Alterations of respiratory resistance in patients with obstructive sleep apnea hypopnea syndrome / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the association between the components of airway resistance and severity of obstructive sleep apnea hypopnea syndrome (OSAHS).</p><p><b>METHODS</b>A total of 234 patients with snoring during sleep underwent full-night polysomnography in our center between January, 2015 and September, 2017. According to the apnea-hypopnea index (AHI) scores, the patients were divided into non-OSAHS group (AHI scores <5), mild or moderate OSAHS group (5-30) group, and severe OSAHS group (>30). The pulmonary function and respiratory resistance of the patients were assessed using spirometry and impulse oscillometry, respectively, and the correlation between the parameters of respiratory resistance and the severity of AHI were analyzed.</p><p><b>RESULTS</b>The non-OSAHS, mild or moderate OSAHS, and severe OSAHS groups consisted of 31, 90 and 113 patients, respectively. The patients with severe OSAHS had significantly higher levels of respiratory resistance at 5 Hz (R5) and 20 Hz (R20), FEF and MMEF than those in the other two groups (P<0.05). Bivariate correlation analysis identified positive correlations of R5 (r=0.259, P=0.000), R20 (r=0.298, P=0.000) and FEF (r=0.176, P=0.007) with AHI scores of the patients.</p><p><b>CONCLUSION</b>Patients with OSAHS have increased respiratory resistance in the large airways and compensatory reduction in small airway resistance.</p>

One-hour post-load plasma glucose: a better indicator of glucose metabolism for obstructive sleep apnea? / 南方医科大学学报

<p><b>OBJECTIVE</b>To assess the value of blood glucose at different time points in oral glucose tolerance test (OGTT), particularly one?hour post load plasma glucose (1 hPG), in evaluating glucose metabolism in adult patients with obstructive sleep apnea (OSA).</p><p><b>METHODS</b>Eighty nine adultswith newly diagnosed OSA were analyzed retrospectively for sleep architecture assessed using polysomnography and glucose metabolism assessed by OGTT at different time points (0, 30, 60, 120, and 180 min). Pearson's correlatives and multiple linear regression models were established to investigate the correlations between glucose metabolism and other indices including sleep architecture, apnea hypopnea index (AHI), mean and lowest oxygen saturation (MSOand LSO) and obesity measurements.</p><p><b>RESULTS</b>The majority (67.4%) of the patients had abnormal 1 hPG, and 41.6% had abnormal 2 hPG. 1 hPG was positively correlated with neck circumference (r=0.245), abdomen circumference (r=0.231), systolic blood pressure (r=0.213), diastolic blood pressure (r=0.276) and AHI (r=0.324), and was negatively associated with MSO(r=-0.341) and LSO(r=-0.387) (all P<0.05). After controlling for age, BMI, neck and abdomen circumferences, 1 hPG was found to inversely correlated with MSO(r=-0.253, P=0.032) and LSO(r=-0.311, P=0.008). In non-obese OSA subgroup, 1 hPG was significantly associated with OSA-related indices, and regression models showed that LSOand N2 were the two most important contributors to 1 hPG (adjusted R=0.349, P<0.001); plasma glucose at other time points did not show such correlations.</p><p><b>CONCLUSIONS</b>1 hPG abnormality occurs earlier than 2 hPG in OSA patients. 1 hPG is significantly associated with OSA independent of obesity and may serve as a better index for measuring OSA-related glucose disorder.</p>

Severe obstructive sleep apnea-hypopnea syndrome with latent renal dysfunction: analysis of 238 cases / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the association between severity of obstructive sleep apnea hypopnea syndrome (OSAHS) without chronic kidney disease (CKD) and serum cystatin C.</p><p><b>METHODS</b>A total of 238 patients with snoring during sleep admitted between January 2012 and June 2015 underwent full-night polysomnography for diagnosis of OSAHS. The patients were divided according to the apnea-hypopnea index (AHI) scores into simple snoring group (AHI<5) and mild (AHI, 5-15), moderate (AHI, 15-30), and severe OSAHS (AHI>30) groups. The medical history, baseline demographic characteristics, blood glucose, blood lipids, peripheral blood cell count and serum cystatin C were measured, and the correlation between polysomnographic parameters and serum cystatin C were analyzed in different groups.</p><p><b>RESULTS</b>The simple snoring, mild, moderate, and severe OSAHS groups consisted of 41, 49, 56, and 92 cases, respectively. Serum cystatin C, WBC and its subtype counts, RBC count, and superoxide dismutase (SOD) were all significantly higher in severe OSAHS group than in the other 3 groups (P<0.05), but serum creatinine and estimated glomerular filtration rate were comparable among the groups (P>0.05). Linear correlation analysis revealed that serum cystatin C was positively correlated with gender, BMI, neck circumference, abdominal circumference, SBP, AHI, and WBC (P<0.01) and inversely correlated with the average pulse oxygen saturation (ASpO2), minimum pulse oxygen saturation (MSpO(2)), and SOD (P<0.01). Multiple regression analysis identified AHI and SOD as independent factors that were positively and inversely correlated with serum cystatin C (β=0.218, P<0.010; β=-0.217, P<0.009), respectively.</p><p><b>CONCLUSION</b>Severe OSAHS is closely correlated with serum cystatin C, WBC, and SOD, suggesting that severe OSAHS may initiate the pathological process of early renal damage possibly in association with chronic intermittent hypoxia-induced oxidative stress and the initiation of the inflammatory cascade.</p>

A Nomogram for Predicting the Likelihood of Obstructive Sleep Apnea to Reduce the Unnecessary Polysomnography Examinations / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The currently available polysomnography (PSG) equipments and operating personnel are facing increasing pressure, such situation may result in the problem that a large number of obstructive sleep apnea (OSA) patients cannot receive timely diagnosis and treatment, we sought to develop a nomogram quantifying the risk of OSA for a better decision of using PSG, based on the clinical syndromes and the demographic and anthropometric characteristics.</p><p><b>METHODS</b>The nomogram was constructed through an ordinal logistic regression procedure. Predictive accuracy and performance characteristics were assessed with the area under the curve (AUC) of the receiver operating characteristics and calibration plots, respectively. Decision curve analyses were applied to assess the net benefit of the nomogram.</p><p><b>RESULTS</b>Among the 401 patients, 73 (18.2%) were diagnosed and grouped as the none OSA (apnea-hypopnea index [AHI] <5), 67 (16.7%) the mild OSA (5 ≤ AHI < 15), 82 (20.4%) the moderate OSA (15 ≤ AHI < 30), and 179 (44.6%) the severe OSA (AHI ≥ 30). The multivariable analysis suggested the significant factors were duration of disease, smoking status, difficulty of falling asleep, lack of energy, and waist circumference. A nomogram was created for the prediction of OSA using these clinical parameters and was internally validated using bootstrapping method. The discrimination accuracies of the nomogram for any OSA, moderate-severe OSA, and severe OSA were 83.8%, 79.9%, and 80.5%, respectively, which indicated good calibration. Decision curve analysis showed that using nomogram could reduce the unnecessary polysomnography (PSG) by 10% without increasing the false negatives.</p><p><b>CONCLUSIONS</b>The established clinical nomogram provides high accuracy in predicting the individual risk of OSA. This tool may help physicians better make decisions on PSG arrangement for the patients referred to sleep centers.</p>

Alteration of telomere length of the peripheral white blood cells in patients with obstructive sleep apnea syndrome / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the alteration of telomere length of the peripheral white blood cells in patients with obstructive sleep apnea syndrome (OSAS) and explore its significance.</p><p><b>METHODS</b>The DNA was extracted from the peripheral white blood cells of 11 patients with OSAS and 10 normal subjects matched for age and gender, and the T/S ratio was measured by fluorescence quantitative PCR.</p><p><b>RESULTS</b>The T/S ratio in the peripheral white blood cells of patients with OSAS was obviously lower than that of the normal subjects (P<0.05).</p><p><b>CONCLUSION</b>The reduction in the telomere length in the peripheral blood cells suggests a possible relationship between OSAS pathogenesis and telomere length, and hypoxemia and hypercapnia make accelerate telomere shortening and promote cell apoptosis.</p>

Role of inflammation factors in impaired glucose tolerance and sleep apnea/hypopnea syndrome in pregnant women / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the possible role of inflammation factors in the pathogenesis of impaired glucose tolerance (IGT) with concurrent obstructive sleep apnea/hypopnea syndrome (OSAHS) in pregnant women.</p><p><b>METHODS</b>Twenty-five pregnant women with IGT and concurrent OSAHS and 35 pregnant women with IGT but not OSAHS were monitored for all night polysomnography (PSG), and the apnea hypopnea index (AHI) and the lowest pulse oxygen saturation (LSpO2) were recorded. The body mass index, glycated serum protein (GSP), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were measured in these women.</p><p><b>RESULTS</b>IL-6 and TNF-α levels increased significantly in women with IGT and OSAHS as compared with those in women without OSAHS. AHI showed significant positive correlations to GSP, IL-6 and TNF-α, whereas LSpO2 was inversely correlated to GSP, IL-6 and TNF-α. IL-6 and TNF-α were significantly correlated to GSP, with correlation coefficients of 0.510 and 0.476, respectively.</p><p><b>CONCLUSION</b>The inflammatory factors may play important roles in IGT complicated by OSAHS in pregnant women, and as a potential risk factor, OSAHS may contribute to the occurrence of progression of IGT.</p>

Relation of advanced oxidation protein products with VEGF and TGF-β1 in colon cancer cells exposed to intermittent hypoxia / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the association of advanced oxidation protein products (AOPP) with oxidative stress in colon cancer cells exposed to intermittent hypoxia (IH).</p><p><b>METHODS</b>Colon cancer SW480 cells were exposed to IH, continuous hypoxia, or normoxia. Enzyme-linked immunosorbent assay (ELISA) was employed to examine the levels of AOPP and vascular endothelial growth factor (VEGF), xanthine oxidase assay was used to determine malonaldehyde (MDA) and glutathione peroxidase (GSH-PX), and Western blotting and immunofluorescence assay were performed for detection of transforming growth factor-β(1) (TGF-β(1)) expression.</p><p><b>RESULTS</b>Compared with the normoxia group, the two hypoxia groups showed significantly increased AOPP and MDA levels (P<0.05) and lowered SOD and GSH-PX levels (P<0.05). The concentration of AOPP was positively correlated to MDA, VEGF, and TGF-β(1) levels (P<0.05), but inversely to SOD. No significant correlation was found between AOPP and GSH-PX levels.</p><p><b>CONCLUSION</b>Compared with continuous hypoxia, IH results in more obvious protein oxidation in relation to oxidative stress. The increased expression of VEGF and TGF-β(1) in the context of hypoxia is closely related to AOPP level.</p>

Immune function changes in patients with obstructive sleep apnea hypopnea syndrome / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the potential changes in the immune function of patients with obstructive sleep apnea hypopnea syndrome (OSAHS).</p><p><b>METHODS</b>We carried out a retrospective cross-sectional study of 187 patients with established OSAHS and 20 healthy subjects (control). For all the patients, the medical history was carefully examined, and overnight sleep monitoring was carried out with detection of the humoral and cellular immunity.</p><p><b>RESULTS</b>We found a significant increase in the levels of C3 and a decrease in both the IgM level and NK cell percentage in OSAHS patients as compared to the control group (P<0.01). Correlation analysis indicated that C3 was positive correlated to AHI but inversely to the lowest pulse oxygen saturation (LSpO(2)); IgM showed a mild positively correlation to LSpO(2), and NK cells had a mild inverse correlation to AHI. The other immunological indices were not found to undergo noticeable changes or show correlations in OSAHS.</p><p><b>CONCLUSION</b>Immune function changes occur in patients with OSAHS, characterized primarily by deteriorations in the humoral and cellular immunity.</p>

Effect of obstructive sleep apnea syndrome on serum C-reactive protein level, left atrial size and premature atrial contraction / 南方医科大学学报

<p><b>OBJECTIVE</b>To assess the changes of serum C-reactive protein (CRP) level, left atrial size and atrial premature contraction (PAC) in patients with obstructive sleep apnea syndrome (OSAS).</p><p><b>METHODS</b>This study involved 277 patients with OSAS diagnosed after an overnight polysomnography, who underwent a 24-h Holter electrocardiography and ambulatory blood pressure monitoring for detection of PAC. According to the apnea-hypopnea index (AHI), 137 patients with PAC identified from these patients were classified into 3 groups, namely the mild (5≥AHI<15), moderate (15≥AHI<30) and severe (AHI≥30) groups. Serum CRP level was assessed by a high-sensitivity radio-immunoassay. The left atrial diameter and echocardiographic parameters were recorded by transthoracic Doppler echocardiography (TTE).</p><p><b>RESULTS</b>We found a high prevalence of PAC in these OSAS patients (137/277, 49.4%). Serum CRP was significantly higher in severe OSAS group (5.01∓4.68 mg/L) than in the moderate (3.03∓1.94 mg/L) and mild OSAS (2.98∓1.82 mg/L) groups (P=0.040 and 0.033, respectively). The left atrial diameter was significantly increased in severe OSAS group (40.1∓7.9 mm) as compared to that in moderate (37.9∓5.5 mm) and mild (33.7 ∓ 3.8 mm) groups (P=0.025 and 0.002, respectively). The severity of OSAS was positively correlated to both CRP (r=0.304, P=0.034) and left atrial diameter (r=0.411, P=0.003). After adjusting for gender, age and body mass index (BMI), a strong correlation was found between the left atrial diameter and CRP (r=0.594, P=0.0005).</p><p><b>CONCLUSION</b>There is a high prevalence of PAC in OSAS patients. The progression of OSAS is associated with increased serum CRP level and left atrial size in patients with premature atrial complexes. Our study suggests that inflammation associated with OSAS might contribute to atrial structural and electrical remodeling in OSAS patients with PAC.</p>

Correlation between sleep apnea hypopnea syndrome and preeclampsia and the possible pathogenesis of preeclampsia / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the relationship between sleep apnea-hypopnea syndrome (SAHS) and preeclampsia and the possible pathogenesis of the latter.</p><p><b>METHODS</b>Twenty-five healthy pregnant women, 43 pregnant women with preeclampsia, and 27 with preeclampsia complicated by SAHS were enrolled in this study. Apnea-hypopnea index (AHI) and the lowest arterial oxygen saturation (LSaO2) were measured through a 7-hour polysomnography (PSG), and the maternal age, gestational age, body mass index and 24-hour urine protein were recorded.</p><p><b>RESULTS</b>All the indexes except for the maternal age and gestational age showed significant differences between the 3 groups. The two groups of preeclampsia patients showed a significant difference in BMI from the control cases. Significant positive correlations of AHI to BMI, MAP and 24-hour urine protein were noted; LSaO2 was found to inversely correlate to BMI, MAP, and 24-hour urine protein. In spite of the significant correlation of BMI to the other indexes, we found that BMI was less important than AHI and LSaO2.</p><p><b>CONCLUSION</b>SAHS may induce or aggravate preeclampsia. Greater attention should be given to the presence of SAHS in pregnant women with obesity, but obesity is not the predominant predisposing factor for preeclampsia.</p>

Effect of terbutaline on sodium transport in alveolar type I and type II cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the effect of terbutaline on sodium transport in rat alveolar type I (ATI) and type II (ATII) cells of rats.</p><p><b>METHODS</b>The whole cell currents were recorded from ATII cells isolated from rat lungs perfused with or without amiloride (inhibitor of epithelial sodium channel) and ZnCl(2) (inhibitor of cyclic nucleotide-gated cation channel) in the whole cell recording mode using the patch-clamp technique. The effect of terbutaline on the currents was examined.</p><p><b>RESULTS</b>The main currents recorded from ATII cells were amiloride-sensitive and Zn(2+)-sensitive. The amiloride-sensitive and Zn(2+)-sensitive current shared a similar proportion (P>0.05). Both currents could be significantly increased by terbutaline (P<0.05), and the proportion of amiloride-sensitive current was 1.7 times that of Zn(2+)-sensitive current (P<0.05).</p><p><b>CONCLUSION</b>There are functional epithelial sodium channels (ENaC) and cyclic nucleotide-gated cation channels (CNG) on freshly isolated ATII cells, both serving as the main channels for sodium transport. Terbutaline increases the absorption of alveolar fluid primarily by increasing sodium transport of ENaC and CNG on ATI and AT II cells.</p>

Correlation between white matter lesion and memory impairment in patients with obstructive sleep apnea syndrome / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the nature of white matter lesion and correlation to memory impairment in patients with obstructive sleep apnea syndrome (OSAS) by diffusion tensor imaging ( DTI).</p><p><b>METHOD</b>We conducted a cross-sectional study of 20 middle-aged male people (10 with OSAS and 10 healthy controls) group-matched by age, educational level, and socioeconomic status. DTI was performed on those people with OSAS and on matched controls. Fractional anisotropy(FA) and average diffusion coefficient(ADC) values were measured respectively in bilateral white matter of the frontal lobe, anterior cingulate gyrus, anterior cingulum, etc. At the same time, WMS values were detected respectively.</p><p><b>RESULTS</b>Relative to controls, patients with OSAS had a lower FA in the white matter of right frontal lobe (0.444-/+0.025), splenium of corpus callosum (0.776-/+0.028 ), left anterior cingulate gyrus (0.154-/+0.021), right anterior cingulate gyrus (0.152-/+0.017), left anterior cingulum (0.372-/+0.022), right anterior cingulum (0.351-/+0.029), left centrum semiovale (0.501-/+0.029), peripheric white matter of left anterior angle (0.242-/+0.031), peripheric white matter of left posterior angle (0.338-/+0.029), peripheric white matter of right posterior angle (0.360-/+0.022 ), left parahippocampal gyrus (0.167-/+0.027), right parahippocampal gyrus (0.177-/+0.023). Besides, FA values of OSAS patients in the white matter of right frontal lobe and left centrum semiovale were strongly positively correlated with WMS values. While in comparison with that of healthy controls, ADC of OSAS patients was significantly higher in the white matter of right frontal lobe (8.589-/+0.264 x e(-10) mm(2)/s), trunk of corpus callosum (8.197-/+0.253 x e(-10) mm(2)/s), splenium of corpus callosum (8.218-/+0.194 x e(-10) mm(2)/s), left anterior cingulate gyrus (12.151-/+0.454 x e(-10) mm(2)/s), right anterior cingulate gyrus (12.113-/+0.524 x e(-10) mm(2)/s), right anterior cingulum (8.954-/+0.177 x e(-10) mm(2)/s),left centrum semiovale (7.333-/+0.220 x e(-10) mm(2)/s) and peripheric white matter of left anterior angle (9.186-/+0.465 x e(-10) mm(2)/s).</p><p><b>CONCLUSIONS</b>This study indicated that white matter and gray matter was both remarkably damaged in OSAS patients, which could contribute to memory impairment.</p>

Role of epithelial sodium channel alpha subunit in terbutaline-induced transient enhancement of pulmonary edema clearance in adult rats with acute lung injury / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the association of epithelial sodium channel alpha subunit (alphaENaC) with terbutaline-induced transient enhancement of pulmonary edema clearance in adult rats with acute lung injury (ALI).</p><p><b>METHODS</b>The effect of 1-h intratracheal terbutaline treatment on pulmonary edema clearance in adult rats with experimental ALI was observed by blood gas analysis, lung tissue HE staining, and extravascular lung water (EVLW) content measurement. The mRNA and protein expressions of alphaENaC in the lung tissues were detected by fluorescence quantitative real-time RT-PCR and Western blotting, respectively.</p><p><b>RESULT</b>Terbutaline treatment of the rats with ALI resulted in significant differences in PaO2, oxygenation index, and EVLW from those in ALI group without treatment. No significant differences in pulmonary alphaENaC mRNA and protein expressions were noted between the normal control, ALI, and terbutaline-treated ALI groups.</p><p><b>CONCLUSIONS</b>Intratracheal terbutaline administration for 1 h can significantly promote pulmonary edema clearance in adult rats with ALI, and this effect is not mediated by alphaENaC gene expression.</p>

Epithelial sodium channel subunit mRNA expression in acutely isolated rat alveolar type II cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the epithelial sodium channel (ENaC) subunit mRNA expression in acutely isolated rat alveolar type II (ATII) cells.</p><p><b>METHODS</b>Acutely isolated ATII cells from 20 SD rats were purified and ENaC alpha, beta, gamma-subunit mRNA levels were determined by reverse transcription-polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>mRNA expressions of all the subunits were detected in the ATII cells, and ENaC alpha-subunit mRNA showed significantly higher expression than beta- and gamma-subunit mRNAs, and the expressions of the latter two mRNAs were comparable.</p><p><b>CONCLUSION</b>As the predominant ENaC subunit expressed at the mRNA level in rat ATII cells, the alpha-subunit of ENAC plays an important role in alveolar fluid clearance.</p>

Clinical application of the Epworth sleepiness score in pregnant women with obstructive sleep apnea-hypopnea syndrome / 南方医科大学学报

<p><b>OBJECTIVE</b>To provide a convenient method for screening obstructive sleep apnea-hypopnea syndrome (OSAHS) in pregnant women.</p><p><b>METHODS</b>Seventy-eight pregnant women with suspected OSAHS were calculated for the EP index using Epworth sleepiness score (ESS) with also measurement of the neck circumference (NC) and body mass index (BMI). The apnea/hypopnea index (AHI) was calculated and the lowest SaO(2) (LSaO(2)) measured through a 7-h polysomnography (PSG). The women were then divided into 4 groups according to the AHI and LSaO(2). The ESS was compared with the PSG-AHI and the receiver operating characteristic curve (ROC) was generated.</p><p><b>RESULTS</b>All the clinical indexes (NC, BMI, EP, AHI, and LSaO(2)) showed significant differences between the 4 groups (P<0.05). EP and PSG were found to have greater correlations to AHI (r=0.759, P=0.000) than NC (r=0.668) and BMI (r=0.663). The area under the ROC of the EP (0.825) was greater than that of NC (0.772) and BMI (0.784). The index of EP showed greater clinical diagnostic value of OSAHS in pregnancy. Base on the ROC, EP at the optimal operating point of 7.5 had a sensitivity of 76.8% and specificity of 68.2% for diagnosis of OSAHS in pregnant women.</p><p><b>CONCLUSION</b>The ESS is an economic and convenient method for screening OSAHS in pregnant women with high diagnostic sensitivity and specificity.</p>

Effect of MAPK signal transduction pathway inhibitor U0126 on aquaporin 4 expression in alveolar type II cells in rats with oleic acid-induced acute lung injury / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the relationship between aquaporin 4 (AQP4) in alveolar type II (AT-II) cells and MAPK signaling pathway in rats with early-stage oleic acid-induced acute lung injury (ALI) and acute respiratory distress syndrome (ARDS).</p><p><b>METHODS</b>Three groups of rats, namely the normal control, ALI and U0126 treatment group were used in this study. After oleic acid-induced ALI in the latter two groups, the rats in the treatment group received 100 micromol/L U0126 treatment at the dose of 10 micro, and dimethyl sulfoxide (DMSO) were given in the normal control and ALI groups. Arterial blood gas and the extravascular lung water (EVLW) content were measured after the treatments, and pathological changes in the lung tissues were observed microscopically. ATII cells were isolated from the lung tissues and identified using tannic acid staining and alkaline phosphatase (APK) staining. The expression of AQP-4 mRNA in the cells was detected with RT-PCR.</p><p><b>RESULTS</b>Blood gas analysis, HE staining and EVLW content measurement revealed severer injury of the lung tissues in ALI group than in the normal control group, but the severity was comparable between the treatment and ALI groups. RT-PCR demonstrated significantly increased AQP-4 mRNA expression in ALI group as compared with that in the normal control group, and U0126 treatment resulted in obvious reduction in AQP-4 mRNA expression in the U0126 treatment group.</p><p><b>CONCLUSION</b>Oleic acid-induced ALI results in the activation of MAPK signaling pathway and up-regulation of AQP-4 mRNA expression in the ATII cells of rats.</p>

Alveolar fluid clearance and changes of alveolar type II cell cAMP and cGMP levels in rats with oleic acid-induced acute respiratory distress syndrome / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the changes of the levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) in acutely isolated alveolar type II (ATII) cells from rats with acute respiratory distress syndrome (ARDS), and test the effects of terbutaline on the cAMP and cGMP levels.</p><p><b>METHODS</b>SD rats were randomized into the control, ARDS, and terbutaline treatment groups, in which the cAMP and cGMP contents in the ATII cells were measured using radioimmunoassay, and the extravascular lung water (EVLW) content was quantified with gravimetric measurement.</p><p><b>RESULTS</b>The cAMP level in the ATII cells was significantly lowered whereas cGMP level and EVLW content increased in rats with oleic acid-induced ARDS. In terbutaline-treated rats with ARDS, the EVLW content were lower than that of non-treated rats, but still higher than that of the control rats. Terbutaline treatment also increased the content of cAMP but produced no significant effect on cGMP content in the ATII cells of the rats with ARDS.</p><p><b>CONCLUSION</b>Alveolar fluid clearance rate is decreased in rats with oleic acid-induced ARDS, and terbutaline can improve the capacity of alveolar fluid clearance, the mechanism of which may involve elevated cAMP content in the ATII cells. cAMP and cGMP in ATII cells might participate in the molecular pathogenesis of ARDS.</p>

Role of AQP-4 in pulmonary water metabolism in rats in early stage of oleic acid-induced acute lung injury / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the capacity of alveolar type II (AT II) cells for water and sodium transport in rats with early-stage oleic acid-induced acute lung injury (ALI)/acute respiratory distress syndrome (ARDS).</p><p><b>METHODS</b>AT II cells were isolated and purified from rats with ALI/ARDS induced by oleic acid, and their morphology was observed using electron microscopy and optical microscopy. The extravascular lung water (EVLW) content in the rats was measured by gravimetric method. The distribution of aquaporin-4 (AQP-4) on the cell membrane was observed with immunohistochemistry, and the expression of AQP-4 mRNA was detected with RT-PCR.</p><p><b>RESULTS</b>Microscopic examination and blood gas analysis indicated severe injury of the lung tissues in ALI group. Smith lung injury score and EVLW in ALI group were significantly higher in ALI group than in the control group (P<0.05). Immunohistochemistry identified intensified AQP-4 expression in rat lung tissues and RT-PCR also demonstrated increased AQP-4 mRNA expression as compared with the control group. The level of APQ-4 whole-cell currents was decreased in AT II cell membrane and increased in cytoplasm in ALI group (P<0.05 ).</p><p><b>CONCLUSIONS</b>Pathophysiological changes occurs in early stage of oleic acid-induced AMI, and AQP-4 mRNA expression is up-regulated on the AT II cell membrane to regulate the exchange of fluid between the alveolar space and alveolar epithelium barrier and play an important compensational role in pulmonary liquid clearance in the event of sodium transport damages in ALI.</p>

Sodium transport and its regulation of acutely isolated alveolar type II cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the sodium current of acutely isolated alveolar type II cells and its regulation.</p><p><b>METHODS</b>After isolation the AT II cells, the whole cell sodium current were recorded in 5 hours with patch-clamp in whole-cell mode, and the effect of amiloride and terbutaline on the current was investigated.</p><p><b>RESULTS</b>The amiloride-sensitive current of AT II cells were recorded, which could be obviously stimulated by terbutaline.</p><p><b>CONCLUSION</b>Acutely isolated AT II cells can be valuable for studying electrophysiological characteristics of sodium channels even under pathological conditions.</p>

Sodium transport of alveolar type II cells in oleic acid-induced acute respiratory distress syndrome / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the changes of sodium transport of alveolar type II cells in oleic acid-induced acute respiratory distress syndrome (ARDS).</p><p><b>METHODS</b>After isolation of the AT II cells as ARDS model induced by oleic acid, the whole cell sodium current was recorded in 5 h with patch-clamp in whole-cell mode. The effect of beta2-agonist terbutaline on the current was also examined.</p><p><b>RESULTS</b>The sodium currents recorded from AT II cells in ARDS were smaller than that of the control cells, but the current could be stimulated to increase obviously by terbutaline.</p><p><b>CONCLUSION</b>AT II cells can actively transport sodium ion even under conditions of ARDS, but this capacity can not match that of the control cells. Terbutaline can obviously stimulate the sodium current.</p>