOG35-55.)MethodsIn utero injections of nanoparticles were performed in C57BL/6 mice at E14 intravenously through the vitelline vein. Post-natal boosters were injected subcutaneously at 2, 4, 6, and 8 weeks of age. Disease inducing injections of MOG with Complete Freud's Adjuvant (CFA) was given at 8 1/7 weeks. Intraperitoneal pertussis toxin (PT) was given on the same day as the MOG/CFA and again 48 hours later. Positive controls got MOG/CFA and PT injections. Negative controls got CFA without MOG as well as the PT injections.Mice were monitored for paralysis using the 5-point EAE scoring system for 4 weeks after the MOG/CFA injection. Spines and brains were harvested 2 weeks after the disease inducing MOG/CFA injection. Spines and brains were filtered and then MNCs were isolated using a Percoll gradient. MNCs were stained for CD45, CD19, CD11b, CD3, CD4, CD8, and I-A(b) MOG35-55 tetramer. Cells were then analyzed on the FACSAria™.Results are expressed as mean±SEM, and statistical analysis was performed using 1-way ANOVA with Bonferroni post-hoc tests. Experimental protocols were approved by the Institutional Animal Care and Use Committee at The Children's Hospital of Philadelphia.ResultsMice that received MOG nanoparticles prenatally along with boosters (Group A) developed disease with less frequency than mice that received MOG nanoparticles postnatally along with boosters (Group B) or positive controls (Group D) (52.0% vs 87.5% vs 90.0% p<0.005) supporting the theory that antigen needs to be expressed prior to E17 in the thymus to develop tolerance. Mice that were injected prenatally with MOG nanoparticles and did not receive booster injections (Group C) also did as poorly as positive controls (85.72% vs 90.0%) suggesting that continued antigen expression is necessary to maintain tolerance. Group A also had significantly lower EAE scores on days 15 to 28 compared to Group B, Group C, and the positive control group (p<0.005).Spinal cord and brain analysis of the Group A mice showed significantly fewer CD45 cells compared to the positive control but not the negative control (133.2±52.0 vs 6062.5±1166.9 vs 79.8±15.0 p<0.0001.) The same is seen with CD3 cells (45.6±17.0 vs 4727.3±1283.0 vs 21.3±2.8 p<0.0001) and CD4 cells (12.6±5.7 vs 3339.6912.1 vs 11.8±0.8 p<0.0001.) Finally, the same is seen with CD4+ Tetramer+ cells (0.7±0.3 vs 379.1±156.6 vs 2.9±1.0 p<0.0001) showing that there is central tolerance to the MOG peptide.ConclusionBy decreasing the frequency and average severity of EAE and demonstrating the lack of CD4+ Tetramer+ cells in the spine, we have shown that autoimmune disease can be prevented by central tolerance to the target antigen. We have demonstrated that this central tolerance is possible with prenatal injections of nanoparticle encapsulated peptide. We have also shown that continued antigen presentation is necessary to maintain central tolerance. We hope that nanoparticle encapsulated peptides could provide a possible pharmacological benefit for numerous autoimmune diseases in the future. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

In Utero Hematopoietic Cell Transplantation of Lineage- c-Kit- Sca-1- Cells Is Responsible for Tolerance Induction

IntroductionIn utero hematopoietic cell transplantation (IUHCT) of allogenic bone marrow mononuclear cells (BM MNC) results in mixed hematopoietic chimerism in the murine model. In contrast, highly enriched HSCs (LSKs: Lin- c-Kit+ Sca-1+ cells) do not engraft after allogeneic IUHCT. Tracking studies in the first 72 hours after IUHCT demonstrate relatively large numbers of donor cells in the fetal thymus after IUHCT of BM MNCs, but not after IUHCT of LSK cells. This suggests that a sub-population of BM MNCs are capable of homing to the thymus within a window of opportunity for tolerance induction and that this population is lost, with enrichment of HSC.The aim of this study is to identify the specific cell population within BM MNCs that is responsible for tolerance induction. To achieve this goal, we developed a practical model for determination of prenatal tolerance induction and tested subpopulations of BM MNC for their ability to induce tolerance.MethodsDonor BM MNCs and subpopulations were isolated from 6-week old C57BL/6TgN(act-EGFP)OsbY01) (B6GFP) mice. Lineage (CD3, B220, CD11b, Gr-1) or CD3 depletion of donor cells was performed using magnetic sorting (Auto-MACS Pro Separator) and anti-Biotin microbeads.To isolate the Lin- subpopulations, anti-biotin antibody was used to exclude Lin+ cells, and then the remaining cells were stained for c-Kit and Sca-1 markers.Donor subpopulations were generated by sorting using the FACSAria.IUHCT was performed at E14 in Balb/c fetuses via vitelline vein injection. Post-natal injections were performed at P0 through the facial vein. Donor cell engraftment was assessed in peripheral blood at 4 and 12 weeks of age by flow cytometry (% GFP+ cells within CD45+ population).Thymi and livers of E16 fetuses were harvested and GFP cells were detected using a fluorescence stereomicroscope.Statistical analysis was performed using 1-way ANOVA with Bonferroni post-hoc tests. Results are expressed as mean±SEM. Experimental protocols were approved by the Institutional Animal Care and Use Committee at The Children's Hospital of Philadelphia.ResultsTo develop the model for tolerance assessment we determined that injection of 10^7 CD3 depleted BM MNCs into Balb/c pups at P0 resulted in no engraftment. In contrast, IUHCT at E14 of 10^7 BM MNCs resulted in chimerism (13.2±2.01% chimerism) at 4 weeks with associated donor specific tolerance. Finally, P0 injection of 10^7 CD3 depleted BM MNCs into in mice that had received E14 injections of 10^7 BM MNCs resulted in engraftment with enhancement of chimerism at 4 weeks (38.02±3.67% in E14 plus P0 group vs 0.008±0.005 in P0 only group, p=0.0001).After establishing the model to test tolerance, we performed IUHCT of subpopulations of cells derived from BM MNCs, using the dose of each subpopulation found in 10^7 BM MNCs, to test their potential for tolerance induction. Mice that underwent IUHCT of 10^5 Lin- cells prior to the P0 injection of 10^7 CD3depleted BM MNCs had higher chimerism at 4 weeks than mice that received E14 injections of 10^5 Lin+ cells (9.843±0.79% vs 0.088±0.056%, p=0.0001).Thymuses were harvested from E16 fetuses that were injected at E14 with different subsets of the Lin- population (c-Kit+ Sca-1+, c-Kit- Sca-1+, c-Kit+ Sca-1-, c-Kit- Sca-1int, and c-Kit- Sca-1- cells). The only thymuses to show GFP cells at E16 were those that had received E14 Lin- c-Kit- Sca-1- cells. Mice that received Lin- c-Kit- Sca-1- cells at E14 prior to P0 injections showed chimerism at 4 weeks when compared to those that had received Lin- c-Kit+ Sca-1-, Lin- c-Kit+ Sca-1+, Lin- c-Kit- Sca-1int, or Lin- c-Kit- Sca-1hi cells at E14, in which chimerism was absent (6.755±0.95% vs 0.0%; p=0.02.)ConclusionWe have demonstrated that it is the Lin- c-Kit- Sca-1- subpopulation of BM MNCs that induces tolerance and prevents rejection of subsequent injections from the same donor. We have also shown that only the Lin- c-Kit- Sca-1- population migrates to the thymus in time for the induction of central tolerance. Furthermore, mouse fetuses that were given Lin- c-Kit- Sca-1- intravascularly at E14 were able to become chimeric with a postnatal CD3 depleted MNCs transplantation without immunosuppression or myeloablation. These findings suggest that a c-Kit- Sca-1- progenitor is responsible for tolerance induction, likely via common dendritic progenitors that home to the thymus. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Atypical protein kinase C is essential for embryonic vascular development in mice.

The atypical PKC (aPKC) subfamily constitutes PKCζ and PKCλ in mice, and both aPKC isoforms have been proposed to be involved in regulating various endothelial cell (EC) functions. However, the physiological function of aPKC in ECs during embryonic development has not been well understood. To address this question, we utilized Tie2-Cre to delete PKCλ alone (PKCλ-SKO) or both PKCλ and PKCζ (DKO) in ECs, and found that all DKO mice died at around the embryonic day 11.5 (E11.5), whereas a small proportion of PKCλ-SKO mice survived till birth. PKCλ-SKO embryos also exhibited less phenotypic severity than DKO embryos at E10.5 and E11.5, suggesting a potential compensatory role of PKCζ for PKCλ in embryonic ECs. We then focused on DKO embryos and investigated the effects of aPKC deficiency on embryonic vascular development. At E9.5, deletion of both aPKC isoforms reduced the diameters of vitelline artery and vein, and decreased branching from both vitelline vessels in yolk sac. Ablation of both aPKC isoforms also disrupted embryonic angiogenesis in head and trunk at the same stage, increasing apoptosis of both ECs and non-ECs. Taken together, our results demonstrated that aPKC in ECs plays an essential role in regulating cell apoptosis, angiogenesis, and embryonic survival.

An inferior vena cava discontinuity with an hepato-renal accessory vein development: A radio-anatomical morphometric case study

Inferior vena cava (IVC) agenesis is an uncommon congenital vascular anomaly stemming from aberrant development during embryogenesis. It results from the failure of one or more of the supracardinal veins, subcardinal veins, vitelline veins or postcardinal veins to connect. The symptomatology resulting from this vascular malformation can be either absent or extremely rich and varied. Thoracoabdominal-pelvic CT scan projections following iodine-based contrast product injection were analyzed and a three-dimensional model of vascularization constructed. Herein, an asymptomatic case of IVC agenesis with absence of the suprarenal and renal segments, with azygos continuation, presenting an accessory hepatorenal vein is reported. The presence of this type of accessory vein has never been described in the literature to date. The etiology of this case of IVC agenesis is explored in depth. We also analyzed the morphometric parameters of the IVC remnant segments and the azygos vein in order to quantify the dilatation of the collateral venous pathway overdeveloped to handle blood return. Using the findings from this case and those reported in the literature, we provide general recommendations that should be taken into account before managing a patient, symptomatic or asymptomatic, admitted to the hospital with IVC agenesis.

A case of perihilar cholangiocarcinoma with bilateral ligamentum teres hepatis treated with hepatopancreatoduodenectomy

BackgroundBilateral ligamentum teres (BLT) hepatis is a very rare anomaly defined as the connection of the bilateral fetal umbilical veins to both sides of the paramedian trunk, and it has never been reported in the English literature.Case presentationA 72-year-old man who presented with obstructive jaundice was referred to our hospital. Contrast-enhanced computed tomography revealed that the patient had right-sided ligamentum teres (RSLT) and left-sided ligamentum teres (LSLT). The umbilical portion of the left portal vein, which the LSLT connected, became relatively atrophic in this patient. The RSLT attached to the tip of the right anterior pedicle and formed the umbilical portion of the right portal vein. The patient was diagnosed with perihilar cholangiocarcinoma which had invaded the root of the posterior branch of the bile duct, LHD, and intrapancreatic bile duct. The central bisectionectomy, in which the liver parenchyma was resected along the RHV on the right side and the LSLT on the left side, and caudate lobectomy combined with pancreatoduodenectomy were performed.The presence of the patient with BLT is important for ascertaining the mechanism of the development of RSLT. Two umbilical veins are present initially during the embryonic stage. In general, the right-sided vein disappears, and the atrophic left-sided vein remains connected to the left portal vein originating from the vitelline vein. Several papers on the mechanism of the development of RSLT have been published. Some authors have mentioned that a residue of the right umbilical vein and the disappearance of the left umbilical vein are the causes of RSLT. On the other hand, some authors have asserted that RSLT is the result of atrophy of the medial liver area. The presence of BLT in patients indicates that the mechanism of the development of RSLT is characterized by a residue of the right umbilical vein and the disappearance of the left umbilical vein.ConclusionsThe mechanism and origin of RSLT can be understood through cases of BLT, and surgeons must pay attention to anomalies of the portal and hepatic veins in patients with abnormal ligamentum teres.

Antenatal sonographic features of persistent extrahepatic vitelline vein aneurysm confused with umbilical vein varix

Background: The persistent vitelline vein is a portal venous system malformation arising during the embryonic period. These abnormal blood vessels frequently thrombose and can lead superior mesenteric vein obstruction or portal hypertension. Case report: We visualized a fetal intra-abdominal cystic mass with turbulent flow on prenatal ultrasound at 28 weeks’ gestation. Initially diagnosed as an umbilical vein varix, it was later determined to be an extrahepatic persistent vitelline vein with an internal thrombus by postnatal ultrasound. It was successfully surgically excised. Conclusion: When an abnormal abdominal vascular structure near the umbilicus is found during prenatal ultrasonography, the persistent vitelline vein should be included in the differential diagnosis to allow prompt evaluation and treatment after birth.

Physical Mechanisms Create and Loop the Embryonic Heart

The morphogenetic mechanisms that drive heart early development are poorly understood. The objective of this study was to determine the role played by physical forces in formation and looping of the heart tube. The work involved integrating experiments on chick embryos with computational models based on the fundamental laws of mechanics.For decades, it was commonly thought that the bilateral heart fields in the early embryo fold directly toward the midline, where they meet and fuse to form the primitive heart tube. Recent studies have challenged this view, however, suggesting that the heart fields fold in a diagonal pattern that carries their cranial aspects toward the midline. Our experiments and models suggest that differential anisotropic growth between mesoderm and endoderm drives diagonal folding to simultaneously create both the heart tube and foregut. Then, contraction along the anterior intestinal portal generates tension that elongates both structures.After the heart tube forms, it begins to loop to create the basic pattern of the mature heart. During the first phase of looping (c‐looping), the heart tube bends and twists into a c‐shaped tube. First, we created cylindrical finite‐element models to simulate the bending process in isolated hearts. With the number of free parameters reduced as much as possible, numerical distributions of mechanical stress and strain were compared to those measured in cultured chick hearts. The results show that published patterns of hypertrophic growth yield results that agree reasonably well with the trends in our data. Next, we extended our model to include realistic 3D geometry and the effects of external loads, including those exerted by the omphalomesenteric veins at the caudal end of the heart tube and splanchnopleuric membrane against the ventral surface. The bending and torsional behaviors of the model are in reasonable agreement with available experimental data from both control and perturbed embryos, suggesting that a combination of differential growth and external loads drives cardiac c‐looping.Support or Funding InformationThis research was supported by NIH grants R01 GM075200, R01 HL083393, and R01 NS070918.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Pancreaticoduodenectomy for periampullary adenocarcinoma in a patient with a prepancreatic portal vein

Background: Prepancreatic portal vein (PPPV) is a rare congenital anomaly that Results in the portal vein coursing anterior to the neck of the pancreas due to aberrant regression of the vitelline veins. The presence of this anomaly can present challenges when planning pancreatectomies, even for experienced surgeons. Previously, distal pancreatectomy and total pancreatectomy of an annular pancreas have been described in patients with PPPV. This case demonstrates that pancreaticoduodenectomy for malignancy can be successfully performed in a patient with a PPPV. Methods: An 80 year old woman presented with abdominal pain and obstructive jaundice. Endoscopy demonstrated a 2.7 centimeter periampullary mass that invaded the distal common bile duct requiring stent placement. Biopsy of the mass confirmed the diagnosis of adenocarcinoma. On pre-operative pancreatic protocol computed tomography, she was found to a have a PPPV without evidence of metastases. Given her good functional status and desire for curative therapy, she was consented for a pancreaticoduodenectomy. Results: After confirming the tumor was resectable, we created a tunnel around the pancreas to the left of the PPPV. Pancreatic dissection was continued in the standard fashion. The splenic vein was identified coursing behind the common hepatic artery and superior to the pancreatic body; it was followed to identify the take-off of the gastroduodenal artery which was adjacent to the splenic vein-portal vein confluence. After the bile duct and proximal duodenum were transected, the pancreatic neck was divided. The pancreas was freed from the retroperitoneum with Ligasure device, taking extreme care to preserve the superior mesenteric artery at the mesenteric root. The pancreas was adhered to the posterior superior mesenteric vein (SMV); it was able to be removed with ligation of the middle colic vein and controlled creation of a small venotomy in the SMV with less than five minutes of clamp time. Reconstruction was performed in the standard fashion. Conclusion: PPPV is a rare congenital vascular anomaly. Identification of unusual vascular anatomy is essential prior to undertaking any procedure in the right upper quadrant. Most descriptions of PPPV in the literature are in the pediatric population; there are two pancreatectomies reported in adults for malignancy but neither required a pancreatic anastomosis. We have shown that PPPV does not preclude successful pancreaticoduodenctomy for a malignant process. Pre-operative imaging and planning are essential when approaching any pancreatic procedure in a patient with PPPV.

Altered VEGF Signaling Leads to Defects in Heart Tube Elongation and Omphalomesenteric Vein Fusion in Quail Embryos.

Formation of the endocardial and myocardial heart tubes involves precise cardiac progenitor sorting and tissue displacements from the primary heart field to the embryonic midline-a process that is dependent on proper formation of conjoining great vessels, including the omphalomesenteric veins (OVs) and dorsal aortae. Using a combination of vascular endothelial growth factor (VEGF) over- and under-activation, fluorescence labeling of cardiac progenitors (endocardial and myocardial), and time-lapse imaging, we show that altering VEGF signaling results in previously unreported myocardial, in addition to vascular and endocardial phenotypes. Resultant data show: (1) exogenous VEGF leads to truncated endocardial and myocardial heart tubes and grossly dilated OVs; (2) decreased levels of VEGF receptor 2 tyrosine kinase signaling result in a severe abrogation of the endocardial tube, dorsal aortae, and OVs. Surprisingly, only slightly altered myocardial tube fusion and morphogenesis is observed. We conclude that VEGF has direct effects on the VEGF receptor 2-bearing endocardial and endothelial precursors, and that altered vascular morphology of the OVs also indirectly results in altered myocardial tube formation. Anat Rec, 302:175-185, 2019. © 2018 Wiley Periodicals, Inc.