This study investigates the effects of hyperglycemia on vascular morphology and hemodynamics during embryogenesis using the chick chorioallantoic membrane (CAM) model. We employed a dual-modality, label-free imaging approach, Optical Coherence Tomography Angiography (OCTA) and biospeckle imaging, to evaluate microvascular architecture and real-time flow dynamics in chick embryos subjected to hyperglycemic conditions. Quantitative metrics such as vessel area, branching junctions, lacunarity, and biospeckle contrast were analyzed to assess angiogenic and metabolic responses. Hyperglycemia caused significant vascular attrition, including a 31% reduction in vessel area, 55% fewer vascular junctions, and a 58% increase in lacunarity, indicating fragmented and simplified networks. Biospeckle imaging revealed reduced blood flow velocities and elevated non-vascular speckle contrast, suggestive of metabolic stress and endothelial apoptosis. These vascular impairments extended to the retina, where hyperglycemic embryos exhibited thinner retinas, smaller lenses, and sparser retinal vasculature. Our findings demonstrate that embryonic hyperglycemia leads to widespread vascular simplification and hemodynamic dysfunction, driven by oxidative stress and disrupted VEGF signaling. Unlike adult diabetic vasculopathy, the embryonic response involves global, not focal, vascular defects. This work establishes a novel multimodal imaging framework for studying developmental angiogenesis and lays the groundwork for future investigations into therapeutic strategies targeting diabetic embryopathy.

Mesencephalosynapsis is characterized by a failure of the dorsal brainstem colliculi to separate into distinct lateral masses (non-cleavage, a.k.a. "fusion"). It is linked to ventriculomegaly and aqueductal stenosis but other associations have not been systematically examined. We reviewed a large cohort of fetal hydrocephalus cases to explore associations of aqueductal stenosis, mesencephalosynapsis, and other pathologies. Among 115 cases of fetal obstructive hydrocephalus (15-41 weeks gestation), mesencephalosynapsis was seen in 44 cases (38.3%). We graded the wide range of abnormal aqueductal histology; mesencephalosynapsis was associated with 67% of severe, 35% of mild, and 10% of borderline aqueductal pathologies. In 75% of cases, it was associated with other CNS anomalies, including rhombencephalosynapsis, holoprosencephaly, hemifacial microsomia, and amniotic rupture sequence. We also identified 2 cases of aqueductal stenosis associated with brainstem tegmental injury, probably ischemic in origin, without mesencephalosynapsis. Clinical and genetic associations of mesencephalosynapsis included diabetic embryopathy, amniotic rupture sequence, chromosomal abnormalities, and mutations in TBCD132, FRAS1, and NECTIN1. This is the largest review of the histology of fetal aqueductal stenosis to date. We conclude that mesencephalosynapsis points to a defect in embryonic brainstem patterning and may be isolated, associated with other malformations, and that it is found in heritable and non-heritable conditions.

Sacral agenesis (SA) is a rare congenital neurological disorder characterized by the incomplete development of the sacral spine. This work summarizes the scientific literature on SA, including the following sections: pathogenesis, epidemiology, risk factors, genetics, clinical manifestations, radiological classification, diagnosis, and management. The aim of this work is to provide the most up-to-date and comprehensive medical narrative literature review for this rare congenital disease. This narrative review used PubMed, MEDLINE, Science Direct, and Embase databases. Between December 2022 and September 2023, the following terms were used for the inclusion of original articles: "rare disease," "caudal regression," "diabetic embryopathy," and "sacral agenesis.? The International Sacral Agenesis/Caudal Regression Association participated in reviewing this manuscript and drafting a paragraph on behalf of those living with this condition. The clinical manifestations of SA are heterogeneous. The most prevalent manifestations involve peripheral neurological, motor, urinary, and digestive issues. The prognosis depends on the severity and associated abnormalities. Patients usually exhibit normal mental function but require a multidisciplinary evaluation and largely supportive treatment that enables them to live successful lives. More awareness and research are needed.

Hyperglycemia in early-stage embryogenesis is linked to diabetic embryopathy. High-glucose-concentration-induced accumulation of hexokinase-2 (HK2) may initiate metabolic dysfunction that contributes to diabetic embryopathy, including increased formation of methylglyoxal (MG). In this study, we evaluated changes in HK2 protein levels and embryo dysmorphogenesis in an experimental model of diabetic embryopathy. Rat embryos were cultured with high glucose concentrations, and the effects of glyoxalase 1 (Glo1) inducer, trans-resveratrol and hesperetin (tRES + HESP) were evaluated. Rat embryos, on gestational day 9, were cultured for 48 h in low and high glucose concentrations with or without tRES + HESP. Embryo crown-rump length, somite number, malformation score, concentrations of HK2 and Glo1 protein, rates of glucose consumption, and MG formation were assessed. Under low-glucose conditions, embryos exhibited normal morphogenesis. In contrast, high-glucose conditions led to reduced crown-rump length and somite number, and an increased malformation score. The addition of 10 μM tRES + HESP reversed these high glucose-induced changes by 60%, 49%, and 47%, respectively. Embryos cultured in high glucose showed increases in HK2 concentration (42%), glucose consumption (75%), and MG formation (27%), normalized to embryo volume. These elevated HK2 levels were normalized by treatment with 10 μM tRES + HESP. Thus, high-glucose-induced metabolic dysfunction and embryopathy may both be initiated by HK2 accumulation and may be preventable with tRES + HESP treatment. Maternal diabetes can adversely affect embryogenesis and fetal development, resulting in multiple congenital anomalies and secondary medical complications collectively termed as "diabetic embryopathy." High maternal blood glucose acts as a major teratogenic agent by altering many normal signaling pathways involved in fetal development and organogenesis. This condition is most commonly associated with pregestational diabetes mellitus (type 1 and type 2), although poorly controlled gestational diabetes can also contribute to teratogenic outcomes if hyperglycemia occurs early in pregnancy. The incidence of congenital anomalies is significantly higher in infants born to diabetic mothers compared to the general population, thereby underscoring the teratogenic risk of maternal hyperglycemia during early embryonic development. Common congenital anomalies associated with diabetic embryopathy include neural tube defects (NTDs; eg, spina bifida and anencephaly), congenital heart defects (particularly outflow tract anomalies), craniofacial anomalies, limb deficiencies, and caudal regression syndrome—a condition uniquely associated with maternal diabetes and characterized by agenesis of the lower spine and associated structures. The teratogenic effects of hyperglycemia may be compounded by genetic predisposition, maternal obesity, and coexisting comorbidities such as hypertension and dyslipidemia. Beyond structural malformations, functional abnormalities—including neurodevelopmental delays and metabolic dysregulation—may also manifest later in life.  Effective prevention of diabetic embryopathy relies on comprehensive preconception care and strict glycemic control during the periconceptional period. Ideally, hemoglobin A1c (HbA1c) levels should be normalized to below 6.5% before conception to minimize the risk of teratogenicity. Early prenatal care, including first-trimester ultrasonography and fetal echocardiography, is critical for the timely detection and management of congenital anomalies in high-risk pregnancies.

Pregestational diabetes, either type 1 or type 2 diabetes, induces structural birth defects including neural tube defects and congenital heart defects in human fetuses. Rodent models of type 1 and type 2 diabetic embryopathy have been established and faithfully mimic human conditions. Hyperglycemia of maternal diabetes triggers oxidative stress in the developing neuroepithelium and the embryonic heart leading to the activation of proapoptotic kinases and excessive cell death. Oxidative stress also activates the unfolded protein response and endoplasmic reticulum stress. Hyperglycemia alters epigenetic landscapes by suppressing histone deacetylation, perturbing microRNA (miRNA) expression, and increasing DNA methylation. At cellular levels, besides the induction of cell apoptosis, hyperglycemia suppresses cell proliferation and induces premature senescence. Stress signaling elicited by maternal diabetes disrupts cellular organelle homeostasis leading to mitochondrial dysfunction, mitochondrial dynamic alteration, and autophagy impairment. Blocking oxidative stress, kinase activation, and cellular senescence ameliorates diabetic embryopathy. Deleting the mir200c gene or restoring mir322 expression abolishes maternal diabetes hyperglycemia-induced senescence and cellular stress, respectively. Both the autophagy activator trehalose and the senomorphic rapamycin can alleviate diabetic embryopathy. Thus, targeting cellular stress, miRNAs, senescence, or restoring autophagy or mitochondrial fusion is a promising approach to prevent poorly controlled maternal diabetes-induced structural birth defects. In this review, we summarize the causal events in diabetic embryopathy and propose preventions for this pathological condition. · Maternal diabetes induces structural birth defects.. · Kinase signaling and cellular organelle stress are critically involved in neural tube defects.. · Maternal diabetes increases DNA methylation and suppresses developmental gene expression.. · Cellular apoptosis and senescence are induced by maternal diabetes in the neuroepithelium.. · microRNAs disrupt mitochondrial fusion leading to congenital heart diseases in diabetic pregnancy..