Digitoxin Attenuates Heart Failure, Reduces Myocardial Hypertrophy, and Preserves the Calcium-Binding Proteins in Infarcted Rats

Mesenchymal Stem Cells Increase Resistance Against Ventricular Arrhythmias Provoked in Rats with Myocardial Infarction

This study evaluated the role of the mesenchymal stem cells derived from adipose tissue (MSCs) in provoked ventricular arrhythmias (VAs) in animals with myocardial infarction (MI). The experimental groups were: sham, subjected to sham surgery and intramyocardial saline injection; MIV, infarcted rats subjected to intramyocardial saline injection; MI + MSCs, infarcted rats subjected to intramyocardial MSCs injection. Injections were performed two days after infarction and the arrhythmogenic inducibility experiment was performed the next day. Only 35% of the MI + MSCs group developed VAs, while the one in the MIV group was 65%. The proportion of nonsustained ventricular tachycardia, sustained tachycardia, and ventricular fibrillation was similar between the infarcted groups, but MSCs animals had shorter duration of nonsustained ventricular tachycardia. However, MSCs increased connexin 43 content in the remote area, even above the levels found in the sham group. MSCs prevented the increase of IL-1β in the different areas of the myocardium. There was higher carbonylation and content of 4-hydroxynonenal (4-HNE, a marker of lipoperoxidation) in the myocardium of infarcted rats, but MSCs attenuated the increase of 4-HNE in the infarcted area. In conclusion, MSCs have a protective effect against the development of arrhythmias, but do not imply a significant benefit for animals that have developed VAs. It is possible to think that the cardioprotection of MSCs involves anti-inflammatory/oxidative actions and improvement in the formation of communicating junctions.Graphical abstract.

Strength training improves heart function, collagen and strength in rats with heart failure

BACKGROUND/OBJECTIVES

Myocardial infarction (MI) frequently leads to cardiac remodeling and failure with impaired life quality, playing an important role in cardiovascular deaths. Although physical exercise is a well-recognized effective non-pharmacological therapy for cardiovascular diseases, the effects of strength training (ST) on the structural and functional aspects of cardiac remodeling need to be further documented. In this study, we aimed to investigate the role of a linear block ST protocol in the rat model of MI.

METHODS AND RESULTS

After 6 weeks of MI induction or sham surgery, male adult rats performed ST for the following 12 weeks. The ladder-based ST program was organized in three mesocycles of 4 weeks, with one load increment for each block according to the maximal carrying load test. After 12 weeks, the infarcted-trained rats exhibited an increase in performance, associated with reduced cardiac hypertrophy and pulmonary congestion compared with the untrained group. Despite not changing MI size, the ST program partially prevented cardiac dilatation and ventricular dysfunction assessed by echocardiography and hemodynamics, and interstitial fibrosis evaluated by histology. In addition, isolated cardiac muscles from infarcted-trained rats had improved contractility parameters in a steady state, and in response to calcium or stimuli pauses.

CONCLUSIONS

The ST in infarcted rats increased the capacity to carry mass, associated with attenuation of cardiac remodeling and pulmonary congestion with improving cardiac function that could be attributed, at least in part, to the improvement of myocardial contractility.

Effect of habitat variations on the chemical composition, antioxidant, and antimicrobial activities of Achillea fragrantissima (Forssk) Sch. Bip

Achilea fragmentisma plant is widely distributed along northern regions of Saudi Arabia with various traditional medical uses. The plant was collected from Tabuk and Arar regions to study the effect of the variation in habitat on the chemical compositions, antimicrobial and antioxidant activities of the plant. The results showed significant differences between the two studied region regarding the parameters of the weather in years from 2010-2016.The antioxidant and antimicrobial of the plant showed significant variation in two habitats. Plant collected from Arar showed high antioxidant activity with IC50 (0.21 ± 0.01 g/L) by DPPH radical scavenging methods, and good antibacterial activity with gram-positive bacteria (Staphylococcus epidermidis, Bacillus cereus and Staphylococccus aureus clinical isolate), antibacterial activity ranging between high to no activity (between 14.5 ± 0.5-6.0 ± 0.0 mm zone of inhibition), On the other side the tested plant extracts showed no effect on, all gram-negative bacteria. GC/MS data showed marked variation in chemical compositions of both phenolic and alkaloid compounds in plants collected from both regions. Phenolic compounds were accumulated with higher amounts(Ferulic acid, Eugenol and Salicylic acid ester) in Arar region, while the alkaloid fractions (Ethyl isoallocholate, Pterin 6-carboxylic-acid and kadain) showed higher concentrations in plants collected from Tabuk region. The results reflect the variation in of weather parameter, affect on chemical compositions and biological activities of the plant in two studied regions.