Long-term follow-up after submandibular gland transplantation in severe dry eyes secondary to cicatrizing conjunctivitis

Enhancement of lacrimal gland cell function by decellularized lacrimal gland derived hydrogel

Sustainable treatment of aqueous deficient dry eye (ADDE) represents an unmet medical need and therefore requires new curative and regenerative approaches based on appropriatein vitromodels. Tissue specific hydrogels retain the individual biochemical composition of the extracellular matrix and thus promote the inherent cell´s physiological function. Hence, we created a decellularized lacrimal gland (LG) hydrogel (dLG-HG) meeting the requirements for a bioink as the basis of a LG model with potential forin vitroADDE studies. Varying hydrolysis durations were compared to obtain dLG-HG with best possible physical and ultrastructural properties while preserving the original biochemical composition. A particular focus was placed on dLG-HG´s impact on viability and functionality of LG associated cell types with relevance for a futurein vitromodel in comparison to the unspecific single component hydrogel collagen type-I (Col) and the common cell culture substrate Matrigel. Proliferation of LG epithelial cells (EpC), LG mesenchymal stem cells, and endothelial cells cultured on dLG-HG was enhanced compared to culture on Matrigel. Most importantly with respect to a functionalin vitromodel, the secretion capacity of EpC cultured on dLG-HG was higher than that of EpC cultured on Col or Matrigel. In addition to these promising cell related properties, a rapid matrix metalloproteinase-dependent biodegradation was observed, which on the one hand suggests a lively cell-matrix interaction, but on the other hand limits the cultivation period. Concluding, dLG-HG possesses decisive properties for the tissue engineering of a LGin vitromodel such as cytocompatibility and promotion of secretion, making it superior to unspecific cell culture substrates. However, deceleration of biodegradation should be addressed in future experiments.

Salivary Gland Transplantation as a Promising Approach for Tear Film Restoration in Severe Dry Eye Disease

With increased awareness of dry eye disease (DED), a multitude of therapeutic options have become available. Nevertheless, the treatment of severe DED remains difficult. In a patient whose DED is related to the loss of lacrimal function without severe destruction of the salivary glands, autologous transplantation of the latter as functioning exocrine tissue to rebuild a stable tear film is an attractive idea. All three major and minor salivary glands have been used for such transplantation. Due to the complications associated with and unfavorable prognosis of parotid duct and sublingual gland transplantation, surgeons now prefer to use the submandibular gland (SMG) for such procedures. The transplantation of the SMG not only has a high survival rate, but also improves dry eye symptoms and signs for more than 20 years post-surgery. The regulation of the secretion of the transplanted SMG is critical because the denervated SMG changes its mechanism of secretion. Innovative procedures have been developed to stimulate secretion in order to prevent the obstruction of the Wharton's duct and to decrease secretion when postoperative "epiphora" occurs. Among the minor salivary glands, the transplantation of the labial salivary glands is the most successful in the long-term. The measurement of the flow rates of minor salivary glands and donor-site selection are critical steps before surgery.

Surgical Procedures in the Treatment of Dry Eye Disease

Dry eye disease (DED) is a multifactorial disease affecting 5% to 50% in different populations. The most severe cases of DED are often caused by aqueous deficient dry eye disease (ADDE) due to lacrimal gland (LG) hypofunction. Many patients with severe ADDE do not experience adequate symptom relief from topical treatment, severely reducing their quality of life. The focus of this review is to describe the surgical interventions presently being used or investigated when topical treatment with eye drops is insufficient. The conventional surgical approach is to proceed to punctal occlusion or partial or total tarsorrhaphy. However, novel surgical procedures have been reported to have higher efficacy and patient satisfaction than conventional treatments. These procedures include amniotic membrane transplantation, transposition or transplantation of the salivary glands, and cell-based injections into the LG, each with strengths and weaknesses. Further development of these treatment modalities might prove pivotal in treating dry eye patients in the future.

Characteristics and management of vascular compromise after an organ transplantation surgery of the head and neck region: Analysis of 220 submandibular glands with autologous transplantation

BACKGROUND

Microvascular submandibular gland transplantation (SMGT) for severe dry eye disease (DED) has rarely been reported in the literature. The aim of this study was to report a case series of SMGT with the special focus on monitoring and management of postoperative vascular compromise.

METHODS

Using a retrospective single-cohort study design, the investigators enrolled a sample of DED patients undergoing SMGT in a Chinese university hospital during 1999 and 2021. The main outcomes were baseline and surgical data, post-operative manifestations, and surgical results. Descriptive, uni- and bivariate statistics were computed with the significant P < 0.05.

RESULTS

During the study period, 220 DED patients (55.9% female) with a mean age of 32.66±14.47 years underwent SMGT. Vascular compromises occurred in 27 grafted glands (12.3%; 22 venous compromises and 5 arterial compromises) at a median of 27 h(range, 3.3 to 288 h) after surgery. Harden texture and swelling of the covering skin flap of the donor indicated venous compromises, while some specific sign was absent for arterial compromise. The accompanying vein of the facial artery (FAV) as a donor's vein was associated with less vascular compromise compared to the anterior facial vein (AFV). Timely reexploration was performed in 25 glands (92.6%), with a salvaged rate of 48%, and more venous compromises were salvaged compared to artery compromises (54.6% vs. 0%, P = 0.047). Temporary hypersecretion on postoperative 2-5 days was noticed in the grafted glands with no or salvaged vascular compromise (Schirmer's test, 35 mm/5 min and 37 mm/5 min, respectively, P = 0.749), while they were absent for the 15 surgically failed grands (Schirmer's test 0 mm/5 min, P<0.001).

CONCLUSIONS

Vascular compromise appears to be a common complication of SMGT. Postoperative hypersecretion of the grafted glands may indicate good circulation, and the use of FAV as the donor's vein could help to decrease the risk of vascular compromise.

Ophthalmic Aspects of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis: A Narrative Review

The aim of our review article was to summarize the current literature on Stevens-Johnson syndrome (SJS) and its severe form, toxic epidermal necrolysis (TEN). SJS/TEN is a serious, rare multi-system, immune-mediated, mucocutaneous disease with a significant mortality rate that can lead to severe ocular surface sequelae and even to bilateral blindness. Restoration of the ocular surface in acute and chronic SJS/TEN is challenging. There are only limited local or systemic treatment options for SJS/TEN. Early diagnosis, timely amniotic membrane transplantation and aggressive topical management in acute SJS/TEN are necessary to prevent long-term, chronic ocular complications. Although the primary aim of acute care is to save the life of the patient, ophthalmologists should regularly examine patients already in the acute phase, which should also be followed by systematic ophthalmic examination in the chronic phase. Herein, we summarize actual knowledge on the epidemiology, aetiology, pathology, clinical appearance and treatment of SJS/TEN.

Microvascular anastomosis of the human lacrimal gland: a concept study towards transplantation of the human lacrimal gland

Introduction

Severe aqueous tear deficiency is caused by primary or secondary main lacrimal gland insufficiency. The transplantation of a human lacrimal gland could become a potential treatment option to provide physiological tears with optimal properties. To this end, we performed an ex vivo study to develop a surgical strategy that would ensure a vascular supply for a lacrimal gland transplant using microvascular techniques.

Material and methods

Five cadaver heads were used to perform a lateral orbitotomy in order to identify the vascular pedicle and the lacrimal gland itself. The principal feasibility and the time of the required surgical steps for an intraorbital microvascular re-anastomosis of the human lacrimal gland were documented. Patency and potential leakage of the anastomosis were tested with hematoxylin intraoperatively. Postoperatively, routine histological, as well as scanning electron microscopy (SEM) of the gland and vascular anastomosis, were performed.

Results

The vascular pedicle of all five glands could be isolated over a minimum stretch of at least 1 cm, severed, and successfully reanastmosed microsurgically. Time for arterial anatomization (n = 4) was 23 ± 7 min and 22 ± 3 min for the vein (p = 0.62). The total time for the entire microvascular anastomosis was 46 ± 9 min. All anastomosis were patent upon testing. SEM revealed well-aligned edges of the anastomosis with tight sutures in place.

Conclusion

Our study demonstrates as proof of principle the feasibility of intraorbital microvascular re-anastomosis of a human lacrimal gland within the presumed window of ischemia of this tissue. This should encourage orbital surgeons to attempt lacrimal gland transplantation in humans in vivo.

Current approaches for the regeneration and reconstruction of ocular surface in dry eye

Significant research revealed the preocular tear film composition and regulations that remain vital for maintaining Ocular surface functional integrity. Inflammation triggered by many factors is the hallmark of Ocular surface disorders or dry eyes syndrome (DES). The tear deficiencies may lead to ocular surface desiccation, corneal ulceration and/or perforation, higher rates of infectious disease, and the risk of severe visual impairment and blindness. Clinical management remains largely supportive, palliative, and frequent, lifelong use of different lubricating agents. However, few advancements such as punctal plugs, non-steroidal anti-inflammatory drugs, and salivary gland autografts are of limited use. Cell-based therapies, tissue engineering, and regenerative medicine, have recently evolved as long-term cures for many diseases, including ophthalmic diseases. The present article focuses on the different regenerative medicine and reconstruction/bioengineered lacrimal gland formation strategies reported so far, along with their limiting factors and feasibility as an effective cure in future.

Submandibular Gland Transplantation vs Minor Salivary Glands Transplantation for Treatment of Dry Eye: A Retrospective Cohort Study

PURPOSE

To compare submandibular gland (SMG) transplantation with minor salivary gland (MSG) transplantation for the treatment of different dry eye diseases (DED).

DESIGN

Retrospective clinical cohort study.

METHODS

A total of 73 refractory DED eyes were divided into 3 groups. Group A comprised 35 end-stage DED eyes that underwent SMG transplantation. Group B comprised 20 end-stage DED eyes with MSG transplantation. Group C comprised 18 non-end-stage DED eyes with MSG transplantation. Schirmer test (ST), tear break-up time (TBUT), corneal fluorescein staining (FL), and best-corrected visual acuity (BCVA) were measured before and after surgery.

RESULTS

Hospital length of stay, length of operation, and hospital fee were significantly higher in group A than in group B or C. Eyes in group A showed the most severe DED disease, with preoperative ST, TBUT, FL, and BCVA of 0.36 mm per 5 minutes, 0.03 seconds, 10.97, and 0.11, respectively, which improved significantly to 20.23 mm per 5minutes, 1.74 seconds, 7.58, and 0.2 at >2-year follow-up. Group B had similar baseline data, and significant but limited improvement only in the ST (0.55 mm per 5 minutes to 3.79 mm per 5 minutes) and FL (11.10 to 9.58) after the operation. Group C had better baseline ST, TBUT, FL, and BCVA of 0.89 mm per 5min, 3.49 seconds, 1.83, and 0.81, respectively, which improved significantly (except for BCVA) to 9.35 mm per 5min, 9.08 s, 0.53, and 0.89 after MSG transplantation.

CONCLUSION

SMG transplantation could be recommended to treat end-stage refractory DED. MSG transplantation may provide satisfying results for refractory DED with relatively less severe impairment of the eye.

Pseudopterygium: An Algorithm Approach Based on the Current Evidence

Pseudopterygium is a non-progressive conjunctival adhesion to the peripheral cornea secondary to a corneal-limbus damage. According to the literature, the main etiology is a previous eye trauma. Nevertheless, this could be biased by the existence of other underdiagnosed causes of pseudopterygium, some of which may have severe consequences for the integrity of the eye and patient’s life. This comprehensive literature review was performed based on a search on the PubMed and Google Scholar databases of relevant pseudopterygium published papers according to our current knowledge and seeks to gather the existing evidence about its diverse etiologies and clinical features, as well as to propose a diagnostic algorithm to simplify its correct approach.

Autologous versus allogeneic versus umbilical cord sera for the treatment of severe dry eye disease: a double-blind randomized clinical trial

PURPOSE

To measure the effects of Autologous serum (AS), Allogeneic Serum (HS) and Umbilical Cord serum (CS) eye drops in severe dry eye disease (DES), as well as to characterize and quantify several molecules in the three sera (albumin, fibronectin; Vitamin A and E; IgG, IgA and IgM; Transforming growth factor β; Epithelial growth factor).

METHODS

Randomized, double-blind, single-centre, three-arm (AS, HS and CS) clinical trial. Sixty-three subjects were included with severe DES, 21 in each arm of the study. Visual acuity, Schirmer test, Breakup time (BUT), lissamine green, fluorescein staining measurements and a questionnaire were performed prior to treatment, and after one-month and three-month follow-up.

RESULTS

There was a significant main effect of time on visual acuities, Schirmer and BUT tests and fluorescein and lissamine green staining measurements and questionnaire scores (p = 0.015, p = 0.002, p < 0.001, p < 0.001, p = 0.031 and p < 0.001, respectively), although there was no significant interaction between time and serum type, nor between serum type and the test performed. Regarding the concentration of molecules, in our study AS contained significantly higher concentrations of IgA, IgG and fibronectin whereas HS contained significantly higher concentration of IgM, vitamins A and E, TGF and albumin. Contrary to previous reports, CS did not show higher concentration of any of the molecules analysed.

CONCLUSIONS AND RELEVANCE

The three sera were effective in the treatment of severe DES. CS did not contain a higher proportion of molecules compared to AS/HS. More research is needed to assess the effect of AS in patients with DES and autoimmune diseases.

Therapie des Trockenen Auges

Die Therapie des Trockenen Auges stellt eine schwierige Aufgabe für den behandelnden Augenarzt dar. Fortschritte in unserem Verständnis der Risikofaktoren, der Ätiologie und Pathophysiologie des Trockenen Auges haben zu einer Weiterentwicklung der Behandlungsstrategien geführt. Vor Beginn der Therapie ist die korrekte Zuordnung in eine wässrig-muzinöse Tränenfilmdysfunktion (Mindersekretion), in eine lipidbedingte Tränenfilmdysfunktion (hyperevaporative Form durch eine abnormen Meibom-Drüsen-Physiologie) oder in eine variable Kombination wichtig. Unter Berücksichtigung aktueller Empfehlungen der DOG, des BVA und des TFOS DEWS II Unterausschusses wurde ein Behandlungsalgorithmus abgeleitet, der ein schrittweises Vorgehen je nach Schweregrad der Erkrankung darstellt.

Global Consensus on the Management of Limbal Stem Cell Deficiency

PURPOSE

In recent decades, the medical and surgical treatment of limbal stem cell deficiency (LSCD) has evolved significantly through the incorporation of innovative pharmacological strategies, surgical techniques, bioengineering, and cell therapy. With such a wide variety of options, there is a need to establish a global consensus on the preferred approaches for the medical and surgical treatment of LSCD.

METHODS

An international LSCD Working Group was established by the Cornea Society in 2012 and divided into subcommittees. Four face-to-face meetings, frequent email discussions, and teleconferences were conducted since then to reach agreement on a strategic plan and methods after a comprehensive literature search. A writing group drafted the current study.

RESULTS

A consensus in the medical and surgical management of LSCD was reached by the Working Group. Optimization of the ocular surface by eyelid and conjunctival reconstruction, antiinflammatory therapy, dry eye and meibomian gland dysfunction treatment, minimization of ocular surface toxicity from medications, topical medications that promote epithelialization, and use of a scleral lens is considered essential before surgical treatment of LSCD. Depending on the laterality, cause, and stage of LSCD, surgical strategies including conjunctival epitheliectomy, amniotic membrane transplantation, transplantation of limbal stem cells using different techniques and sources (allogeneic vs. autologous vs. ex vivo-cultivated), transplantation of oral mucosal epithelium, and keratoprosthesis can be performed as treatment. A stepwise flowchart for use in treatment decision-making was established.

CONCLUSIONS

This global consensus provides an up-to-date and comprehensive framework for the management of LSCD.

Disease-Induced Changes in Salivary Gland Function and the Composition of Saliva

Although the physiological control of salivary secretion has been well studied, the impact of disease on salivary gland function and how this changes the composition and function of saliva is less well understood and is considered in this review. Secretion of saliva is dependent upon nerve-mediated stimuli, which activate glandular fluid and protein secretory mechanisms. The volume of saliva secreted by salivary glands depends upon the frequency and intensity of nerve-mediated stimuli, which increase dramatically with food intake and are subject to facilitatory or inhibitory influences within the central nervous system. Longer-term changes in saliva secretion have been found to occur in response to dietary change and aging, and these physiological influences can alter the composition and function of saliva in the mouth. Salivary gland dysfunction is associated with different diseases, including Sjögren syndrome, sialadenitis, and iatrogenic disease, due to radiotherapy and medications and is usually reported as a loss of secretory volume, which can range in severity. Defining salivary gland dysfunction by measuring salivary flow rates can be difficult since these vary widely in the healthy population. However, saliva can be sampled noninvasively and repeatedly, which facilitates longitudinal studies of subjects, providing a clearer picture of altered function. The application of omics technologies has revealed changes in saliva composition in many systemic diseases, offering disease biomarkers, but these compositional changes may not be related to salivary gland dysfunction. In Sjögren syndrome, there appears to be a change in the rheology of saliva due to altered mucin glycosylation. Analysis of glandular saliva in diseases or therapeutic interventions causing salivary gland inflammation frequently shows increased electrolyte concentrations and increased presence of innate immune proteins, most notably lactoferrin. Altering nerve-mediated signaling of salivary gland secretion contributes to medication-induced dysfunction and may also contribute to altered saliva composition in neurodegenerative disease.

Lateral Canthal Sling Procedure for Meibomian Gland Dysfunction? Results of a Pilot Study

Background: Involutional changes of lid structures often induce horizontal lid laxity; this can result in a reduction of Meibomian gland expression, potentially leading to symptoms of dry eye. The aim of this study was to evaluate the effect of tightening the lower eyelid via a lateral canthal sling (LCS) procedure on dry eye parameters.Methods: Patients with Meibomian Gland Dysfunction (MGD), lower lid laxity (positive Snap-back Test and positive Pinch Test) and no previous lid surgery were evaluated before and 3 months after LCS procedure for symptoms by OSDI. The fellow eye without surgery functioned as a control group. MGD parameters included lipid layer thickness (LLT), non-invasive breakup time (NIBUT), tear meniscus height, loss of Meibomian glands, lid margin parallel conjunctival folds (LIPCOFs), Schirmer's test, the number of expressible Meibomian glands as well as quality of Meibum.Results: Fourteen patients (8 men and 6 women; 79.2 ± 4.0 years) were enrolled in this prospective clinical study. After 3 months, the OSDI showed a significant reduction (preop 42.9 ± 24.7; postop 23.8 ± 21.6; p = .002); NIBUT (5.5 ± 2.6 s to 9.9 ± 6.8 s p = .08) and LLT (64.3 ± 30.4 to 74.1 ± 27.8; p = .025) improved, while Schirmer Test (15.3 ± 4.7 mm to 11.9 ± 2.9 mm; p = .03) and tear meniscus height were reduced (0.8 ± 0.3 to 0.6 ± 0.2; p = .05). Meibomian gland loss scored by the meiboscale slightly increased postoperatively (1.2 ± 0.9 to 1.4 ± 0.9; p = .18). The number of expressible Meibomian glands improved (4.4 ± 2.6 to 6.8 ± 2.1, p = .002) as well as the quality of Meibum (0.9 ± 1.0 to 0.5 ± 0.8, p = .04). Snap back test as well the pinch test were negative in all patients postoperatively.Conclusion: Addressing lower lid laxity with an LCS procedure simultaneously enhances tear drainage, reduces tear film volume parameters and increases tear film stability results with an improvement of dry eye symptoms. It is likely that increased lower eyelid tension and thus excretory pressure on the Meibomian glands is responsible for these alterations.

Towards Lacrimal Gland Regeneration: Current Concepts and Experimental Approaches

Dry eye disease (DED) is a complex and multifactorial disease resulting in a continual cycle of tear hyperosmolarity and inflammation. Patients suffering from DED experience severe pain and visual impairments leading to a reduced quality of life. Aqueous-deficient dry eye (ADDE), mainly caused through a loss of functional lacrimal gland tissue, results in the most severe forms of DED. Despite a high prevalence, the current treatments remain palliative and may be insufficient to alleviate the symptoms. Consequently, investigations on experimental approaches for in situ lacrimal gland regeneration are of great clinical interest. This article reviews the current knowledge about processes involved in lacrimal gland regeneration, about lacrimal gland resident stem cells, and offers deductions about possible concepts for in situ lacrimal gland regeneration. Promising starting points might be the utilization of therapeutic proteins, such as bone morphogenetic protein 7, mesenchymal stem cells (MSC) or MSC-based treatments such as conditioned medium, lyophilized cell extracts or adult acinar cells. This review further summarizes current experimental approaches for the treatment of ADDE in animal models and patients. Approaches investigating side population stem cells, epithelial progenitor cells and MSC showed that the transplantation of these cells had therapeutic effects on ADDE. However, the most promising and best-studied experimental approach is the use of MSC for induction/enhancement of in situ lacrimal gland regeneration. Their immunomodulatory effects, low immunogenicity, promotion of tissue regeneration and involvement during spontaneous lacrimal regeneration are favorable traits for clinical applications. In addition, the efficacy and safety of allogeneic MSC transplantation have already been demonstrated in a small patient cohort.

Analysis of lacrimal gland derived mesenchymal stem cell secretome and its impact on epithelial cell survival

In situ regeneration of lacrimal gland (LG) tissue would be a promising approach to curatively treat dry eye disease (DED). Mesenchymal stem cells (MSC) exhibit therapeutic effects in a variety of pathological conditions and our group recently reported that their number increases in regenerating mouse LG. Since the therapeutic effects are suggested to arise from secreted trophic factors, the application of MSC-secreted proteins seems to be a promising approach to induce/enhance LG regeneration. Therefore, this study aims to optimize the isolation of murine LG-MSC and analyze their secretome to investigate its potential for LG epithelial cell survival in vitro. For optimization, LG-MSC were isolated by an explant technique or cell sorting and their secretome was investigated under normal and inflammatory conditions. Results showed that the secretome of MSC had beneficial effects on the viability of ethanol-damaged LG epithelial cells. Additional, Lipocalin-2, prosaposin, ras GTPase-activating protein-binding protein 1 (Rac1) and signal transducer and activator of transcription 1 (STAT1), proteins that were up-regulated under inflammatory conditions, further improved the cell survival of ethanol-damaged LG epithelial cells. Interestingly, recovery of cell viability was highest, when the cells were incubated with STAT1. Summarizing, this study identified promising proteins for further studies on LG regeneration.

Labial Salivary Gland Transplantation for Severe Dry Eye in a Rhesus Monkey Model

Purpose

To evaluate the effectiveness of autologous labial salivary gland with labial mucous membrane graft in a rhesus monkey model with severe dry eye.

Methods

Eight eyes of eight rhesus monkeys with severe dry eye were included. Four eyes underwent autologous labial salivary gland and mucous membrane graft (group 1) and four eyes served as controls (group 2). The ocular surface was evaluated before and after transplantation surgery (at 1, 4, 8, 12, and 24 weeks). Conjunctival impression cytology was performed before and 24 weeks after transplantation. Finally, a histological analysis of the cornea, conjunctiva, and transplanted grafts was performed.

Results

At inclusion (n = 8) the mean Schirmer test was 1.31 ± 0.53 mm, the mean fluorescein score was 4.7 ± 1.65, and the mean lissamine green staining was 4.38 ± 0.48. After transplantation, a significant increase in tear secretion was observed with the mean Schirmer test results in group 2 significantly higher than those observed for group 1 at all time points (P < 0.05). Similarly, fluorescein and lissamine green scores were significantly lower in group 2 than in group 1 at all time points after transplantation (P < 0.05). Impression cytology specimens showed severe conjunctival squamous metaplasia without goblet cells in both groups. Under light microscopy, no significant difference was observed between the cornea and the conjunctiva of the two groups.

Conclusions

Labial salivary gland transplantation provided a basal secretion of tears and improved ocular surface staining scores during the first 3 months in a severe rhesus monkey model of dry eye. However, this was not accompanied by major improvement of ocular surface tissues.

Chinese Abstract.

Oral mucosa grafting in periorbital reconstruction

To provide an extensive literature review on the clinical indications of oral mucosa grafts (OMG) and minor salivary gland grafts (MSGG) in periorbital reconstruction together with safe practice graft harvesting techniques to minimize donor-site morbidity. A literature review was performed by searching the databases of PUBMED, EMBASE, and COCHRANE library using the keywords: minor salivary glands; oral mucosal graft; orbit; and eye. The bibliographies of the pertinent articles were examined for additional papers. Indications for OMG include treatment of recurrent pterygia; socket contracture in anophthalmic patients; repair of eyelid deformities; ocular surface and fornix reconstruction following tumour resection, cicatricial ocular surface disorders, or chemical burns. More novel uses include repair of glaucoma aqueous drainage device erosions or leaking trabeculectomy blebs; scleral buckle exposure; and keratoprosthesis-related corneal melts as well as lining the dacryocystorhinostomy tract to prevent closure. Simultaneous MSGG transplantation may be used in the treatment of severe dry eyes or dry anophthalmic cavities. Harvesting from the inner cheek is preferred to lower lip as it causes less post-operative discomfort and neurosensory deficits. Suturing is recommended for smaller ovoid grafts as it allows less painful closure without tension, while larger rectangular defects are best left to heal by secondary intention. OMG and MSGG transplantation is a viable alternative to replace conjunctiva and restore the ocular surface. The donor site is readily accessible and widely available in most patients, grafting is fast and cheap, and the same site may undergo repeated harvesting with few donor site complications.

Synergistic effects of ischemic preconditioning and immediate post-conditioning in the protection against ischemia/reperfusion injury in rabbit submandibular glands

Submandibular gland autotransplantation is an effective approach for treating severe keratoconjunctivitis sicca. However, ischemia/reperfusion (I/R) injury, which inevitably occurs during transplantation, is involved in the hypofunction and structural damage that occur early after transplantation. Therefore, it is critical to identify effective strategies to ameliorate I/R injury in submandibular glands. In this study, we investigated the ability of immediate post-conditioning combined with ischemic preconditioning to attenuate I/R injury. We observed that after I/R injury, the level of reactive oxygen species was increased, inflammatory response was strengthened, and severe apoptosis had occurred. In addition, the salivary flow rate was greatly decreased. However, the pathogenesis of I/R injury was significantly ameliorated by ischemia post-conditioning or ischemia preconditioning treatments. In addition, the combination of ischemia preconditioning and post-conditioning achieved synergistic protective effects against I/R injury compared with ischemia preconditioning or ischemia post-conditioning alone. The secretion function was restored in the combination group. Furthermore, the combination treatment involved the same mechanisms of ischemia preconditioning or ischemia post-conditioning, including suppression of the inflammatory reaction and neutrophil accumulation, attenuation of oxidation stress, and inhibition of apoptosis. In conclusion, the combination of ischemia preconditioning and ischemia post-conditioning treatment is a simple and effective approach for treating I/R injury in submandibular glands.

Botulinum toxin A treatment of epiphora secondary to autologous submandibular gland transplantation

The aim of this study was to explore whether botulinum toxin A (BTXA) injection treats epiphora secondary to submandibular gland (SMG) transplantation for severe keratoconjunctivitis sicca. Fifteen patients with epiphora after SMG transplantation were separated to three groups, and received 15U, 20U and 25U BTXA injection in the transplanted SMG, respectively. Secretion of transplanted SMG was assessed subjectively by visual analogue scale (VAS) regarding epiphora, and objectively by Schirmer test. There were no significant differences in the 15-U BTXA group regarding the values of the VAS on epihora before and 1 month after BTXA injection. While in 20-U group and 25-U group, the values of VAS on epihora decreased significantly after BTXA injection, and lasted for 6months. Under resting conditions, the secretion of transplanted SMG decreased 64.4%, 73.0% and 78.0% in 15-U, 20-U and 25-U groups, respectively (P<0.01), in 1month after BTXA injection; significant secretion decreasing lasted 3months only in the 25-U BTXA group. BTXA injection can decrease the secretion of transplanted SMG significantly, relieving the symptoms of epiphora; 25U BTXA is a suitable dose to treat 'opportunistic epiphora' after SMG transplantation.

Autonomic reinnervation and functional regeneration in autologous transplanted submandibular glands in patients with severe keratoconjunctivitis sicca

Autologous submandibular gland (SMG) transplantation has been proved to ameliorate the discomforts in patients with severe keratoconjunctivitis sicca. The transplanted glands underwent a hypofunctional period and then restored secretion spontaneously. This study aims to investigate whether autonomic nerves reinnervate the grafts and contribute to the functional recovery, and further determine the origin of these nerves. Parts of the transplanted SMGs were collected from the epiphora patients, and a rabbit SMG transplantation model was established to fulfill the serial observation on the transplanted glands with time. The results showed that autonomic nerves distributed in the transplanted SMGs and parasympathetic ganglionic cells were observed in the stroma of the glands. Low-dense and unevenly distributed cholinergic axons, severe acinar atrophy and fibrosis were visible in the patients’ glands 4–6 months post-transplantation, whereas the cholinergic axon density and acinar area were increased with time. The acinar area or the secretory flow rate of the transplanted glands was statistically correlated with the cholinergic axon density in the rabbit model, respectively. Meanwhile, large cholinergic nerve trunks were found to locate in the temporal fascia lower to the gland, and sympathetic plexus concomitant with the arteries was observed both in the adjacent fascia and in the stroma of the glands. In summary, the transplanted SMGs are reinnervated by autonomic nerves and the cholinergic nerves play a role in the morphological and functional restoration of the glands. Moreover, these autonomic nerves might originate from the auriculotemporal nerve and the sympathetic plexus around the supplying arteries.

Regenerated nerves play a role in restoring the function of transplanted submandibular glands (SMGs) in treating dry eye syndrome. Dry eye syndrome, or keratoconjunctivitis sicca (KCS), is a leading cause of patients visiting ophthalmologists, and one effective treatment in severe cases is transplanting SMGs (to the temporal area). Autonomic nerves have an important function in maintaining the secretory function of salivary glands, and a team headed by Yan Zhang and Guang-Yan Yu at Peking University, China investigated whether those nerves underwent reinnervation (restoration of nerve control) with transplanted SMGs in KCS patients and in a rabbit model. The authors found that in both the patients and rabbit model, the transplanted SMGs were reinnervated and the regenerated nerves played a role in restoring the glands’ function. The findings offer new insights into managing SMG transplantation.

Management of duct obstruction in transplanted submandibular glands

BACKGROUND

Submandibular gland (SMG) transplantation is a successful treatment approach for patients with severe dry eye. However, duct obstruction can occur post-transplant.

METHODS

We studied nineteen patients with duct obstruction of transplanted SMGs, including five interventional modalities: stone removal; secretory stimulation (to mimic "internal irrigation" with substantial secretory flow); irrigation; surgical opening of stenosis and orifice reconstruction; cephalic vein bypass and Wharton's duct reconstruction.

RESULTS

A solitary stone was found and removed in one patient. Duct blockages like mucus plug were cleared by secretory stimulation in three patients, and by normal saline irrigation in two grafts. In the remaining 13 patients, irrigation failed and surgical opening was performed. Orifice reconstruction succeeded in six of the eight patients, whose stenosis was near the orifice. Wharton's duct reconstruction was successful in two of the five cases where stenosis was located in the middle segment of the duct.

CONCLUSION

Transplanted SMGs obstruct for various reasons. Stone, which is easy to diagnose and treat, should be excluded first. Non-organic blockage and stenosis were semblable in clinic. Therefore, subsequent steps should be a diagnostic/therapeutic trial of secretory stimulation, followed by irrigation; failure of these interventions suggests the diagnosis of duct stenosis, necessitating surgical recanalization.

Optimising tear replacement rheology in canine keratoconjunctivitis sicca

Dry eye is a substantial problem in a large number of human and canine patients. Numerous laboratory models for tear deficiency exist using genetically predisposed rodent models, animals treated with topical anti-muscarinics, or those kept in environments with increased air flow to produce the ocular surface changes seen in human patients. Canine keratoconjunctivitis sicca, seen in many thousands of dogs kept as companion animals, can provide a valuable spontaneous model for testing tear replacement medications that might better model disease in human patients, existing as it does in an outbred population that live in the same environments as their owners. Here the development of a crosslinked hyaluronic acid topical drop is described together with the results of trials on dogs with spontaneous keratoconjunctivitis sicca. Although hyaluronic acid in its native form in tear replacement drops shows a Newtonian rheology, the crosslinked product described here behaves in a non-Newtonian manner, with the same shear thinning shown by the tear film itself. The crosslinked product thus shows itself as a potentially valuable tear replacement medication for the human dry eye population as well as for dogs with the same condition.

Effect of computed tomographic venography on donor selection in submandibular gland transplantation in patients with severe dry eye

BACKGROUND

A reliable anterior facial vein (AFV, donor vein) is cardinal for the success of submandibular gland (SMG) transplantation. This study determined the impact of computed tomographic (CT) venography in identifying AFV variations for SMG transplantation.

METHODS

CT venography was performed in consecutive patients with severe dry eye prior to SMG transplantation in order to identify disadvantageous AFV variations for vascular anastomosis, namely, AFVs that did not drain the SMG and those that did not match the superficial temporal vein (STV, recipient vein; AFV:STV caliber ratio, ≥3). The CT results were compared with the intraoperative findings for the diagnostic accuracy.

RESULTS

Forty-two donors were included. Compared with the intraoperative findings, the CT results accurately identified AFV-STV caliber mismatches (P = 1.00; sensitivity and specificity, 100%). In the identification of AFVs not draining the SMG, CT showed 94.7% sensitivity and 100% specificity (P = 0.25). According to the CT findings, 10 contralateral SMGs with AFVs (23.8%), instead of ipsilateral donors, were selected for transplantations (conventionally ipsilateral donor was the first choice). The surgical success rate was 95.2% (40/42).

CONCLUSION

CT venography is valuable in determining disadvantageous AFV variations for anastomosis and choosing a reliable donor for SMG transplantation.

Paradigm shifts, peregrinations and pixies in ophthalmology

Human ingenuity is challenged by defending vision, our highest bandwidth sense. Special challenges are presented by the replacement or repair of highly specialized but scarce tissue within the constraints of transparency, tissue shape and alignment, tissue borders and pressure maintenance. Many, mostly destructive, surgical procedures were developed prior to an understanding of underlying pathophysiology. For a number of conditions, both reconstructive and destructive procedures co-exist, yet there are few guidelines as to the better approach. Because the consequences of these procedures may take many years to surface (consistent with a stem cell role in long-term tissue maintenance), guidance may be provided by the elucidation of underlying principles from these approaches. Illustrative examples from clinical, basic research and biotechnology, particularly relating to pterygium, ocular surface squamous neoplasia, dry-eye syndrome, corneal rehabilitation and replacement, cataract surgery, strabismus surgery and bionic eye research, are described. An unexpected consequence of bionic device development has been an appreciation of the sophistication of tissues being replaced, given the limitations of available biomaterials. Examples of how this has provided insights into ocular disease will be illustrated. Stem cell and biomaterial technologies are starting to impact at a time when cost-effectiveness is under scrutiny. Both efficacy and cost will need to be considered as these interventions are introduced. It appears that the paradigm shift rate is accelerating and there is evidence of this in ophthalmology. Lessons learned from the areas of destructive versus reconstructive surgery and the limitations of development of bionic replacements will be used to illustrate how new procedures and technologies can be developed.

Development and validation of the Chinese version of dry eye related quality of life scale

Background

To develop the Chinese version of quality of life scale for dry eye patients based on the Impact of Dry Eye on Everyday Life (IDEEL) questionnaire and to assess the reliability and validity of the developed scale.

Methods

The original IDEEL was adapted cross-culturally to Chinese language and further developed following standard procedures. A total of 100 Chinese patients diagnosed with dry eye syndrome were included to investigate the psychometric properties of the Chinese version of scale. Psychometric tests included internal consistency (Cronbach’s ɑ coefficients), construct validity (exploratory factor analysis), and known-groups validity (the analysis of variance).

Results

The Chinese version of Dry Eye Related Quality of Life (CDERQOL) Scale contains 45 items classified into 5 domains. Good to excellent internal consistency reliability was demonstrated for all 5 domains (Cronbach’s ɑ coefficients range from 0.716 to 0.913). Construct validity assessment indicated a consistent factorial structure of the CDERQOL scale with hypothesized construct, with the exception of “Dry Eye Symptom-Bother” domain. All domain scores were detected with significant difference across three severity groups of dry eye patients (P < 0.05) except for “Satisfaction with Treatment” domain, indicating good known-groups validity.

Conclusions

The results indicated that the CDERQOL scale is a reliable and valid instrument for patients with dry eye syndrome among Chinese population, and could be used as a supplementary diagnostic and treatment-effectiveness measure.

Electronic supplementary material

The online version of this article (doi:10.1186/s12955-017-0718-5) contains supplementary material, which is available to authorized users.

Effects of histatin-1 peptide on human corneal epithelial cells

Purpose

Ocular surface and corneal epithelial wounds are common and potentially debilitating problems. Ideal treatments for these injuries would promote epithelial healing without inflammation, infection and scarring. In addition the best treatments would be cost-efficient, effective, non-toxic and easily applied. Histatin-1 peptides have been shown to be safe and effective enhancers of epithelial wound healing in other model systems. We sought to determine whether histatin-1 peptides could enhance human corneal epithelial wound healing in vitro.

Methods

Histatin-1 peptides were applied to human corneal epithelial cells and compared over useful dose ranges in scratch assays using time-lapse microscopy. In addition, path finding analysis, cell spreading assays, toxicity and proliferation assays were performed to further characterize the effects of histatin-1 peptide on human corneal limbal epithelial (HCLE).

Results

Histatin-1 enhanced human corneal epithelial wound healing in typical wound healing models. There was minimal toxicity and no significant enhancement of proliferation of corneal epithelium in response to histatin-1 application. Corneal epithelial spreading and pathfinding appeared to be enhanced by the application of histatin-1 peptides.

Conclusions

Histatin -1 peptide may enhance migration of HCLE cells and wound healing in vitro. These peptides may have benefit in corneal epithelial wounds and need to be investigated further.

An Experimental Study on Botulinum Toxin Type A for the Treatment of Excessive Secretion after Submandibular Gland Transplantation in Rabbits

Objectives. To investigate whether botulinum toxin type A (BTXA) could control excessive secretion after submandibular gland (SMG) transplantation in rabbits and its possible mechanisms. Methods. A new SMG transplantation model was established in rabbit. 30 successfully constructed models were randomly assigned to five groups including control group and four experimental groups. Secretion outputs were used to analyze the effect of BTXA injection on excessive secretion. Hematoxylin and eosin (HE) staining, transmission electron microscopy (TEM), Western blot, and immunofluorescence were performed to analyze its possible mechanisms. Results. After BTXA injection, a significant decrease of excessive secretion after SMG transplantation was found in 2 and 4 weeks groups, but no significant effect on 12 and 24 weeks groups. HE and TEM results showed that BTXA led to morphological and ultrastructural changes of acinar cells of transplanted SMG. Western blot results suggested that BTXA decreased the aquaporin-5 (AQP5) protein expression after BTXA injection for 2 and 4 weeks. Immunofluorescence results showed that AQP5 protein was mainly expressed in the cytoplasm after BTXA injection for 2 and 4 weeks, which might indicate that BTXA promoted AQP5 expression from the cell membrane to cytoplasm. Conclusion. BTXA could effectively control excessive secretion after SMG transplantation in rabbits.

Review: The Lacrimal Gland and Its Role in Dry Eye

The human tear film is a 3-layered coating of the surface of the eye and a loss, or reduction, in any layer of this film may result in a syndrome of blurry vision and burning pain of the eyes known as dry eye. The lacrimal gland and accessory glands provide multiple components to the tear film, most notably the aqueous. Dysfunction of these glands results in the loss of aqueous and other products required in ocular surface maintenance and health resulting in dry eye and the potential for significant surface pathology. In this paper, we have reviewed products of the lacrimal gland, diseases known to affect the gland, and historical and emerging dry eye therapies targeting lacrimal gland dysfunction.

Stevens-Johnson syndrome: The role of an ophthalmologist

Stevens-Johnson syndrome (SJS) is an acute blistering disease of the skin and mucous membranes. Acute SJS leads to the acute inflammation of the ocular surface and chronic conjunctivitis. If not properly treated, it causes chronic cicatricial conjunctivitis and cicatricial lid margin abnormalities. Persistent inflammation and ulceration of the ocular surface with cicatricial complications of the lids leads to chronic ocular sequelae, ocular surface damage, and corneal scarring. The destruction of the glands that secrete the tear film leads to a severe form of dry eye that makes the management of chronic SJS difficult. The option that is routinely used for corneal visual rehabilitation, keratoplasty, is best avoided in such cases. We describe the management strategies that are most effective during the acute and chronic stages of SJS. Although treatments for acute SJS involve immunosuppressive and immunomodulatory therapies, amniotic membrane transplantation is also useful. The options for visual rehabilitation in patients with chronic SJS are undergoing radical change. We describe the existing literature regarding the management of SJS and highlight recent advances in the management of this disorder.

Effects of Capsaicin and Carbachol on Secretion From Transplanted Submandibular Glands and Prevention of Duct Obstruction

PURPOSE

To investigate whether capsaicin and carbachol promote secretion from and prevent duct obstruction in transplanted submandibular glands (SMGs).

METHODS

This retrospective cohort study included consecutive patients with severe keratoconjunctivitis sicca and successful SMG transplantation. Patients were divided into 2 groups: an exposed group receiving both capsaicin and carbachol after surgery and an unexposed group receiving neither. Secretion changes in response to capsaicin and carbachol administration were recorded in the exposed group. The main outcome measures were the secretory flow rate and duct obstruction rate in the transplanted SMGs.

RESULTS

Forty-four patients (44 eyes) in the unexposed group and 115 patients (128 eyes) in the exposed group were followed up for more than 3 months postoperatively. The baseline characteristics were similar between the groups. The secretory flow rate before and 5, 25, 55 minutes after administration was 1 mm (0-2 mm) (median with interquartile range), 3 mm (1-5 mm), 4 mm (2-5 mm), 1 mm (0-2.5 mm), respectively, for capsaicin and 1 mm (0-3 mm), 1050 mm (450-1500 mm), 375 mm (150-600 mm), 0 mm (0-150 mm), respectively, for carbachol (P < 0.001 for both). In the exposed group, 6.2% of eyes had duct obstruction, whereas 18.2% of eyes in the unexposed group had duct obstruction (P = 0.031) (odds ratio = 0.3, 95% confidence interval, 0.105-0.856).

CONCLUSIONS

This study provides evidence that capsaicin and carbachol effectively promote secretion from and prevent duct obstruction in transplanted SMGs during at least 3 months after transplantation.

Microvascular autologous submandibular gland transplantation in severe cases of keratoconjunctivitis sicca

Dry eye syndrome is a relatively common disease of the tears and ocular surfaces that results in discomfort, visual disturbance, and tear film instability with possible damage to the ocular surfaces. Microvascular submandibular gland (SMG) transfer offers a surgical alternative for a permanent autologous substitution of tears using the basal secretion of a transplanted SMG. Long-term follow-up reveals that this technique is a lasting and effective solution for patients with severe dry eye syndrome. The uncomfortable symptoms were relieved, and the frequency of use of pharmaceutical tear substitutes was reduced. Objective examination showed significant improvement in tear film and some features of ocular surface such as breakup time of tear film and corneal staining. Patients may suffer from obstruction of Wharton's duct or epiphora after surgery. Activation of secretion-related receptors could improve the early hypofunction of the denervated SMG and prevent the duct obstruction. Reduction surgery, partial SMG transplantation, uses of atropine gel or Botulinum toxin A could be the choices of treatment for epiphora.

Salivary gland scintigraphy in patients suffering from severe keratoconjunctivitis sicca. Evaluation of the viability of submandibular glands before and after transfer into the temporal fossa

Low tear production or elevated tear evaporation can lead to severe keratoconjunctivitis sicca. In patients with this disease, the transfer of an autologous submandibular gland into the temporal fossa is currently the most common surgical lacrimal gland substituting procedure.

AIM

We compared the pre- and postoperative viability of transferred submandibular glands.

PATIENTS, METHODS

Altogether 16 submandibular glands had been transferred in 12 patients. The graft's viability was evaluated before and 0.5-1, 1-6 and 8-12 months after transplantation by dynamic salivary gland scintigraphies after application of 40-50 MBq 99mTc-pertechnetate. Quantitative analysis was performed by calculation and comparison of the glandula submandibularis-to-background-ratio (SBR) and the transplant-to-background-ratio (TBR). The scintigraphic results were correlated with the clinical follow-up.

RESULTS

All grafts remained viable during clinical follow-up. Salivary gland scintigraphy yielded 15 true positive results and 1 false-negative result. Comparison of presurgical SBR and postsurgical TBR showed good correlation with the clinical course. In 10 patients at least one transplant-reduction was necessary due to excessive epiphora occurring averagely 8 months after transplantation.

CONCLUSION

Our results show that salivary gland scintigraphy very exactly reflects the morphological and biochemical postsurgical changes in a transferred submandibular gland. Thus, it is a reliable tool to exactly and objectively evaluate the viability of the grafts in the postsurgical course.