Mast Cells Appearing in Long-term Skeletal Muscle Cell Cultures of Rat

Histomorphometric and immunohistochemical evaluation of angiogenesis in ischemia by tissue engineering in rats: Role of mast cells

The aim of this study was to find a proper method for improvement of ischemic condition in the rat hind limb and also to observe the efficacy of cell engraftment with alginate/gelatin three-dimensional scaffolds. Eighteen male Wistar rats weighing 200 to 250 g were randomly divided into three groups (n = 6) including a) ischemia group; in which femoral artery was removed after ligation at the distance of 5 mm, b) scaffold group; in which hydrogel scaffold was added to the site of transected femoral artery and c) test group; in which in addition to hydrogel scaffold, mast cells (MCs) were also added (1 × 106 cells). Analysis of capillary density, artery diameter, histomorphometric parameters and immunohistochemistry in transected location were done on day 14 after femoral artery transection. The average number of blood capillary was significantly higher in the test group than other groups. Also, the average number of medium and large blood vessels was significantly higher in the test group compared to ischemia and scaffold groups. Application of MCs through the use of hydrogel scaffolds (alginate/gelatin) can be considered as a new approach in the application of stem cells for therapeutic angiogenesis under ischemic conditions which can improve the angiogenesis process in patients with peripheral artery diseases.

Pathophysiological mechanisms of exercise-induced anaphylaxis: an EAACI position statement

This document is the result of a consensus on the mechanisms of exercise-induced anaphylaxis (EIAn), an unpredictable and potentially fatal syndrome. A multidisciplinary panel of experts including exercise physiologists, allergists, lung physicians, paediatricians and a biostatistician reached the given consensus. Exercise-induced anaphylaxis (EIAn) describes a rare and potentially fatal syndrome in which anaphylaxis occurs in conjunction with exercise. The pathophysiological mechanisms underlying EIAn have not yet been elucidated although a number of hypotheses have been proposed. This review evaluates the validity of each of the popular theories in relation to exercise physiology and immunology. On the basis of this evidence, it is concluded that proposed mechanisms lack validity, and it is recommended that a global research network is developed with a common approach to the diagnosis and treatment of EIAn in order to gain sufficient power for scientific evaluation.

Identification of histamine receptor subtypes in skeletal myogenesis

To date, conventional and/or novel histamine receptors (HRs) have not been investigated in mouse skeletal myogenesis. Therefore, the present study aimed to investigate the HR-subtypes in skeletal myogenesis. The myogenesis of C2C12 skeletal myoblasts was evaluated using desmin, myogenin and myosin heavy chain (Myh) as early, intermediate and late differentiation markers, respectively. Reverse transcription-quantitative polymerase chain reaction and immunostaining were performed and the messenger RNA (mRNA) expression levels of the HR-subtypes and markers were determined. H₁R mRNA was found to be highly expressed in myoblasts at day 0; however, the expression levels were reduced as differentiation progressed. By contrast, H₂R mRNA expression remained constant, while H₃R mRNA expression increased by 28-, 103- and 198-fold at days 2, 4 and 6 compared with the baseline level (day 0), respectively. In addition, Myh expression increased by 7,718-, 94,487- and 286,288-fold on days 2, 4 and 6 compared with the baseline expression level (day 0). Weak positive staining of the cells for H₃R protein was observed on day 2, whereas highly positive staining was observed on days 4 and 6. HR expression during myogenesis was, in part, regulated by the stage of differentiation. These results along with previous findings indicated possible involvement of H₁R in the regulation of progenitor cell mitogenesis and of H₂R in the relaxation of acetylcholine-stimulated contraction of muscle cells, following the activation of professional histamine-producing cells, including mast cells. By contrast, H₃R may participate in the regulation of specialized myocyte functions, potentially by maintaining the relaxed state under the influence of constitutive H₃R activity and low histamine concentrations, locally produced/released by non-professional histamine-producing cells.

Proposed new mechanism for food and exercise induced anaphylaxis based on case studies

We present two cases of food and exercise-induced anaphylaxis (FEIA) in patients with a diagnosis of oral allergy syndrome (OAS) to the implicated foods. Patient A had FEIA attributed to fresh coriander and tomato and Patient B to fresh celery. These food allergens have been implicated in OAS and have structural antigenic similarity to that of birch and/or grass. Both patients' allergies were confirmed by fresh skin prick tests. In both cases, strenuous exercise was antecedent to the systemic anaphylaxis reaction and subsequent ingestion without exercise produced only local symptoms of perioral pruritus. We review the current proposed mechanisms for food and exercise induced anaphylaxis to oral allergens and propose a novel and more biologically plausible mechanism. We hypothesize that the inhibitory effects of exercise on gastric acid secretion decreases the digestion of oral allergens and preserves structural integrity, thereby allowing continued systemic absorption of the allergen whether it be profilins, lipid transfer proteins, or other antigenic determinants.

Pathophysiology, diagnosis and management of exercise-induced anaphylaxis

PURPOSE OF REVIEW

The aim of this review is to challenge the current opinions of the pathophysiological mechanisms that give rise to food dependent exercise-induced anaphylaxis (FDEIA) and to consider these mechanisms within the wider context of exercise physiology to further inform our understanding and treatment of this condition.

RECENT FINDINGS

Exercise-induced anaphylaxis (food dependent and nonfood dependent) is a clinical syndrome in which anaphylaxis occurs in conjunction with exercise. Given the rarity of the condition, our current understanding relies on the many case studies and reviews of the topic. The pathophysiology of FDEIA remains to be fully elucidated with well constructed trials but current working hypotheses to date involve alterations in plasma osmolaltiy and pH, tissue enzyme activity, blood flow redistribution, altered gastrointestinal permeability and facilitated epitope recognition/allergen binding.

SUMMARY

Implications for future research are the physiological changes that occur during exercise need deeper consideration to ensure that proposed mechanisms are realistic and actually occur within the time frame and exercise-intensity domain during which the reported FDEIA occurred. These theories must be tested rigorously with sufficiently powered studies if progress is to be made in determining the perplexing pathophysiology of FDEIA.