Sex-Specific ADHD-Like Behaviour, Altered Metabolic Functions, and Altered EEG Activity in Sialyltransferase ST3GAL5-Deficient Mice

A deficiency in GM3-derived gangliosides, resulting from a lack of lactosylceramide-alpha-2,3-sialyltransferase (ST3GAL5), leads to severe neuropathology, including epilepsy and metabolic abnormalities. Disruption of ganglioside production by this enzyme may also have a role in the development of neuropsychiatric disorders. ST3Gal5 knock-out (St3gal5−/−) mice lack a-, b-, and c-series gangliosides, but exhibit no overt neuropathology, possibly owing to the production of compensatory 0-series glycosphingolipids. Here, we sought to investigate the possibility that St3gal5−/− mice might exhibit attention-deficit/hyperactivity disorder (ADHD)-like behaviours. In addition, we evaluated potential metabolic and electroencephalogram (EEG) abnormalities. St3gal5−/− mice were subjected to behavioural testing, glucose tolerance tests, and the levels of expression of brain and peripheral A and B isoforms of the insulin receptor (IR) were measured. We found that St3gal5−/− mice exhibit locomotor hyperactivity, impulsivity, neophobia, and anxiety-like behavior. The genotype also altered blood glucose levels and glucose tolerance. A sex bias was consistently found in relation to body mass and peripheral IR expression. Analysis of the EEG revealed an increase in amplitude in St3gal5−/− mice. Together, St3gal5−/− mice exhibit ADHD-like behaviours, altered metabolic and EEG measures providing a useful platform for better understanding of the contribution of brain gangliosides to ADHD and associated comorbidities.

Anti-Hyperglycemic Effects of Refined Fractions from Cyclocarya Paliurus Leaves on Streptozotocin-Induced Diabetic Mice

To identify the chemical components responsible for the anti-hyperglycemic effect of Cyclocarya paliurus (Batal.) Iljinsk (Juglandaceae) leaves, an ethanol extract (CPE) and a water extract (CPW) of C. paliurus leaves, as well as their total flavonoids (CPF), triterpenoids (CPT) and crude polysaccharides (CPP), were prepared and assessed on streptozotocin (STZ)-induced diabetic mice. After being orally administrated once a day for 24 days, CPF (300 mg/kg), CPP (180 mg/kg), or CPF+CPP (300 mg/kg CPF + 180 mg/kg CPP) treatment reversed STZ-induced body weight and muscle mass losses. The glucose tolerance tests and insulin tolerance tests suggested that CPF, CPP, and CPF+CPP showed anti-hyperglycemic effect in STZ-induced diabetic mice. Furthermore, CPF enhances glucose-stimulated insulin secretion in MIN6 cells and insulin-stimulated glucose uptake in C2C12 myotubes. CPF and CPP suppressed inflammatory cytokine levels in STZ-induced diabetic mice. Additionally, CPF and CPP improved STZ-induced diabetic nephropathy assessed by H&E staining, blood urea nitrogen content, and urine creatinine level. The molecular networking and Emperor analysis results indicated that CPF showed potential anti-hyperglycemic effects, and HPLC–MS/MS analysis indicated that CPF contains 3 phenolic acids and 9 flavonoids. In contrast, CPT (650 mg/kg) and CPC (300 mg/kg CPF + 180 mg/kg CPP + 650 mg/kg CPT) did not show anti-hyperglycemic effect. Taken together, polysaccharides and flavonoids are responsible for the anti-hyperglycemic effect of C. paliurus leaves, and the clinical application of C. paliurus need to be refined.

Chronic cerebral hypoperfusion in male rats results in sustained HPA activation, and hyperinsulinemia

Vascular contributions to cognitive impairment and dementia (VCID) is a spectrum of cognitive deficits caused by cerebrovascular disease, for which insulin resistance is a major risk factor. A major cause of VCID is chronic cerebral hypoperfusion (CCH). Under stress, sustained hypothalamic-pituitary-adrenal axis (HPA) activation can result in insulin resistance. Little is known about the effects of CCH on the HPA axis. We hypothesized that CCH causes sustained HPA activation and insulin resistance. Male rats were subjected to bilateral carotid artery stenosis (BCAS) for 12 weeks to induce CCH and VCID. BCAS reduced cerebral blood flow and caused memory impairment. Plasma adrenocorticotropic hormone was increased in the BCAS rats (117.2 ± 9.6 vs. 88.29 ± 9.1 pg/mL, BCAS vs. sham, p = 0.0236), as was corticosterone (220 ± 21 vs. 146 ± 18 ng/g feces, BCAS vs. sham, p = 0.0083). BCAS rats were hypoglycemic (68.1 ± 6.1 vs. 76.5± 5.9 mg/dL, BCAS vs. sham, p = 0.0072), with increased fasting insulin (481.6 ± 242.6 vs. 97.94± 40.02 pmol/L, BCAS vs. sham, p = 0.0003) indicating BCAS rats were insulin resistant (HOMA-IR:11.71 ± 6.47 vs. 2.62 ± 0.93; BCAS vs. control, p = 0.0008). Glucose tolerance tests revealed that BCAS rats had lower blood glucose AUCs than controls (250 ± 12 vs. 326 ± 20 mg/dL/h, BCAS vs. sham, p = 0.0075). These studies indicate that CCH causes sustained activation of the HPA and results in insulin resistance, a condition that is expected to worsen VCID.

A pilot study about the development and characterization of a Roux en Y gastric bypass model in obese Yucatan minipigs

Performing the Roux-en-Y gastric bypass (RYGBP) in obese Yucatan minipigs provides an opportunity to explore the mechanisms behind the effects of this surgery in controlled environmental and nutritional conditions. We hypothesized that RYGBP in these minipigs would induce changes at multiple levels, as in obese humans. We sought to characterize RYGBP in a diet-induced obese minipig model, compared with a pair-fed sham group. After inducing obesity with an ad libitum high-fat/high-sugar diet, we performed RYGBP (n = 7) or sham surgery (n = 6). Oral glucose tolerance tests (OGTT) were performed before and after surgery. Histological analyses were conducted to compare the alimentary limb at sacrifice with tissue sampled during RYGBP surgery. One death occurred in the RYGBP group at postoperative day (POD) 3. Before sacrifice, weight loss was the same across groups. GLP-1 secretion (OGTT) was significantly higher at 15, 30 and 60 min at POD 7, and at 30 and 60 min at POD 30 in the RYGBP group. Incremental insulin area under the curve increased significantly after RYGBP (p = 0.02). RYGBP induced extensive remodeling of the alimentary limb. Results show that RYGBP can be safely performed in obese minipigs, and changes mimic those observed in humans.

The Deterrence of Rapid Metabolic Decline within 3 Months after Teplizumab Treatment in Individuals at High Risk for Type 1 Diabetes

Endpoints that provide an early identification of treatment effects are needed to implement type 1 diabetes prevention trials more efficiently. To this end, we assessed whether metabolic endpoints can be used to detect a teplizumab effect on rapid β-cell decline within 3 months after treatment in high-risk individuals in the TrialNet teplizumab trial. Glucose and C-peptide response curves (GCRCs) were constructed by plotting mean glucose and C-peptide values from 2-hour oral glucose tolerance tests on a 2-dimensional grid. Groups were compared visually for changes in GCRC shape and movement. GCRC changes reflected marked metabolic deterioration in the placebo group within 3 months of randomization. By 6 months, GCRCs resembled typical GCRCs at diagnosis. In contrast, GCRC changes in the teplizumab group suggested metabolic improvement. Quantitative comparisons, including two novel metabolic endpoints that indicate GCRC changes, the Within Quadrant Endpoint (WQE) and the Ordinal Directional Endpoint (ODE), were consistent with visual impressions of an appreciable treatment effect at 3 and 6-month timepoints. In conclusion, an analytic approach combining visual evidence with novel endpoints, demonstrated that Teplizumab delays rapid metabolic decline, and improves the metabolic state within 3 months after treatment; this effect extends for at least 6 months.

The Deterrence of Rapid Metabolic Decline within 3 Months after Teplizumab Treatment in Individuals at High Risk for Type 1 Diabetes

Endpoints that provide an early identification of treatment effects are needed to implement type 1 diabetes prevention trials more efficiently. To this end, we assessed whether metabolic endpoints can be used to detect a teplizumab effect on rapid β-cell decline within 3 months after treatment in high-risk individuals in the TrialNet teplizumab trial. Glucose and C-peptide response curves (GCRCs) were constructed by plotting mean glucose and C-peptide values from 2-hour oral glucose tolerance tests on a 2-dimensional grid. Groups were compared visually for changes in GCRC shape and movement. GCRC changes reflected marked metabolic deterioration in the placebo group within 3 months of randomization. By 6 months, GCRCs resembled typical GCRCs at diagnosis. In contrast, GCRC changes in the teplizumab group suggested metabolic improvement. Quantitative comparisons, including two novel metabolic endpoints that indicate GCRC changes, the Within Quadrant Endpoint (WQE) and the Ordinal Directional Endpoint (ODE), were consistent with visual impressions of an appreciable treatment effect at 3 and 6-month timepoints. In conclusion, an analytic approach combining visual evidence with novel endpoints, demonstrated that Teplizumab delays rapid metabolic decline, and improves the metabolic state within 3 months after treatment; this effect extends for at least 6 months.

Role of miR-181c in Diet-Induced Obesity Through Regulation of Lipid Synthesis in Liver

We recently identified a nuclear-encoded miRNA (miR-181c) in cardiomyocytes that can translocate into mitochondria to regulate mitochondrial gene (mt-COX1), and influence obesity-induced cardiac dysfunction through mitochondrial pathway. Liver plays a pivotal role during obesity. Therefore, we hypothesized that miR-181c plays an important role in pathophysiological complications associated with obesity. We used miR-181c/d -/- mice to study the miR-181c role in lipogenesis in hepatocytes during diet-induced obesity (DIO). Indirect calorimetric measurements were made during the 26 weeks high fat diet (HFD) exposure. qPCR was performed to examine the gene expression involved in lipid synthesis. Here, we show that miR-181c/d -/- mice are not protected against all metabolic consequences of HFD exposure. After 26 weeks of the HFD, miR-181c/d -/- mice had a significantly higher body fat (%) compared to WT. Glucose tolerance tests showed hyperinsulinemia and hyperglycemia, indicative of insulin insensitivity in the miR-181c/d -/- mice. HFD-fed miR-181c/d -/- mice had higher serum and liver triglyceride levels compared to HFD-fed WT mice. qPCR data demonstrated that several genes which are regulated by isocitrate dehydrogenase 1 (IDH1) were upregulated in miR-181c/d -/- liver compared to WT liver. Furthermore, an AAV-8 was used to deliver miR-181c, in vivo , to validate the potential role of miR-181c in the liver. miR-181c delivery attenuate the lipogenesis by downregulating the same lipid synthesis genes in the liver. In hepatocytes, miR-181c regulates lipid biosynthesis by targeting IDH1. Taken together, the data indicate that overexpression of miR-181c can be beneficial for various lipid metabolism disorders.

Crohn's disease and peptic ulcer disease: A personal comparative analysis

Until the Hruska Postulate and its intellectual fulfillment [1-7], Crohn's disease was a disease entity without either cure or validation. The explanation put forward for its pathogenesis is that the body's immune system selectively turned against something within the gastrointestinal tract. That disruption of the immune system's pro-inflammatory Th1 response could produce evidence of mucosal healing and temporary abatement of disease was aggressively pushed as documentation of the concepts validity. Crohn's disease became the linchpin for 193 journals, 86 conferences and 15,631 articles about or related to autoimmunity. When sought for antibodies to a specific target organ could be demonstrated in a number of diseases. In congenital rubella, the presence of anti-islet cell antibodies introduced the hypothesis that autoimmunity was responsible for the higher incidence of abnormal glucose tolerance tests observed [9]. An equally plausible explanation was that the documented viral replication within islet cells of the pancreas sufficiently altered cellular structure so as to create cross-reacting antibodies. Most claims of autoimmunity have been based upon the demonstration of an antibody that cross-reacts with a cell or subunit within the target organ.

The glucose tolerance test in mice: sex, drugs and protocol.

Background and Purpose: Glucose tolerance tests (GTTs) are commonly used in preclinical studies but are poorly standardised. Male mice are often preferred due to more severe phenotypes which may aid in detecting drug effects. Using novel glucose telemetry in undisturbed mice, the effect of different pre-GTT protocols on blood glucose concentrations, GTTs and detection of drug effects were considered. Experimental Approach: Seven male and female C57Bl/6J mice (8-10 weeks) were implanted with HD-XG glucose telemetry devices. Mice were fasted for 16h overnight or 6h in the daytime following a whole cage change, cage change with retention of used bedding or no cage change prior to i.p.GTTs. Glucose tolerance following oral glucose gavage was compared to voluntary ingestion of gels. Using the most refined procedures, 250mg/kg oral metformin and 10nmol/kg i.p. exendin-4 were tested. Key Results: Blood glucose initially increased following cage changing at the start of the fast. For 6h fasting, retaining bedding reduced these initial responses and produced more timely glucose reductions whereas 16h fasts caused pronounced hypoglycaemia. Impaired glucose tolerance in males was exaggerated following 16h fasting or whole cage changes. Refined procedures including voluntarily ingested glucose gels blunted responses but the effects of exendin-4 and metformin were still observable in both sexes. Conclusion and Implications: Variations in GTT protocol can have profound effects on glucose homeostasis. Improved glucose tolerance due to protocol refinement and/or the use of females still allows for detection of drug effects providing evidence that more severe phenotypes are not required when testing drugs.