Epac-Rap Signaling Reduces Oxidative Stress in the Tubular Epithelium

Activation of Rap1 by exchange protein activated by cAMP (Epac) promotes cell adhesion and actin cytoskeletal polarization. Pharmacologic activation of Epac-Rap signaling by the Epac-selective cAMP analog 8-pCPT-2′-O-Me-cAMP during ischemia-reperfusion (IR) injury reduces renal failure and application of 8-pCPT-2′-O-Me-cAMP promotes renal cell survival during exposure to the nephrotoxicant cisplatin. Here, we found that activation of Epac by 8-pCPT-2′-O-Me-cAMP reduced production of reactive oxygen species during reoxygenation after hypoxia by decreasing mitochondrial superoxide production. Epac activation prevented disruption of tubular morphology during diethyl maleate–induced oxidative stress in an organotypic three-dimensional culture assay. In vivo renal targeting of 8-pCPT-2′-O-Me-cAMP to proximal tubules using a kidney-selective drug carrier approach resulted in prolonged activation of Rap1 compared with nonconjugated 8-pCPT-2′-O-Me-cAMP. Activation of Epac reduced antioxidant signaling during IR injury and prevented tubular epithelial injury, apoptosis, and renal failure. Our data suggest that Epac1 decreases reactive oxygen species production by preventing mitochondrial superoxide formation during IR injury, thus limiting the degree of oxidative stress. These findings indicate a new role for activation of Epac as a therapeutic application in renal injury associated with oxidative stress.Renal ischemia-reperfusion (IR) injury is an important cause of AKI¹ and a significant risk factor for the development of renal dysfunction after kidney transplantation.² During IR injury, morphologic and functional alterations of the proximal tubular epithelium occur that are linked to the development of renal failure and activation of immune cells via release of proinflammatory cytokines.³Exchange protein activated by cAMP (Epac) is a guanine nucleotide exchange factor for the small GTPase Rap1.⁴ Activation of Epac by cAMP or by the Epac-selective cAMP analog 8-pCPT-2′-O-Me-cAMP (also referred to as 007) induces functional activation of Rap1.⁵ Initial studies showed that Epac-Rap signaling enhances cell adhesion by supporting maturation of cell-cell junctions^6,7 and promoting integrin-mediated cell-matrix adhesion.^8,9 In line with these studies, we recently demonstrated that selective activation of Epac reduces proximal tubular epithelial cell (PTEC) detachment during IR injury using in vitro and in vivo models.¹⁰ Activation of Epac-Rap was associated with reduced expression of markers for cellular stress in PTECs. In addition, in vitro cisplatin-induced apoptosis of PTECs could be significantly reduced by activation of Epac and this was also associated with improved adhesion of cells.¹¹ On the basis of these findings, we hypothesized that activation of Epac-Rap signaling may protect against a common cytotoxic event in these injury models.Unbalanced and uncontrolled production of reactive oxygen species (ROS) is an important mediator of cell injury and occurs during cisplatin nephrotoxicity,¹² IR injury,¹³ and renal fibrosis.¹⁴ In renal pathology, intracellular ROS can be produced enzymatically such as by NADPH oxidase (NOX) complexes or derive from dysfunctional mitochondrial activity. Mitochondrial ROS production appears to be the driving force behind hypoxia-reoxygenation cell injury¹⁵ and cisplatin cytotoxicity.¹⁶Here we studied the role of specific proximal tubular activation of Epac and how this protects against renal injury in both in vitro and in vivo models for IR injury. We found that ROS production during reoxygenation after hypoxia was decreased by activation of Epac. Selective proximal tubular activation of Epac by renal targeting of 8-pCPT-2′-O-Me-cAMP conjugated to lysozyme (LZM-007) reduced oxidative stress in an in vivo model for IR injury and significantly decreased IR injury–associated renal failure and tubular damage. Our data show that Epac activation reduces ROS-mediated cellular injury in renal disease and may be a therapeutic strategy for modulation of oxidative stress.     

Primary myeloproliferative disorder and hepatic vein thrombosis. A prospective study of erythroid colony formation in vitro in 20 patients with Budd-Chiari syndrome

We assessed the prevalence of overt and latent primary myeloproliferative disorders in hepatic vein thrombosis. Cultures of bone marrow or peripheral blood mononuclear cells were done in 20 patients with Budd-Chiari syndrome. Erythroid colony formation in the absence of erythropoietin, which is a reliable indicator for a primary myeloproliferative disorder, was seen in 16 patients in whom Budd-Chiari syndrome was due to hepatic vein thrombosis, including 13 women aged 18 to 45 years. Among these 16 patients, the conventional criteria for the diagnosis of a primary myeloproliferative disorder were met in only 2. Primary myeloproliferative disorder, often without peripheral blood changes, is a major cause of hepatic vein thrombosis in young women.     

Long-term cysteine fortification impacts cysteine/glutathione homeostasis and food intake in ageing rats

Purpose

Healthy ageing is associated with higher levels of glutathione. The study aimed to determine whether long-term dietary fortification with cysteine increases cysteine and glutathione pools, thus alleviating age-associated low-grade inflammation and resulting in global physiological benefits.

Methods

The effect of a 14-week dietary fortification with cysteine was studied in non-inflamed (NI, healthy at baseline) and in spontaneously age-related low-grade inflamed (LGI, prefrail at baseline) 21-month-old rats. Fifty-seven NI rats and 14 LGI rats received cysteine-supplemented diet (4.0 g/kg of free cysteine added to the standard diet containing 2.8 g/kg cysteine). Fifty-six NI rats and 16 LGI rats received a control alanine-supplemented diet.

Results

Cysteine fortification in NI rats increased free cysteine (P < 0.0001) and glutathione (P < 0.03) in the liver and the small intestine. In LGI rats, cysteine fortification increased total non-protein cysteine (P < 0.0007) and free cysteine (P < 0.03) in plasma, and free cysteine (P < 0.02) and glutathione (P < 0.01) in liver. Food intake decreased over time in alanine-fed rats (r ² = 0.73, P = 0.0002), whereas it was constant in cysteine-fed rats (r ² = 0.02, P = 0.68). Cysteine fortification did not affect inflammatory markers, mortality, body weight loss, or tissue masses.

Conclusion

Doubling the dietary intake of cysteine in old rats increased cysteine and glutathione pools in selected tissues. Additionally, it alleviated the age-related decline in food intake. Further validation of these effects in the elderly population suffering from age-related anorexia would suggest a useful therapeutic approach to the problem.     

COVID‐19 lockdown consequences on body mass index and perceived fragility related to physical activity: A worldwide cohort study

BackgroundThis paper is a follow‐up study continuing the COVISTRESS network previous research regarding health‐related determinants.ObjectiveThe aim was to identify the main consequences of COVID‐19 lockdown on Body Mass Index and Perceived Fragility, related to Physical Activity (PA), for different categories of populations, worldwide.DesignThe study design included an online survey, during the first wave of COVID‐19 lockdown, across different world regions.Setting and participantsThe research was carried out on 10 121 participants from 67 countries. The recruitment of participants was achieved using snowball sampling techniques via social networks, with no exclusion criteria other than social media access.Main outcome measures Body Mass Index, Physical Activity, Perceived Fragility and risk of getting infected items were analysed. SPSS software, v20, was used. Significance was set at P < .05.Results Body Mass Index significantly increased during lockdown. For youth and young adults (18‐35 years), PA decreased by 31.25%, for adults (36‐65 years) by 26.05% and for the elderly (over 65 years) by 30.27%. There was a high level of Perceived Fragility and risk of getting infected for female participants and the elderly. Correlations between BMI, Perceived Fragility and PA were identified.Discussion and ConclusionsThe research results extend and confirm evidence that the elderly are more likely to be at risk, by experiencing weight gain, physical inactivity and enhanced Perceived Fragility. As a consequence, populations need to counteract the constraints imposed by the lockdown by being physically active.     

Prevalence of mandibular asymmetry in different skeletal sagittal patterns:: A systematic review

ObjectivesTo analyze the prevalence of mandibular asymmetry in skeletal sagittal malocclusions.Materials and MethodsPubMed/MEDLINE, EMBASE, LILACS, Web of Science, Scopus, LIVIVO and gray literature (OpenGrey, ProQuest, and Google Scholar) were electronically searched. Two independent investigators selected the eligible studies, and assessed risk of bias and certainty of evidence (GRADE). One reviewer independently extracted the data and the second reviewer checked this information. Any disagreement between the reviewers in each phase was resolved by discussion between them and/or involved a third reviewer for final decision.ResultsElectronic search identified 5,132 studies, and 5 observational studies were included. Risk of bias was low in two studies, moderate in one, and high in two. The studies showed high heterogeneity. Mandibular asymmetry ranged from 17.43% to 72.95% in overall samples. Horizontal chin deviation showed a prevalence of 17.66% to 55.6% asymmetry in Class I malocclusions, and 68.98% in vertical asymmetry index. In Class II patients, prevalence of mandibular asymmetry varied from 10% to 25.5% in horizontal chin deviation, and 71.7% in vertical asymmetry index. The Class III sample showed a prevalence of mandibular asymmetry ranging from 22.93% to 78% in horizontal chin deviation and 80.4% in vertical asymmetry index. Patients seeking orthodontic or orthognathic surgery treatment showed greater prevalence of mandibular asymmetry.ConclusionsSkeletal Class III malocclusion showed the greatest prevalence of mandibular asymmetry. Mandibular vertical asymmetry showed a marked prevalence in all malocclusions. However, conclusions should be interpreted with caution due to use of convenience samples and low-quality study outcomes.     

Evolution of clinical,electrophysiological, and radiological aspects of the carpal tunnel syndrome before and after surgery

The aim of the study was to analyze the evolution of the clinical, electrophysiological, and ultrasound aspects of carpal tunnel syndrome (CTS) before and 4 and 8 weeks after surgery. A Boston Carpal Tunnel Questionnaire, an ultrasound scan, and an electrophysiological exam were performed in 14 patients the day of surgery, 4 and 8 weeks after. The nerve conduction study included: median nerve sensory conduction stimulating digit 3 and 4, median motor conduction from the abductor pollicis brevis, ulnar nerve sensory, and motor conduction. A significant improvement of the symptoms and a significant decrease of the median nerve proximal cross-sectional area on the ultrasound scan were observed 4 weeks after surgery. Distal motor latency (DML) was > 4.2 ms in six patients and decreased along the three visits. DML was ≤ 4.2 ms in the eight others and stayed stable after surgery. We observed a significant increase of the sensory median nerve amplitude response at the wrist stimulating the third digit 8 weeks after surgery. When operated patients are referred for control, we recommend to perform: (1) 4 weeks after surgery, an ultrasonography, and a measure of the DML of the median nerve; (2) 8 weeks after surgery, a measure of the sensory conduction velocity of the median nerve.     

Overview on the sub-grouping of the crustacean hyperglycemic hormone family

The Crustacean hyperglycemic hormones (CHHs) are an ever extending family of crustacean hormones mainly involved in carbohydrate metabolism, molt and reproduction. In this paper, we drew together 32 available CHH sequences, and applied the techniques of multiple sequence alignment, motif searching and amino acid conservation analysis to the characterization of the molecules independently of their biological function. The analysis clearly showed that the proteins clustered into two groups (CHH and VIH). Amino acid conservation analysis also subdivided the VIH group into sequences involved in reproduction (RIH) or in molt (MIH). Motif searching identified five motifs in each group of mature hormones. Motifs A2 and A3 were conserved in all sequences while motifs A1 and A1' were specific of the CHH and VIH groups respectively. This approach demonstrated the S. gregaria ion transport peptides as true members of the CHH group. The two main groups, CHH and VIH, are also discussed in terms of functional homogeneity.