Senescence induces fundamental changes in the secretome of mesenchymal stromal cells (MSCs): implications for the therapeutic use of MSCs and their derivates

Mesenchymal stromal cells (MSCs) are a heterogeneous population containing multipotent adult stem cells with a multi-lineage differentiation capacity, which differentiated into mesodermal derivatives. MSCs are employed for therapeutic purposes and several investigations have demonstrated that the positive effects of MSC transplants are due to the capacity of MSCs to modulate tissue homeostasis and repair via the activity of their secretome. Indeed, the MSC-derived secretomes are now an alternative strategy to cell transplantation due to their anti-inflammatory, anti-apoptotic, and regenerative effects. The cellular senescence is a dynamic process that leads to permanent cell cycle arrest, loss of healthy cells' physiological functions and acquiring new activities, which are mainly accrued through the release of many factors, indicated as senescence-associated secretory phenotype (SASP). The senescence occurring in stem cells, such as those present in MSCs, may have detrimental effects on health since it can undermine tissue homeostasis and repair. The analysis of MSC secretome is important either for the MSC transplants and for the therapeutic use of secretome. Indeed, the secretome of MSCs, which is the main mechanism of their therapeutic activity, loses its beneficial functions and acquire negative pro-inflammatory and pro-aging activities when MSCs become senescent. When MSCs or their derivatives are planned to be used for therapeutic purposes, great attention must be paid to these changes. In this review, we analyzed changes occurring in MSC secretome following the switch from healthy to senescence status.

Coronary angioplasty and stenting in orthotopic heart transplants: a fruitful act or a futile attempt?

Accelerated allograft coronary artery disease remains the major cause of mortality after the first year of transplantation. Despite the extensive use of stents and angioplasty in coronary artery disease, there is a paucity of data about the efficacy of such interventions in orthotopic heart transplants. The authors herein report the outcome of those patients in their institution who had undergone percutaneous coronary artery angioplasty and stenting at a late stage of their transplantation. Within a 12-year period, 106 adult patients underwent orthotopic heart transplantation at their institution. Eight of these patients with 17 lesions underwent deployment of nine stents and eight angioplasties 8.1 +/- 3.2 years posttransplantation. There were 15 denovo and two restenotic lesions. The indications for intervention were presence of symptoms in five patients and severity of lesions in three asymptomatic patients detected on their follow-up angiogram. All patients had angiographic worsening of lesions at their follow-up angiogram. The initial procedural success for both stented and angioplastied lesions was 100%. Within a mean angiographic follow-up of 261 days, all balloon angioplastied lesions had developed restenosis, whereas within a mean period of 67 days, 50% of stented lesions had developed restenosis. On the follow-up angiogram, deterioration of the nontreated segments were noted throughout the coronary arterial tree; however, the immediate proximal and distal parts of the target segments demonstrated an exaggerated hyperproliferative response as compared to other sites. The overall median time to the detection of restenosis for both stented and angioplastied lesions was 5.2 months (inner quartile 2.5-6.2 months). The authors conclude that angioplasty and stenting late in the course of transplantation is associated with a significant restenosis rate and in such patients earlier or alternative catheter-based interventions must be considered.

Epidemiology of adults hospitalized with burns in Karachi, Pakistan

Burns are a leading cause of adult death in Karachi slums, therefore we reviewed 1 year's logged experience (November 1992 to October 1993) at Karachi's two adult burn units for patient age, sex, burn severity and outcome. Also 47 inpatients were interviewed regarding their circumstances of injury. We grouped these using Haddon's Matrix. The log identified 832 patients. Females (57 per cent) outnumbered males and were younger on average (25.1 vs 27.6 years, P = 0.002). Females had more severe burns than males (57 per cent vs 50 per cent total body surface area (TBSA) burn, P = 0.002). At the unit with outcome data (n = 556), the case fatality was 56 per cent. The estimated adult mortality due to burns in Karachi was 10.2/100 000, 6.8/100 000 and 14.1/100 000 for men and women, respectively. Burns of interviewed patients were most often associated with flames (33/47), but stove bursts caused the most severe injury (52 per cent TBSA). These patients were predominantly young uneducated female houseworkers, clothed in loose attire who were injured during daylight at home around a floor-level stove, unaware of fire safety, and who received no first aid. It was concluded that the high burn severity and case fatality rates demand: (1) preventive measures, such as kitchen sand buckets, safer stove design and placement and education on fire safety and first aid, and (2) risk factor analysis to refine interventions.