Qualitative Hormonal Profiling of the Lacrimal Drainage System: Potential Insights into the Etiopathogenesis of Primary Acquired Nasolacrimal Duct Obstruction

scRNA-Seq: First Atlas and Cellular Landscape of Lacrimal Sac: Implications in Primary Acquired Nasolacrimal Duct Obstruction Pathogenesis

Purpose

The aim of this study was to describe the transcriptional changes of individual cellular components in the lacrimal sac in patients with primary acquired nasolacrimal duct obstruction (PANDO) and attempt to construct the first lacrimal sac cellular atlas to elucidate the potential mechanisms that may drive the disease pathogenesis.

Methods

Lacrimal sac samples were obtained intra-operatively during the endoscopic dacryocystorhinostomy (EnDCR) procedure from five patients. Single-cell RNA sequencing was performed to analyze each individual cell population including epithelial and immune cells during the early inflammatory and late inflammatory phases of the disease.

Results

Eleven cell types were identified among 25,791 cells. T cells and B cells were the cell populations with the greatest variation in cell numbers between the two phases and were involved in immune response and epithelium migration-related pathways. The present study showed that epithelial cells highly expressed the genes of senescence-associated secretory phenotype (SASP) and were involved in influencing the inflammation, neutrophil chemotaxis, and migration during the late inflammatory stage. Enhanced activity of CXCLs-CXCRs between the epithelial cells and neutrophils was noted by the cell-cell communication analysis and is suspected to play a role in inflammation by recruiting more neutrophils.

Conclusions

The study presents a comprehensive single-cell landscape of the lacrimal sac cells in different phases of PANDO. The contribution of T cells, B cells, and epithelial cells to the inflammatory response, and construction of the intercellular signaling networks between the cells within the lacrimal sac has further enhanced the present understanding of the PANDO pathogenesis.

Microbiology and Antimicrobial Susceptibility in Adult Dacryocystitis

Purpose

To investigate the microbiology and antimicrobial susceptibility of dacryocystitis in adults and identify the changing trends over time in Taiwan.

Methods

This is a single-centered, retrospective study. We retrospectively reviewed adult patients with dacryocystitis from January 2012 to December 2021 in a tertiary medical center in Taiwan. The pathogens and in vitro antimicrobial susceptibility of the pus cultures from the lacrimal sac were collected.

Results

Thirty-five cultures in acute and 211 cultures in chronic dacryocystitis were collected. Of the 220 isolates, a similar proportion of gram-positive (44%) and gram-negative (43%) aerobes were demonstrated in chronic dacryocystitis and more gram-negative aerobes (50%) than gram-positive aereobes (41%) in acute dacryocystitis. The most common pathogens were methicillin-resistant Staphylococcus aureus (MRSA; 28.1%) and Pseudomonas aeruginosa (28.1%) in acute dacryocystitis, while coagulase-negative Staphylococci was the most common micro-organism in chronic dacryocystitis. The effective antibiotics for gram-positive aerobes were vancomycin (100%), moxifloxacin (88%) and trimethoprim/sulfamethoxazole (78%). Meropenem (95%), amikacin (93%), and levofloxacin (91%) were sensitive to more than 90% of gram-negative aerobes in current study. High resistant species were also isolated in our cohort.

Conclusion

More gram-negative pathogens and more resistant species are rising in adult dacryocystitis. Understanding the bacteriology and antimicrobial susceptibility of the region is crucial for the empirical antibiotic selection in clinical practice.

Familial Occurrence of Isolated Late-onset Nasolacrimal Duct Obstruction in Two Unrelated Families

Late-onset nasolacrimal duct obstruction (NLDO) as a result of inflammatory processes causing dacryo-stenosis is a common entity affecting mostly women. While a few mechanisms have been suggested as contributors to the expression of NLDO, the trigger for the inflammation remains mostly unknown. Familial predilection for this condition has not been previously reported. We present two families with multiple individuals affected with congenital or late-onset NLDO, describe the signs and symptoms of the affected individuals, and explore their medical history for any contributing factors. Family A, spanning four generations, included 7 female patients affected by late-onset NLDO. Family B, spanning two generations, included 8 individuals affected by either congenital or late-onset NLDO. This case series suggests a familial predisposition to NLDO, apparently with an autosomal dominant inheritance pattern. Further studies are needed to elucidate the molecular basis of this genetic predisposition.

Etiopathogenesis of primary acquired nasolacrimal duct obstruction (PANDO)

Primary acquired nasolacrimal duct obstruction, or PANDO, is a common adult lacrimal drainage disorder. The current treatment modality of dacryocystorhinostomy to bypass the obstructed nasolacrimal duct has excellent outcomes. However, the understanding of the disease etiopathogenesis needs to be revisited. There are not many studies that specifically assessed any hypothesis or ones that convincingly put forth the presumed or confirmed interpretations regarding the PANDO pathogenesis or the mechanisms or pathways involved therein. Histopathological evidence points to recurrent inflammation of the nasolacrimal duct, subsequent fibrosis, and the resultant obstruction. The disease etiopathogenesis is considered multifactorial. Several implicated suspects include anatomical narrowing of the bony nasolacrimal duct, vascular factors, local hormonal imbalance, microbial influence, nasal abnormalities, autonomic dysregulation, surfactants, lysosomal dysfunction, gastroesophageal reflux, tear proteins, and deranged local host defenses. The present work reviewed the literature on the etiopathogenesis of primary acquired nasolacrimal duct obstruction (PANDO) to gain insights into the present state of the understanding and the high-value translational implications of precisely decoding the disease etiology.

Balloon Dacryocystoplasty with Pushed Monocanalicular Intubation as a Primary Management for Primary Acquired Nasolacrimal Duct Obstruction

Given the improvement in the instrument and techniques, novel surgical interventions emerged to avoid the osteotomy from the gold standard dacryocystorhinostomy (DCR) for treating primary acquired nasolacrimal duct obstruction (PANDO). This study's aim is to compare the surgical outcomes of antegrade balloon dacryocystoplasty (DCP) with pushed monocanalicular intubation (MCI) to balloon DCP alone in patients with complete PANDO. Adult patients with complete PANDO receiving balloon DCP followed by pushed MCI or balloon DCP alone from December 2014 to May 2019 were retrospectively reviewed. A total of 37 eyes of 29 patients were treated with balloon DCP with pushed MCI for 1 month, whereas 35 eyes of 28 patients were treated with balloon DCP alone. The success rates at 1 month, 3 months, and 6 months after operation were 89.2%, 73.0%, and 70.2%, respectively, in balloon DCP with MCI group, and 62.9%, 62.9%, and 60.0%, respectively, in the balloon DCP alone group. The balloon DCP with pushed MCI group had a better success rate but only reached statistical significance at 1 month postoperatively (p < 0.01). Subgroup analysis was performed based on age. The success rate in those under 65 in the combined balloon DCP with MCI group was significantly higher than in balloon DCP alone group (72.7% vs. 9.1%, p = 0.004), whereas there was no significant difference between those aged at least 65 in the combined group and the balloon DCP alone group (69.2% vs. 83.3%, p = 0.2). Conclusively, there was no significant difference in the success rate between antegrade balloon DCP with and without pushed MCI in general. Nevertheless, the former procedure was associated with significantly higher surgical success rate than the latter in younger patients.

[Disorders of lacrimal drainage: the way from theory to practice]

The article summarizes the results of research conducted over the past decade concerning the current problems of dacryology, analyzes the improvements made to the methods of diagnostics used in disorders of lacrimal passages on the basis of modern imaging and functional studies, describes the techniques aimed at improving the clinical effectiveness of the intervention, as well as drug and non-drug methods of intraoperative prevention of excessive scarring in the area of the artificial ostium. The article also analyzes the experience of using balloon dacryoplasty in relapses of tear duct obstruction after dacryocystorhinostomy, and presents the modern minimally invasive surgical techniques, including nasolacrimal duct intubation, as well as balloon dacryoplasty and endoscopic plastic surgery of the ostium of the nasolacrimal duct. Additionally, the work lists the fundamental and applied tasks of dacryology and outlines promising directions of its development.

Quantitative analysis of both lacrimal glands in unilateral primary acquired nasolacrimal duct obstruction, based on three-dimensional fast spin echo-Cube-Flex

OBJECTIVE

To investigate whether unilateral primary acquired nasolacrimal duct obstruction (PANDO) changes the volume and water fraction of both lacrimal glands, using three-dimensional fast spin echo (3D-FSE)-Cube-Flex images, and to identify whether the lacrimal gland is a target organ in this disease.

METHODS

3D-FSE-Cube-Flex images of both lacrimal glands in 25 healthy volunteers and 31 patients with unilateral PANDO were retrospectively reviewed. The differences in volume and water content in the lacrimal glands between the controls, non-PANDO side, and PANDO side groups were examined. Moreover, the associations between magnetic resonance imaging (MRI) parameters and disease duration were assessed with correlation analysis.

RESULTS

The lacrimal gland volumes were not significantly different between the PANDO and non-PANDO side groups, compared to the control group (P = 0.484). However, the gland volumes tended to be increased bilaterally in patients with PANDO. In contrast, the gland water fractions in the PANDO and non-PANDO side groups were significantly higher than those in the control group (P = 0.009 and P = 0.014, respectively), and similar between the non-PANDO and PANDO side groups (P = 0.897). No correlation was found between the disease duration and the gland MRI parameters (volume and water fraction).

CONCLUSIONS

Both lacrimal glands are affected by unilateral PANDO. A change in the water fraction of these glands appears to precede the change in volume and may be a sensitive early indicator.

Endoscopic dacryocystorhinostomy with short-term, pushed-type bicanalicular intubation vs. pulled-type monocanalicular intubation for primary acquired nasolacrimal duct obstruction

Dacryocystorhinostomy (DCR) has been a primary treatment for adults with nasolacrimal duct obstruction, while the optimal approach and technique remain controversial. With the advancement of endoscopic DCR and the silicone stents, an update of the surgical outcomes and preferable approaches is required. This study aims at comparing the surgical outcomes of endoscopic DCR using pushed bicanalicular intubation (BCI) to pulled monocanalicular intubation (MCI) in adults with primary acquired nasolacrimal duct obstruction (PANDO). Forty five eyes of 45 patients were enrolled, including 22 eyes of 22 patients treated with endoscopic DCR with pulled MCI and 23 eyes of 23 patients with pushed BCI from January 2014 to June 2021. The success rates at stent removal, 1 month and 3 months after removal were 95, 91, and 82%, respectively, in the MCI group, and 100, 87, and 87% in the BCI group. The BCI group had better success rates but failed to reach a significant difference (p = 0.49, p = 0.67, p = 0.24, respectively). After analyzing with binary logistic regression, the implant material was demonstrated as the predictive of surgical success (p = 0.045). There was no significant difference in success rates between patients with dacryocystitis and those without dacryocystitis. We conclude that endoscopic DCR with pushed BCI is easily manipulated and has a promising surgical outcome over pulled MCI. Stent indwelling duration as well as history of dacryocystitis have less influence on the success rates.

Prolactin Inducible Protein, but Not Prolactin, Is Present in Human Tears, Is Involved in Tear Film Quality, and Influences Evaporative Dry Eye Disease

Purpose

Decreased production of the aqueous component of the tear film is an important cause of the development of dry eye disease (DED). Tear production is influenced by hormones and hormone-like factors. Prolactin (PLR), a multifunctional pituitary gland hormone, is regularly present in the lacrimal gland of rats and rabbits. In humans, serum PLR concentration correlates with tear quality. To gain deeper insights of possible effects of PRL, prolactin receptor (PRLR) and prolactin inducible protein (PIP), we analyzed the three proteins in the human lacrimal apparatus and in reflex tears of healthy volunteers as well as patients suffering from DED.

Methods

Gene expression of PRLR and PIP was analyzed by RT-PCR in cadaveric human lacrimal gland and ocular surface tissues, immortalized human corneal epithelial cells (HCE and hTEPI) and human Meibomian gland epithelial cells (HMGECs). At the protein level, the expression and localization of PRL, PRLR and PIP in formalin-fixed paraffin sections of the lacrimal apparatus were studied by immunohistochemistry. In addition, tear fluid from DED patients and healthy volunteers was analyzed by ELISA to determine the concentration of PRL and PIP.

Results

RT-PCR analyses revealed gene expression of PRLR and PIP in human tissue samples of cornea, lacrimal glands, and eyelids, whereas only PIP, but not PRLR, was detectable in immortalized corneal epithelial cells. Immunohistochemistry revealed for the first time the expression and localization of PRL, PRLR, and PIP in human tissues of the lacrimal apparatus and at the ocular surface. PRL and PRLR were detectable in corneal epithelium, lacrimal glands, and Meibomian glands. Reflex tears from DED patients revealed significantly increased PIP concentrations, whereas PRL was undetectable in tears of DED patients and healthy volunteers.

Conclusion

PRL, PRLR, and PIP are found in the lacrimal apparatus and on the ocular surface. PIP, but not PRL, is present in human tears and appears to be involved in the physiology of tear film quality. Our clinical data revealed that PIP may affect tear quality, but further functional analyses are needed to fully elucidate the effects of PRL and PIP-associated factors in tear secretion as well as in the connection of DED.

Lacrimal sac diverticulum: clinical presentation and endoscopic management

BACKGROUND

To describe the clinical presentation, surgical intervention and clinical outcomes of patients with a lacrimal sac diverticulum.

METHODS

Retrospective chart review of all patients who underwent endonasal endoscopic dacryocystorhinostomy (DCR) in a single medical center from January 2010 to October 2020. The diagnosis of a lacrimal sac diverticulum was based upon intraoperative findings.

RESULTS

In total, 406 patients underwent endonasal endoscopic DCR during the study period. Eight female patients (mean age 35 years) were diagnosed with a lacrimal diverticulum and underwent DCR by an endonasal endoscopic approach. The mean follow-up period was 11.5 months. All eight patients had cystic findings at the lacrimal fossa on imaging studies prior to surgery. Five patients had a history of dacryocystitis. The main presenting symptoms were epiphora and/or medial canthal swelling. The diverticulum was identified on the inferior wall in seven cases. A dacryolith in the lacrimal sac was identified intraoperatively in two patients. All patients showed full resolution of symptoms after surgery. There were no intraoperative or postoperative complications.

CONCLUSION

Lacrimal sac diverticulum is a rare entity with female predominance. It may be the underlying etiology of epiphora and/or dacryocystitis. The diagnosis is based upon identifying the presence of a diverticulum intraoperatively. Endoscopic DCR is an effective approach for integrating both the lacrimal sac and diverticulum cavities into a single space, leading to resolution of symptoms.

Altered Surfactant Protein Expression in Primary Acquired Nasolacrimal Duct Obstruction

PURPOSE

To investigate the presence and distribution patterns of 6 surfactant proteins in lacrimal drainage tissues of patients with primary acquired nasolacrimal duct (NLD) obstruction.

METHODS

The presence and distribution of surfactant proteins (SP)-G and SP-H was first assessed in normal cadaveric lacrimal systems. The study was then performed in 10 samples of lacrimal sac and the respective NLDs obtained from patients suffering from primary acquired NLD obstruction who underwent either a dacryocystorhinostomy or a dacryocystectomy. The lacrimal sac samples were further divided into fundus and body, soon after their removal. Immunohistochemical labeling was performed for assessing the presence and distribution of SPs: SP-A, SP-B, SP-C, SP-D, SP-G/SFTA2, and SP-H/SFTA3. The results were then scored as positive or negative and the distribution pattern, if any, within the lacrimal sac and NLDs was assessed. Human lung tissues were used as controls.

RESULTS

SP-H was demonstrated in the lining epithelia of the normal lacrimal drainage systems, whereas SP-G was uniformly negative. Immunohistochemical labeling revealed wide variations in the staining patterns of different SPs in different regions of the lacrimal sac and the NLD. SP-D and SP-G revealed uniformly negative immunoreactivity. Variable staining patterns were also noted between the superficial and basal layers of the lining epithelia. However, the goblet cells and intraepithelial mucous glands did not express any of the SPs.

CONCLUSIONS

This study provides a proof of principle for the presence of SP-H and absence of SP-G in the normal lacrimal drainage systems. In cases of primary acquired nasolacrimal duct obstruction, there were alterations or loss of SP expression in the lining epithelia of the lacrimal sac and NLDs, reflecting their possible role in the etiopathogenesis of primary acquired nasolacrimal duct obstruction.In cases of primary-acquired nasolacrimal duct obstruction, the expression of multiple surfactant proteins was either deranged or lost in the lining epithelium of the lacrimal sac and nasolacrimal ducts.

Etiopathogenesis of Primary Acquired Nasolacrimal Duct Obstruction: What We Know and What We Need to Know

PURPOSE

To provide a systematic review of the literature on the etiopathogenesis of primary acquired nasolacrimal duct obstruction (PANDO).

METHODS

The authors performed a PubMed search of all articles published in English with specific reference to etiopathogenesis of PANDO or associations of PANDO. Data captured include demographics, study techniques, hypothesis, presumed or confirmed interpretations with regards to pathogenesis, mechanisms, or pathways. Specific emphasis was laid on addressing the lacunae and potential directions for future research.

RESULTS

Numerous factors are believed to contribute to the etiopathogenesis of PANDO. The basic pathogenesis involves inflammation, vascular congestion, mucosal edema, fibrosis, obstruction, and stasis. Bony nasolacrimal duct diameter does not appear to play a significant role. There is no convincing data to substantiate nose as the site of disease origin and nasal factors appear to be comorbidities. Hormonal mechanisms are more evidence-based but can only partly explain the pathogenesis. Vascular theories are based on the behavior of perilacrimal cavernous bodies, their autonomic control, and additional structural changes in the helical patterns of connective tissue fiber arrangements. Repeated vascular malfunction leading to structural epithelial and subepithelial changes currently appears to be the most evidence-based and accepted theory. Tear proteomics holds a promise in decoding the etiopathogenesis of PANDO, at least in part.

CONCLUSIONS

The etiopathogenesis of PANDO appears to be multifactorial. Hormonal microenvironments, vascular factors, and tear proteomics are promising candidates for further work. There is a need for focused work by Clinician-Scientists and the answers can have far reaching clinical implications.

Soluble glycoproteins of the lacrimal sac: role in defense with special reference to prolactin-inducible protein (PIP)

Purpose: Glycoproteins play an important role in human mucosal defenses and immunity-related cell-to-cell interactions. The aim of the present study is to investigate the presence and patterns of lacrimal sac glycoproteins involved in defense mechanisms with a special reference to prolactin-inducible protein (PIP). Methods: The study was performed on healthy lacrimal sacs obtained from exenteration samples immediately after surgery and frozen at -80 degrees for subsequent analysis. Four lectins namely Concanavalin A (Con A), Dolichos lablab lectin (DLL), Wheat Germ agglutinin (WGA), and Momordica charantia lectin (MCL) were purified by affinity chromatography. Soluble proteins extract of the lacrimal sac was subjected to chromatography on lectin-affigel columns. Eluted samples from each of the lectin coupled-affigels were analyzed by 10% SDS-PAGE under reducing conditions and the protein bands were visualized using Coomassie blue stain. The protein gel bands were further subjected to mass spectrometry for glycoprotein analysis. Results: Mass spectrometry identified several glycoproteins from the lacrimal sac extracts, with known roles in defense mechanisms. The number of such glycoproteins identified were 9 each from Con A and DLL-I affinity eluted gel bands and 8 and 14 from MCL and WGA affinity eluted gel bands, respectively. Interestingly, PIP was detected in significant proportions in all the eluted gel bands with WGA showing the highest expression. Conclusions: This study is the first step towards the lacrimal sac glycoprotein profiling. PIP could be a major lead for further work on the etiopathogenesis of lacrimal drainage obstructions.

Pathological changes of the nasolacrimal duct in rabbit models of chronic dacryocystitis: correlation with lacrimal endoscopic findings

PURPOSE

The aim of this study was to explore the pathological changes of the nasolacrimal duct in rabbits with experimentally induced obstructive dacryocystitis in correlation with lacrimal endoscopic findings.

METHODS

The rabbit model of obstructive dacryocystitis was created by injecting 0.15 ml of self-curing resin into the lacrimal duct. The control group received 0.15 ml of normal saline. Within 16 weeks after the obstructive, lacrimal endoscopy and pathological examination of the nasolacrimal duct were conducted at different time points of 1, 2, 4, 8, and 16 weeks.

RESULTS

In the control group, lacrimal endoscopy revealed pink and smooth mucosa; and the pathological analysis revealed an epithelial layer that was composed of superficial columnar cells and a deep basal epithelial layer. The experimental rabbits showed clinical manifestations of obstructive dacryocystitis a week after the injection of self-curing resin. At weeks 1 and 2, the lacrimal endoscopy showed mucosal hyperemia and hemorrhagic spots on the nasolacrimal duct; and the pathological features included epithelial cell swelling and inflammatory cell infiltration. At weeks 4 and 8, the experimental group showed alternatively red and white mucosa under the lacrimal endoscopy, and the pathological features included proliferative epithelium accompanied by papillary hyperplasia. At week 16, the experimental group showed pale and coarse mucosa and white membrane-like layer covering the mucosal surface, and the pathological features included epithelial necrosis, squamous metaplasia, and sub-epithelial fibrosis.

CONCLUSION

The mucosa of the nasolacrimal duct showed different pathological features at different time points after lacrimal duct obstruction, which was well correlated with the endoscopic findings. It is possible to predict the pathological stages by the endoscopic observation in NLOD patients.