Effect of hyperglycemia on cerebral blood flow in patients with diabetes

Heterogeneity and synaptic plasticity analysis of hippocampus based on db-/- mice induced diabetic encephalopathy

Chronic hyperglycemia can cause changes in synaptic plasticity of hippocampal cells, which has accelerated the pathological process of cognitive dysfunction. However, the heterogeneity of the hippocampal cell populations under long term high glucose statement remains largely unknown. To mimic chronic hyperglycemia induced cognitive function deficit in vivo, db-/- diabetic mice was selected and Novel Object Recognition(NOR) behavior tests were performed. Based on diabetic induced cognitive impairment(CI) animal model, single-cell RNA sequencing was performed in the hippocampus of CI group (21,379 cells) or control group (20,045 cells), and single cell RNA sequencing was applied, and then the single cell atlas of gene expression was profiled. The comprehensive analysis explicated 18 nerve cell clusters, including 9 distinct sub-clusters, More in-depth analysis of oligodendrocyte precursor cells(OPCs) showed five distinct OPCs sub-clusters including expressing marker gene Lingo2-OPCs, Kcnc1-OPCs, Sst-OPCs, Slc6a1-OPCs and Lhfpl3-OPCs, which seems to be able to proliferate, migrate, and finally differentiate into mature oligodendrocytes and produce myelin. To be noted, differentially expressed genes(DEGs) of the Sst-OPCs sub-cluster indicated that the genes participating in neuroactive ligand-receptor interaction, nervous system development and inflammatory process were up-regulated in diabetic induced cognitive impairment(DCI) groups compared to normal control groups. Integrating the data of neuroplasticity regulation, the 20th top-enriched biological process was associated with neuroplasticity regulation in CI groups compared to control groups. Among these neuroplasticity-related genes, the intersectional gene Sstr2 may play an important role in neuroplasticity regulation. Focused on neuroplasticity regulation and its related specific genes may provide potential new clues for the treatment of diabetes mellitus complicated with cognitive impairment. In summary, we showed the comprehensively transcriptional landscape of hippocampal cells in the db-/- diabetic mice with cognitive dysfunction, distinctive cell sub-clusters and the gene expression characteristics were identified, and also their special functions were proposed, which may give new clues and potential targets for diagnosis and treatment of diabetic encephalopathy.

Antioxidant and anti-inflammatory properties of ginsenoside Rg1 for hyperglycemia in type 2 diabetes mellitus: systematic reviews and meta-analyses of animal studies

Background: According to existing laboratory data, ginsenoside Rg1 may help cure diabetes and its complications by reducing oxidative stress (OS) and managing inflammation. However, this conclusion lacks reliability and is unclear. As a result, the purpose of this systematic review and meta-analysis was to evaluate the antioxidant and anti-inflammatory effects of ginsenoside Rg1 in the treatment of diabetes and its complications. Methods: We searched for relevant studies published through December 2022, including electronic bibliographic databases such as PubMed, EMBASE, Web of Science, CNKI, and Wanfang. The SYstematic Review Center for Laboratory Animal Experimentation Risk of Bias (SYRCLE RoB) tool was used to conduct a meta-analysis to assess the methodological quality of animal research. The meta-analysis was conducted using RevMan5.4 software, following the Cochrane Handbook for Systematic Reviews of Interventions. This study is registered in the International Systems Review Prospective Registry (PROSPERO) as CRD42023386830. Results: Eighteen eligible studies involving 401 animals were included. Ginsenoside Rg1 was significantly correlated with blood glucose (BG), insulin levels, body weight, superoxide dismutase (SOD), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) levels. In addition, according to subgroup analysis, the hypoglycemic, anti-inflammatory, and antioxidant effects of ginsenoside Rg1 in type 2 diabetic animals were not affected by experimental species, modeling, experimental drug dosage, or course of treatment. Conclusion: This meta-analysis presents a summary of the hypoglycemic effects of ginsenoside Rg1, which are achieved through anti-inflammatory and antioxidant mechanisms. These findings provide evidence-based support for the medical efficacy of ginsenoside Rg1. Specifically, ginsenoside Rg1 reduced MDA levels and restored SOD activity to exert its antioxidant activity. It had a positive effect on the reduction of IL-6 and TNF-α levels. However, the inclusion of studies with low methodological quality and the presence of publication bias may undermine the validity of the results. Further investigation with a more rigorous experimental design and comprehensive studies is necessary to fully understand the specific glycemic mechanisms of ginsenosides. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/, identifier https://CRD42023386830.

Acute stroke-like deficits associated with nonketotic hyperglycemic hyperosmolar state: an illustrative case and systematic review of literature

Introduction

Nonketotic hyperglycemic hyperosmolar state (NKHHS) is associated with a wide spectrum of neurological syndromes including acute stroke-like deficits. Clinical features and etiology have not been established yet.

Methods

Here we provide a case illustration and systematic review on non-epileptic acute neurological deficits in NKHSS. The systematic literature search followed PRISMA guidelines and a predefined protocol, including cases of NKHSS with acute stroke-like presentation.

Results

The database search yielded 18 cases. Hemianopia was the most common clinical presentation (73%), followed by partial or total anterior circulation syndrome (26%). Patients with symptoms of acute anterior circulation infarct were significantly older (69.5 ± 5.1 vs. 52.2 ± 13.9 years; p = 0.03) and showed higher mean glucose levels at the admission vs. those with hemianopia (674.8 ± 197.2 vs. 529.4 ± 190.8 mg/dL; p = 0.16). Brain MRI was performed in 89% of patients, resulting abnormal in 71% of them, especially hemianopic (91%). Subcortical hypointensities in T2-FLAIR MR sequences were present in all the analyzed cases. Cortical DWI hyperintensities were also common (64%). EEG showed diffuse or focal slow wave activity in 68% of patients, especially with visual hallucinations (85%). Neurological symptoms completely resolved in 78% of patients within 6 (IQR 3–10) days, following aggressive treatment and glucose normalization.

Conclusions

Our results suggest neuronal dysfunction on a metabolic basis as the leading cause of acute neurological deficits in NKHHS. Despite the generally favorable prognosis, prompt identification and aggressive treatment are crucial to avoid irreversible damage. Larger cohort studies are needed to confirm our findings.

Modification of pea dietary fiber by ultrafine grinding and hypoglycemic effect in diabetes mellitus mice

This study was designed to investigate the effects of ultrafine grinding on the physicochemical properties of pea dietary fiber (PDF) and the hypoglycemic effect of ultrafine grinding dietary fiber on diabetes mellitus (DM). So, the PDF was treated by ultrafine grinding technology, and its microstructure and physicochemical properties were determined. Then, the DM model was established, and the 4-week ultrafine grinded pea dietary fiber (UGPDF) diet intervention was conducted by using gavage and feeding. During this period, the blood glucose and body weight of the mice were measured, and an oral glucose tolerance test was measured on the last day. The biochemical blood indexes of the mice were determined, and the pancreas was stained with HE after dissecting. The results showed that after ultrafine grinding, the structure fragmentation, specific surface area increased, and UGPDF showed higher swelling ability as well as water and oil holding capacities. Simultaneously, UGPDF had a significant effect on reducing blood glucose and glycosylated hemoglobin in DM mice, improving the wasting state of mice and increasing the tolerance to glucose. Further, the results of the HE section showed that the pancreatic islet cells gradually returned to normal regular morphology. In biochemical blood indicators, UGPDF reduced TC and TG levels in the blood. This study provided a specific data basis for the following research on the hypoglycemic mechanism, and broadens the application field of PDF. PRACTICAL APPLICATION: The physicochemical properties of pea dietary fiber were improved by ultrafine grinding technology. Because of this, the application of pea dietary fiber in the field of hypoglycemic had a better effect, laying a foundation for the next research on hypoglycemic mechanism.

Retinal Vascular Reactivity in Type 1 Diabetes Patients Without Retinopathy Using Optical Coherence Tomography Angiography

Purpose

We hypothesize that patients with type 1 diabetes (T1D) may have abnormal retinal vascular responses before diabetic retinopathy (DR) is clinically evident. Optical coherence tomography angiography (OCTA) was used to dynamically assess the retinal microvasculature of diabetic patients with no clinically visible retinopathy.

Methods

Controlled nonrandomized interventional study. The studied population included 48 eyes of 24 T1D patients and 24 demographically similar healthy volunteers. A commercial OCTA device (AngioVue) was used, and two tests were applied: (1) the hypoxia challenge test (HCT) and (2) the handgrip test to induce a vasodilatory or vasoconstrictive response, respectively. The HCT is a standardized test that creates a mild hypoxic environment equivalent to a flight cabin. The handgrip test (i.e., isometric exercise) induces a sympathetic autonomic response. Changes in the parafoveal superficial and deep capillary plexuses in both tests were compared in each group. Systemic cardiovascular responses were also comparatively evaluated.

Results

In the control cohort, the vessel density of the median parafoveal superficial and deep plexuses increased during hypoxia (F_1,23 = 15.69, P < 0.001 and F_1,23 = 16.26, P < 0.001, respectively). In the T1D group, this physiological response was not observed in either the superficial or the deep retinal plexuses. Isometric exercise elicited a significant decrease in vessel density in both superficial and deep plexuses in the control group (F_1,23 = 27.37, P < 0.0001 and F_1,23 = 27.90, P < 0.0001, respectively). In the T1D group, this response was noted only in the deep plexus (F_1,23 = 11.04, P < 0.01).

Conclusions

Our work suggests there is an early impairment of the physiological retinal vascular response in patients with T1D without clinical diabetic retinopathy.