Homeostasis of the airways is maintained through a mucociliary clearance, which is a biological defense system that traps inhaled fine particles with mucus and eliminates them from the lower respiratory tract by ciliary movement. However, in airway inflammation, mucin gene expression in mucus-producing cells is stimulated by various inflammatory mediators, cytokines, growth factors, and reactive oxygen species that are produced by recruited inflammatory cells, such as neutrophils and eosinophils, thereby increasing the production and secretion of airway mucus. On the other hand, the ciliary transport function is remarkably impaired by inflammatory epithelial cell damage and changes in the biophysical properties of mucus, resulting in an airway hypersecretory condition. In particular, mucin 5AC, which is produced by goblet cells, plays a central role in the formation of mucus plugs, which contributes to the poor prognosis of airway hypersecretory diseases. Recently, a molecular biological analysis of airway mucins revealed the function, distribution, and gene regulatory mechanism of mucin in various pathological conditions of airway inflammation. This paper reviews the mechanism of action underlying airway hypersecretion and its therapeutic approaches in airway inflammatory diseases.

Objective: Early diagnosis and appropriate respiratory care are important for the management of airway lesions. We studied the initial symptoms of infants with airway lesions and the clinical course of each symptom.

Methods: We retrospectively reviewed 31 patients admitted to our institution. We classified initial symptoms into 3 groups: A: difficulty in weaning from respiratory care, B: decrease in SpO₂, and C: stridor or suckling disorder. We investigated the clinical course of each group.

Results: The gestational age of A was significantly earlier than that of B and C (32.3, 37.9, and 39.7 weeks, respectively). The age in days of recognizing initial symptoms of A was significantly later than C (10, 1, respectively). Mechanical ventilation was performed in over 90% cases of A and B; on the other hand, 37.5% of C did not need mechanical ventilation. The median duration of treatment for A was significantly longer than that for B and C (61, 45.5, and 25.5 days, respectively).

Conclusion: The most frequent symptom was difficulty in weaning from respiratory care, and those cases needed more time for diagnosis and treatment due to prematurity. A decrease in SpO₂ is a more severe symptom than stridor or suckling disorder because these cases were diagnosed later and artificial respiration was performed for longer. Our study suggests that it is useful to focus on the initial symptoms to understand the pathology of airway lesions.

Progress in dialysis therapy has widely improved the prognosis of chronically ill dialysis patients, but kidney transplantation is particularly known to improve patient prognosis significantly. However, the shortage of organ transplant donors remains a global issue. Additionally, the donor's pre-transplant serum creatinine (sCr) is a known indicator of post-transplant kidney function, but the time point of sCr measurement has not been sufficiently reported. In this study, we defined 2 time points of pre-transplantation donor sCr measurement: (1) sCr taken just before surgical resection (final sCr) and (2) sCr taken on admission to the hospital (sCr_min). Thus, we investigated the level of pre-transplantation sCr in the donor and post-transplantation renal function in the transplant patients.

In this single-center study, we included 157 patients who underwent donated kidney transplantation between January 1995 and December 2015 at the Department of Surgery, Kidney Center, Tokyo Women's Medical University Hospital. We compared the postoperative renal function with sCr_min and final sCr before transplantation. Donor sCr may be affected by acute renal failure or acute tubular necrosis under various situations, such as reduction in organ blood flow in the period from admission to organ donation. Therefore, donor sCr was highly likely to change depending on the time point in the treatment.

The comparison showed a significant difference between the levels of sCr and postoperative renal function (sCr of more than 1.0 mg/dl and lower). However, there was no correlation between higher final sCr and lower postoperative renal function. We believed that donor sCr_min reflected the original renal function of the donor, and we obtained a significant difference in the multivariate analysis to designate it as a prognostic factor.

We concluded that that sCr_min values are a better reflection of the donor's original renal function as compared to final sCr. Our findings are significant because they address the current research gap on preoperarive sCr values and prove that sCr taken on admission can accurately predict the donor's post-transplant kidney health, which could lead to better post-operative care for the donor.