Morphological Evaluation Of Obstructive Meibomian Glands Dysfunction And Analysis Of Lipids Present In Human Meibomian Gland Secretions

Meibomian gland dysfunction(MGD)is a chronic,diffuse abnormality of the meibomian glands,commonly characterized by terminal duct obstruction and/or qualitative/quantity change in patient,which can cause redness,itching,irritation,burning,dry sensation,eye discomfort and so on.However,due to the MGD no-specific symptoms,the difficulty of clinical examination and lacking an effective and simple detective method,most patients are diagnosed only when the MGD has reached an advanced stage.Most of MGD patient is the type of OMGD.Human meibomian gland secretions is meibum.It is reported that meibum can affect lipid metabolism of the OMGD.Lipidomics is a newly developed technology in recent years,the analytical technology which is high sensitivity include extraction,separation and analysis of lipid.The lipidomics of the OMGD may contribute to early diagnostic biomarkers and understanding the mechanism of OMGD.Objective: To examine the morphological changes in the OMGD patients using the non-contact infrared meibograhhy system and to assess their relationship between two groups with the ocular surface,eyelid and meibomian gland Parameters.Our study focused on finding potential biomarkers and alterations in the metabolic pathway by analyzing the lipidomics difference between the patients and the normal controls.Methods: 120 patients with OMGD were recruited and 120 age-and-gender matched healthy controls.All participants administered the Ocular Surface Disease Index(OSDI)questionnaire,tear film break-up time,tear meniscus height,Schirme test without anesthesia,corneal fluorescein staining,tear lipid layer thickness,eye lid examinations,meibomian gland orifices,Marx line,meibum and meibomian glands dropout.The correlations among variables were evaluated between the OMGD group and the control group.The meibum from 6 healthy volunteer and 6 OMGD patients was separated and analyzed by UPLC-ESI-QTOF-MS.UPLC-ESI-QTOF-MS was performed C18 CSH column,the mobile phase A: ACN/H2O(60:40,v:v)mixed with10 mM ammonium formate and 0.1% formic acid,phase B: IPA/ACN(90:10,v:v)mixed with 10 mM ammonium formate and 0.1% formic acid.Mass spectrometrywas performed using a Q-TOF premier for global lipid profiling and a XevoG2-S Q-TOF for the recovery study with an electrospray ionization(ESI)source.MassLynx software version 1.4.1was used for data acquisition and analysis.Results: The OMGD group and control group with the OSDI,BUT,TMH,CFS,Schirmer test,Eyelid score,meibomian gland orifices,ML score,meibomian gland secretion and dropout were compared,the differences were statistically significant(P<0.05).The OMGD inter-group with BUT,TMH,CFS,eyelid score,meibomian gland orifices,ML score,meibomian gland secretion and meibomian gland dropout were compared,the differences were statistically significant(P<0.05).The lower meibomian gland in ML score,meibomian gland secretion and dropout was higher than the upper(P<0.05).UPLC-ESI-QTOF-MS technique can identify meibum,which contain 476 lipid,11 lipid candidate metabolites.Conclusions: The OMGD group and normal group were observed the ocular surface,eyelid and meibomian gland parameter.The OMGD inter-group were observed the ocular surface,eyelid and meibomian gland Parameter.Both differences were statistically significant(P<0.05).Marx line can be used as a simple,rapid and low-invasive diagnostic tool for OMGD.LipiView interference are assessed tear lipid layer thickness.Keratograph 5M are observed and assessed for meibomian gland morphology.UPLC-MS can qualitatively and quantitatively analysis of assessment of meibum component,which high sensitivity,precision and accuracy.Meibum lipid has a wide variety of components,11 lipid levels were significantly changed in OMGD group compared with the normal group,which better understanding t he mechanism of OMGD.