Chemical characterization of a hypoglycemic extract from Cucurbita ficifolia bouche that induces liver glycogen accumulation in diabetic mice

Background: The aqueous extract of Cucurbita ficifolia (C. ficifolia) fruit has demonstrated hypoglycemic effect, which may be attributed to some components in the extract. However, the major secondary metabolites in this fruit have not yet been identified and little is known about its extra-pancreatic action, in particular, on liver carbohydrate metabolism. Therefore, in addition to the isolation and structural elucidation of the principal components in the aqueous extract of C. ficifolia, the aim of this study was to determine whether or not the hypoglycemic effect of the aqueous extract of Cucurbita ficifolia (C. ficifolia) fruit is due to accumulation of liver glycogen in diabetic mice.Materials and Methods: The aqueous extract from fruit of C. ficifolia was fractionated and its main secondary metabolites were purified and chemically characterized (NMR and GC-MS). Alloxan-induced diabetic mice received daily by gavage the aqueous extract (30 days). The liver glycogen content was quantified by spectroscopic method and by PAS stain; ALT and AST by spectrometric method; glycogen synthase, glycogen phosphorylase and GLUT2 by Western blot; the mRNA expression of GLUT2 and glucagon-receptor by RT-PCR; while serum insulin was quantified by ELISA method. A liver histological analysis was also performed by H&E stain.Results: Chemical fingerprint showed five majoritarian compounds in the aqueous extract of C. ficifolia: p-coumaric acid, p-hydroxybenzoic acid, salicin, stigmast-7,2,2-dien-3-ol and stigmast-7-en-3-ol. The histological analysis showed accumulation of liver glycogen. Also, increased glycogen synthase and decreased glycogen phosphorylase were observed. Interestingly, the histological architecture evidenced a liver-protective effect due the extract.Conclusion: Five compounds were identified in C. ficifolia aqueous extract. The hypoglycemic effect of this extract may be partially explained by liver glycogen accumulation. The bioactive compound responsible for the hypoglycemic effect of this extract will be elucidated in subsequent studies.Keywords: Cucurbita ficifolia, Cucurbitaceae, liver glycogen, hypoglycemic plants, p-coumaric acid, salicin, p-hydroxybenzoic aci

CHEMICAL CHARACTERIZATION OF A HYPOGLYCEMIC EXTRACT FROM CUCURBITA FICIFOLIA BOUCHE THAT INDUCES LIVER GLYCOGEN ACCUMULATION IN DIABETIC MICE.

Background: The aqueous extract of Cucurbita ficifolia (C. ficifolia) fruit has demonstrated hypoglycemic effect, which may be attributed to some components in the extract. However, the major secondary metabolites in this fruit have not yet been identified and little is known about its extra-pancreatic action, in particular, on liver carbohydrate metabolism. Therefore, in addition to the isolation and structural elucidation of the principal components in the aqueous extract of C. ficifolia, the aim of this study was to determine whether or not the hypoglycemic effect of the aqueous extract of Cucurbita ficifolia (C. ficifolia) fruit is due to accumulation of liver glycogen in diabetic mice. Materials and Methods: The aqueous extract from fruit of C. ficifolia was fractionated and its main secondary metabolites were purified and chemically characterized (NMR and GC-MS). Alloxan-induced diabetic mice received daily by gavage the aqueous extract (30 days). The liver glycogen content was quantified by spectroscopic method and by PAS stain; ALT and AST by spectrometric method; glycogen synthase, glycogen phosphorylase and GLUT2 by Western blot; the mRNA expression of GLUT2 and glucagon-receptor by RT-PCR; while serum insulin was quantified by ELISA method. A liver histological analysis was also performed by H&E stain. Results: Chemical fingerprint showed five majoritarian compounds in the aqueous extract of C. ficifolia: p-coumaric acid, p-hydroxybenzoic acid, salicin, stigmast-7,2,2-dien-3-ol and stigmast-7-en-3-ol. The histological analysis showed accumulation of liver glycogen. Also, increased glycogen synthase and decreased glycogen phosphorylase were observed. Interestingly, the histological architecture evidenced a liver-protective effect due the extract. Conclusion: Five compounds were identified in C. ficifolia aqueous extract. The hypoglycemic effect of this extract may be partially explained by liver glycogen accumulation. The bioactive compound responsible for the hypoglycemic effect of this extract will be elucidated in subsequent studies

In vivo biocompatibility testing of nanoparticle-functionalized alginate–chitosan scaffolds for tissue engineering applications

Background: There is a strong interest in designing new scaffolds for their potential application in tissue engineering and regenerative medicine. The incorporation of functionalization molecules can lead to the enhancement of scaffold properties, resulting in variations in scaffold compatibility. Therefore, the efficacy of the therapy could be compromised by the foreign body reaction triggered after implantation.Methods: In this study, the biocompatibilities of three scaffolds made from an alginate–chitosan combination and functionalized with gold nanoparticles (AuNp) and alginate-coated gold nanoparticles (AuNp + Alg) were evaluated in a subcutaneous implantation model in Wistar rats. Scaffolds and surrounding tissue were collected at 4-, 7- and 25-day postimplantation and processed for histological analysis and quantification of the expression of genes involved in angiogenesis, macrophage profile, and proinflammatory (IL-1β and TNFα) and anti-inflammatory (IL-4 and IL-10) cytokines.Results: Histological analysis showed a characteristic foreign body response that resolved 25 days postimplantation. The intensity of the reaction assessed through capsule thickness was similar among groups. Functionalizing the device with AuNp and AuNp + Alg decreased the expression of markers associated with cell death by apoptosis and polymorphonuclear leukocyte recruitment, suggesting increased compatibility with the host tissue. Similarly, the formation of many foreign body giant cells was prevented. Finally, an increased detection of alpha smooth muscle actin was observed, showing the angiogenic properties of the elaborated scaffolds.Conclusion: Our results show that the proposed scaffolds have improved biocompatibility and exhibit promising potential as biomaterials for elaborating tissue engineering constructs

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Genome sequencing reveals Zika virus diversity and spread in the Americas

Although the recent Zika virus (ZIKV) epidemic in the Americas and its link to birth defects have attracted a great deal of attention, much remains unknown about ZIKV disease epidemiology and ZIKV evolution, in part owing to a lack of genomic data. Here we address this gap in knowledge by using multiple sequencing approaches to generate 110 ZIKV genomes from clinical and mosquito samples from 10 countries and territories, greatly expanding the observed viral genetic diversity from this outbreak. We analysed the timing and patterns of introductions into distinct geographic regions; our phylogenetic evidence suggests rapid expansion of the outbreak in Brazil and multiple introductions of outbreak strains into Puerto Rico, Honduras, Colombia, other Caribbean islands, and the continental United States. We find that ZIKV circulated undetected in multiple regions for many months before the first locally transmitted cases were confirmed, highlighting the importance of surveillance of viral infections. We identify mutations with possible functional implications for ZIKV biology and pathogenesis, as well as those that might be relevant to the effectiveness of diagnostic tests

“ESTUDIO SOBRE ALGUNOS ASPECTOS DE LA BIOLOGIA DE LA REPRODUCCION DE PEROMYSCUS WINKELMANNI”

La mastofauna mexicana se caracteriza por su alto grado de endemismo: casi un tercio de las especies de mamíferos terrestres de México (144) son endémicas. De estas especies, la mayoría pertenece al orden Rodentia. De la gran mayoría de las especies se desconocen aún los aspectos básicos de sus patrones reproductores. Este desconocimiento hace que los planes de conservación de muchas de las especies estén basados más en el sentido común que en información científica confiable. Por esto, los estudios sobre la biología de la reproducción de roedores endémicos de México son valiosos. Diversos trabajos en el género Peromyscus demuestran su importancia en el área biomédica. En este género existen especies de las que no se tienen datos sobre sus patrones reproductores, este es el caso de Peromyscus winkelmanni, roedor endémico de Michoacán. El objetivo de esta tesis es describir la anatomía macroscópica y microscópica del aparato reproductor de P. winkelmanni, y contribuir al conocimiento de la biología de la reproducción de la especie. Los ejemplares empleados provienen de seis colectas (Dos Aguas, Michoacán), de 1994 a 1998. Dos machos y 2 hembras fueron sacrificados por colecta. El aparato reproductor se fijó por inmersión y riego intravascular, se procesó para microscopía de luz y electrónica, respectivamente. Las tinciones empleadas para microscopía de luz fueron: H-E, Masson, PAS, Papanicolau, azul de alciano y de toluidina. Para microscopía electrónica de barrido, recubrimiento con oro y para microscopía electrónica de transmisión citrato de plomo y acetato de uranilo. Así mismo, se analizó la citología vaginal de hembras en condiciones de bioterio. Parte del material procesado se analizó estereológicamente con el programa KS-300, para su valoración estadística. La anatomía macroscópica de los aparatos reproductores masculino y femenino, en general, muestran gran similitud a lo reportado en otras especies del mismo género. La organización histológica de los aparatos reproductores presentan características similares a géneros de la familia Muridae. Sin embargo, se aprecian diferencias en el ciclo del epitelio seminífero, clara regionalización del epidídimo y variaciones en algunas glándulas accesorias a los conductos del aparato reproductor masculino. El espermatozoide presenta un número diferente de fibras densas externas, con respecto a otras especies de mamíferos. Los ovarios, oviductos, útero, y vagina, muestran variaciones estacionales, así como zonas de presumible reabsorción embrionaria uterina. Las diferencias anatómicas, probablemente representen zonas de control de la maduración y capacitación de los espermatozoides, tal como se ha planteado en otros mamíferos. Las diferentes asociaciones celulares del ciclo del epitelio seminífero se pueden atribuir a estados de regresión y reactivación testicular. La regionalización tisular y celular encontrada en el epidídimo sugiere una estrategia reproductora adicional que regula la maduración de los espermatozoides de manera estacional. La variabilidad de las glándulas accesorias a los conductos del aparato reproductor femenino, podría ser reflejo de diferencias individuales. En tanto que la variabilidad en ovarios, oviductos, utero y vagina constituyen los cambios propios de una reproducción estacional. El hallazgo uterino de reabsorción embrionaria evidencia una estrategia reproductora acorde a los factores ambientales. Los rasgos morfológicos descritos en conjunto y en relación a datos de campo y de bioterio, sugieren que P. winkelmanni presenta un ciclo estacional, oportunístico y poliéstrico.The Mexican fauna is characterized for its high level of endemism: almost one third of the terrestrial mammalian species are endemic. Of these, most of them belong to the Rodentia order and at the present time the basic aspects of their reproductive patterns are not known. For this, the studies of reproduction biology of endemic rodents of Mexico are valuable. Therefore the objective of this work is to describe the macroscopic and microscopic anatomy of the reproductive organs of Peromyscus winkelmanni. The specimens come from five collections (Dos Aguas, Michoacan), from 1994 to1998. Two males and two females were sacrificed of each collection. The reproductive organs were processed for light and electronic microscopy, respectively. The stains used for the light microscopy was: Hematoxylin-Eosin, Masson, PAS, Papanicolau, alcian blue and toluidin blue. For the covering electronic microscopy with gold and citrate of lead-uranyl acetate. The vaginal cytology and the specimens conduct in during captivity were also analyzed. Part of the material was analyzed stereologicaly. The macroscopic and microscopic anatomy of the male and female reproductive organs, in general shows a great similarity to other species of the Muridae family. In spite of this, differences in the testicle, epididymis and the accessory glands are seen. The sperm presents structural asymmetry. The female reproductive organs, shows seasonal variations, as well as uterine embryonic reabsorption. The different cell associations of the semniferous epithelium cycle can be attributed to regression states and testicular reactivation. The tisular and cellular regionalization in the epithelium suggests an additional reproductive strategy that regulates the maturation of the sperms in a seasonal way. The variability in the female reproductive organs represents their own changes of a seasonal reproduction. The morphological features described as a whole and in relation to field and biotheric data, suggest that Peromyscus winkelmanni presents a opportunistic and poliestric seasonal cycle

Gastric Tissue Damage Analysis Generated by Ischemia: Bioimpedance, Confocal Endomicroscopy, and Light Microscopy

The gastric mucosa ischemic tissular damage plays an important role in critical care patients’ outcome, because it is the first damaged tissue by compensatory mechanism during shock. The aim of the study is to relate bioimpedance changes with tissular damage level generated by ischemia by means of confocal endomicroscopy and light microscopy. Bioimpedance of the gastric mucosa and confocal images were obtained from Wistar male rats during basal and ischemia conditions. They were anesthetized, and stain was applied (fluorescein and/or acriflavine). The impedance spectroscopy catheter was inserted and then confocal endomicroscopy probe. After basal measurements and biopsy, hepatic and gastric arteries clamping induced ischemia. Finally, pyloric antrum tissue was preserved in buffered formaldehyde (10%) for histology processing using light microscopy. Confocal images were equalized, binarized, and boundary defined, and infiltrations were quantified. Impedance and infiltrations increased with ischemia showing significant changes between basal and ischemia conditions (). Light microscopy analysis allows detection of general alterations in cellular and tissular integrity, confirming gastric reactance and confocal images quantification increments obtained during ischemia

Histomorphometric analysis with a proposed tissue lesion index in ischemia-reperfusion induced gastric mucosa damage

Damage to the gastrointestinal mucosa caused by ischemia - reperfusion is a significant clinical problem associated with various physiopathological conditions. Our group has conducted various studies in patients in critical conditions and in animal models to identify early damage to the gastric mucosa under ischemia using impedance spectroscopy. It is important to perform a quantitative histopathological analysis which can be linked to changes in impedance of the gastric mucosa under conditions of ischemia and I/R. Aim. To propose a tissue lesion index which considers pathological alterations inherent to the inflammatory process and cell damage which may be directly related to changes in impedance under conditions of ischemia and I/R. Methods. The animals were randomly distributed into 4 groups: control, ischemia (30 min), and I/R (30 and 60 min). Qualitative histopathological analysis was performed; the vascular area, glandular lumen area, the number of damaged cells, and the depth of the erosion were also quantified to obtain a scale to propose a tissue lesion index (TLI). Results. Under ischemic conditions, histopathological analysis showed edema and necrosis in epithelial cells, and vascular congestion. In I/R (30 and 60 min) conditions, areas of epithelial erosion were generated. Damage was classified based on the TLI. A TLI threshold of 3 showed a predictive value of tissue lesion. Conclusion. The proposed gastric lesion index allows us to objectively quantify and classify damage to the gastric mucosa produced by I/R

Evaluation of HIF-1α and iNOS in ischemia/reperfusion gastric model: bioimpedance, histological and immunohistochemical analyses

Gastrointestinal ischemia/reperfusion (I/R) generates pathological alterations that could lead to death. Early ischemic damage markers could be used to guide therapy and improve outcomes. Aim. To relate hypoxia-inducible factor 1α (HIF-1α) activation and inducible nitric oxide synthase (iNOS) expression to gastric impedance changes due to I/R damage. Methods. Experimental animals were randomly distributed into 3 groups: control, ischemia (30 min) and I/R (60 min). Gastric ischemia was generated by celiac artery clamping for 30 min, and then blood flow was restored for 60 min. Impedance spectra and biopsies of the glandular portion were obtained for histological and immunohistochemical analyses. Immunodetection of both HIF-1α and iNOS was performed. Results. Under ischemia and I/R conditions, there was an increase (p<0.05) in the impedance parameters. Histologically, under ischemic conditions, edema and necrosis were observed in epithelium and significant vascular congestion. In I/R condition, alterations of the glandular and luminal integrity were found, which generated areas of epithelial erosion. Immunohistochemical analysis of HIF-1α revealed an increase (p<0.01) in the number of immunoreactive cells in the ischemia (35.7±13.9) and I/R (119.9±18.8) conditions compared to the control (0.8±1.2). Immunodetection of iNOS showed an increase (p<0.01) in the number of cells expressing iNOS under the ischemia (5.4±2.9) and I/R conditions (27.4±11.3) was observed compared to the control (0.4±0.8). Conclusion. Early changes in impedance in response to I/R is related to histopathological changes, the nuclear stabilization and translocation of HIF-1α as well as expression of iNOS

Sodium Alginate/Chitosan Scaffolds for Cardiac Tissue Engineering: The Influence of Its Three-Dimensional Material Preparation and the Use of Gold Nanoparticles

Natural biopolymer scaffolds and conductive nanomaterials have been widely used in cardiac tissue engineering; however, there are still challenges in the scaffold fabrication, which include enhancing nutrient delivery, biocompatibility and properties that favor the growth, maturation and functionality of the generated tissue for therapeutic application. In the present work, different scaffolds prepared with sodium alginate and chitosan (alginate/chitosan) were fabricated with and without the addition of metal nanoparticles and how their fabrication affects cardiomyocyte growth was evaluated. The scaffolds (hydrogels) were dried by freeze drying using calcium gluconate as a crosslinking agent, and two types of metal nanoparticles were incorporated, gold (AuNp) and gold plus sodium alginate (AuNp+Alg). A physicochemical characterization of the scaffolds was carried out by swelling, degradation, permeability and infrared spectroscopy studies. The results show that the scaffolds obtained were highly porous (>90%) and hydrophilic, with swelling percentages of around 3000% and permeability of the order of 1 × 10−8 m2. In addition, the scaffolds proposed favored adhesion and spheroid formation, with cardiac markers expression such as tropomyosin, troponin I and cardiac myosin. The incorporation of AuNp+Alg increased cardiac protein expression and cell proliferation, thus demonstrating their potential use in cardiac tissue engineering