Expressible Meibomian Glands Have Occult Fixed Obstructions: Findings From Meibomian Gland Probing to Restore Intraductal Integrity

Meibomian Gland Probing Stimulates a Proliferative Epithelial Response Resulting in Duct Regeneration

Purpose

To demonstrate that the meibomian gland ductal basement membrane and basal epithelial cell layer are in continuity with and may derive from lid margin orifice-associated rete ridge epithelial/basement membrane structures (OARREBS) and to characterize changes in the distal duct microanatomy after meibomian gland probing (MGP) using in vivo confocal microscopy (IVCM).

Patients and Methods

Pre/post-MGP IVCM examinations were performed on upper lids. Thirty-six identical glands from 20 lids of 16 patients (49.24 ±17.11 y/o with 13:3 F:M) were identified, analyzed, and compared to control cases. Statistical analyses were performed using ImageJ software and IBM SPSS version 27. All MGPs were performed within 12 weeks of the initial examination. Post-MGP follow-up exams occurred at 5.03 ±4.48 months.

Results

Post-MGP images showed more superficially organized OARREBS with accelerated and more superficial basement membrane formation, and an average increase of 32.2%, 25.4%, 32.04%, 77.7%, and 81.3% in duct wall epithelial cell layers (DWECL) (p < 0.001, compared to control (CTC) p < 0.001), distal duct wall thickness (DWT) (p < 0.001, CTC p < 0.001), proximal DWT (p < 0.001, CTC p < 0.001), distal lumen area (p < 0.001, CTC p = 0.037), and proximal lumen area (p < 0.001, CTC p = 0.007), respectively. The increase in the distal DWT and lumen area correlated with the months of follow-up (p = 0.004 and p = 0.010, respectively). Immediate post-MGP imaging revealed the probe track confined to the ductal epithelial compartment.

Conclusion

MGP appears to stimulate a proliferative epithelial response characterized by an accelerated more superficial formation of ductal basement membrane with increased DWECL as well as DWT and lumen area at two separate duct foci. These findings suggest activation of lid margin meibomian gland precursor cells and confirm that MGP stimulates an epithelial regenerative phenomenon, not a fibrotic one.

Isolation and Culture of Human Meibomian Gland Ductal Cells

Purpose

Hyperkeratinization of meibomian gland (MG) ducts is currently recognized as the primary pathologic mechanism of meibomian gland dysfunction (MGD). This research figured out a method to isolate the MG ducts and established a novel system to culture the human meibomian gland ductal cells (HMGDCs) for investigating the process of MGD.

Methods

The MG ducts were obtained from the eyelids of recently deceased donors and subjected to enzymatic digestion. The acini were then removed to isolate independent ducts. These MG ducts were subsequently cultivated on Matrigel-coated wells and covered with a glass plate to obtain HMGDCs. The HMGDCs were further cultivated until passage 2, and when they reached 60% confluence, they were treated with IL-1β and rosiglitazone for a duration of 48 hours. Immunofluorescence staining and Western blot techniques were employed to identify ductal cells and analyze the effects of IL-1β on HMGDCs in an in vitro setting.

Results

Ophthalmic micro-forceps and insulin needles can be employed for the purpose of isolating ducts. Within this particular culture system, the rapid expansion of HMGDCs occurred in close proximity to the duct tissue. MG ducts specifically expressed keratin 6 (Krt6) and hardly synthesized lipids. Furthermore, the expression of Krt6 was significantly higher (P < 0.0001) in HMGDCs compared to human meibomian gland cells. Upon treatment with IL-1β, HMGDCs exhibited an overexpression of keratin 1, which was effectively blocked by the administration of rosiglitazone.

Conclusions

The present study successfully isolated human MG ducts and cultured HMGDCs, providing a valuable in vitro model for investigating the mechanism of MGD. Additionally, the potential therapeutic efficacy of rosiglitazone in treating hyperkeratinization of ducts in patients with MGD was identified.

Review of Literature on Intraductal Meibomian Gland Probing with Insights from the Inventor and Developer: Fundamental Concepts and Misconceptions

Obstructive Meibomian gland dysfunction (MGD) affects millions of patients around the world. Its effective treatment with intraductal meibomian gland probing (MGP), was first reported in 2010. Since then, MGP has provided relief to thousands of patients globally suffering with refractory MGD. The purpose of Meibomian gland probing is restoring the integrity of the gland's central duct by entering the gland through the natural orifice, releasing fixed obstruction thought to be periductal fibrosis, thereby establishing and/or confirming the patency of the duct, and concurrently equilibrating intraductal pressure as well as promoting gland functionality with meibum production. There may or may not be immediate secretion of meibum upon successful restoration of ductal integrity depending on the gland's state of function and degree of atrophy. One double-blind placebo-controlled study has been conducted and, with the accumulated evidence of over 12 other peer reviewed articles in the scientific literature, overwhelmingly indicates that MGP is a safe and effective treatment for the MGD patient refractory to prior standard care and as a first-line treatment. This paper describes relevant fundamental concepts, dispels commonly held misconceptions, and provides an objective review of the current understanding and effectiveness of MGP for the treatment of obstructive MGD. Our analysis will better equip clinicians to draw informed conclusions about both subjective and objective findings reported in MGP studies and researchers to design future robust studies that provide meaningful results.

Successful reversal of neuropathic eye pain by treatment of occult ocular surface disease: Case series and implications

Purpose

To report the successful approach to managing neuropathic dry eye-like pain (NP) in three consecutive patients described as severe: 1) “burning fire,” “burning acid,” and “horrible burning pain” with hyperalgesia and allodynia, 2) refractory to topical anesthetic (TA), and 3) without surface hyperemia nor vital staining.

Observations

Two of three patients' pain was reversed with significant symptom relief within 48 hours by identification of occult obstructive Meibomian gland dysfunction (o-MGD) and treatment using Meibomian gland probing (MGP) with intraductal steroid lavage (MGP_(s)) and aqueous tear deficiency (ATD) treated with punctal thermocautery (PO). The third patient's pain was reversed within one week after treatment of superior conjunctivochalasis (CCh) using amniotic membrane surface reconstruction and ATD using PO with subsequent MGP and MGP_(s) for o-MGD.

Conclusions and importance

It has been generally thought that central (NP) is strongly suggested by triad of 1) severe chronic burning pain with hyperalgesia and allodynia, 2) refractory to TA with 3) minimal signs. In this three-case series, treatment of occult surface disease consistently led to symptom reversal. Results may represent salutary effect of successful treatment to suppress nociceptive inflammation leading to reversal of central NP. Alternatively, the current triad of diagnostic criteria may be unable to differentiate centralized NP from peripheral sensitization alone, thereby requiring rigorous examination to uncover occult, yet treatable, surface disease to restore eye comfort and reverse psychosocial sequelae when possible. Furthermore, rigorous targeting of surface disease in patients with this pain triad may obviate unnecessary systemic treatments with associated risks of serious side effects.

Intraductal meibomian gland probing and its efficacy in the treatment of meibomian gland dysfunction

Meibomian gland dysfunction (MGD) is a major cause of dry eye, affecting millions worldwide. Intraductal meibomian gland probing (MGP) aims to open obstructed meibomian glands using a small probe to promote meibum secretion. MGP has received increasing interest since 2010, and we critically evaluated the literature on the efficacy and safety of MGP. Despite positive results of MGP on dry eye symptoms in early single-group studies, MGP was not shown to consistently outperform controls in later controlled trials. Furthermore, MGP alone did not show improvement beyond placebo in the only placebo-controlled RCT conducted. Overall, the procedure appears safe. Self-limited intraoperative bleeding was frequent, but no major complications were reported. In conclusion, MGP has not yet been shown to be an effective treatment for MGD. Larger placebo-controlled trials need to be conducted to establish the potential effect of this novel treatment modality.

Meibography guided intraductal meibomian gland probing using real-time infrared video feed

Purpose

To evaluate use of infrared meibography video to visualise meibomian gland probing and correlate probe findings of intraductal space with meibography images.

Methods

Videos were reviewed and probe findings recorded of 996 probed gland orifices from 38 lower lids.

Results

996/997 (99.9%) of gland orifices were successfully probed with 91.8% revealing probe location. There were no false passages. 14% (140/997) of all gland orifices showed whole gland atrophy (WGA) with 99.3% (139/140) probed to 1 mm. Cumulative probe findings for all WGA (not differ significantly from non-WGA) showed 106 (76%), 21 (15%) and 12 (9%) glands with fixed, non-fixed and no resistance (NR), respectively. Lids without WGA showed increased NR/total glands probed while lids with WGAs (≥5) showed increased NR/WGA compared with lids with only 1–4 WGAs (p=0.011, p=0.005, respectively, Mann-Whitney U test) suggesting bimodal NR profile. Visualisation of microtube placement was successfully obtained for therapeutic injections and retrieval of meibum specimens.

Conclusion

Video confirmed intraductal location and safety of devices. For 73% of non-WGA and 76% of WGAs as well as proximal ducts of glands with proximal atrophy, probing released fixed resistance restoring ductal integrity. A bimodal profile of NR suggests it is found with less diseased gland ducts as well as more advanced atrophic gland disease. Gland and ducts appeared flexible but not distendable while periglandular tissue appeared spongy. Visualisation of devices enables whole or localised gland therapy and meibum specimen retrieval, elegantly raising future research, therapeutic and regenerative opportunities.

Intraductal meibomian gland probing: background, patient selection, procedure, and perspectives

Obstructive meibomian gland dysfunction is the most common cause of dry eye. Its conventional treatment has focused on using heat and pressure with anti-inflammatory and antimicrobial therapies but has often been a frequent, frustrating experience for patient and physician. New evidence from Meibomian gland intraductal probing suggests fixed intraductal strictures and obstruction correlating to periductal fibrosis first described in 1997. The use of intraductal probing has been reported, by this author and in at least ten independent peer-reviewed academic papers from around the world, to consistently lead to statistically significant improvement in signs and symptoms of gland dysfunction including cases refractory to other extensive treatments. This review will focus on the background of meibomian gland intraductal probing as well as patient selection, procedure, and perspectives.

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