Intravital Assessment of Pre-capillary Pulmonary Arterioles of Type-1 Diabetic Mice Shows Oxidative Damage and Increased Tone in Response to NOS Inhibition

Author(s):  
Andrew M. Roberts ◽  
Nayeem Z. Moulana ◽  
Rekha Jagadapillai ◽  
Lu Cai ◽  
Evelyne Gozal

Microvascular dilation, important for peripheral tissue glucose distribution, also modulates alveolar perfusion and is inhibited by loss of bioavailable nitric oxide (NO) in diabetes mellitus (DM). We hypothesized that DM-induced oxidative stress decreases bioavailable NO and pulmonary pre-capillary arteriolar diameter, causing endothelial injury. We examined sub-pleural pulmonary arterioles after acute NO synthase (NOS) inhibition with L-NAME in streptozotocin (STZ) and saline (CTRL)-treated C57BL/6J mice. Microvascular changes were assessed by intravital microscopy in the right lung of anesthetized mice with open-chest and ventilated lungs. Arteriolar tone in pulmonary arterioles (27.2 to 48.7 µm diameter), increased in CTRL mice (18.0 ± 11% constriction p=0.034, n=5) but decreased in STZ (13.6 ± 7.5% dilation p= 0.009, n=5), after L-NAME. Lung tissue DHE fluorescence (superoxide), inducible NOS expression, and protein nitrosylation (3-nitrotyrosine) increased in STZ mice and correlated with increased glucose levels (103.8 ± 8.8 mg/dL). Fluorescently-labeled fibrinogen administration and fibrinogen immunostaining showed fibrinogen adhesion, indicating endothelial injury in STZ mice. In CTRL mice, vasoconstriction to L-NAME was likely due to the loss of bioavailable NO. Vasodilation in STZ mice may be due to decreased formation of a vasoconstrictor or emergence of a vasodilator. These findings provide novel evidence that DM targets the pulmonary microcirculation and that decreased NO bioavailability and increased precapillary arteriolar tone could potentially lead to ventilation-perfusion abnormalities, exacerbating systemic DM complications.

Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 776-P
Author(s):  
RACHEL BRANDT ◽  
MINSUN PARK ◽  
LAURIE T. QUINN ◽  
MINSEUNG CHU ◽  
YOUNGKWAN SONG ◽  
...  

MEDISAINS ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 19
Author(s):  
Fairuz Fairuz ◽  
Hasna Dewi ◽  
Humaryanto Humaryanto

Background: Therapies for hyperglycemic treatment, including insulin and oral diabetes medications, have been confirmed to cause several side effects. Thus, finding new drugs with fewer side effects is of high importance. Salung leaf herb (Psychotria malayana Jack) reported used in traditional societies as a treatment for diabetes. However, the scientific proof of this plant for diabetes treatment is still lacking.Objective: To evaluate the antidiabetic effect of the P. malayana jack in induced type 1 diabetic rats by assessing blood glucose level and pancreatic cells in white rats.Methods: Alloxan used to induce type I diabetes. Rats randomly divided into six groups. A Group P1 received 250 mg/kg BW; group P2 received 500 mg/kg BW, group P3 received 1000 mg/kg BW. While group 4 basal received no treatment, group 5 received distilled water as a negative control, and group 6 received glibenclamide as a positive control. Medications are given for six days. Glucose levels were measured, and observation of pancreatic Langerhans cell damages.Results:  A decrease in blood glucose levels observed in all treatment groups. The most significant reduction (49.76%; 1000 mg/kg BW) occurred in the P3 group. Morphological features of pancreatic Langerhans cell damage were slightly high in the P1 group.Conclusion: P. malayana Jack can consider having an antidiabetic effect in a type 1 diabetic rat by reducing blood glucose levels.


BMC Neurology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Chenyang Zhang ◽  
Kang Zhang ◽  
Bing Chen ◽  
Jiao Yin ◽  
Miaomiao Dong ◽  
...  

Abstract Background Neuromyelitis optica spectrum disorders (NMOSD), a group of autoimmune neurological diseases, involve the optic nerve, spinal cord, and brain. Meningitis is rarely reported as the primary clinical manifestation of both anti-aquaporin-4 (AQP4)/ anti-myelin oligodendrocyte glycoprotein (MOG) antibody-negative NMOSD (NMOSDneg). Case presentation A 30-year-old man initially presented with fever, headache, and neck stiffness. Lumbar puncture revealed mixed cell reaction and decreased glucose levels. As a result, tuberculous meningitis was suspected. After 1 month, the patient developed longitudinally extensive transverse myelitis and area postrema syndrome. This was followed by the presentation of meningitis-like symptoms once again in the third attack, but his condition eventually improved after corticosteroid treatment without relapse for 2 years. However, he was readmitted to our hospital owing to symptoms of diplopia, hiccup, and numbness in the right hand. Brain magnetic resonance imaging (MRI) revealed that the area postrema still contained lesions. Spinal MRI revealed several segmental enhancements at the C4–C5, T1, and T5 levels. Anti-AQP4 and anti-MOG antibodies were persistently absent in the serum and cerebrospinal fluid (CSF). The patient was finally diagnosed with NMOSDneg. Conclusions Meningitis could be a recurrent manifestation of NMOSDneg and requires more careful evaluation.


2021 ◽  
Vol 22 (2) ◽  
pp. 484
Author(s):  
Martijn H. van der Ree ◽  
Jeroen Vendrik ◽  
Jan A. Kors ◽  
Ahmad S. Amin ◽  
Arthur A. M. Wilde ◽  
...  

Patients with Brugada syndrome (BrS) can show a leftward deviation of the frontal QRS-axis upon provocation with sodium channel blockers. The cause of this axis change is unclear. In this study, we aimed to determine (1) the prevalence of this left axis deviation and (2) to evaluate its cause, using the insights that could be derived from vectorcardiograms. Hence, from a large cohort of patients who underwent ajmaline provocation testing (n = 1430), we selected patients in whom a type-1 BrS-ECG was evoked (n = 345). Depolarization and repolarization parameters were analyzed for reconstructed vectorcardiograms and were compared between patients with and without a >30° leftward axis shift. We found (1) that the prevalence of a left axis deviation during provocation testing was 18% and (2) that this left axis deviation was not explained by terminal conduction slowing in the right ventricular outflow tract (4th QRS-loop quartile: +17 ± 14 ms versus +13 ± 15 ms, nonsignificant) but was associated with a more proximal conduction slowing (1st QRS-loop quartile: +12[8;18] ms versus +8[4;12] ms, p < 0.001 and 3rd QRS-loop quartile: +12 ± 10 ms versus +5 ± 7 ms, p < 0.001). There was no important heterogeneity of the action potential morphology (no difference in the ventricular gradient), but a left axis deviation did result in a discordant repolarization (spatial QRS-T angle: 122[59;147]° versus 44[25;91]°, p < 0.001). Thus, although the development of the type-1 BrS-ECG is characterized by a terminal conduction delay in the right ventricle, BrS-patients with a left axis deviation upon sodium channel blocker provocation have an additional proximal conduction slowing, which is associated with a subsequent discordant repolarization. Whether this has implications for risk stratification is still undetermined.


2003 ◽  
Vol 148 (1) ◽  
pp. 157-167 ◽  
Author(s):  
J Buren ◽  
HX Liu ◽  
J Lauritz ◽  
JW Eriksson

OBJECTIVE: The purpose of this study was to investigate the cellular effects of long-term exposure to high insulin and glucose levels on glucose transport and insulin signalling proteins. DESIGN AND METHODS: Rat adipocytes were cultured for 24 h in different glucose concentrations with 10(4) microU/ml of insulin or without insulin. After washing, (125)I-insulin binding, basal and acutely insulin-stimulated d-[(14)C]glucose uptake, and insulin signalling proteins and glucose transporter 4 (GLUT4) were assessed. RESULTS: High glucose (15 and 25 mmol/l) for 24 h induced a decrease in basal and insulin-stimulated glucose uptake compared with control cells incubated in low glucose (5 or 10 mmol/l). Twenty-four hours of insulin treatment decreased insulin binding capacity by approximately 40%, and shifted the dose-response curve for insulin's acute effect on glucose uptake 2- to 3-fold to the right. Twenty-four hours of insulin treatment reduced basal and insulin-stimulated glucose uptake only in the presence of high glucose (by approximately 30-50%). At high glucose, insulin receptor substrate-1 (IRS-1) expression was downregulated by approximately 20-50%, whereas IRS-2 was strongly upregulated by glucose levels of 10 mmol/l or more (by 100-400%). Insulin treatment amplified the suppression of IRS-1 when combined with high glucose and also IRS-2 expression was almost abolished. Twenty-four hours of treatment with high glucose or insulin, alone or in combination, shifted the dose-response curve for insulin's effect to acutely phosphorylate protein kinase B (PKB) to the right. Fifteen mmol/l glucose increased GLUT4 in cellular membranes (by approximately 140%) compared with 5 mmol/l but this was prevented by a high insulin concentration. CONCLUSIONS: Long-term exposure to high glucose per se decreases IRS-1 but increases IRS-2 content in rat adipocytes and it impairs glucose transport capacity. Treatment with high insulin downregulates insulin binding capacity and, when combined with high glucose, it produces a marked depletion of IRS-1 and -2 content together with an impaired sensitivity to insulin stimulation of PKB activity. These mechanisms may potentially contribute to insulin resistance in type 2 diabetes.


2011 ◽  
Vol 120 (02) ◽  
pp. 68-72 ◽  
Author(s):  
A. Jawiarczyk ◽  
M. Bolanowski ◽  
J. Syrycka ◽  
G. Bednarek-Tupikowska ◽  
M. Kałużny ◽  
...  

AbstractWe are reporting a case of 68-year-old woman with insulinoma, after a non-successful tumor surgery and a long-term diazoxide treatment. She had a lot of hypoglycemia cases, and a weight gain of 50 kg. An abdominal CT scan demonstrated a tumor 28 mm in the diameter, in the head of the pancreas. The patient did not agree for the repeated insulinoma surgery. Furthermore, we found a lesion in the left adrenal gland (14 mm in the diameter) and in the right lung (8 mm in the diameter). Pheochromocytoma was diagnosed on the basis of hypertension, elevated levels of normetanephrine in the 24-h urine collection, and an elevated level of norepinephrine in a plasma sample. After the left adrenal gland removal we observed lower blood pressure. Since we had revealed the presence of somatostatin receptors by the somatostatin receptors scintigraphy, we decided to control hypoglycemia by a monthly subcutaneous administration of the long-acting lanreotide. Because of higher glucose levels (300–400 mg/dl) we started an intense insulin therapy. Nowadays, the patient feels better, she has lost 20 kg of her body weight, and we have observed normal blood glucose levels during the long-term lanreotide treatment. We have noticed neither side effects nor hypoglycemic episodes and we have reduced the dose of insulin. The presented case can be an evidence of the effective treatment of the pancreatic neuroendocrine tumor of insulinoma type, with somatostatin analogue.


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