Aerobic Exercise Attenuates Pressure Overload-Induced Myocardial Remodeling and Myocardial Inflammation via Upregulating miR-574-3p in Mice

BACKGROUND

Exercise training can promote cardiac rehabilitation, thereby reducing cardiovascular disease mortality and hospitalization rates. MicroRNAs (miRs) are closely related to heart disease, among which miR-574-3p plays an important role in myocardial remodeling, but its role in exercise-mediated cardioprotection is still unclear.

METHODS

A mouse myocardial hypertrophy model was established by transverse aortic coarctation, and a 4-week swimming exercise training was performed 1 week after the operation. After swimming training, echocardiography was used to evaluate cardiac function in mice, and histopathologic staining was used to detect cardiac hypertrophy, myocardial fibrosis, and cardiac inflammation. Quantitative real-time polymerase chain reaction was used to detect the expression levels of miR-574-3p and cardiac hypertrophy markers. Western blotting detected the IL-6 (interleukin-6)/JAK/STAT inflammatory signaling pathway.

RESULTS

Echocardiography and histochemical staining found that aerobic exercise significantly improved pressure overload-induced myocardial hypertrophy (n=6), myocardial interstitial fibrosis (n=6), and cardiac inflammation (n=6). Quantitative real-time polymerase chain reaction detection showed that aerobic exercise upregulated the expression level of miR-574-3p (n=6). After specific knockdown of miR-574-3p in mouse hearts with adeno-associated virus 9 using cardiac troponin T promoter, we found that the protective effect of exercise training on the heart was significantly reversed. Echocardiography and histopathologic staining showed that inhibiting the expression of miR-574-3p could partially block the effects of aerobic exercise on cardiac function (n=6), cardiomyocyte cross-sectional area (n=6), and myocardial fibrosis (n=6). Western blotting and immunohistochemical staining showed that the inhibitory effects of aerobic exercise on the IL-6/JAK/STAT pathway and cardiac inflammation were partially abolished after miR-574-3p knockdown. Furthermore, we also found that miR-574-3p exerts cardioprotective effects in cardiomyocytes by targeting IL-6 (n=3).

CONCLUSIONS

Aerobic exercise protects cardiac hypertrophy and inflammation induced by pressure overload by upregulating miR-574-3p and inhibiting the IL-6/JAK/STAT pathway.

Loss of USP22 alleviates cardiac hypertrophy induced by pressure overload through HiF1-α-TAK1 signaling pathway

Ubiquitin-specific protease 22 (USP22) is a member of the ubiquitin specific protease family (ubiquitin-specific protease, USPs), the largest subfamily of deubiquitinating enzymes, and plays an important role in the treatment of tumors. USP22 is also expressed in the heart. However, the role of USP22 in heart disease remains unclear. In this study, we found that USP22 was elevated in hypertrophic mouse hearts and in angiotensin II (Ang II)-induced cardiomyocytes. The inhibition of USP22 expression with adenovirus significantly rescued hypertrophic phenotype and cardiac dysfunction induced by pressure overloaded. Consistent with in vivo study, silencing by USP22 shRNA expression in vitro had similar results. Molecular analysis revealed that transforming growth factor-β-activating protein 1 (TAK1)-(JNK1/2)/P38 signaling pathway and HIF-1α was activated in the Ang II-induced hypertrophic cardiomyocytes, whereas HIF-1α expression was decreased after the inhibition of USP22. Inhibition of HIF-1α expression reduces TAK1 expression. Co-immunoprecipitation and ubiquitination studies revealed the regulatory mechanism between USP22 and HIF1α.Under hypertrophic stress conditions, USP22 enhances the stability of HIF-1α through its deubiquitination activity, which further activates the TAK1-(JNK1/2)/P38 signaling pathway to lead to cardiac hypertrophy. Inhibition of HIF-1α expression further potentiates the in vivo pathological effects caused by USP22 deficiency. In summary, this study suggests that USP22, through HIF-1α-TAK1-(JNK1/2)/P38 signaling pathway, may be potential targets for inhibiting pathological cardiac hypertrophy induced by pressure overload.

Infectious keratitis in South Australia: emerging resistance to cephazolin

PURPOSE

To analyze the microbiologic spectrum and patterns of resistance of infectious keratitis in patients treated at a tertiary hospital in South Australia.

METHODS

Retrospective review of microbiology laboratory records of all patients with infectious keratitis who had corneal scrapings, from 1998 to 2003. All records were subsequently reviewed for Gram staining and culture results, as well as antibiotic sensitivity and resistance.

RESULTS

Positive corneal cultures were obtained in 134 out of 211 patients who had corneal scrapings (63.5%). Coagulase negative Staphylococcus was the commonest pathogen identified (29.8% of positive cultures), followed by Staphylococcus aureus (18.7%), Pseudomonas aeruginosa (12.7%), Moraxella (6.7%), Streptococcus pneumonia (6.0%), and fungal keratitis (5.2%). In 43.3% of culture positive cases, the organisms were also identified in Gram stain, and in all these cases there was a full correlation between the two methods. In vitro sensitivities were highest for gentamicin. Fourteen cases (35%) of coagulase negative Staphylococcus were found to be resistant to cephazolin. No ciprofloxacin resistance was identified in all Pseudomonas isolates tested.

CONCLUSIONS

Staphylococcus species continue to be the commonest causative organism for infectious keratitis; however, there is an emerging resistance to cephazolin, which is commonly used as the first-line antibiotic for Gram-positive cocci.

Infectious keratitis in South Australia: Emerging resistance to cephazolinq

PURPOSE

To analyze the microbiologic spectrum and patterns of resistance of infectious keratitis in patients treated at a tertiary hospital in South Australia.

METHODS

Retrospective review of microbiology laboratory records of all patients with infectious keratitis who had corneal scrapings, from 1998 to 2003. All records were subsequently reviewed for Gram staining and culture results, as well as antibiotic sensitivity and resistance. RESULTS Positive corneal cultures were obtained in 134 out of 211 patients who had corneal scrapings (63.5%). Coagulase negative Staphylococcus was the commonest pathogen identified (29.8% of positive cultures), followed by Staphylococcus aureus (18.7%), Pseudomonas aeruginosa (12.7%), Moraxella (6.7%), Streptococcus pneumonia (6.0%), and fungal keratitis (5.2%). In 43.3% of culture positive cases, the organisms were also identified in Gram stain, and in all these cases there was a full correlation between the two methods. In vitro sensitivities were highest for gentamicin. Fourteen cases (35%) of coagulase negative Staphylococcus were found to be resistant to cephazolin. No ciprofloxacin resistance was identified in all Pseudomonas isolates tested.

CONCLUSIONS

Staphylococcus species continue to be the commonest causative organism for infectious keratitis; however, there is an emerging resistance to cephazolin, which is commonly used as the first-line antibiotic for Gram-positive cocci. (Eur J Ophthalmol 2005; 15: 23-6).

Social adjustment and alcoholism among Chinese immigrants in New York City

Based upon the patient files (N = 132) maintained by the Chinatown Alcoholism Services (CAS), interviews with CAS staff, and the clinical experience of the authors with Chinese alcoholics, this paper describes the social contexts of alcoholism among a group of working-class Chinese males in New York City. It focuses on the relationship between social adjustment and drinking behaviors, and analyzes the meaning of alcohol use and abuse within the ethnic community. The paper also examines the role of significant others in the alcoholics' drinking and help-seeking behaviors. Finally, treatment and research issues pertaining to alcoholism among the Chinese are discussed.