The effects of homocysteine and folic acid on angiogenesis and VEGF expression during chicken vascular development

Influence of Maternal Nutrition and One-Carbon Metabolites Supplementation during Early Pregnancy on Bovine Fetal Small Intestine Vascularity and Cell Proliferation

To investigate the effects of nutrient restriction and one-carbon metabolite (OCM) supplementation (folate, vitamin B12, methionine, and choline) on fetal small intestine weight, vascularity, and cell proliferation, 29 (n = 7 ± 1 per treatment) crossbred Angus beef heifers (436 ± 42 kg) were estrous synchronized and conceived by artificial insemination with female sexed semen from a single sire. Then, they were allotted randomly to one of four treatments in a 2 × 2 factorial arrangement with the main factors of nutritional plane [control (CON) vs. restricted feed intake (RES)] and OCM supplementation [without OCM (-OCM) or with OCM (+OCM)]. Heifers receiving the CON level of intake were fed to target an average daily gain of 0.45 kg/day, which would allow them to reach 80% of mature BW by calving. Heifers receiving the RES level of intake were fed to lose 0.23 kg/heifer daily, which mimics observed production responses in heifers that experience a diet and environment change during early gestation. Targeted heifer gain and OCM treatments were administered from d 0 to 63 of gestation, and then all heifers were fed a common diet targeting 0.45 kg/d gain until d 161 of gestation, when heifers were slaughtered, and fetal jejunum was collected. Gain had no effect (p = 0.17) on the fetal small intestinal weight. However, OCM treatments (p = 0.02) displayed less weight compared to the -OCM groups. Capillary area density was increased in fetal jejunal villi of RES - OCM (p = 0.02). Vascular endothelial growth factor receptor 2 (VEGFR2) positivity ratio tended to be greater (p = 0.08) in villi and was less in the crypts (p = 0.02) of the RES + OCM group. Cell proliferation decreased (p = 0.02) in villi and crypts of fetal jejunal tissue from heifers fed the RES + OCM treatment compared with all groups and CON - OCM, respectively. Spatial cell density increased in RES - OCM compared with CON + OCM (p = 0.05). Combined, these data show OCM supplementation can increase expression of VEGFR2 in jejunal villi, which will promote maintenance of the microvascular beds, while at the same time decreasing small intestine weight and crypt cell proliferation.

Imbalance of Angiogenic and Growth Factors in Placenta in Maternal Hyperhomocysteinemia

Numerous studies have shown that various adverse factors of different nature and action mechanisms have similar negative influence on placental angiogenesis, resulting in insufficiency of placental blood supply. One of the risk factors for pregnancy complications with placental etiology is an increased level of homocysteine in the blood of pregnant women. However, the effect of hyperhomocysteinemia (HHcy) on the development of the placenta and, in particular, on the formation of its vascular network is at present poorly understood. The aim of this work was to study the effect of maternal HHcy on the expression of angiogenic and growth factors (VEGF-A, MMP-2, VEGF-B, BDNF, NGF), as well as their receptors (VEGFR-2, TrkB, p75NTR), in the rat placenta. The effects of HHcy were studied in the morphologically and functionally different maternal and fetal parts of the placenta on the 14th and 20th day of pregnancy. The maternal HHcy caused increase in the levels of oxidative stress and apoptosis markers accompanied by an imbalance of the studied angiogenic and growth factors in the maternal and/or fetal part of the placenta. The influence of maternal HHcy in most cases manifested in a decrease in the protein content (VEGF-A), enzymatic activity (MMP-2), gene expression (VEGFB, NGF, TRKB), and accumulation of precursor form (proBDNF) of the investigated factors. In some cases, the effects of HHcy differed depending on the placental part and stage of development. The influence of maternal HHcy on signaling pathways and processes controlled by the studied angiogenic and growth factors could lead to incomplete development of the placental vasculature and decrease in the placental transport, resulting in fetal growth restriction and impaired fetal brain development.

Empagliflozin induces apoptotic-signaling pathway in embryonic vasculature: In vivo and in silico approaches via chick’s yolk sac membrane model

The present investigation was conducted to evaluate the vascular-toxicity of empagliflozin (EMP) in embryonic vasculature. Firstly, the vascular-toxicity of the drug as well as its interaction with apoptotic regulator proteins was predicted via in silico approach. In the next step, the apoptotic-signaling pathway in embryonic vasculature was evaluated using a chick’s YSM model. In silico simulation confirmed vascular-toxicity of EMP. There was also an accurate affinity between EMP, Bax and Bcl-2 (−7.9 kcal/mol). Molecular dynamics assay revealed complex stability in the human body conditions. Furthermore, EMP is suggested to alter Bcl-2 more than BAX. Morphometric quantification of the vessels showed that the apoptotic activity of EMP in embryonic vasculature was related to a marked reduction in vessel area, vessel diameter and mean capillary area. Based on the qPCR and immunohistochemistry assays, enhanced expression level of BAX and reduced expression level of Bcl-2 confirmed apoptotic responses in the vessels of the YSM. We observed that induction of an apoptotic signal can cause the embryonic defect of the vascular system following EMP treatment. The acquired data also raised suspicions that alteration in apoptotic genes and proteins in the vasculature are two critical pathways in vascular-toxicity of EMP.

Fetotoxicity and Subacute Toxicity of Some Plants Involved in the Treatment of Infectious Diarrhea in Benin

This study aimed to provide data on the subacute toxicity and fetotoxicity of aqueous and hydroethanolic extracts of Daniellia oliveri (Rolfe) Hutch. & Dalziel, Anacardium occidentale L., Diospyros mespiliformis Hochst. ex A. DC., Khaya senegalensis (Desv.) A. Juss., Ocimum gratissimum L., Vernonia amygdalina Delile, Pterocarpus erinaceus Poir., and Manihot esculenta Crantz used in the treatment of diarrheal diseases in Benin. For subacute toxicity, each male and female Wistar rat received by esophageal gavage a maximum of 1000 mg/kg over 28 days following the Organization for Economic Co-operation and Development (OECD) Guideline No. 407. Bodyweight changes, biochemical and hematological parameters were assessed. The fetotoxicity of the extracts was evaluated on Dutch Blue hen eggs at 100 mg/kg and 300 mg/kg. The hatching rate, biochemical and hematological constants were subsequently determined. The subacute toxicity data did not indicate any mortality or signs of toxicity. Also, no significant difference in the bodyweight of the rats and the hematological parameters was noted. Concerning fetotoxicity, a low hatching rate (varying from 20% to 50%) was observed in the batches treated with the extracts at 300mg/kg compared to the rate obtained in the negative control batch (80%). The batches that received the hydroethanolic extracts of Vernonia amygdalina and Manihot esculenta at the tested doses had a hatching rate of 0%. When looking at hematological parameters, no significant difference was noted for all batches. However, an increase in the Aspartate Amino-Transferase (ASAT) values was noted in the batches that received the hydroethanolic extract of Khaya senegalensis and the aqueous extract of Diospyros mespiliformis at 100 and 300 mg/kg. These results explicitly show that the hydroethanolic extracts of Manihot esculenta and Vernonia amygdalina are fetotoxic at the tested doses.

Assessment of Larval Toxicity and the Teratogenic Effect of Three Medicinal Plants Used in the Traditional Treatment of Urinary Tract Infections in Benin

Objective

Mangifera indica Linn, Bridelia ferruginea Benth, and Alstonia boonei De Wild are three plants commonly used in the traditional treatment of urinary tract infections in Benin. This study sets out to assess the cytotoxic and teratogenic effects of extracts of these plants on Artemia salina larvae and hen embryos.

Methods and Results

The aqueous and ethanolic extracts were obtained by maceration of the powders in solvents. Larval cytotoxicity was performed on Artemia salina larvae. The teratogenic effect of these plants was evaluated on chick embryos at 100 mg/kg and 300 mg/kg. The extracts were injected on the 7th and 14th days of incubation. The quality of the hatched chicks was evaluated by the Tona score followed by the hematological and the biochemical parameter assays. The extracts did not show cytotoxicity on the larvae. The eggs treated with plant extracts at 300 mg/kg significantly lowered the hatchability rate, except for the Mangifera indica Linn. The chicks obtained were all at the very good quality. Then, no significant variation was observed between hematological parameters except white blood cells. For the biochemical parameters, only ASAT showed some significant variations for a few extracts. It would be important to assess the genotoxicity of the plant extracts to determine more broader toxicity. These data justify the use of these medicinal plants in traditional Beninese medicine and constitute in fact a source of production of anti-infectious drugs.

Prenatal Stress in Maternal Hyperhomocysteinemia: Impairments in the Fetal Nervous System Development and Placental Function

The article presents current views on maternal hyperhomocysteinemia (HHcy) as an important factor causing prenatal stress and impaired nervous system development in fetuses and newborns in early ontogenesis, as well as complications in adulthood. Experimental data demonstrate that prenatal HHcy (PHHcy) affects the morphological maturation of the brain and activity of its neurotransmitter systems. Cognitive deficit observed in the offspring subjected to PHHcy in experimental studies can presumably cause the predisposition to various neurodegenerative diseases, as the role of maternal HHcy in the pathogenesis such diseases has been proven in clinical studies. The review also discusses molecular mechanisms of the HHcy neurotoxic action on the nervous system development in the prenatal and early postnatal periods, which include oxidative stress, apoptosis activation, changes in the DNA methylation patterns and microRNA levels, altered expression and processing of neurotrophins, and neuroinflammation induced by an increased production of pro-inflammatory cytokines. Special attention is given to the maternal HHcy impact on the placenta function and its possible contribution to the brain function impairments in the offspring. Published data suggest that some effects of PHHcy on the developing fetal brain can be due to the disturbances in the transport functions of the placenta resulting in an insufficient supply of nutrients necessary for the proper formation and functioning of brain structures.

Homocysteine-induced neural tube defects in chick embryos via oxidative stress and DNA methylation associated transcriptional down-regulation of miR-124

Although moderate homocysteine (HCY) elevation is associated with neural tube defects (NTDs), the underlying mechanisms have not been elucidated. In this study, we aimed to investigate that whether HCY-induced NTDs were associated with oxidative stress and methyl metabolism in chick embryos. The potential role of miR-124 in neurogenesis was also investigated. In this study, increased intracellular oxidative species and alterations in DNA methylation were observed following HCY treatment. This alteration coincided with decreases of Mn superoxide dismutase and glutathione peroxidase activities, as well as the expression of anti-rabbit DNA methyltransferase (DNMT) 1 and 3a. In addition, HCY induced significant decreases of S-adenosylmethionine (SAM)/S-adenosylhomocysteine (SAH) (P < 0.05). N-acetyl-L-cysteine and choline ameliorated global DNA hypomethylation induced by HCY. MiR-124 levels were significantly suppressed by HCY (P < 0.05), while elevated by 5-aza-2'-deoxycytidine (5-aza-dC). MiR-124 knockdown resulted in spina bifida occulta. Our research suggests that HCY-induced NTDs were associated with oxidative stress and methyl metabolism in chick embryos. MiR-124 down-regulation may occur via epigenetic mechanisms and contribute to HCY-induced NTDs in chick embryo models.

Mechanosensitive Pathways in Heart Development: Findings from Chick Embryo Studies

The heart is the first organ that starts to function in a developing embryo. It continues to undergo dramatic morphological changes while pumping blood to the rest of the body. Genetic regulation of heart development is partly governed by hemodynamics. Chick embryo is a major animal model that has been used extensively in cardiogenesis research. To reveal mechanosensitive pathways, a variety of surgical interferences and chemical treatments can be applied to the chick embryo to manipulate the blood flow. Such manipulations alter expressions of mechanosensitive genes which may anticipate induction of morphological changes in the developing heart. This paper aims to present different approaches for generating clinically relevant disturbed hemodynamics conditions using this embryonic chick model and to summarize identified mechanosensitive genes using the model, providing insights into embryonic origins of congenital heart defects.

Embryo-toxicity of docosahexaenoic and eicosapentaenoic acids: In vivo and in silico investigations using the chick embryo model

OBJECTIVE

The objective of the current study was to evaluate the embryo-toxicity of omega-3 fatty acids.

METHODS

Firstly, the embryo-toxicity of docosahexaenoic (DHA) and eicosapentaenoic acids (EPA), as well as their interaction with Bcl-2 family members, were predicted using an in silico assay. In the next step, the embryonic pathological lesions and amniotic fluid biochemical changes following omega-3 treatment were investigated using a chick embryo model. Finally, the drug's vascular apoptotic effect on the chick's yolk sac membrane (YSM) was assessed.

RESULTS

In silico simulations revealed the embryo-toxicity, tissue-toxicity (respiratory and cardiovascular), and vascular-toxicity (apoptotic activity) of DHA and EPA. There was also an accurate interaction between DHA and EPA with Bax (Binding affinity: -7.6 and -10.6 kcal/mol) and Bcl-2 (Binding affinity: -8.0 and -12.2 kcal/mol), respectively. Moreover, DHA and EPA administrations were related to various adverse consequences, including weight loss and lesions in the respiratory and cardiovascular systems. Histopathological findings consisted of pulmonary edema, airway dilatation, increased interstitial tissue, and hyperemia in the lungs, heart, liver, kidney, and brain. Morphometric evaluation of the YSM vasculature revealed that the vascular apoptotic effect of omega-3was associated with a significant reduction in mean capillary area. In immunohistochemistry assay, increased expression of BAX and low expression of Bcl-2 affirmed apoptosis in YSM vessels.

CONCLUSION

According to the results of this study, one could confirm that the possible embryo-toxicity of omega-3 was approved by data presented in this research. The obtained results also support the suspicion that alteration of the apoptotic-related proteins in vessels is an essential pathway in embryo-toxicity of omega-3.

Teucrium polium Alters the Vascular Branching Pattern and VEGF-A Expression in the Chick Extra-Embryonic Membrane Model

Background: The Teucrium polium is used in traditional medicine for the treatment of various diseases, including inflammations, rheumatism, diabetes, and ulcers. While this herb and its aqueous extract have been consumed in Iran for hypoglycemia treatment, medicine has proved several side effects such as hepatitis, vomiting, changes in the kidney functions, and allergic responses. Also, using this herb is not safe during pregnancy or lactation. The chick embryo is a live animal model applicable for assessing the pathological property of herbs. In this regard, some details of the embryonic vascular toxicity of the Teucrium polium were evaluated via a chick embryo model. Objectives: The current study assessed vessels' alteration in the chick's extra embryonic membrane following Teucrium polium treatment. Change in molecular cues involved in early embryonic angiogenesis has also been investigated. Methods: The eggs of the chicken were divided into three equal treatment groups; as follow: first group one: considered as a sham, next groups: herbal extract that eggs injected with T. polium extract of 3 (150 µg/50 µL) or 6 (300 µg/50 µL) mg/kg, respectively. Results: The anti-angiogenic effect of the herb extract in which vessel area, total vessel length, and vascular branching decreased, whereas lacunarity increased in a dose-dependent manner. VEGF-A expression was also down-regulated in herb-exposed extra-embryonic membranes. Concerns regarding the side effects of T. polium during pregnancy were confirmed. Conclusions: We conclude that changes in early vascular expansion and gene expression might finally lead to developmental defects in embryos following consumption of T. polium. Thus, this herb's consumption should be decreased during embryonic development, and clinicians should limit the herb prescription in pregnant women, particularly at dosages > 3 mg/kg.

The effect of methenamine on vascular development: Experimental investigation using in vivo and insilico methods

Background

Methenamine is a worldwide antibacterial agent for urinary system infections in human and animals. The effect of methenamine consumption during early phase of pregnancy is not fully clarified in previous studies. Vascular development is the essential part of the early embryonic growth.

Objective

In this study, we used chicken chorioallantoic membrane to evaluate the effects of methenamine administration on angiogenesis process as a model.

Materials and Methods

In this experimental study, 20 Ross 308 eggs (mean weight 55 ± 4) were incubated. The eggs were divided into two equal groups (n = 10/each). In the first group, methenamine (150 mg/kg egg weight) was injected on the shell membrane, and in the second group (control group) phosphate-buffered salineas injected. Methenamine was inoculated at 96 and 120 hrafter incubation; 24 hrafter the last inoculation, the eggs were removed and the egg's shell was incised. Then, the development of vascular network and vascular endothelial growth factor Aexpression was evaluated.

Results

Angiogenesis was significantly decreased after methenamine treatment. The indexes such as areas containing vessels, the vessels' length, the percentage of angiogenesis developing areas, and vascular complexity in the treatment group receiving methenamine were significantly reduced compared to the control group. Vascular endothelial growth factor Aexpression was suppressed in the methenamine treated group.

Conclusion

According to the achieved results, it was defined that methenamine could have an inhibitory effect on the growth and development procedures of extraembryonic vasculature.

Effect of gestation dietary methionine/lysine ratio on placental angiogenesis and reproductive performance of sows1

The current study aims to evaluate the effects of different gestation dietary Met/Lys (methionine, Met/lysine) ratios on the production performance of sows. Specifically, it measured the effect of Met on plasma urea and AA concentrations and placental vascular density of pregnant sows. A total of 325 multiparous sows (third parity, Large × White) were randomly allocated to five dietary treatments (n = 65) with five dietary Met/Lys ratios 0.27 (nutrient requirements of swine [NRC] 2012 level), 0.32, 0.37, 0.42, and 0.47). The litter size and weight at birth were measured and recorded. Blood samples were obtained on days 0, 40, 90, and 114 of gestation, and placenta samples were collected at parturition. The effects of different dietary Met/Lys ratios on the reproductive performance were evaluated based on the prolificacy of sows as either high (≥13 total piglets born) or low (<13 total piglets born). The results showed that dietary Met/Lys ratio had no significant effect on the reproductive performance of lower prolificacy sows (P > 0.05). However, for high-prolificacy sows, litter weight of born alive significantly increased in 0.37 Met/Lys ratios group compared with control group (P < 0.05). The gestation dietary Met/Lys ratio showed significant quadratic effects on the litter birth weight and percentage of piglets born with weight <0.9 kg (P < 0.05), and the Met/Lys ratios to achieve the best reproductive performance determined to be 0.37. Furthermore, plasma urea concentrations of sows also changed with Met/Lys ratios quadratically (P < 0.05). Increasing dietary Met/Lys ratios elevated the concentration of most plasma AA. Although the dietary Met/Lys ratio had no significant effect on the placental vascular density (P > 0.05), the gestation dietary Met/Lys ratio showed significant quadratic effects on the placental vascular density (P < 0.05). In addition, the birth weight of piglets of high-prolificacy sows was positively correlated with the placental vascular density (P < 0.01). Taken as a whole, the dietary Met/Lys ratio showed a quadratic curve relation with birth weight performance and placental angiogenesis performance, to which 0.37 ratio contributed to the best performance of high-prolificacy sows.

Vascular alteration in relation to fosfomycine: In silico and in vivo investigations using a chick embryo model

Fosfomycin residues are found in the egg following administration in the layer hen. In this regard, some aspects of embryo-toxicity of fosfomycin have been documented previously. The exact mechanism by which fosfomycin causes embryo-toxicity is not clearly understood. We hypothesis that fosfomycin may alter vasculature as well as normal expression of genes, which are associated with vascular development. Therefore, the present study aimed to address these issues through in silico and in vivo investigations. At first, embryo-toxicity and anti-angiogenic effects of fosfomycin were tested using computerized programs. After that, fertile chicken eggs were treated with fosfomycin and chorioallantoic membrane vasculature was assessed through morphometric, molecular and histopathological assays. The results showed that fosfomycin not only interacted with VEGF-A protein and promoter, but also altered embryonic vasculature and decreased expression level of VEGF-A. Reticulin staining of treated group was also confirmed decreased vasculature. The minor groove of DNA was the preferential binding site for fosfomycin with its selective binding to GC-rich sequences. We suggested that the affinity of fosfomycin for VEGF-A protein and promoter as well as alteration of the angiogenic signaling pathway may cause vascular damage during embryonic growth. Hence, veterinarians should be aware of such effects and limit the use of this drug during the developmental stages of the embryo, particularly in breeder farms. Considering the anti-angiogenic activity and sequence selectivity of fosfomycin, a major advantage that seems to be very promising is the fact that it is possible to achieve a sequence-selective binding drug for cancer.

Astaxanthin inhibits homocysteine‑induced endothelial cell dysfunction via the regulation of the reactive oxygen species‑dependent VEGF‑VEGFR2‑FAK signaling pathway

Increased plasma levels of homocysteine (Hcy) can cause severe damage to vascular endothelial cells. Hcy‑induced endothelial cell dysfunction contributes to the occurrence and development of human cerebrovascular diseases (CVDs). Our previous studies have revealed that astaxanthin (ATX) exhibits novel cardioprotective activity against Hcy‑induced cardiotoxicity in vitro and in vivo. However, the protective effect and mechanism of ATX against Hcy‑induced endothelial cell dysfunction requires further investigation. In the present study, treatment of human umbilical vascular endothelial cells (HUVECs) with Hcy inhibited the migration, invasive and tube formation potentials of these cells in a dose‑dependent manner. Hcy treatment further induced a time‑dependent increase in the production of reactive oxygen species (ROS), and downregulated the expression of vascular endothelial growth factor (VEGF), phosphorylated (p)‑Tyr‑VEGF receptor 2 (VEGFR2) and p‑Tyr397‑focal adhesion kinase (FAK). On the contrary, ATX pre‑treatment significantly inhibited Hcy‑induced cytotoxicity and increased HUVEC migration, invasion and tube formation following Hcy treatment. The mechanism of action may involve the effective inhibition of Hcy‑induced ROS generation and the recovery of FAK phosphorylation. Collectively, our findings suggested that ATX could inhibit Hcy‑induced endothelial dysfunction by suppressing Hcy‑induced activation of the VEGF‑VEGFR2‑FAK signaling axis, which indicates the novel therapeutic potential of ATX in treating Hcy‑mediated CVD.

Restoration of skeletal muscle homeostasis by hydrogen sulfide during hyperhomocysteinemia-mediated oxidative/ER stress condition 1

Elevated homocysteine (Hcy), i.e., hyperhomocysteinemia (HHcy), causes skeletal muscle myopathy. Among many cellular and metabolic alterations caused by HHcy, oxidative and endoplasmic reticulum (ER) stress are considered the major ones; however, the precise molecular mechanism(s) in this process is unclear. Nevertheless, there is no treatment option available to treat HHcy-mediated muscle injury. Hydrogen sulfide (H₂S) is increasingly recognized as a potent anti-oxidant, anti-apoptotic/necrotic/pyroptotic, and anti-inflammatory compound and also has been shown to improve angiogenesis during ischemic injury. Patients with CBS mutation produce less H₂S, making them vulnerable to Hcy-mediated cellular damage. Many studies have reported bidirectional regulation of ER stress in apoptosis through JNK activation and concomitant attenuation of cell proliferation and protein synthesis via PI3K/AKT axis. Whether H₂S mitigates these detrimental effects of HHcy on muscle remains unexplored. In this review, we discuss molecular mechanisms of HHcy-mediated oxidative/ER stress responses, apoptosis, angiogenesis, and atrophic changes in skeletal muscle and how H₂S can restore skeletal muscle homeostasis during HHcy condition. This review also highlights the molecular mechanisms on how H₂S could be developed as a clinically relevant therapeutic option for chronic conditions that are aggravated by HHcy.

Role of amino acid metabolism in angiogenesis

The role of endothelial metabolism represents a crucial element governing the formation and the differentiation of blood vessels, termed angiogenesis. Besides glycolysis and fatty acid oxidation, endothelial cells rely on specific amino acids to proliferate, migrate, and survive. In this review we focus on the metabolism of those amino acids and the intermediates that hold an established function within angiogenesis and endothelial pathophysiology. We also discuss recent work which provides a rationale for specific amino acid-restricted diets and its beneficial effects on vascular tissues, including extending the life span and preventing the development of a variety of diseases.

Vascular apoptosis associated with meglumine antimoniate: In vivo investigation of a chick embryo model

The vasculo-toxic effect of meglumine antimoniate (MA) was confirmed in our previous investigation. The current study investigates the association of this effect with altered VEGF-A and VEGF-R2 expression. Additional mechanisms by which MA causes vascular toxicity are not clearly understood. We hypothesized that MA may alter normal expression of apoptotic genes and cause vascular toxicity. The current investigation was designed to address this issue using a chick embryo model. Fertile chicken eggs were treated with MA and the extra-embryonic membrane (EEM) vasculature was evaluated by morphometric, molecular and immunohistochemistry assays. The results showed that MA not only altered apoptotic gene expression, but that this alteration may disturb the normal development of the vascular network and cause embryo malformation. The relative expression level of the CASP3, CASP7, CASP9, APAF1, AIF1 and TP53 genes increased in drug-exposed EEMs. In addition, IHC assay confirmed the low expression BCL2 and increased expression of Bax, which are associated with a high rate of apoptosis. We suggest that induction of an apoptotic signaling pathway can lead to vascular defects during embryo development and the consecutive cascade of events can lead to the embryo malformation.

Embryonic toxico-pathological effects of meglumine antimoniate using a chick embryo model

Leishmaniasis is one of the diverse and neglected tropical diseases. Embryo-toxicity of drugs has always been a major concern. Chick embryo is a preclinical model relevant in the assessment of adverse effects of drugs. The current study aimed to assess embryonic histopathological disorders and amniotic fluid biochemical changes following meglumine antimoniate treatment. The alteration of vascular branching pattern in the chick’s extra-embryonic membrane and exploration of molecular cues to early embryonic vasculogenesis and angiogenesis were also quantified. Embryonated chicken eggs were treated with 75 or 150 mg/kg of meglumine antimoniate. Embryo malformations, growth retardation and haemorrhages on the external body surfaces were accompanied by histopathological lesions in the brain, kidney, liver and heart in a dose-dependent manner. Significant rise occurred in the biochemical indices of alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase and amylase in the amniotic fluid. Quantification of the extra-embryonic membrane vasculature showed that the anti-angiogenic and anti-vasculogenic effects of the drug were revealed by a significant decrease in fractal dimension value and mean capillary area. The relative expression levels of vascular endothelial growth factor A and vascular endothelial growth factor receptor 2 mRNA also significantly reduced. Concerns of a probable teratogenicity of meglumine antimoniate were established by data presented in this study. It is concluded that tissue lesions, amniotic fluid disturbance, altered early extra-embryonic vascular development and gene expression as well as the consecutive cascade of events, might eventually lead to developmental defects in embryo following meglumine antimoniate treatment. Therefore, the use of meglumine antimoniate during pregnancy should be considered as potentially embryo-toxic. Hence, physicians should be aware of such teratogenic effects and limit the use of this drug during the growing period of the fetus, particularly in rural communities. Further pharmaceutical investigations are crucial for planning future strategies.

VEGF levels in plasma in relation to metabolic control, inflammation, and microvascular complications in type-2 diabetes: A cohort study

The vascular endothelial growth factor (VEGF) level in human circulation may reflect the severity of endothelial dysfunction in patients with diabetes mellitus, which leads to diabetic microvascular complications.We determined plasma VEGF levels as well as metabolic control and inflammatory factors in 26 healthy subjects and 52 type-2 diabetes mellitus (T2DM) patients with or without diabetic microvascular complications. Pearson correlation coefficient was used to evaluate the associations among those indices.The results showed that VEGF levels in plasma were positively correlated with fasting blood glucose level, glycosylated hemoglobin (HbA1c) level, type 1 helper T cell (Th1) percentage, and Th1/Th2 ratio, while they were negatively correlated with regulatory T cell percentage. Multiple linear regression analysis showed that HbA1c and Th1/Th2 ratio were the independent predictors of VEGF levels in T2DM patients.Thus, in T2DM patients with poor glycemic control as well as an elevated Th1/Th2 cell ratio, more VEGF might be released.

Dual Roles of Ascidian Chondromodulin-1: Promoting Cell Proliferation Whilst Suppressing the Growth of Tumor Cells

Chondromodulin-1 (ChM-1) is an extracellular matrix protein that plays crucial roles in tumor cell growth and angiogenesis in vertebrates and humans. ChM-1 is highly expressed in the invertebrate Ciona savignyi, a marine ascidian chosen as a model. The effect of the recombinant Ciona mature ChM-1 peptide (Cs-mChM-1) on cell proliferation, migration and angiogenesis was evaluated on cultured cells. The results revealed that low concentrations of Cs-mChM-1 (12.5 nM) promoted osteoblastic cell (MC3T3-E1) growth and protected cells from H₂O₂-induced damage. However, a higher concentration of Cs-mChM-1 (i.e., 500 nM) not only suppressed both growth and migration of tumor cells, including human cervical cancer (HeLa) cells and human neuroblastoma (SH-SY5Y) cells, but also significantly inhibited proliferation and angiogenesis of human umbilical vein endothelial cells (HUVECs). The expression levels of cyclinD1 and mitogen-activated protein kinase 1 (MAPK1) were slightly increased in Cs-mChM-1 treated MC3T3-E1 cells, whereas these genes decreased in treated HeLa cells, SH-SY5Y cells and HUVECs. This result indicates that Cs-mChM-1 modifies cell behavior by regulating cell cycle and cell adhesion. Thus, the present results reveal that recombinant peptides of ChM-1 from invertebrates can play a dual role in cell proliferation and migration of different cell types. The inhibition effects on tumor cell growth and angiogenesis indicate potential pharmaceutical applications for recombinant Cs-mChM-1.

Homocysteine inhibits angiogenesis through cytoskeleton remodeling

Homocysteine (Hcy) is an intermediate non-diet amino acid connecting methionine and folate cycles. Elevated total Hcy level in blood, denoted as hyperhomocysteinemia, has emerged as a prevalent and strong risk factor for multiple diseases including atherosclerotic vascular disease in coronary, cerebral, and peripheral vessels. Its detrimental effect on vascular system implies the potential application as an inhibitor of angiogenesis. However, the detailed mechanism is unveiled. Inhibitory effect of Hcy was assessed on vascular endothelial growth factor (VEGF) induced cell proliferation and migration with endothelial cell (EC) culture system. Its effect on angiogenesis was further examined in vitro and in vivo After Hcy treatment, key angiogenic factors were measured by RT-qPCR. Cellular skeletal structure was also evaluated by actin stress fiber staining. VEGF-induced human umbilical vein EC (HUVEC) proliferation and migration were dramatically down-regulated by Hcy in a dose-responsive manner. Hcy treatment significantly inhibited the VEGF-induced angiogenesis in vitro by tube formation assay and chick chorioallantoic membrane (CAM) vessel formation in vivo Key angiogenic factors like VEGFR1/2 and angiopoietin (Ang)1/2 were substantially reduced by Hcy in HUVEC- and VEGF-induced actin stress fiber cytoskeletal structure was abolished. We demonstrated that Hcy could inhibit angiogenesis by targetting key angiogenic factor and disruption of actin cytoskeleton which is crucial for cell migration.

Maternal and Fetal Folate, Vitamin B12, and Homocysteine Concentrations and Childhood Kidney Outcomes

Background

Folate, vitamin B₁₂ and homocysteine concentrations during pregnancy are important factors for early development and may persistently influence kidney function in the offspring. We examined the associations of folate, vitamin B₁₂, and homocysteine concentrations during pregnancy with kidney outcomes in school-aged children.

Study design

Population-based prospective cohort study from fetal life onwards.

Settings & participants

This study was performed among 4,226 pregnant women and their children.

Predictors

Folate, vitamin B₁₂ and homocysteine blood concentrations measured in early pregnancy (median gestational age 13.2 weeks (25th to 75th percentiles 12.2, 14.8) and at birth (cord blood).

Outcomes & measurements

At the median age of 6.0 years (25th to 75th percentiles 5.9, 6.3) we measured combined kidney volume with ultrasound, estimated glomerular filtration rate based on creatinine (eGFR_creat) and cystatin C (eGFR_cystC) concentrations and microalbuminuria.

Results

We observed that higher maternal folate concentrations were associated with larger childhood combined kidney volume, whereas higher maternal vitamin B₁₂ concentrations were associated with higher childhood eGFR_cystC (p-values <0.05). These associations were independent of homocysteine concentrations. Higher maternal homocysteine concentrations were associated with smaller combined kidney volume and lower childhood eGFR_cystC (p-values <0.05). The association of maternal homocysteine concentrations with childhood eGFR_cystC was largely explained by combined kidney volume. Higher cord blood homocysteine concentrations were associated with larger combined kidney volume and lower eGFR_cystC (p-values <0.05). Folate, vitamin B₁₂ or homocysteine concentrations were not associated microalbuminuria.

Limitations

Observational study, so causality cannot be established.

Conclusion

Our findings suggest that folate, vitamin B₁₂ and homocysteine concentrations during fetal life are associated with offspring kidney development. However, the effect sizes are small. Further studies are needed to replicate these findings and assess the causality and consequences for kidney health in later life.

Homocysteine deteriorates intrahepatic derangement and portal-systemic collaterals in cirrhotic rats

In liver cirrhosis, the altered levels of vasoactive substances, especially endothelin-1 (ET-1) and nitric oxide (NO) lead to elevated intrahepatic resistance, increased portal-systemic collaterals and abnormal intra- and extra-hepatic vascular responsiveness. These derangements aggravate portal hypertension-related complications such as gastro-oesophageal variceal bleeding. Homocysteine, a substance implicated in cardiovascular diseases, has been found with influences on vasoresponsiveness and angiogenesis. However, their relevant effects in liver cirrhosis have not been investigated. In the present study, liver cirrhosis was induced by common bile duct ligation (BDL) in Sprague–Dawley rats. In acute study, the results showed that homocysteine enhanced hepatic vasoconstriction to ET-1 but decreased portal-systemic collateral vasocontractility to arginine vasopressin (AVP). Homocysteine down-regulated hepatic phosphorylated endothelial NO synthase (p-eNOS) and p-Akt protein expressions. Inducible NOS (iNOS) and cyclooxygenase (COX)-2 expressions were up-regulated by homocysteine in splenorenal shunt (SRS), the most prominent intra-abdominal collateral vessel. In chronic study, BDL or thioacetamide (TAA) rats received homocysteine or vehicle for 14 days. The results revealed that homocysteine increased hepatic collagen fibre deposition and fibrotic factors expressions in both BDL- and TAA-induced liver fibrotic rats. Portal-systemic shunting and expressions of mesenteric angiogenetic factors [vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), PDGF receptor β (PDGFRβ) and p-eNOS] were also increased in BDL rats. In conclusion, homocysteine is harmful to vascular derangements and liver fibrosis in cirrhosis.

In ovo toxico-teratological effects of aluminum on embryonic chick heart and vascularization

In spite of extensive research and persistent arguments, the mechanism of aluminum (Al) toxicity is still obscure. It is firmly established that aluminum is a potent neurotoxicant. So, the aim based on is aluminum damage chicken heart, as well as the vitelline circulation. In the first 3 days of incubation (D0-D2), 1.0, 2.0, or 4.0 mg aluminum chloride/0.3 ml avian saline was injected into the center of each viable fertilized egg yolk (AL1, AL2, and AL3 groups, respectively). Control eggs were either uninjected (AL0) or injected (ALS, 0.3 ml saline). Crown rump length was significantly decreased, while, embryonic mortalities, growth delay, as well as congenital heart defects were increased in the eggs injected 2.0 or 4.0 mg of Al. Although no relationship is clear about the embryonic mortality induced by Al in chicken embryos to the dose concentration, the higher mortality occurs in early developmental stages in developing chick embryos. Furthermore, chick embryos exposed to 4.0 mg/Al showed a high incidence of defects of ventricular septation and ventricular myocardium. Configuration and density of branched vitelline vessels were also significantly deteriorated after injection with 4.0 mg/Al. It concluded that Al is a cardiac teratogen for a chick in a dose-dependent way. These data highlight a novel approach for aluminum in congenital cardiovascular defects. Therefore, further research is needed to explain the teratogenicity of Al on the embryonic heart development.

Folate Deficiency Could Restrain Decidual Angiogenesis in Pregnant Mice

The mechanism of birth defects induced by folate deficiency was focused on mainly in fetal development. Little is known about the effect of folate deficiency on the maternal uterus, especially on decidual angiogenesis after implantation which establishes vessel networks to support embryo development. The aim of this study was to investigate the effects of folate deficiency on decidual angiogenesis. Serum folate levels were measured by electrochemiluminescence. The status of decidual angiogenesis was examined by cluster designation 34 (CD34) immunohistochemistry and the expression of angiogenic factors, including vascular endothelial growth factor A (VEGFA), placental growth factor (PLGF), and VEGF receptor 2 (VEGFR2) were also tested. Serum levels of homocysteine (Hcy), follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), progesterone (P4), and estradiol (E2) were detected by Enzyme-linked immunosorbent assay. The folate-deficient mice had a lower folate level and a higher Hcy level. Folate deficiency restrained decidual angiogenesis with significant abnormalities in vascular density and the enlargement and elongation of the vascular sinus. It also showed a reduction in the expressions of VEGFA, VEGFR2, and PLGF. In addition, the serum levels of P4, E2, LH, and PRL were reduced in folate-deficient mice, and the expression of progesterone receptor (PR) and estrogen receptor α (ERα) were abnormal. These results indicated that folate deficiency could impaire decidual angiogenesis and it may be related to the vasculotoxic properties of Hcy and the imbalance of the reproductive hormone.

Homocysteine disrupts outgrowth of microvascular endothelium by an iNOS-dependent mechanism

OBJECTIVE

To test the hypothesis that Hcy impairs angiogenic outgrowth through an iNOS-dependent mechanism.

METHODS

Adult C57Bl/6 mouse choroid explants were used in angiogenic outgrowth assays. Mouse microvascular endothelial cells were studied in culture during scrape-induced migration and dispersed cell locomotion experiments. Activity of iNOS was manipulated with pharmacology (1400 W), siRNA, and by use of choroid explants from iNOS knockout mice (iNOS(-/-)).

RESULTS

Hcy (20 μM) significantly decreased the area of endothelial outgrowth without altering the number of cells in the choroid explant angiogenic assay, resulting in more densely packed outgrowth. Hcy prevented the outward orientation of actin filaments and decreased the number of actin projections along the leading edge of outgrowth. Hcy also slowed outgrowth from the edge of a scraped endothelial monolayer and in cultures of dispersed cells, Hcy impaired cell locomotion without affecting proliferation. Inhibition of iNOS activity rescued the effect of Hcy on area of explant outgrowth, cell density, number of projections, cell locomotion, and rate of outgrowth following scraping.

CONCLUSIONS

Hcy impairs microvascular endothelial outgrowth, but not proliferation, by disrupting cell locomotion through an iNOS-dependent mechanism.

Homocysteine causes disruptions in spinal cord morphology and changes the expression of Pax 1/9 and Sox 9 gene products in the axial mesenchyme

BACKGROUND

Neural tube defects (NTD) involve disruptions in the axial mesenchyme, and are related to an imbalance between folic acid (FA) and homocysteine (Hcy). This study evaluated the effects of FA/Hcy imbalance on cell proliferation and expression of the Pax 1/9 and Sox 9 gene products in the axial mesenchyme of chickens.

METHODS

Embryos were incubated (38°C) and pretreated at 24 h and treated at 46 h of incubation. The experimental groups were: FA-pretreated with saline and treated with 0.5 μg FA/saline; Hcy-pretreated with 50 μl saline and treated with 20 μmol D,L-Hcy/50 μl saline; FA+Hcy-pretreated with 0.5 μg FA/50 μl saline and treated with 20 μmol D,L-Hcy/50 μl saline; and the control embryos were pretreated and treated with saline. Embryos were analyzed at E4 and E6. Immunohistochemistry was performed to identify proliferating cells and the expression of the gene products of Pax 1/9 and Sox 9. Total RNA of the E4 embryos was extracted and a RT-qPCR assay was performed to quantify Pax 1/9 mRNA expression.

RESULTS

Hcy treatment caused spinal NTD and abnormalities in axial mesenchyme development, affecting the distribution of sclerotomal cells and chondrification. Hcy also reduced cell proliferation and changed the expression of Pax 1/9 and Sox 9 in the mesenchyme.

CONCLUSIONS

Our data clarified the relationship between spinal NTD genesis and disruptions of Pax 1/9 and Sox 9 gene products in the axial mesenchyme caused by the FA/Hcy imbalance.

Maternal first-trimester dietary intake and childhood blood pressure: the Generation R Study

Suboptimal maternal dietary intake during pregnancy might lead to fetal cardiovascular adaptations and higher blood pressure in the offspring. The aim of the present study was to investigate the associations of maternal first-trimester dietary intake with blood pressure in children at the age of 6 years. We assessed first-trimester maternal daily dietary intake by a FFQ and measured folate, homocysteine and vitamin B₁₂ concentrations in the blood, in a population-based prospective cohort study among 2863 mothers and children. Childhood systolic and diastolic blood pressure was measured using a validated automatic sphygmomanometer. First-trimester maternal daily intake of energy, fat, protein and carbohydrate was not associated with childhood blood pressure. Furthermore, maternal intake of micronutrients was not associated with childhood blood pressure. Also, higher maternal vitamin B₁₂ concentrations were associated with a higher diastolic blood pressure (0·31 mmHg per standard deviation increase in vitamin B₁₂ (95% CI 0·06, 0·56)). After taking into account multiple testing, none of the associations was statistically significant. Maternal first-trimester folate and homocysteine concentrations were not associated with childhood blood pressure. The results from the present study suggest that maternal Fe intake and vitamin B₁₂ concentrations during the first trimester of pregnancy might affect childhood blood pressure, although the effect estimates were small and were not significant after correction for multiple testing. Further studies are needed to replicate these findings, to elucidate the underlying mechanisms and to assess whether these differences in blood pressure persist in later life.

Alterations of retinal vasculature in cystathionine-Beta-synthase mutant mice, a model of hyperhomocysteinemia

PURPOSE

Mice with moderate/severe hyperhomocysteinemia due to deficiency or absence of the cbs gene encoding cystathionine-beta-synthase (CBS) have marked retinal disruption, ganglion cell loss, optic nerve mitochondrial dysfunction, and ERG defects; those with mild hyperhomocysteinemia have delayed retinal morphological/functional phenotype. Excess homocysteine is a risk factor for cardiovascular diseases; however, it is not known whether excess homocysteine alters retinal vasculature.

METHODS

Cbs(+/+), cbs(+/-), and cbs(-/-) mice (age ∼3 weeks) were subjected to angiography; retinas were harvested for cryosections, flat-mount preparations, or trypsin digestion and subjected to immunofluorescence microscopy to visualize vessels using isolectin-B4, to detect angiogenesis using anti-VEGF and anti-endoglin (anti-CD105) and activated glial cells (anti-glial fibrillary acidic protein [anti-GFAP]) and to investigate the blood-retinal barrier using the tight junction markers zonula occludens-1 (ZO-1) and occludin. Expression of vegf was determined by quantitative RT-PCR (qRT-PCR) and immunoblotting. Human retinal endothelial cells (HRECs) were treated with excess homocysteine to analyze permeability.

RESULTS

Angiography revealed vascular leakage in cbs(-/-) mice; immunohistochemical analysis demonstrated vascular patterns consistent with ischemia; isolectin-B4 labeling revealed a capillary-free zone centrally and new vessels with capillary tufts midperipherally. This was associated with increased vegf mRNA and protein, CD105, and GFAP in cbs(-/-) retinas concomitant with a marked decrease in ZO-1 and occludin. Homocysteine-treated HRECs showed increased permeability.

CONCLUSIONS

Severe elevation of homocysteine in cbs(-/-) mutant mice is accompanied by alterations in retinal vasculature (ischemia, neovascularization, and incompetent blood-retinal barrier). The marked disruption of retinal structure and decreased visual function reported in cbs(-/-) mice may reflect vasculopathy as well as neuropathy.

A 205-nucleotide deletion in the 3' untranslated region of avian leukosis virus subgroup J, currently emergent in China, contributes to its pathogenicity

In the past 5 years, an atypical clinical outbreak of avian leukosis virus subgroup J (ALV-J), which contains a unique 205-nucleotide deletion in its 3' untranslated region (3'UTR), has become epidemic in chickens in China. To determine the role of the 205-nucleotide deletion in the pathogenicity of ALV-J, a pair of viruses were constructed and rescued. The first virus was an ALV-J Chinese isolate (designated HLJ09SH01) containing the 205-nucleotide deletion in its 3'UTR. The second virus was a chimeric clone in which the 3'UTR contains a 205-nucleotide sequence corresponding to a region of the ALV-J prototype virus. The replication and pathogenicity of the rescued viruses (rHLJ09SH01 and rHLJ09SH01A205) were investigated. Compared to rHLJ09SH01A205, rHLJ09SH01 showed a moderate growth advantage in vitro and in vivo, in addition to exhibiting a higher oncogenicity rate and lethality rate in layers and broilers. Increased vascular endothelial growth factor A (VEGF-A) and vascular endothelial growth receptor subtype 2 (VEGFR-2) expression was induced by rHLJ09SH01 more so than by rHLJ09SH01A205 during early embryonic vascular development, but this increased expression disappeared when the expression levels were normalized to the viral levels. This finding suggests that the expression of VEGF-A and VEGFR-2 is associated with viral replication and may also represent a novel molecular mechanism underlying the oncogenic potential of ALV-J. Overall, our findings not only indicate that the unique 205-nucleotide deletion in the ALV-J genome occurred naturally in China and contributes to increased pathogenicity but also point to the possible mechanism of ALV-J-induced oncogenicity.

Homocysteine exposure affects early hemodynamic parameters of embryonic chicken heart function

Maternal hyperhomocysteinemia has been associated with an increased risk of newborns with a congenital heart defect. This has been substantiated in the chicken embryo, as congenital heart defects have been induced after homocysteine treatment. Comparable heart defects are observed in venous clipping studies, a model of altered embryonic blood flow. Because of this overlap in heart defects, our aim was to test the hypothesis that homocysteine would cause alterations in embryonic heart function that precede the structural malformations previously described. Therefore, Doppler flow velocity waveforms were recorded in both primitive ventricles and the outflow tract of the embryonic heart of homocysteine treated and control chicken embryos at embryonic day 3.5. Homocysteine treatment consisted of 50 μL 0.05 M L-homocysteine thiolactone at 24, 48, and 72 hr. Homocysteine-treated embryos displayed significantly lower mean heart rates of 134 (SD 22) bpm, compared to 150 (14) bpm in control embryos. Homocysteine treatment caused an inhibiting effect on hemodynamic parameters, and altered heart function was presented by a shift in the proportions of the different wave times in percentage of total cycle time. Homocysteine induces changes in hemodynamic parameters of early embryonic chicken heart function. These changes may precede morphological changes and contribute to the development of CHD defects through alterations in shear stress and shear stress related genes, as seen before in venous clipping studies.