The applications of high-flow nasal cannulas in pediatric intensive care units in Taiwan.

BACKGROUND: /purpose: The use of high-flow nasal cannulas (HFNC) in patients admitted to the pediatric intensive care unit (PICU) has gradually increased worldwide; however, details on clinical efficacy remain limited in Taiwan. Therefore, we explored the clinical characteristics and outcomes of pediatric patients using HFNC in the PICU. METHODS: Medical records were retrospectively collected from pediatric patients (aged <18 years) who received HFNC support from December 2021 to January 2023 in the PICU of a medical center. Outcome parameters included treatment failure (defined as increased respiratory support to advanced non-invasive ventilators or intubations), duration of support from HFNC, and changes in clinical parameters after initiating HFNC. RESULTS: A total of 261 episodes of HFNC use were included, with a failure rate of 24.5% and a median support length of 4 days. Multivariable analysis showed that infant age (adjusted odds ratio [aOR]: 2.1, p = 0.02) and accompanying complex chronic disease (aOR: 4.4, p = 0.014) were risk factors for treatment failure and a diagnosis of asthma or bronchiolitis had a lower hazard of treatment failure (aOR: 0.29, p = 0.025) than other diagnoses did. Improvements in clinical parameters, including pulse rate, respiratory rate, SpO2, and CO2 levels, were observed 24 h after the initiation of HFNC. CONCLUSION: The application of HFNC in the PICU in Taiwan is effective but should be performed with care in infants with accompanying complex chronic diseases. In addition to low treatment failure, HFNC utilizations stabilized the clinical parameters of children with asthma/bronchiolitis within one day.

High incidence of cerebrovascular lesions on magnetic resonance imaging in pediatric COVID-19 during omicron outbreak - A retrospective case series.

BACKGROUND: The incidence of pediatric hospitalizations has significantly increased since the spread of the omicron variant of COVID-19. Changes of characteristics in respiratory and neurological symptoms have been reported. We performed a retrospective, cross-sectional study to characterize the MRI change in children with an emphasis on the change of cerebral vasculatures. METHODS: We retrospectively collected clinical and MRI data of 31 pediatric patients with neurological symptoms during the acute infection and abnormalities on MRI during the outbreak of omicron variant from April 2022 to June 2022 in Taiwan. The clinical manifestations and MRI abnormalities were collected and proportion of patients with vascular abnormalities was calculated. RESULTS: Among 31 pediatric patients with post-COVID-19 neurological symptoms, MRI abnormalities were observed in 15 (48.4%), predominantly encephalitis/encephalopathy (73.3%). Notable MRI findings included focal diffusion-weighted imaging (DWI) hyperintensity in cerebral cortex and thalamus, diffuse cortical T2/DWI hyperintensity, and lesions in the medulla, pons, cerebellum, and splenium of corpus callosum. Vascular abnormalities were seen in 12 (80%) patients with MRI abnormalities, mainly affecting the middle cerebral arteries. The spectrum of neurological manifestations ranged from seizures to Alice in Wonderland syndrome, underscoring the diverse impact of COVID-19 on pediatric patients. CONCLUSION: A high proportion of vascular abnormalities was observed in pediatric patients with neurological involvements, suggesting that vascular involvement is an important mechanism of neurological manifestations in omicron variant infection.

Clinical manifestations and risk factors of shock in children with multisystem inflammatory syndrome.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is a novel disease associated with COVID-19. The COVID-19 epidemic peaked in May 2022 in Taiwan, and we encountered our first case of MIS-C in late May 2022. We aimed to present patients' clinical manifestations and identify risk factors for shock. METHODS: We included patients diagnosed with MIS-C at two medical centers from May 2022 to August 2022. We separated those patients into two groups according to whether they experienced shock. We collected demographic, clinical manifestation, and laboratory data of the patients and performed statistical analysis between the two groups. RESULTS: We enrolled 28 patients, including 13 (46 %) with shock and 15 (54 %) without shock. The median age was 6.4 years (IQR: 1.9-7.5). In single variable analysis, patients with shock tended to be older, had more neurological symptoms, more conjunctivitis and strawberry tongue, lower lymphocyte count, lower platelet counts, and higher C-reactive protein, higher procalcitonin, higher ferritin, and higher D-dimer levels than those without shock. The area under the ROC curve that used procalcitonin to be the risk factor of shock with MIS-C was 0.815 (95 % CI 0.644 to 0.987). The cutoff value obtained by ROC analysis of procalcitonin was 1.68 ng/mL. With this cutoff, the test characteristics of procalcitonin were as follows: sensitivity 77 %, specificity 93 %, positive predictive value 91 %, negative predictive value 82 %. Multivariable analysis revealed that procalcitonin was the only independent risk factor of shock with MIS-C on admission (OR, 26.00, 95 % CI, 1.01-668.89). CONCLUSIONS: MIS-C patients with high initial procalcitonin levels have higher risks of experiencing shock and may need ICU admission.

Increasing Trend and Effects of Pediatric Palliative Care on Children With Noncancer Diagnoses.

OBJECTIVES: Pediatric palliative care (PPC), especially among noncancer pediatric patients, faces challenges including late referral, limited patient care, and insufficient data for Asian patients. METHODS: This retrospective cohort study used the integrative hospital medical database between 2014 and 2018 to analyze the clinical characteristics, diagnoses, and end-of-life care for patients aged less than 20 who had died in our children's hospital, a tertiary referral medical center implementing PPC shared-care. RESULTS: In our cohort of 323 children, 240 (74.3%) were noncancer patients who a younger median age at death (5 vs. 122 months, P < 0.001), lower rate of PPC involvement (16.7 vs. 66%, P < 0.001), and fewer survival days after PPC consult compared to cancer patients (3 vs. 11, P = 0.01). Patients not receiving PPC had more ventilator support (OR 9.9, P < 0.001), and less morphine use on their final day of life (OR 0.1, P < 0.001). Also, patients not receiving PPC had more cardiopulmonary resuscitation on the last day of life (OR 15.3, P < 0.001) and died in the ICU (OR 8.8, P < 0.001). There was an increasing trend of noncancer patients receiving PPC between 2014 and 2018 (P < 0.001). CONCLUSIONS: High disparities exist between children receiving PPC in cancer versus noncancer patients. The concept of PPC is gradually becoming accepted in noncancer children and is associated with more pain-relief medication and less suffering during end-of-life care.

Clinical characteristics and factors associated with severe COVID-19 in hospitalized children during the SARS-CoV-2 Omicron pandemic in Taiwan.

BACKGROUND: Since April 2022, a notable increase in COVID-19 cases with the rapid spread of the SARS-CoV-2 Omicron variant has been reported in Taiwan. In the epidemic, children were one of the most vulnerable groups, so we analyzed their clinical presentations and factors associated with severe complications of COVID-19 in children. METHODS: We included hospitalized patients under 18 years old with lab-confirmed SARS-CoV-2 infection from March 1, 2022, to July 31, 2022. We collected the demographic and clinical characteristics of the patients. Patients requiring intensive care were defined as severe cases. RESULTS: Among the 339 enrolled patients, the median age was 31 months (interquartile range (IQR), 8-79.0 months); and 96 patients (28.3%) had underlying diseases. Fever was noted in 319 patients (94.1%) with a median duration of two days (IQR 2-3 days). Twenty-two patients (6.5%) were severe cases, including 10 patients (2.9%) with encephalopathy with abnormal neuroimaging and ten patients (2.9%) with shock. Two patients (0.6%) died. Patients with congenital cardiovascular disease (aOR: 21.689), duration of fever up to four days or more (aOR: 6.466), desaturation (aOR: 16.081), seizure (aOR: 20.92), and procalcitonin >0.5 ng/mL (aOR: 7.886) had a higher risk of severe COVID-19. CONCLUSIONS: Vital signs need close monitoring, early management and/or intensive care may be applied in COVID-19 patients with congenital cardiovascular diseases, fever lasting ≥4 days, seizures, desaturation and/or elevated procalcition since they are at higher risks of severe diseases.

The implications of airway anomalies on children with congenital heart disease and bronchiolitis.

BACKGROUND: Bronchiolitis is a common airway infection in young children. Hemodynamically significant congenital heart disease (CHD) predicts a more complicated course. However, the role of airway anomalies remains unknown. METHODS: We retrospectively reviewed the records of patients under 2 years old, diagnosed with CHD, and admitted between January 2011 and December 2013, before the palivizumab era. Records of bronchiolitis admissions were also extracted. Patients were grouped according to CHD condition and airway anomalies. RESULTS: A total of 230 patients with CHD were enrolled. A total of 180 (78%) and 71 (31%) patients had hemodynamically significant CHD and airway anomalies, respectively. A total of 52 (22.6%) patients were admitted for bronchiolitis 78 times. Among them, 33 (63.5%) had hemodynamically significant CHD, and 28 (53.8%) had airway anomalies. In patients with bronchiolitis admissions, the mean ventilator use, intensive care unit stay, and hospital stay were 1.08, 4.08, and 15.19 days, respectively. When compared, the mean hospital stay for bronchiolitis patients with airway anomalies was significantly longer than that of those without airway anomalies (19.8 vs. 9.9 days, p = 0.008). When further divided the patients by the presence hemodynamic significance, patients with hemodynamically significant CHD and airway anomaly had longer hospital stay than those who had neither. (21.7 vs. 8.3 days, p = 0.004) Airway anomaly was a significant risk factor for longer hospital stay in linear regression model (p = 0.007). CONCLUSIONS: Airway anomalies are common in children with CHD and are associated with longer hospital stays on bronchiolitis admission. An active survey for airway anomalies and adequate prophylaxis for bronchiolitis infection might be important in the care of children with CHD associated with airway anomalies.

Normal ECG standards and percentile charts for infants, children and adolescents.

BACKGROUND: Normal ECG standards in newborns, infants, children and adolescents have been collected and published by many authors. Only those by Davignon et al., Rijinbeek et al. and our two studies covered all ages from birth to adolescence. The standards reflecting the growth and development of the heart in infants, children and adolescents remained to be studied and explored. METHODS: We selected from our ECG database, after discussions and consultation, 15 key ECG parameters and analyzed for their age- and sex-specific mean, standard deviation and 2nd to 98th percentiles and their percentile charts were constructed. RESULTS: The ranges and distributions of the normal ECG standards, means and 2nd to 98th percentiles of 15 key parameters were established. CONCLUSION: A complete set of normal ECG standards of 15 key parameters from birth to adolescents is available for clinicians and researchers.

Application of nested multiplex polymerase chain reaction respiratory and pneumonia panels in children with severe community-acquired pneumonia.

Community-acquired pneumonia (CAP) is a serious clinical concern. A lack of accurate diagnosis could hinder pathogen-directed therapeutic strategies. To solve this problem, we evaluated clinical application of nested multiplex polymerase chain reaction (PCR) in children with severe CAP. We prospectively enrolled 60 children with severe CAP requiring intensive care between December 2019 and November 2021 at a tertiary medical center. Nested multiplex PCR respiratory panel (RP) and pneumonia panel (PP) were performed on upper and lower respiratory tract specimens. We integrated standard-of-care tests and quantitative PCR for validation. The combination of RP, PP, and standard-of-care tests could detect at least one pathogen in 98% of cases and the mixed viral-bacterial detection rate was 65%. The positive percent agreement (PPA), and negative percent agreement (NPA) for RP were 94% and 99%; the PPA and NPA for PP were 89% and 98%. The distribution of pathogens was similar in the upper and lower respiratory tracts, and the DNA or RNA copies of pathogens in the lower respiratory tract were equal to or higher than those in the upper respiratory tract. PP detected bacterial pathogens in 40 (67%) cases, and clinicians tended to increase bacterial diagnosis and escalate antimicrobial therapy for them. RP and PP had satisfactory performance to help pediatricians make pathogenic diagnoses and establish therapy earlier. The pathogens in the upper respiratory tract had predictive diagnostic values for lower respiratory tract infections in children with severe CAP.

The impact of the coronavirus disease 2019 epidemic and national public restrictions on Pediatric Intensive Care Units in Taiwan.

BACKGROUND/PURPOSE: Coronavirus disease 2019 (COVID-19) pandemic challenges pediatric health globally by limited medical accessibility. In response to COVID-19 epidemic in Taiwan, public restrictions were applied and the Level 3 alert was announced from May to July in 2021 for local outbreak. This study aims to analyze patients' clinical features and outcomes in the pediatric intensive care unit (PICU) during the COVID-19 epidemic with the Level 3 alert in Taiwan. METHODS: Medical records were retrospectively collected in patients admitted to the PICU of National Taiwan University Children's Hospital from May to July 2021 (Level 3 alert) and May to July 2019 and 2020 (control periods). Clinical characteristics and outcomes were compared between patients in the period with the Level 3 alert and control periods. RESULTS: During the study period, PICU monthly admissions significantly decreased in the Level 3 alert period and were negatively correlated with monthly newly confirmed COVID-19 cases. Patients admitted during the Level 3 alert were older, had higher disease severity, lower proportion of cardiovascular disease, and higher proportion of hematology-oncology diseases than those in the control group. After adjusting for the above factors, admission during Level 3 alert was an independent factor for higher mortality rate and prolonged length of stay (>14 days) in the PICU. CONCLUSION: During the COVID-19 epidemic with strict public restrictions, critically ill patients admitted to the PICU decreased but had increased disease severity, prolonged length of stay in the PICU, and higher mortality, reflecting the impact of quarantine and limited medical access.

Therapeutic Ultrasound Halts Progression of Chronic Kidney Disease In Vivo via the Regulation of Markers Associated with Renal Epithelial-Mesenchymal Transition and Senescence.

Low-intensity pulsed ultrasound (LIPUS), a therapeutic type of ultrasound, is known to enhance bone fracture repair processes and help some tissues to heal. Here, we investigated the therapeutic potential of LIPUS for the treatment of chronic kidney disease (CKD) in two CKD mouse models. CKD mice were induced using both unilateral renal ischemia/reperfusion injury (IRI) with nephrectomy and adenine administration. The left kidneys of the CKD mice were treated using LIPUS with the parameters of 3 MHz, 100 mW/cm2, and 20 min/day, based on the preliminary experiments. The mice were euthanized 14 days after IRI or 28 days after the end of adenine administration. LIPUS treatment effectively alleviated the decreases in the body weight and albumin/globulin ratio and the increases in the serum renal functional markers, fibroblast growth factor-23, renal pathological changes, and renal fibrosis in the CKD mice. The parameters for epithelial-mesenchymal transition (EMT), senescence-related signal induction, and the inhibition of α-Klotho and endogenous antioxidant enzyme protein expression in the kidneys of the CKD mice were also significantly alleviated by LIPUS. These results suggest that LIPUS treatment reduces CKD progression through the inhibition of EMT and senescence-related signals. The application of LIPUS may be an alternative non-invasive therapeutic intervention for CKD therapy.

Microrna-486-5P Regulates Human Pulmonary Artery Smooth Muscle Cell Migration via Endothelin-1.

Pulmonary arterial hypertension (PAH) is a fatal or life-threatening disorder characterized by elevated pulmonary arterial pressure and pulmonary vascular resistance. Abnormal vascular remodeling, including the proliferation and phenotypic modulation of pulmonary artery smooth muscle cells (PASMCs), represents the most critical pathological change during PAH development. Previous studies showed that miR-486 could reduce apoptosis in different cells; however, the role of miR-486 in PAH development or HPASMC proliferation and migration remains unclear. After 6 h of hypoxia treatment, miR-486-5p was significantly upregulated in HPASMCs. We found that miR-486-5p could upregulate the expression and secretion of ET-1. Furthermore, transfection with a miR-486-5p mimic could induce HPASMC proliferation and migration. We also found that miRNA-486-5p could downregulate the expression of SMAD2 and the phosphorylation of SMAD3. According to previous studies, the loss of SMAD3 may play an important role in miRNA-486-5p-induced HPASMC proliferation. Although the role of miRNA-486-5p in PAH in in vivo models still requires further investigation and confirmation, our findings show the potential roles and effects of miR-486-5p during PAH development.

Clinical implications of airway anomalies and stenosis in patients with heterotaxy syndrome.

In heterotaxy syndrome, bronchopulmonary situs usually reflects atrial situs, resulting in either right (RAI) or left atrial isomerism (LAI). This study determines airway anomalies and its implications in patients with heterotaxy. This retrospective study included 223 patients with heterotaxy syndrome who received an integrated cardiac computed tomography evaluation. Patient database from 1995 to 2020 was reviewed. The patients were examined by a congenital heart disease team comprising pediatric cardiologists, radiologists, pulmonologists, and cardiovascular surgeons. Among the 223 patients, 189 (84.8%, M/F = 1.66) had RAI and 29 had LAI (13.0%, M/F = 0.71). Five patients had indeterminate isomerism (2.2%, M/F = 1.5). Discordant bronchopulmonary and atrial situs occurred in 4% patients, while discordant bronchopulmonary, atrial, and splenic situs occurred in 23.2% patients. Lower airway stenosis was observed in 61 patients (27.4%), including 27.5%, 20.7%, and 60% RAI, LAI, and indeterminate isomerism patients, respectively (p = 0.189). One patient had an intrinsic long segment lower tracheal stenosis and received slide tracheoplasty. Initial cardiac operation was performed in 213 patients. Higher surgical mortality occurred in patients with RAI (19.5% vs. none for LAI and indeterminate isomerism, p = 0.038). In patients with RAI, lower airway anomaly/stenosis increased the duration of ventilator usage (p = 0.030) but did not affect surgical mortality. Total anomalous pulmonary venous return to systemic veins and pulmonary venous stenosis were major surgical risk factors. Bronchopulmonary isomerism shares a similar isomeric pattern to cardiac atrial appendage. Lower airway anomalies/stenosis was common in patients with heterotaxy, resulting in prolonged ventilator therapy in patients with RAI.

Low-Dose Acrolein, an Endogenous and Exogenous Toxic Molecule, Inhibits Glucose Transport via an Inhibition of Akt-Regulated GLUT4 Signaling in Skeletal Muscle Cells.

Urinary acrolein adduct levels have been reported to be increased in both habitual smokers and type-2 diabetic patients. The impairment of glucose transport in skeletal muscles is a major factor responsible for glucose uptake reduction in type-2 diabetic patients. The effect of acrolein on glucose metabolism in skeletal muscle remains unclear. Here, we investigated whether acrolein affects muscular glucose metabolism in vitro and glucose tolerance in vivo. Exposure of mice to acrolein (2.5 and 5 mg/kg/day) for 4 weeks substantially increased fasting blood glucose and impaired glucose tolerance. The glucose transporter-4 (GLUT4) protein expression was significantly decreased in soleus muscles of acrolein-treated mice. The glucose uptake was significantly decreased in differentiated C2C12 myotubes treated with a non-cytotoxic dose of acrolein (1 µM) for 24 and 72 h. Acrolein (0.5-2 µM) also significantly decreased the GLUT4 expression in myotubes. Acrolein suppressed the phosphorylation of glucose metabolic signals IRS1, Akt, mTOR, p70S6K, and GSK3α/ß. Over-expression of constitutive activation of Akt reversed the inhibitory effects of acrolein on GLUT4 protein expression and glucose uptake in myotubes. These results suggest that acrolein at doses relevant to human exposure dysregulates glucose metabolism in skeletal muscle cells and impairs glucose tolerance in mice.

End-of-Life Care in Taiwan: Single-Center Retrospective Study of Modes of Death.

OBJECTIVES: Medical advances and the National Health Insurance coverage in Taiwan mean that mortality in the PICU is low. This study describes change in modes of death and end-of-life care in a single center, 2011-2017. SETTING: Multidisciplinary PICU in a tertiary referral Children's Hospital in Taiwan. PATIENTS: There were 316 deaths in PICU patients. INTERVENTIONS: Palliative care consultation in the PICU service occurred after the 2013 "Hospice Palliative Care Act" revision. MEASUREMENTS AND MAIN RESULTS: In the whole cohort, 22 of 316 patients (7%) were determined as "death by neurologic criteria". There were 94 of 316 patients (30%) who had an event needing cardiopulmonary resuscitation within 24 hours of death: 17 of these patients (17/94; 18%) died after failed cardiopulmonary resuscitation without a do-not-resuscitate order, and the other 77 of 94 patients (82%) had a do-not-resuscitate order after cardiopulmonary resuscitation. Overall, there were 200 of 316 patients (63%) who had a do-not-resuscitate order and were entered into the palliative program: 169 of 200 (85%) died after life-sustaining treatment was limited, and the other 31 of 200 (15%) died after life-sustaining treatment was withdrawn. From 2011 to 2017, the time-trend in end-of-life care showed the following associations: 1) a decrease in PICU mortality utilization rate, from 22% to 7% (p < 0.001); 2) a decrease in use of catecholamine infusions after do-not-resuscitate consent, from 87% to 47% (p = 0.001), in patients having limitation in life-sustaining treatment; and 3) an increase in withdrawal of life-sustaining treatment, from 4% to 31% (p < 0.001). CONCLUSIONS: In our practice in a single PICU-center in Taiwan, we have seen that the integration of a palliative care consultation service, developed after the revision of a national "Palliative Care Act," was associated with increased willingness to accept withdrawal of life-sustaining treatment and a lowered PICU care intensity at the end-of-life.

Reappraisal of the Subtropical Guidelines on Palivizumab Prophylaxis in Congenital Heart Disease.

Objective: To define the impact of associated abnormalities on the efficacy of the novel subtropical guidelines for palivizumab prophylaxis on respiratory syncytial virus (RSV)-related hospitalizations in patients with hemodynamically significant congenital heart disease (hsCHD). Method: This prospective study enrolled every patient seen at a tertiary care center for hsCHD, who was born between 2014 and 2018 and received at least 1 dose of palivizumab, according to the subtropical guidelines. The patients were followed until the age of 2 years. Results: A total of 772 patients (49% male) were enrolled. Cyanotic CHD was seen in 46% of patients, of whom 23% had associated abnormalities. Lung/airway abnormalities (14%) were the most common followed by the genetic syndromes associated with CHD (7.3%). Among the 772 patients, RSV-related hospitalizations occurred in 3.2 and 2.2% children aged ≤ 12 and 13-24 months, respectively. Most of the RSV infections occurred in patients no longer satisfying the criteria for palivizumab prophylaxis. The patients with associated abnormalities but not the type of CHD, patient age, and patient sex were risk factors for RSV-related hospitalizations. The rates of RSV-related hospitalizations, admission to the intensive care unit, and endotracheal intubation were higher for patients with associated anomalies than for other patients before 24 months of age (10.2 vs. 4.0%, 67 vs. 33%, and 39 vs. 4.2%, p = 0.004, 0.06, 0.013, respectively). Conclusion: Children with abnormalities, especially genetic syndromes and lung/airway problems associated with CHD, are at high risk for RSV-related hospitalization. Our current subtropical guidelines for palivizumab prophylaxis in patients with hsCHD, should be revised to include the results of this study.

Bilevel Positive Airway Pressure ventilation efficiently improves respiratory distress in initial hours treating children with severe asthma exacerbation.

OBJECTIVE: Treatment of severe asthma exacerbation could be challenging, especially in the initial hours of acute attack when systemic corticosteroid is yet to take effect. In spite of using inhaled agents, the role of non-invasive ventilation (NIV), including Bilevel Positive Airway Pressure (BiPAP), had been addressed recently. METHODS: We reviewed 5-year experience in our hospital for records of patients who were admitted to pediatric intensive care unit because of severe asthma attack. The included admission records from 2012 to 2017 were grouped according to BiPAP use (Yes/No). Clinical parameters (heart rate (HR), respiratory rate (RR), SpO2 and serum pCO2) at selected time intervals of treatment were collected for both groups and analyzed. RESULTS: We included data of 46 admissions from 33 different patients (24 with BiPAP and 21 without BiPAP.) The BiPAP group had significantly higher initial RR as well as higher severity scores compared with the other group (p < 0.001). The RR improved significantly in the following time intervals in BiPAP group. There was no significant difference in HR between groups in any of the time intervals. The serum pCO2 levels decreased significantly after initiation of ventilation support in the BiPAP group, and SpO2 levels improved significantly for both groups. CONCLUSION: BiPAP seemed efficient in improving respiratory rate and oxygenation in our study. It does not seem to cause additional irritation regarding that HR was not increased in BiPAP group compared with non-BiPAP group. Overall, BiPAP ventilation is safe and efficient in treating children with severe asthma attack.

Excessive Tracheal Length in Patients With Congenital Tracheal Stenosis.

BACKGROUND: Slide tracheoplasty is the preferred approach for treating long-segment congenital tracheal stenosis (CTS). However, little research has been conducted on the tracheobronchial anatomy before and after slide tracheoplasties in patients with CTS. METHODS: We reviewed 23 patients with CTS who received slide tracheoplasties. We measured the intrathoracic tracheal length and the carina angle from computed tomography images. To account for each patient's body size, we divided the intrathoracic tracheal length by the length of the thorax to obtain the trachea-thorax ratio (TTR). These measurements were used to compare patients before and after slide tracheoplasties as well as normal control subjects. RESULTS: Two patients had upper tracheal CTS and 21 patients had lower tracheal CTS. For the 21 patients with lower tracheal stenosis, their TTRs before slide tracheoplasty were 0.42 ± 0.04, which were significantly larger than those of the control subjects (0.32 ± 0.04; p < 0.0001). After slide tracheoplasty, the TTR was 0.32 ± 0.04, similar to the control TTRs (p = 0.94). The carina angle was significantly wider in the 21 patients than in the control subjects (120.7 ± 11.7 degrees versus 86.4 ± 13.1 degrees; p < 0.0001). After slide tracheoplasty, the carina angle was significantly narrower (from 120.7 ± 11.7 degrees to 92.2 ± 15.2 degrees; p < 0.0001), which was similar to control subjects. CONCLUSIONS: The trachea was longer and the carina angle wider in patients with lower tracheal CTS than in control subjects. Excessive tracheal length is favorable for slide tracheoplasty. Slide tracheoplasty not only corrects CTS, but also restores tracheobronchial morphology.

Adverse effects of acrolein, a ubiquitous environmental toxicant, on muscle regeneration and mass.

BACKGROUND: Acrolein is an extremely electrophilic aldehyde. Increased urinary acrolein adducts have been found in type 2 diabetic patients and people with a smoking habit. The increased blood acrolein was shown in patients who received the cancer drug cyclophosphamide. Both diabetes and smoking are risk factors for skeletal muscle wasting or atrophy. Acrolein has been found to induce myotube atrophy in vitro. The in vitro and in vivo effects and mechanisms of acrolein on myogenesis and the in vivo effect of acrolein on muscle wasting still remain unclear. METHODS: C2C12 myoblasts were used to assess the effects of low-dose acrolein (0.125-1 µM) on myogenesis in vitro. Mice were exposed daily to acrolein in distilled water by oral administration (2.5 and 5 mg/kg) for 4 weeks with or without glycerol-induced muscle injury to investigate the effects of acrolein on muscle wasting and regeneration. RESULTS: Non-cytotoxic-concentration acrolein dose dependently inhibited myogenic differentiation in myoblasts (myotube formation inhibition: 0.5 and 1 µM, 66.25% and 46.25% control, respectively, n = 4, P < 0.05). The protein expression for myogenesis-related signalling molecules (myogenin and phosphorylated Akt: 0.5 and 1 µM, 85.15% and 51.52% control and 62.63% and 56.57% control, respectively, n = 4, P < 0.05) and myosin heavy chain (MHC: 0.5 and 1 µM, 63.64% and 52.53% control, n = 4, P < 0.05) were decreased in acrolein-treated myoblasts. Over-expression of the constitutively active form of Akt in myoblasts during differentiation prevented the inhibitory effects of acrolein (1 µM) on myogenesis (MHC and myogenin protein expression: acrolein with or without constitutively active Akt, 64.65% and 105.21% control and 69.14% and 102.02% control, respectively, n = 5, P < 0.05). Oral administration of acrolein for 4 weeks reduced muscle weights (5 mg/kg/day: 65.52% control, n = 6, P < 0.05) and cross-sectional area of myofibers in soleus muscles (5 mg/kg/day: 79.92% control, n = 6, P < 0.05) with an up-regulation of atrogin-1 and a down-regulation of phosphorylated Akt protein expressions. Acrolein retarded soleus muscle regeneration in a glycerol-induced muscle regeneration mouse model (5 mg/kg/day: 49.29% control, n = 4, P < 0.05). Acrolein exposure reduced muscle endurance during rotarod fatigue performance in mice with or without glycerol-induced muscle injury (5 mg/kg/day without glycerol: 30.43% control, n = 4, P < 0.05). Accumulation of acrolein protein adducts could be detected in the soleus muscles of acrolein-treated mice. CONCLUSIONS: Low-dose acrolein significantly inhibited myogenic differentiation in vitro, which might be through inhibition of Akt signalling. Acrolein induced muscle wasting and retarded muscle regeneration in mice. These results suggest that acrolein may be a risk factor for myogenesis and disease-related myopathy.

Islet-like clusters derived from skeletal muscle-derived stem/progenitor cells for autologous transplantation to control type 1 diabetes in mice.

A population of muscle-derived stem/progenitor cells (MDSPCs) contained in skeletal muscle is responsible for muscle regeneration. MDSPCs from mouse muscle have been shown to be capable of differentiating into pancreatic islet-like cells. However, the potency of MDSPCs to differentiate into functional islet-like cluster remains to be confirmed. The therapeutic potential of autologous MDSPCs transplantation on type 1 diabetes still remains unclear. Here, we investigated a four-stage method to induce the differentiation of MDSPCs into insulin-producing clusters in vitro, and tested the autologous transplantation to control type 1 diabetes in mice. MDSPCs isolated from the skeletal muscles of mice possessed the ability to form islet-like clusters through several stages of differentiation. The expressions of pancreatic progenitor-related genes, insulin, and islet-related genes were significantly upregulated in islet-like clusters determined by the quantitative reverse transcription polymerase chain reaction. The autologous islet-like clusters transplantation effectively improved hyperglycaemia and glucose intolerance and increased the survival rate in streptozotocin-induced diabetic mice without the use of immunosuppressants. Taken together, these results provide evidence that MDSPCs from murine muscle tissues are capable of differentiating into insulin-producing clusters, which possess insulin-producing ability in vitro and in vivo, and have the potential for autologous transplantation to control type 1 diabetes.