Cannabidiol attenuates high glucose-induced endothelial cell inflammatory response and barrier disruption.

A nonpsychoactive cannabinoid cannabidiol (CBD) has been shown to exert potent anti-inflammatory and antioxidant effects and has recently been reported to lower the incidence of diabetes in nonobese diabetic mice and to preserve the blood-retinal barrier in experimental diabetes. In this study we have investigated the effects of CBD on high glucose (HG)-induced, mitochondrial superoxide generation, NF-kappaB activation, nitrotyrosine formation, inducible nitric oxide synthase (iNOS) and adhesion molecules ICAM-1 and VCAM-1 expression, monocyte-endothelial adhesion, transendothelial migration of monocytes, and disruption of endothelial barrier function in human coronary artery endothelial cells (HCAECs). HG markedly increased mitochondrial superoxide generation (measured by flow cytometry using MitoSOX), NF-kappaB activation, nitrotyrosine formation, upregulation of iNOS and adhesion molecules ICAM-1 and VCAM-1, transendothelial migration of monocytes, and monocyte-endothelial adhesion in HCAECs. HG also decreased endothelial barrier function measured by increased permeability and diminished expression of vascular endothelial cadherin in HCAECs. Remarkably, all the above mentioned effects of HG were attenuated by CBD pretreatment. Since a disruption of the endothelial function and integrity by HG is a crucial early event underlying the development of various diabetic complications, our results suggest that CBD, which has recently been approved for the treatment of inflammation, pain, and spasticity associated with multiple sclerosis in humans, may have significant therapeutic benefits against diabetic complications and atherosclerosis

Role of nitrosative stress and peroxynitrite in the pathogenesis of diabetic complications. Emerging new therapeutical strategies

Macro- and microvascular disease are the most common causes of morbidity and mortality in patients with diabetes mellitus. Diabetic cardiovascular dysfunction represents a problem of great clinical importance underlying the development of various severe complications including retinopathy, nephropathy, neuropathy and increase the risk of stroke, hypertension and myocardial infarction. Hyperglycemic episodes, which complicate even well-controlled cases of diabetes, are closely associated with increased oxidative and nitrosative stress, which can trigger the development of diabetic complications. Hyperglycemia stimulates the production of advanced glycosylated end products, activates protein kinase C, and enhances the polyol pathway leading to increased superoxide anion formation. Superoxide anion interacts with nitric oxide, forming the potent cytotoxin peroxynitrite, which attacks various biomolecules in the vascular endothelium, vascular smooth muscle and myocardium, leading to cardiovascular dysfunction. The pathogenetic role of nitrosative stress and peroxynitrite, and downstream mechanisms including poly(ADP-ribose) polymerase (PARP) activation, is not limited to the diabetes-induced cardiovascular dysfunction, but also contributes to the development and progression of diabetic nephropathy, retinopathy and neuropathy. Accordingly, neutralization of peroxynitrite or pharmacological inhibition of PARP is a promising new approach in the therapy and prevention of diabetic complications. This review focuses on the role of nitrosative stress and downstream mechanisms including activation of PARP in diabetic complications and on novel emerging therapeutical strategies offered by neutralization of peroxynitrite and inhibition of PARP

Role for nitrosative stress in diabetic neuropathy: evidence from studies with a peroxynitrite decomposition catalyst

Nitrosative stress, that is, enhanced peroxynitrite formation, has been documented in both experimental and clinical diabetic neuropathy (DN), but its pathogenetic role remains unexplored. This study evaluated the role for nitrosative stress in two animal models of type 1 diabetes: streptozotocin‐diabetic mice and diabetic NOD mice. Control (C) and streptozotocin‐diabetic (D) mice were treated with and without the potent peroxynitrite decomposition catalyst FP15 (5 mg kg−1 d−1) for 1 wk after 8 wk without treatment. Sciatic nerve nitrotyrosine (a marker of peroxynitrite‐induced injury) and poly(ADP‐ribose) immunoreactivities were present in D and absent in C and D+FP15. FP15 treatment corrected sciatic motor and hind‐limb digital sensory nerve conduction deficits and sciatic nerve energy state in D, without affecting those variables in C. Nerve glucose and sorbitol pathway intermediate concentrations were similarly elevated in D and D+FP15 vs C. In diabetic NOD mice, a 7‐day treatment with either 1 or 3 mg kg−1 d−1 FP15 reversed increased tail‐flick latency (a sign of reduced pain sensitivity); the effect of the higher dose was significant as early as 3 days after beginning of the treatment. In conclusion, nitrosative stress plays a major role in DN in, at least, type 1 diabetes. This provides the rationale for development of agents counteracting peroxynitrite formation and promoting peroxynitrite decomposition, and their evaluation in DN.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154323/1/fsb2fj041913fje-sup-0001.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154323/2/fsb2fj041913fje.pd

Assessment of NADPH-diaphorase stained myenteric neurons of the jejunum of diabetic rats supplemented with ascorbic acid Avaliação dos neurônios NADPH-diaforase reativos do jejuno de raots diabéticos suplementados com ácido ascórbico

The relation between hyperglycemia and diabetic neuropathy has already been demonstrated in some studies. Among the theories proposed for its etiology the oxidative stress stands out. The performance of nitric oxide as a link between the metabolic and vascular neuropathogenic factors that triggers the diabetic neuropathy has already been put forward. This study aimed to assess the quantification and measurements of the cell body profile area (CBPA) of NADPH-diaphorase reactive (NADPH-dp) myenteric neurons of the jejunum of diabetic rats (induced by streptozotocin) supplemented with Ascorbic Acid (AA). These changes in the myenteric neurons seem to be related to the gastrointestinal disturbances observed in diabetes mellitus (DM). Twenty male Wistar rats (Rattus norvegicus) were distributed in 4 groups (n=5): controls (C), control supplemented (CS), diabetic (D), and diabetic suplemented (DS). DM was induced by estreptozotocin (50mg/kg body wt). One week after the induction and confirmation of the DM (glycemia exam), animals of the groups CS and DS received 50mg of AA three times a week by gavage. After 90 days of experiment, the animals were anesthetized with lethal thiopental dose (40mg/kg) and the collected jejunum processed for the histochemistry NADPH-diaphorase technique. Whole-mount preparations were obtained for quantitative and morphometric analysis of the myenteric neurons. A quantity of jejunum neurons in the Group D (96&plusmn;7.5) was not different (P>0.05) from Group DS (116&plusmn;8.08), C (92&plusmn;9.7), and CS (81&plusmn;5.4), but in Group DS the quantity was higher (P<0.05) than in Group C and CS. The CBPA of neurons from Group D (189.50&plusmn;2.68µm²) and DS (195.92&plusmn;3.75µm²) were lower (P<0.05) than from Group C (225.13&plusmn;4.37µm²) and CS (210.23&plusmn;3.15µm²). The streptozotocin-induced DM did not change the jejunum-ileum area, the jejunum myenteric plexus space organization and the density of NADPH-dp neurons. The 50g AA-supplementation, three times a week, during 90 days, did not decrease hyperglycemia; however, it had a neuroprotective effect on the myenteric neurons, minimizing the increase on the CBPA of NADPH-dp neurons and increasing the amount of NADPD-dp neurons.<br>A relação entre hiperglicemia e neuropatia diabética foi demonstrada em várias pesquisas. Entre as teorias propostas para sua etiologia destaca-se o estresse oxidativo. O papel do óxido nítrico como elo entre os fatores neuropatogênicos metabólico e vascular que ativam a neuropatia diabética tem sido ressaltado. Este estudo objetivou avaliar a quantificação e a morfometria da área do perfil do corpo celular (CBPA) de neurônios mioentéricos NADPH-diaforase reativos (NADPH-dp) do jejuno de ratos diabéticos e suplementados com Ácido Ascórbico (AA), uma vez que alterações nos neurônios mioentéricos parecem estar relacionadas aos distúrbios gastrointestinais observados no diabetes mellitus (DM). Vinte ratos machos da linhagem Wistar (Rattus norvergicus) foram distribuídos em 4 grupos (n=5): controle (C), controle suplementado (CS), diabético (D) e diabético suplementado (DS). O DM foi induzido através de injeção de estreptozootocina (50mg/kg de peso corporal). Uma semana depois da indução e confirmação do DM (glicemia), animais dos grupos CS e DS receberam, via gavagem, 50mg de AA três vezes por semana. Após 90 dias de período experimental, os animais foram anestesiados com dose letal de thiopental intravenosa (40mg/kg) e o jejuno foi retirado e processado para a técnica histoquímica da NADPH-diaforase. Preparados de membrana foram obtidos para análises quantitativa e morfométrica dos neurônios mioentéricos. A quantidade de neurônios do jejuno do Grupo D (96&plusmn;7,5) não diferiu (P>0,05) dos Grupos DS (116&plusmn;8,08), C (92&plusmn;9,7) e CS (81&plusmn;5,4), mas no Grupo DS o número de neurônios foi superior (P<0,05) aos Grupos C e CS. A CBPA de neurônios do Grupo D (189,50&plusmn;2,68µm²) e DS (195,92&plusmn;3,75µm²) foi menor (P<0,05) do que a dos Grupos C (225,13&plusmn;4,37µm²) e CS (210,23&plusmn;3,15µm²). O DM induzido por estreptozootocina não alterou a área do jejuno-íleo, a organização espacial do plexo mioentérico e a densidade de neurônios de NADPH-dp do jejuno. A suplementação de 50mg de AA, três vezes por semana, durante 90 dias, não diminuiu a hiperglicemia, porém teve efeito neuroprotetor nos neurônios mioentéricos, minimizando o aumento na CBPA dos neurônios NADPH-dp e aumentando a quantidade de neurônios reativos a NADPD-diaforase