The Study Of Counterclockwise Maxillomandibular Advancement Treating Severe OSAHS And The Exploration Of OSAHS Regulating BMSCS Osteogenic Differentiation

ObjectiveSurgical treatment of severe obstructive sleep apnea-hypopnea syndrome(OSAHS)is still a big challenge all over the world.The outcomes of soft tissue operations are often unsatisfactory and the traditional maxillomandibular advancement(MMA)has a risk of aesthetic problems in chinese patiens.We designed counterclockwise maxillomandibular advancement(CMMA)to get the balance between airway enlargement and facial appearance.Firstly,this study is aimed to evaluate the objective and subjective outcomes of CMMA in treating severe OSAHS,so to clarify its value in the treatment of OSAHS in Chinese.Secondly,via analyzing failure cases,we want to provide data for the standardization of operation indications and operation procedure.According to the fact that the age of OSAHS patients treated with MMA are relatively high,and that more and more research indicated the potential impact of OSAHS on the status of bone development and metabolism,another purpose of this study is to investigate the effects of intermittent hypoxia(IH)on the proliferation?osteogenic differentiation and other biological behaviors of bone marrow mesenchymal stem cells(BMSCs)and explore the potential mechanism.Methods1.In the first part,33 patients from 2008 to 2015 in sleep center of Shanghai Jiao Tong University School of Medicine affiliated Ninth People's Hospital who accepted large CMMA treatment were enrolled,the objective outcomse were evaluated by polysomnography(PSG)and cephalometric analysis,the subjective outcomes were evaluated by Epworth sleepiness scale(ESS)and patients' satisfaction.2.In the second part,we screened CMMA failure cases of OSAHS in our center since 1990,6 cases were chosen with 7 cases losing follow-up,also,15 successful cases were selected as control.The causes of failure were analyzed by cephalometric analysis and PSG parameters.3.In the third part,firstly,the stable IH model was established.BMSCs were obtained from SD rats.The survival status of BMSCs was evaluater by MTT.Malondialdehyde(MDA)was detected to evaluate the oxidative stress index at multiple time points.Western-blot was used to evaluate the level of HIF-1a and RUNX2.The ALP was detected by qualitative staining and protein semi-quantitative kit.RT-PCR was used to detect osteogenic differentiation indicators.RNA-Seq was carried out to evaluate the whole RNA transcription of BMSCs after treated with short term intermittent hypoxia.Finally,we explore the effect of PI3K/Akt pathway on the BMSCs survival under IH.Results1.After CMMA for severe OSAHS,the apnea-hypopnea index(AHI)and lowest arterial oxygen saturation(LSAT)improved significantly.Cephalometric analysis confirmed the counterclockwise advancement maxillomandibular complex,combined with the enlargement of upper airway.ESS scale also improved and the patients were generally satisfied with their facial satisfaction.2.In both of the failure and sucessful cases,cephalometric analysis indicated slightly relapse of the maxillomandibular position and the upper airway diameter.However,in general,the upper airway enlargement and counterclockwise rotation of the maxillomandibular complex were smaller in failure cases.3.MTT test indicated that the survival of BSMCs kept no obvious change under short term IH,but with the extension of time,the survival BSMCs began to decline.The increase of MDA was not obvious in short time,but speeded up in late time.Western blot indicated that HIF-1a was upregulated transiently.The expression of osteogenesis related index like BMP-2 and RUNX2 was upregulated after short time IH exposure.RNA-Seq indicated that IH for 48 h,many differential expressed genes enriched in the pathways about metabolism,antioxidant,anti-apoptosis and chemoattractant.Inhibition of PI3K/Akt did not block the survival of BMSCs under short time IH exposure.Conclusion1.With careful patient selection and surgical design,CMMA is an effective way to treat OSAHS without destroying facial appearance.CMMA is a promising treatment for severe Chinese OSAHS.2.The failure of CMMA may be attributed to the aquired maxillomandibular position or/and the upper airway enlargement function.3.BMSCs may undergo the oxidative stress and hypoxia at the same time,and experience a transiently compensatory procedure in survival after IH exposure.Short time IH upregulated osteogenic differentiation in BMSCs.From the overall level of RNA transcription,short time IH triggered the activity of metabolism,antioxidant,anti-apoptosis and chemoattractant in BMSCs.