title: Relationship between surfactant proteins B and C and obstructive sleep apnea: is serum SP-B concentration a potential biomarker of obstructive sleep apnea?
abstract: BACKGROUND
  Surfactant proteins B and C are mainly synthesized, secreted by alveolar type II cells, and affected by hypoxia and mechanical stretches. We hypothesized that their serum levels might be altered by intermittent hypoxia and swing of intrathoracic pressure of obstructive sleep apnea (OSA).
  
  
  METHODS
  Consecutive 140 middle-aged males, suspicious of OSA determined by polysomnography, were studied. Surfactant proteins B and C were determined by ELISA.
  
  
  RESULTS
  Surfactant protein B (41.39 ± 6.01 vs 44.73 ± 7.62 ng/L, p = 0.005), not C (32.60 ± 6.00 vs 32.43 ± 6.44 ng/L, p = 0.61), significantly lowered in moderate to severe OSA subjects than in non to mild OSA subjects. Severity of OSA is inversely correlated with serum surfactant protein B. Adjusting age, body mass index, and smoking history, compared to subjects with surfactant protein B (SP-B) ≥43.35 ng/L, those with SP-B <43.35 ng/L showed significantly increased 1.528-fold risk for moderate to severe OSA (p = 0.009), whereas no association between surfactant protein C and OSA was observed. Prevalence of moderate to severe OSA in lower SP-B group is higher than that in higher SP-B group (62.7 vs 38.4 %, p = 0.003). Serial and parallel tests on Epworth sleep scale (ESS) and SP-B evaluation can be complementary and prove helpful with high specificity (94.44 %) and sensitivity (84.48 %) to detect moderate to severe OSA.
  
  
  CONCLUSIONS
  Serum surfactant protein B, rather than C, is decreased in some individuals with moderate to severe OSA, compared to non to mild OSA subjects. Serum surfactant protein B might be a potential biomarker to diagnose OSA.
authors.affiliation: Graduate School of Xinjiang Medical University, Urumqi, 830000, Xinjiang, China.|The Center of Hypertension of the People's Hospital of Xinjiang Uygur Autonomous Region, The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, No. 91 Tianchi Road Tianshan District, Urumqi, 830001, Xinjiang, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Shao
authors.affiliation: The Center of Hypertension of the People's Hospital of Xinjiang Uygur Autonomous Region, The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, No. 91 Tianchi Road Tianshan District, Urumqi, 830001, Xinjiang, China. lnanfang2010@sina.com.
authors.forename: Nanfang
authors.initials: N
authors.lastname: Li
authors.affiliation: The Center of Hypertension of the People's Hospital of Xinjiang Uygur Autonomous Region, The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, No. 91 Tianchi Road Tianshan District, Urumqi, 830001, Xinjiang, China.
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Yao
authors.affiliation: The Center of Hypertension of the People's Hospital of Xinjiang Uygur Autonomous Region, The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, No. 91 Tianchi Road Tianshan District, Urumqi, 830001, Xinjiang, China.
authors.forename: Mulalibieke
authors.initials: M
authors.lastname: Heizati
authors.affiliation: Graduate School of Xinjiang Medical University, Urumqi, 830000, Xinjiang, China.|The Center of Hypertension of the People's Hospital of Xinjiang Uygur Autonomous Region, The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, No. 91 Tianchi Road Tianshan District, Urumqi, 830001, Xinjiang, China.
authors.forename: Arikin
authors.initials: A
authors.lastname: Abdireim
authors.affiliation: The Center of Hypertension of the People's Hospital of Xinjiang Uygur Autonomous Region, The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, No. 91 Tianchi Road Tianshan District, Urumqi, 830001, Xinjiang, China.
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Wang
authors.affiliation: The Center of Hypertension of the People's Hospital of Xinjiang Uygur Autonomous Region, The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, No. 91 Tianchi Road Tianshan District, Urumqi, 830001, Xinjiang, China.
authors.forename: Zufeiya
authors.initials: Z
authors.lastname: Abulikemu
authors.affiliation: The Center of Hypertension of the People's Hospital of Xinjiang Uygur Autonomous Region, The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, No. 91 Tianchi Road Tianshan District, Urumqi, 830001, Xinjiang, China.
authors.forename: Delian
authors.initials: D
authors.lastname: Zhang
authors.affiliation: The Center of Hypertension of the People's Hospital of Xinjiang Uygur Autonomous Region, The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, No. 91 Tianchi Road Tianshan District, Urumqi, 830001, Xinjiang, China.
authors.forename: Guijuan
authors.initials: G
authors.lastname: Chang
authors.affiliation: The Center of Hypertension of the People's Hospital of Xinjiang Uygur Autonomous Region, The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, No. 91 Tianchi Road Tianshan District, Urumqi, 830001, Xinjiang, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Zhou
authors.affiliation: The Center of Hypertension of the People's Hospital of Xinjiang Uygur Autonomous Region, The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, No. 91 Tianchi Road Tianshan District, Urumqi, 830001, Xinjiang, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Hong
authors.affiliation: Graduate School of Xinjiang Medical University, Urumqi, 830000, Xinjiang, China.|The Center of Hypertension of the People's Hospital of Xinjiang Uygur Autonomous Region, The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, No. 91 Tianchi Road Tianshan District, Urumqi, 830001, Xinjiang, China.
authors.forename: Yongping
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: The Center of Hypertension of the People's Hospital of Xinjiang Uygur Autonomous Region, The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, No. 91 Tianchi Road Tianshan District, Urumqi, 830001, Xinjiang, China.
authors.forename: Jianqiong
authors.initials: J
authors.lastname: Kong
authors.affiliation: Graduate School of Xinjiang Medical University, Urumqi, 830000, Xinjiang, China.
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D000860:Hypoxia / Q000097:blood / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D011650:Pulmonary Alveoli / Q000503:physiopathology; D037701:Pulmonary Surfactant-Associated Protein B / Q000097:blood*; D037721:Pulmonary Surfactant-Associated Protein C / Q000097:blood*; D012016:Reference Values; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000175:diagnosis*; D013223:Statistics as Topic
chemical_list: D015415:Biomarkers; D037701:Pulmonary Surfactant-Associated Protein B; D037721:Pulmonary Surfactant-Associated Protein C; C489679:SFTPC protein, human
keywords: Biomarker; Obstructive sleep apnea; Surfactant protein