Dapagliflozin: a sodium glucose cotransporter 2 inhibitor in development for type 2 diabetes

Type 2 diabetes mellitus (T2DM) is a growing worldwide epidemic. Patients face lifelong therapy to control hyperglycemia and prevent the associated complications. There are many medications, with varying mechanisms, available for the treatment of T2DM, but almost all target the declining insulin sensitivity and secretion that are associated with disease progression. Medications with such insulin-dependent mechanisms of action often lose efficacy over time, and there is increasing interest in the development of new antidiabetes medications that are not dependent upon insulin. One such approach is through the inhibition of renal glucose reuptake. Dapagliflozin, the first of a class of selective sodium glucose cotransporter 2 inhibitors, reduces renal glucose reabsorption and is currently under development for the treatment of T2DM. Here, we review the literature relating to the preclinical and clinical development of dapagliflozin

Age-related changes in the morphology of preganglionic neurons projecting to the rat hypogastric ganglion

The aim of this study was to investigate age-related changes in preganglionic neurons of the lumbar and sacral spinal cord of the male rat that may underlie impaired control of the urogenital system in old age. Preganglionic sympathetic and parasympathetic neurons of 4- and 24-month-old rats were identified by retrograde axonal tracing with cholera toxin subunit-B followed by immunocytochemistry. Labelled preganglionic neurons were scanned on the confocal microscope. Measurements were made of soma area, number of primary dendrites, number of dendritic branch points and total dendritic length. there were significant decreases in the number of dendritic branch points and total dendritic length of sympathetic preganglionic neurons in the aged rats compared to the adult group. The soma area and number of primary dendrites were not significantly different. Some cells exhibited signs of degeneration, such as swelling of the soma and distension of the proximal part of primary dendrites. No significant differences were found in any of the parameters measured for the parasympathetic neurons. The changes in dendritic morphology of sympathetic preganglionic neurons may reflect altered central and peripheral control of pelvic viscera in old age

South America's tropopause variability in relation to global teleconnection (2001–2017): A GNSS-radio occultation assessment

Analysing tropopause variability is widely acknowledged to inform the understanding of global/regional warming. Tropopause variability studies are generally undertaken where radiosonde data abound. For the radiosonde data deficient South American continent, taking advantage of atmospheric remote sensing using Global Navigation Satellite Systems - Radio Occultation (GNSS-RO) could offer the means to understand its tropopause variability. In this study, 622,914 GNSS-RO measurements of Challenging Minisatellite Payload (CHAMP), Gravity Recovery and Climate Experiment (GRACE) and Constellation Observing System for Meteorology Ionosphere & Climate (FORMOSAT-3/COSMIC), from 2001 to 2017 are used to analyze the annual variability patterns of tropopause heights and temperatures over South America and its relation to global teleconnections. Firstly, the RO measurements are validated using atmospheric profiles for 54 radiosonde stations across the continent. The results show increased trend of 13.450 ± 39.577 m/dec for the tropopause height and a corresponding slow decrease in temperature of −0.021 ± 0.115 K/dec, both statistically insignificant (i.e., p-value test) at 95% of confidence level (two-tailed student's t-test). The first mode of PCA (Principal Component Analysis) of the tropopause anomalies (of temperatures and heights) present significant temporal correlation (at 95% confidence level) with the ENSO 1 + 2 (El Niño–Southern Oscillation) index (i.e., a correlation coefficient of 0.6). The South America tropopause, therefore, varies over time albeit with slow changes and trends. This contribution highlights the importance of its monitoring

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