Role Of Blebs Research Articles

Mechanisms of aging and programmed death of erythrocytes

Erythrocytes lack nuclei and mitochondria, critical elements in the machinery of nucleated cell apoptosis. However, most recently, it became obvious that erythrocytes may undergo programmed aging, as well as suicidal death. The term eryptosis has been coined to describe the suicidal erythrocyte death. Eryptosis is triggered mainly by increased cytosolic Ca(2+) activity, in turn, Ca(2+) activates Ca(2+)-sensitive K(+) channels, scramblase, calpain and other proteases, respectively. A series of molecular events of erythrocyte programmed death induced. The cascade reaction of related molecules and finally lead to cell clearance. There is evidence suggesting that erythrocytes aging and death process are regulated tightly and there are many molecular participants and signaling pathways involved in aging and death process of erythrocytes. Erythrocytes have already been used as a model for aging study, and the knowledge about mechanisms involved in eryptosis may provide an important clue to understand the mechanisms involved in suicidal death of nucleated cells. In this review the factors influencing programmed death of erythrocytes, the role of Ca(2+) and ceramide in programmed death of erythrocytes, the role of blebbing in process of erythrocyte aging, the antigens of erythrocyte aging and so on are summarized.

Invited Commentary

Current guidelines do not clearly recommend computed tomography (CT) after the first episode of primary spontaneous pneumothorax (PSP). However, a growing body of evidence suggests a compelling role of CT in predicting recurrence after the first episode. The article by Casali and colleagues [1Casali C. Stefani A. Ligabue G. et al.Role of blebs and bullae detected by high-resolution computed tomography and recurrent spontaneous pneumothorax.Ann Thorac Surg. 2013; 95: 249-256Abstract Full Text Full Text PDF PubMed Scopus (62) Google Scholar] confirms these recent findings. The authors analyzed 176 patients admitted for a first episode of PSP and found that the presence of air-containing lesions in the lung was associated with a 68% risk of ipsilateral recurrence—data that in the authors' opinion would warrant surgical treatment right after the first episode. One of the most interesting aspects of their work is the external validation of a “dystrophy score,” a multifactorial scoring system based on high-resolution CT scan findings. They found that freedom from recurrence decreased from 93% to 22% in patients without air-containing lesions in comparison with patients with dystrophy scores greater than 5. Analyzing their Kaplan-Meier estimates, 50% of patients with even a single ipsilateral bleb identifiable at CT scan (low-grade score) experienced an ipsilateral recurrence. This proportion increased to 70% to 80% among those with intermediate or high-grade dystrophy scores. Of interest, most of the recurrences occurred within the first 12 months from the first PSP episode. If these results will be confirmed by future prospective studies, they will certainly warrant a more liberal use of a surgical procedure (reputedly the most effective form of preventative measure) after the first episode, particularly in those patients with the presence of blebs or bullae at CT scan. Future studies are needed to conciliate this observation with additional/alternative lung pathologic conditions, which have been associated with the occurrence of PSP (ie, pleural porosity). Finally, in light of the mounting evidence about the role of CT in predicting recurrence after the first episode of PSP, the current guidelines need probably to be updated. Role of Blebs and Bullae Detected by High-Resolution Computed Tomography and Recurrent Spontaneous PneumothoraxThe Annals of Thoracic SurgeryVol. 95Issue 1PreviewThe prevention of recurrence after a first episode of primary spontaneous pneumothorax (PSP) remains a debated issue. The likelihood of recurrence based on the presence of blebs and bullae detected on high-resolution computed tomography (HRCT) imaging is controversial. Full-Text PDF

Role of Blebs and Bullae Detected by High-Resolution Computed Tomography and Recurrent Spontaneous Pneumothorax

The prevention of recurrence after a first episode of primary spontaneous pneumothorax (PSP) remains a debated issue. The likelihood of recurrence based on the presence of blebs and bullae detected on high-resolution computed tomography (HRCT) imaging is controversial. We evaluated patients conservatively treated for PSP who underwent chest HRCT scan in a single-institution retrospective longitudinal study. Absolute risk values and positive and negative predictive values of recurrence based on HRCT findings were the primary end points. We analyzed 176 patients. Ipsilateral and contralateral recurrence developed in 44.8% and 12% of patients, respectively. The risk of recurrence was significantly related to the presence of blebs or bullae, or both, at HRCT. The risk of ipsilateral recurrence for patients with or without blebs and bullae was 68.1% and 6.1%, respectively (positive predictive value, 68.1%; negative predictive value, 93.9%). The risk of contralateral pneumothorax for patients with or without blebs and bullae was 19% and 0%, respectively (positive predictive value, 19%; negative predictive value, 100%). The risk of ipsilateral recurrence was directly related to the dystrophic severity score: recurrence risk increased by up to 75% in patients with bilateral multiple lesions. Multivariate analysis showed that a positive HRCT was significantly related to ipsilateral recurrence. The presence of blebs and bullae at HRCT after a first episode of PSP is significantly related to the development of an ipsilateral recurrence or a contralateral episode of pneumothorax. Further studies are needed to validate the dystrophic severity score in the selection of patients for early surgical referral.