A new gestational diabetes mellitus model: hyperglycemia-induced eye malformation via inhibition of Pax6 in the chick embryo

LGZGD for Gestational Diabetes Mellitus: Integration of Traditional Chinese Medicine With Modern Research Evidence-A Letter to the Editor

This letter responds to recent research on Lingguizhugan decoction (LGZGD) in treating gestational diabetes mellitus (GDM). While acknowledging the significance of their findings regarding PI3K-AKT pathway modulation and oxidative stress reduction, we suggest expanding future research directions. We highlight the importance of incorporating animal models alongside cell studies, considering multiple mechanistic pathways, and integrating traditional Chinese medicine approaches with modern research methodologies. Recent studies on natural antioxidants and traditional Chinese medicines in GDM treatment provide supporting evidence for these recommendations. These perspectives aim to enhance understanding of LGZGD's therapeutic potential and contribute to developing more effective GDM treatments.

Early exposure to Western Diet exacerbates visual outcomes in female mice

Obesity, a growing pandemic in Western societies, significantly impacts metabolic health and contributes to visual disorders. While the systemic consequences of obesity, such as chronic inflammation and insulin resistance, are well-studied in adults, its early-life effects on retinal health remain underexplored. Using a maternal Western Diet (WD) exposure model, we investigated the developmental impact of early-life metabolic disturbances on retinal and cognitive function. Our findings reveal that WD exposure from gestation to early adulthood accelerates the onset of features resembling diabetic retinopathy, including increased retinal vascularization, inflammation, and compromised blood-retina barrier integrity, observed within just four months. Females exhibited heightened vulnerability, showing pronounced ocular defects such as anophthalmia, microphthalmia, and congenital cataracts. These results underscore a critical developmental window during which metabolic disruptions predispose to sex-specific retinal and neurovascular pathologies. This work bridges the link between pediatric and adult obesity, highlighting the urgent need for early interventions to mitigate long-term visual impairments that could further impair recognition memory.

PDX1 Methylation, NGN3 and Pax6 Expression Levels in Pregnant Women with Gestational Diabetes Mellitus and their association with neonatal blood sugars and birth weight

Objective

To investigate the correlation of maternal PDX1 methylation, NGN3 and Pax6 expression levels with neonatal blood sugars and birth weight in pregnant women with GDM and non GDM.

Methods

This was a prospective cohort study. Total 80 pregnant women who were examined and delivered in the Department of Obstetrics of Affiliated Hospital of Hebei University from January 2019 to June 2022 were recruited and divided into two groups according to the results of oral glucose tolerance test (OGTT): the control group and the observation group, with 40 cases in each group. PDXl methylation rate was measured by the methylation-specific PCR method, whereas gene expression levels of PDX1, NGN3 and Pax6 were measured by RT-PCR meanwhile, neonatal blood glucose and hemoglobin A1c (HbA1c) levels were also measured.

Results

In comparison with the control group, the observation group had higher levels of FBG, 2-hour postprandial blood glucose (2hPBG) and HbA1c (P<0.05). Neonatal birth weight and insulin levels in the observation group were significantly higher than those in the control group, while Apgar scores and blood glucose were lower than those in the control group(P<0.05). Moreover, the observation group had significantly lower gene expression levels of PDX1, NGN3 and Pax6, and a higher PDX1 methylation rate than the control group (P<0.05). Correlation analysis revealed a negative correlation between neonatal blood glucose levels and PDX1, NGN3 and Pax6 levels in the observation group, with statistical significance (P<0.05).

Conclusion

Changes in maternal PDX1 methylation, NGN3 and Pax6 expression levels may lead to abnormal glucose metabolism in neonates, which has a close bearing on neonatal hypoglycemia and blood glucose levels caused by GDM.

Chemical signaling in the developing avian retina: Focus on cyclic AMP and AKT-dependent pathways

Communication between developing progenitor cells as well as differentiated neurons and glial cells in the nervous system is made through direct cell contacts and chemical signaling mediated by different molecules. Several of these substances are synthesized and released by developing cells and play roles since early stages of Central Nervous System development. The chicken retina is a very suitable model for neurochemical studies, including the study of regulation of signaling pathways during development. Among advantages of the model are its very well-known histogenesis, the presence of most neurotransmitter systems found in the brain and the possibility to make cultures of neurons and/or glial cells where many neurochemical functions develop in a similar way than in the intact embryonic tissue. In the chicken retina, some neurotransmitters or neuromodulators as dopamine, adenosine, and others are coupled to cyclic AMP production or adenylyl cyclase inhibition since early stages of development. Other substances as vitamin C and nitric oxide are linked to the major neurotransmitter glutamate and AKT metabolism. All these different systems regulate signaling pathways, including PKA, PKG, SRC, AKT and ERK, and the activation of the transcription factor CREB. Dopamine and adenosine stimulate cAMP accumulation in the chick embryo retina through activation of D1 and A2a receptors, respectively, but the onset of dopamine stimulation is much earlier than that of adenosine. However, adenosine can inhibit adenylyl cyclase and modulate dopamine-dependent cAMP increase since early developmental stages through A1 receptors. Dopamine stimulates different PKA as well as EPAC downstream pathways both in intact tissue and in culture as the CSK-SRC pathway modulating glutamate NMDA receptors as well as vitamin C release and CREB phosphorylation. By the other hand, glutamate modulates nitric oxide production and AKT activation in cultured retinal cells and this pathway controls neuronal survival in retina. Glutamate and adenosine stimulate the release of vitamin C and this vitamin regulates the transport of glutamate, activation of NMDA receptors and AKT phosphorylation in cultured retinal cells. In the present review we will focus on these reciprocal interactions between neurotransmitters or neuromodulators and different signaling pathways during retinal development.

Co-expression and Interaction of Pax6 with Genes and Proteins of Immunological Surveillance in the Brain of Mice

The Pax6 binds to promoter sequence elements of genes involved in immunological surveillance and interacts with Iba1, p53, Ras-GAP, and Sparc in the brain of mice. The Pax6 also affects the expression pattern of genes involved in neurogenesis and neurodegeneration. However, the expression and association of Pax6 in the brain under immunologically challenged conditions are still elusive. Therefore, it has been intended to analyze the association of Pax6 in the immunity of the brain using the immune-challenged Dalton's lymphoma (DL) mice model. The expressions of Pax6, Iba1, and Tmem119 decreased, but expressions of Ifn-γ, Tnf-α, Bdnf, and Tgf-β increased in the brain of immune-challenged mice as compared to the control. The level of co-expression of Pax6 decreased in dual positive cells with Iba1, Tmem119, Sparc, p53, Bdnf, and Tgf-β in the brain of immune-challenged mice. Binding of Pax6 to multiple sites of the promoter sequences of Bdnf and Tgf-β indicates their Pax6-associated differential expression and association with immune responsive gene. The levels of binding of Pax6 to Tmem119, Iba1, Ifn-γ, and Tnf-α got altered during the immune-challenged state as compared to control. Results provide the first evidence of the association of Pax6 in brain-specific immunity.

Association of maternal diabetes during pregnancy with visual acuity development in offspring: a prospective cohort study

AIMS

We aimed to investigate the association between maternal diabetes before or during pregnancy and visual acuity development in offspring at 1 and 4 years old.

METHODS

This prospective cohort study comprised 301 individuals born in 2015-2017. Those who had maternal diabetes during or before pregnancy (type 1 diabetes, type 2 diabetes and gestational diabetes) were investigated. Two visual examinations were routinely performed on children relatively at the age of 1 at physical examination and at the age of 4 at admission to school to assess the possible effects of gestational exposure to diabetes on the visual system of the offspring.

RESULTS

Data were collected on children aged 1 and 4, which consisted of 173 children of mothers exposed to diabetes and 128 children of mothers without diabetes). We found no significant association between maternal diabetes during pregnancy and visual acuity development in 1-year-old offspring. At 4 years old, the incidence of amblyopia and strabismus was similar in both groups. Prenatal exposure to maternal diabetes was associated with a 171% increased risk of high RE: OR 2.71 (95% CI 1.08, 6.81), p < 0.05. Astigmatism (13.3% vs 5.5%) was found to be significantly more prevalent in children born to mothers with GD than in the controls (p = 0.025 in both groups). Moreover, offspring exposed to PGDM had a higher overall risk of high RE than those exposed to GDM during pregnancy (25.0% vs 17.4%). We further found that in the offspring of diabetic mothers, the risk of high RE was significantly increased among children who were female or who spent more time using electronic devices daily.

CONCLUSIONS

Our findings suggest that maternal diabetes during pregnancy is associated with an increased risk of high RE in offspring. Regular ophthalmological screening should be advised to offspring of mothers with diabetes diagnosed before or during pregnancy.

Association of maternal diabetes during pregnancy with high refractive error in offspring: a nationwide population-based cohort study

AIMS/HYPOTHESIS

We aimed to investigate the associations between maternal diabetes before or during pregnancy and the risk of high refractive error (RE) in offspring until the age of 25 years.

METHODS

This nationwide register-based cohort study comprised 2,470,580 individuals born in 1977-2016. The exposure was maternal diabetes during or before pregnancy (type 1 diabetes, type 2 diabetes and gestational diabetes). Cox regression was used to examine the association between maternal diabetes and the risk of high RE in offspring from birth until the age of 25 years, adjusting for multiple potential confounders.

RESULTS

During up to 25 years of follow-up, 553 offspring of mothers with diabetes and 19,695 offspring of mothers without diabetes were diagnosed with high RE. Prenatal exposure to maternal diabetes was associated with a 39% increased risk of high RE: HR 1.39 (95% CI 1.28, 1.51), p < 0.001; standardised cumulative incidence in unexposed offspring at 25 years of age 1.18% (95% CI 1.16%, 1.19%); cumulative incidence difference 0.72% (95% CI 0.51%, 0.94%). The elevated risks were observed for hypermetropia (HR 1.37 [95% CI 1.24, 1.51], p < 0.001), myopia (HR 1.34 [95% CI 1.08, 1.66], p = 0.007) and astigmatism (HR 1.58 [95% CI 1.29, 1.92], p < 0.001). The increased risks were more pronounced among offspring of mothers with diabetic complications (HR 2.05 [95% CI 1.60, 2.64], p < 0.001), compared with those of mothers with diabetes but no diabetic complications (HR 1.18 [95% CI 1.02, 1.37], p = 0.030).

CONCLUSIONS/INTERPRETATION

Our findings suggest that maternal diabetes during pregnancy is associated with an increased risk of high RE in offspring, in particular among those of mothers with diabetic complications. Early ophthalmological screening should be recommended in offspring of mothers with diabetes diagnosed before or during pregnancy.

Ophthalmic Pathology in the Offspring of Pregnant Women with Gestational Diabetes Mellitus

BACKGROUND

Gestational diabetes (GD) occurs in 5.8% to 25.1% of pregnant women. This disorder has been linked with intrauterine growth delays, congenital anomalies, and neurobehavioral disorders following birth. As to ophthalmological effects, changes in macular thickness and hypoplasia of the upper quadrant of the papilla have been described.

OBJECTIVE

To investigate whether GD has an effect on ophthalmological development in the children born of mothers with this condition.

METHODS

Observational study carried out in children seen in the ophthalmological outpatient clinic of a pediatric hospital in Barcelona (Spain) between January 2011 and December 2015. Participants were ultimately divided into two groups, a study group whose mothers had GD managed either by insulin or diet (GD group) and a control group of children with non-diabetic mothers. Pregestational diabetes cases, were excluded. Complete information was collected on the children's refraction status, ophthalmological disease, and congenital malformations.

RESULTS

Data were compiled on 350 children (229 children born of mothers with GD-186 managed with diet vs 43, with insulin- and 121 controls). The prevalence of amblyopia and strabismus was similar between the groups, but children of mothers with GD had a three-fold greater probability of having refractive errors than children born to mothers without GD. Hyperopia (14.8% vs. 7.4%) and myopia (3.5% vs 0%) were found to be significantly more prevalent in children born of mothers with GD than in the controls (p = 0.027 in both groups).The prevalence of astigmatism was similar in both groups (1.7% vs 0.8%).

CONCLUSIONS FOR PRACTICE

Refractive errors are more common in children born of mothers with GD. These conditions are easily managed, but if they are not detected, they can lead to amblyopia or accommodative strabismus, interfere with acquisition of fine motor skills, and lead to learning problems. Regular ocular examinations would be recommended in these patients.

Abnormal retinal pigment epithelium melanogenesis as a major determinant for radiation-induced congenital eye defects

Recent studies highlighted a link between ionizing radiation exposure during neurulation and birth defects such as microphthalmos and anophthalmos. Because the mechanisms underlying these defects remain largely unexplored, we irradiated pregnant C57BL/6J mice (1.0 Gy, X-rays) at embryonic day (E)7.5, followed by histological and gene/protein expression analyses at defined days. Irradiation impaired embryonic development at E9 and we observed a delayed pigmentation of the retinal pigment epithelium (RPE) at E11. In addition, a reduced RNA expression and protein abundance of critical eye-development genes (e.g. Pax6 and Lhx2) was observed. Furthermore, a decreased expression of Mitf, Tyr and Tyrp1 supported the radiation-induced perturbation in RPE pigmentation. Finally, via immunostainings for proliferation (Ki67) and mitosis (phosphorylated histone 3), a decreased mitotic index was observed in the E18 retina after exposure at E7.5. Overall, we propose a plausible etiological model for radiation-induced eye-size defects, with RPE melanogenesis as a major determining factor.

Level of hydrogen peroxide affects expression and sub-cellular localization of Pax6

The Pax6 is a multifunctional pairedbox and homeobox containing transcription factor which is involved in several functions of brain, eyes, and pancreas. It regulates expression of genes involved in cell proliferation, differentiation, inflammation, oxidative stress management, and neuropathy. Dynamic changes in the sub-cellular localization of Pax6 are proposed to regulate its activity, however, the underlying mechanism remains poorly understood. The oxidative stress mediated changes were studied in sub-cellular localization of Pax6 in cultured cells derived from the eye (cornea) and pancreas. The impact of induced oxidative stress was investigated on reactive oxygen species scavenger molecules, Superoxide dismutase1 (SOD1) and Catalase, and a critical cell signalling molecule Transforming growth factor-beta (TGF-β1). The cells were treated with three different concentrations of H₂O_2, viz., 0.3, 1.5, and 3.0 mM. The cell viability was analysed through Trypan blue dye exclusion assay. The localization of Pax6 was observed by immunofluorescence labeling, and alterations in levels of Pax6, SOD1, Catalase, and TGF-β1 were investigated by semi-quantitative RT-PCR. Nucleo-cytoplasmic shuttling of Pax6 was observed in cells of corneal epithelial (SIRC) and pancreatic origins (MIA-PaCa2). The percentage distribution of Pax6 in nuclear and cytoplasmic compartments of SIRC and MIA-PaCa2 cells was analyzed through ImageJ software. Level of hydrogen peroxide affects expression and sub-cellular localization of Pax6. Expression of Pax6 and TGF-β1 are directly associated with changes in sub-cellular localization of Pax6 and modulation in expression of Catalase. This may be the result of a cellular protective mechanism against peroxide-dependent cellular stress.

The chick eye in vision research: An excellent model for the study of ocular disease

The domestic chicken, Gallus gallus, serves as an excellent model for the study of a wide range of ocular diseases and conditions. The purpose of this manuscript is to outline some anatomic, physiologic, and genetic features of this organism as a robust animal model for vision research, particularly for modeling human retinal disease. Advantages include a sequenced genome, a large eye, relative ease of handling and maintenance, and ready availability. Relevant similarities and differences to humans are highlighted for ocular structures as well as for general physiologic processes. Current research applications for various ocular diseases and conditions, including ocular imaging with spectral domain optical coherence tomography, are discussed. Several genetic and non-genetic ocular disease models are outlined, including for pathologic myopia, keratoconus, glaucoma, retinal detachment, retinal degeneration, ocular albinism, and ocular tumors. Finally, the use of stem cell technology to study the repair of damaged tissues in the chick eye is discussed. Overall, the chick model provides opportunities for high-throughput translational studies to more effectively prevent or treat blinding ocular diseases.