The Posthyaluronidase Syndrome: Dosing Strategies for Hyaluronidase in the Dissolving of Facial Filler and Independent Predictors of Poor Outcomes.

Background: Hyaluronic acid dermal fillers are used extensively in periocular aesthetic medicine, and the incidence of filler-related complications is increasing. This study aimed to investigate the optimal dosing strategy for hyaluronidase and to identify predictors of poor outcomes. Methods: We performed a retrospective review of 157 orbits of 90 patients treated with hyaluronidase over a 4-year period. Demographic data, indication, and details of hyaluronidase treatment and outcomes were recorded. Results: The primary indication for dissolving filler was swelling in 52%, lumpiness in 20%, and before surgical blepharoplasty in 17%. The most frequently used hyaluronidase concentration was 150 U per mL in 66%, followed by 75 U per mL in 31%, 37.5 U per mL in 3%, and 100 U per mL in 1%. Outcomes were characterized as follows: 59% with a satisfactory result; 24% as insufficient treatment requiring further hyaluronidase; and 18% complaining of facial changes such as hollowing, indicating a post hyaluronidase syndrome. There was no statistical difference in outcomes between the 75 and 150 U per mL dosage groups (P = 0.625). A significant correlation was identified between posthyaluronidase syndrome and duration of filler in situ (P = 0.00019) and volume of filler (P = 0.000017). Conclusions: The posthyaluronidase syndrome may be related to previous filler volume and duration, rather than the concentration or dose of hyaluronidase used. All patients should be informed about the risks of adverse effects after hyaluronidase treatment; patients with longer histories of filler use and higher total volumes should be advised of the increased risk.

Combined upper lid skin crease and endoscopic approach to frontal sinus mucocoeles.

PURPOSE: This case series describes the ophthalmic manifestations of frontal sinus mucoceles and reports the long-term surgical outcomes of a combined endoscopic and upper-lid skin crease drainage approach carried out jointly with otorhinolaryngology. METHODS: We present a retrospective case review of 18 orbits and 15 patients presenting with frontal sinus mucocoeles, all of whom underwent drainage via an adapted anterior orbitotomy approach between January 2015 and July 2023. Data collection included preoperative and postoperative examination findings (visual acuity, extraocular motility, lid retraction, and lagophthalmos), mucocoele recurrence, cosmetic satisfaction, and surgical complications. Patients were followed up for an average of 22 months. RESULTS: All patients underwent successful frontal mucocoele drainage via a modified anterior orbitotomy and simultaneous endonasal approach. At presentation, three (20%) had extraocular restriction leading to diplopia, and six (40%) had proptosis in the eye adjacent to the mucocoele. One patient presented acutely with no light perception in the affected eye due to compressive optic neuropathy. All patients who had reduced extraocular motility before surgery regained full motility post-operatively. Treatment was successful in all cases, and there was no documented mucocoele recurrence during follow-up. Satisfactory aesthetic outcomes were achieved in all cases. Reported complications included temporary forehead numbness and ptosis of the affected eyelid, which resolved without intervention. CONCLUSION: The modified anterior orbitotomy approach to frontal mucocoeles allows optimal frontal sinus access and mucocoele treatment while preserving cosmesis.

A multidisciplinary approach to frontal sinus mucocoeles using an upper lid skin crease incision combined with endoscopic drainage allows full access to the frontal sinus and treatment of the mucocoele while preserving cosmesis.

A Novel Simulation Model Significantly Improves Confidence in Canthotomy and Cantholysis Among Ophthalmology and Emergency Medicine Trainees.

BACKGROUND: Orbital compartment syndrome is a potentially blinding eye condition. Timely diagnosis and treatment are paramount to optimize visual outcomes. Lateral canthotomy and cantholysis is the definitive management and a required competency for emergency physicians and ophthalmologists. Lack of confidence in the procedure can result in delayed treatment and poor outcomes. OBJECTIVES: Our aim was to create a low-cost, realistic, simulation model to ensure trainees were confident in performing lateral canthotomy and cantholysis. METHODS: A model was created using equipment found in the emergency department. This model's efficacy was assessed using pre- and post-teaching questionnaires measuring learner's self-perceived confidence. RESULTS: Forty-seven emergency medicine and 18 ophthalmology registrars rated their confidence in the procedure using a 5-point Likert scale (1 = not very confident, 5 = extremely confident); 42% (n = 27) of participants felt 'quite confident' (4 on Likert scale) in carrying out the procedure unsupervised out of hours after the teaching session, compared with 9.23% (n = 6) before (p < 0.01). Our model resulted in significant increases in all three measures of confidence (diagnosing orbital compartment syndrome, locating the necessary equipment and performing canthotomy and cantholysis) and was rated as 4.35 (1 = not at all helpful, 5 = extremely helpful) in understanding the anatomy of the region. Sixty-six percent (n = 43) of participants stated they would like further simulation teaching. CONCLUSIONS: Our model is low cost, easy to assemble, and anatomically correct. The user can 'strum' the inferior canthal tendon without cutting the lower lid, appreciating the difference between canthotomy and cantholysis. Use of this model significantly increased the number of learners who felt "quite confident" with performing the procedure. Use of this model should be considered for trainees in ophthalmology and emergency medicine.

Collagen VI Is a Gi-Biased Ligand of the Adhesion GPCR GPR126/ADGRG6.

GPR126/ADGRG6, a member of the adhesion G-protein-coupled receptor family, balances cell differentiation and proliferation through fine-tuning of intracellular cAMP levels, which is achieved through coupling to Gs and Gi proteins. While GPR126-mediated cAMP increase has been proven to be essential for differentiation of Schwann cells, adipocytes and osteoblasts, Gi-signaling of the receptor was found to propagate breast cancer cell proliferation. Extracellular ligands or mechanical forces can modulate GPR126 activity but require an intact encrypted agonist sequence, coined the Stachel. Even though coupling to Gi can be seen for constitutively active truncated receptor versions of GPR126 as well as with a peptide agonist derived from the Stachel sequence, all known N-terminal modulators have so far only been shown to modulate Gs coupling. Here, we identified collagen VI as the first extracellular matrix ligand of GPR126 that induces Gi signaling at the receptor, which shows that N-terminal binding partners can mediate selective G protein signaling cascades that are masked by fully active truncated receptor variants.

Tear Trough Filler Using the Three-point Tangent Technique: Lessons from 1452 Tear Trough Applications.

This study describes a novel three-point tangent technique for tear trough filler and the results from the largest series to date. Methods: A retrospective case review was performed for all patients treated between 2016 and 2020. Patient demographics, filler details and complications were recorded. The injection technique involves using a blunt cannula to deliver filler along three linear tangents bespoke to each patient. Results: A total of 1452 applications of filler to the orbits of 583 patients were recorded. The median patient age was 41 years (range 19-77), and 84% were women. The mean volume of applied filler at the first appointment was 0.34 mL to each orbit (range 0.1--1.5); 82% reported no complication, 10% reported swelling with a median duration of 4 weeks (range 1-52), 4.3% experienced bruising, 4.6% reported contour irregularities, and 3.3% experienced a Tyndall effect. Retrobulbar hemorrhage occurred in one patient (0.17%), which was managed immediately with no lasting visual compromise. Volume of filler injected was significantly associated with a risk of edema (P < 0.00001) and contour irregularities (P = 0.012). In total, 50% of cases of edema resolved spontaneously after 4 weeks. Filler was dissolved in 1.9% of orbits. Patients with a history of dissolving were significantly more likely to require dissolving after subsequent reinjection (P = 0.043). Conclusions: The three-point tangent technique is a safe and effective method. Increasing volume of filler administered is associated with complications of edema and contour irregularities. Edema is the most common complication and resolves spontaneously in half of patients by 4 weeks.

PTK7 is a positive allosteric modulator of GPR133 signaling in glioblastoma.

The adhesion G-protein-coupled receptor GPR133 (ADGRD1) supports growth of the brain malignancy glioblastoma. How the extracellular interactome of GPR133 in glioblastoma modulates signaling remains unknown. Here, we use affinity proteomics to identify the transmembrane protein PTK7 as an extracellular binding partner of GPR133 in glioblastoma. PTK7 binds the autoproteolytically generated N-terminal fragment of GPR133 and its expression in trans increases GPR133 signaling. This effect requires the intramolecular cleavage of GPR133 and PTK7's anchoring in the plasma membrane. PTK7's allosteric action on GPR133 signaling is additive with but topographically distinct from orthosteric activation by soluble peptide mimicking the endogenous tethered Stachel agonist. GPR133 and PTK7 are expressed in adjacent cells in glioblastoma, where their knockdown phenocopies each other. We propose that this ligand-receptor interaction is relevant to the pathogenesis of glioblastoma and possibly other physiological processes in healthy tissues.

Persistent orbital inflammation following complete excision of deep dermoid cysts.

Piecemeal excision of dermoid cysts carries the risk of implanting epithelial fragments into orbital fat, which is well recognized to continue secreting oily debris, inciting chronic, often granulomatous inflammation. The authors present the clinical and histological details for two patients with persistent lipogranulomatous inflammation for years after piecemeal excision of deep orbital dermoid cysts, in the absence of any residual epithelium. The importance of copious saline lavage - to 'float-out" and reduce microscopic lipid droplets - is also emphasised.

Presenting features for developmental cysts of the orbit.

PURPOSE: To evaluate the clinical features of developmental cysts of the orbit. PATIENTS AND METHODS: Retrospective study of patients who had excision of cysts between 1992 and 2020. RESULTS: Three hundred and 58 patients (189 male; 53%) with orbital developmental cysts were identified, all being unilateral. Age at surgery varied from birth to 77 years (mean 17, median 18 years) and the average symptom duration was 5 years (median 18 months; range 1 day-50 years). The commonest presenting features were a peribulbar lump or upper lid swelling, followed by proptosis, pain, diplopia and reduced vision. Most patients (82%) had a palpable mass, with epidermoids, sebaceous dermoids and keratinised dermoids commonly affecting the superotemporal quadrant, and conjunctiva-containing cysts usually being biased to a medial location. Cysts were lined by keratinised epithelium with dermal structures (224/358; 63%), non-keratinised epithelium with dermal structures (69/358; 19%), epidermis without identifiable dermal structures (19/358 'epidermoids'; 5%), conjunctiva (12/358; 3%), respiratory epithelium (4/358; 1%), or mixed dermal and conjunctival epithelia (30/358 'dermo-conjunctival' cysts; 8%). Overall, two-thirds (242/358; 66%) had histological evidence of chronic intramural inflammation, and a half of cysts showed granuloma formation (178/358 cysts). Chronic inflammation was less common with conjunctival cysts (54%, 7/12 patients) and none showed granuloma formation. CONCLUSION: Developmental cysts of the orbit vary from the relatively common dermoid cysts to the extremely rare respiratory epithelial-lined cysts. Respiratory cysts, being deeper, may present late in life and cysts containing conjunctival epithelium tend to be less inflamed and typically favour the superonasal quadrant.

Orbital compartment syndrome following tear trough filler injection.

A patient was treated with tear trough filler and developed a retrobulbar haemorrhage. This was managed acutely with a lateral canthotomy and cantholysis with no lasting visual compromise. This is the first reported case of an orbital compartment syndrome following filler injection and highlights the potential blinding complications which can occur. There should be an increased awareness of this complication amongst practitioners administering tear trough filler.

Frontal sinus mucocele with orbital extension drained via a combined upper lid skin crease and endoscopic approach.

This case report discusses the ophthalmic complications of frontal sinus mucoceles and describes the favorable long-term surgical outcomes of a combined endoscopic and upper-lid skin crease drainage approach carried out jointly with otorhinolaryngology. A 47-year-old single mother presented to eye casualty with markedly swollen eyelids and visual acuity of 6/6 in the left eye, no perception of light in the right. Ophthalmic examination revealed right-sided hypoglobus and proptosis with exposure keratopathy inferiorly. There was complete ophthalmoplegia in the right eye and a hemorrhagic optic disc visible on fundoscopy. CT orbit with contrast confirmed a diagnosis of giant frontal mucocele with orbital extension. The patient underwent mucocele drainage via a modified anterior orbitotomy approach and FESS (Functional Endoscopic Sinus Surgery) drainage performed jointly with otorhinolaryngology. Two weeks post-operatively her proptosis was resolving and by three months she had regained full extraocular motility. As expected, vision was not restored in the right eye. At one year, the patient's upper lid skin crease scar was completely buried in the eyelid's natural contour, and repeat CT scanning confirmed no re-stenosis or mucocele recurrence. This case demonstrates, that a multidisciplinary approach to far-lateral frontal sinus mucoceles with orbital extension and ophthalmic complications which combines an upper lid skin crease incision with FESS drainage, allows adequate access to the frontal sinus while preserving cosmesis.

The N Terminus of Adhesion G Protein-Coupled Receptor GPR126/ADGRG6 as Allosteric Force Integrator.

The adhesion G protein-coupled receptor (aGPCR) GPR126/ADGRG6 plays an important role in several physiological functions, such as myelination or peripheral nerve repair. This renders the receptor an attractive pharmacological target. GPR126 is a mechano-sensor that translates the binding of extracellular matrix (ECM) molecules to its N terminus into a metabotropic intracellular signal. To date, the structural requirements and the character of the forces needed for this ECM-mediated receptor activation are largely unknown. In this study, we provide this information by combining classic second-messenger detection with single-cell atomic force microscopy. We established a monoclonal antibody targeting the N terminus to stimulate GPR126 and compared it to the activation through its known ECM ligands, collagen IV and laminin 211. As each ligand uses a distinct mode of action, the N terminus can be regarded as an allosteric module that can fine-tune receptor activation in a context-specific manner.

Translating the force-mechano-sensing GPCRs.

Incorporating mechanical cues into cellular responses allows us to experience our direct environment. Specialized cells can perceive and discriminate between different physical properties such as level of vibration, temperature, or pressure. Mechanical forces are abundant signals that also shape general cellular responses such as cytoskeletal rearrangement, differentiation, or migration and contribute to tissue development and function. The molecular structures that perceive and transduce mechanical forces are specialized cytoskeletal proteins, cell junction molecules, and membrane proteins such as ion channels and metabotropic receptors. G protein-coupled receptors (GPCRs) have attracted attention as metabotropic force receptors as they are among the most important drug targets. This review summarizes the function of mechano-sensitive GPCRs, specifically, the angiotensin II type 1 receptor and adrenergic, apelin, histamine, parathyroid hormone 1, and orphan receptors, focusing particularly on the advanced knowledge gained from adhesion-type GPCRs. We distinguish between shear stress and cell swelling/stretch as the two major types of mechano-activation of these receptors and contemplate the potential contribution of the force-from-lipid and force-from-tether models that have previously been suggested for ion channels.

Congenital Conjunctival Cysts of the Orbit.

PURPOSE: To evaluate the clinical presentation, anatomical location, and histological features of congenital conjunctival cysts of the orbit. The location and the histological features of inflammation in these patients were compared with those for 293 orbital dermoid cysts. PATIENTS AND METHODS: Retrospective review of the clinical details, imaging, and histopathology for patients who had excision of conjunctival cysts from their orbit between 1992 and 2020; patients with a history of trauma or surgery were omitted. RESULTS: Twelve patients (7 male; 58%) with congenital conjunctival cysts were identified, the patients presenting at an average age of 16 years (median 26; range 1-61) with a symptoms for a mean duration of 20 months (median 24; range 6-36). The commonest symptoms were peribulbar lump (6/12 patients; 50%), and eyelid swelling and blepharoptosis (6/12 patients; 50%). An orbitaxl mass was palpable in 10 patients (83%), 3 patients (25%) had mild proptosis (1-3 mm), and the cysts were most commonly located superiorly (6/12 patients; 50%) or superonasally (3/12; 25%) in the anterior half of the orbit. Imaging was performed in 7 cases, this showing an intimate relation to the common sheath of the superior rectus/levator complex in 3 patients (25%) and to the trochlea in 1 (8%). All cysts were excised completely, and no patient had postoperative complications or recurrence. Chronic mild and nonspecific inflammation was evident within the cyst wall in 7 cases (54%), but-unlike 55% of the 293 dermoid cysts-none showed granuloma formation. CONCLUSION: Congenital conjunctival cysts are rare and usually present with a palpable mass in the upper eyelid sulcus. A significant proportion of these cysts have an intimate relationship with the trochlea, or the superior rectus, levator palpebrae or superior oblique muscles and, to minimize the risk of postoperative diplopia or ptosis, particular care must be exercised during surgery.

Corneal Neurotization Using the Great Auricular Nerve for Bilateral Congenital Trigeminal Anesthesia.

PURPOSE: The purpose of this study was to describe an indirect corneal neurotization (CN) technique for congenital bilateral trigeminal anesthesia using the greater auricular nerve (GAN) as a donor. METHOD: CN was performed to preserve the integrity of the only seeing eye in a 4-year-old boy with pontine tegmental cap dysplasia and bilateral trigeminal anesthesia. He had recurrent corneal ulceration and scarring despite full medical treatment. The GAN was used as a donor, and the sural nerve was harvested and used as a bridge which was tunneled to the sub-Tenon space in the inferior fornix. The fascicles were distributed into the 4 quadrants and sutured to the sclera near the limbus. RESULT: This technique resulted in providing corneal sensation and improving stability of the epithelium. Corneal opacity gradually decreased allowing significant visual improvement evidenced in the early postoperative months. CONCLUSIONS: Using the GAN technique for CN bypasses trigeminal innervation and has the potential to improve corneal sensation. The GAN is a large caliber nerve and provides a large amount of axons and robust neurotization. This technique would be desirable for cases with bilateral congenital trigeminal anesthesia, such as pontine tegmental cap dysplasia.

Functional impact of intramolecular cleavage and dissociation of adhesion G protein-coupled receptor GPR133 (ADGRD1) on canonical signaling.

GPR133 (ADGRD1), an adhesion G protein-coupled receptor (GPCR) whose canonical signaling activates GαS-mediated generation of cytosolic cAMP, has been shown to be necessary for the growth of glioblastoma (GBM), a brain malignancy. The extracellular N terminus of GPR133 is thought to be autoproteolytically cleaved into N-terminal and C- terminal fragments (NTF and CTF, respectively). However, the role of this cleavage in receptor activation remains unclear. Here, we used subcellular fractionation and immunoprecipitation approaches to show that the WT GPR133 receptor is cleaved shortly after protein synthesis and generates significantly more canonical signaling than an uncleavable point mutant GPR133 (H543R) in patient-derived GBM cultures and HEK293T cells. After cleavage, the resulting NTF and CTF remain noncovalently bound to each other until the receptor is trafficked to the plasma membrane, where we demonstrated NTF-CTF dissociation occurs. Using a fusion of the CTF of GPR133 and the N terminus of thrombin-activated human protease-activated receptor 1 as a controllable proxy system to test the effect of intramolecular cleavage and dissociation, we also showed that thrombin-induced cleavage and shedding of the human protease-activated receptor 1 NTF increased intracellular cAMP levels. These results support a model wherein dissociation of the NTF from the CTF at the plasma membrane promotes GPR133 activation and downstream signaling. These findings add depth to our understanding of the molecular life cycle and mechanism of action of GPR133 and provide critical insights that will inform therapeutic targeting of GPR133 in GBM.

Orbital Crystal-Storing Histiocytosis: A Clinicopathologic Study of 4 Cases.

The authors report the clinicopathological features of crystal-storing histiocytosis (CSH) that involved the orbit and conjunctiva and review published cases of CSH. Cases of histologically proven CSH were identified from archives at the Institute of Ophthalmology, London, and a retrospective review of clinical details and pathology was performed for cases between 1997 and 2017. Four cases of CSH were identified: 1 might have arisen from an inflammatory reaction to a silicone retinal buckle and 3 others occurred with localized B-cell lymphomas. Two patients presented with a conjunctival mass, and 2 had an orbital mass causing proptosis and hypoglobus. One case was associated with amyloid deposition and another had an earlier diagnosis of IgG4-related disease. In the patient without underlying lymphoma, the condition settled with removal of the explant and orbital mass, and the 3 with lymphoma underwent orbital radiotherapy with cessation of disease progression. All patients retained good vision. Ocular CSH is rare, can present in several ways, and should prompt investigation for an underlying lymphoproliferative disorder.

In vivo identification of small molecules mediating Gpr126/Adgrg6 signaling during Schwann cell development.

Gpr126/Adgrg6, an adhesion family G protein-coupled receptor (aGPCR), is required for the development of myelinating Schwann cells in the peripheral nervous system. Myelin supports and insulates vertebrate axons to permit rapid signal propagation throughout the nervous system. In mammals and zebrafish, mutations in Gpr126 arrest Schwann cells at early developmental stages. We exploited the optical and pharmacological tractability of larval zebrafish to uncover drugs that mediate myelination by activating Gpr126 or functioning in parallel. Using a fluorescent marker of mature myelinating glia (Tg[mbp:EGFP-CAAX]), we screened hypomorphic gpr126 mutant larvae for restoration of myelin basic protein (mbp) expression along peripheral nerves following small molecule treatment. Our screens identified five compounds sufficient to promote mbp expression in gpr126 hypomorphs. Using an allelic series of gpr126 mutants, we parsed the ability of small molecules to restore mbp, suggesting differences in drug efficacy dependent on Schwann cell developmental state. Finally, we identify apomorphine hydrochloride as a direct small molecule activator of Gpr126 using combined in vivo/in vitro assays and show that aporphine class compounds promote Schwann cell development in vivo. Our results demonstrate the utility of in vivo screening for aGPCR modulators and identify small molecules that interact with the gpr126-mediated myelination program.

Genetic basis of functional variability in adhesion G protein-coupled receptors.

The enormous sizes of adhesion G protein-coupled receptors (aGPCRs) go along with complex genomic exon-intron architectures giving rise to multiple mRNA variants. There is a need for a comprehensive catalog of aGPCR variants for proper evaluation of the complex functions of aGPCRs found in structural, in vitro and animal model studies. We used an established bioinformatics pipeline to extract, quantify and visualize mRNA variants of aGPCRs from deeply sequenced transcriptomes. Data analysis showed that aGPCRs have multiple transcription start sites even within introns and that tissue-specific splicing is frequent. On average, 19 significantly expressed transcript variants are derived from a given aGPCR gene. The domain architecture of the N terminus encoded by transcript variants often differs and N termini without or with an incomplete seven-helix transmembrane anchor as well as separate seven-helix transmembrane domains are frequently derived from aGPCR genes. Experimental analyses of selected aGPCR transcript variants revealed marked functional differences. Our analysis has an impact on a rational design of aGPCR constructs for structural analyses and gene-deficient mouse lines and provides new support for independent functions of both, the large N terminus and the transmembrane domain of aGPCRs.

Ploidy Variation in Kluyveromyces marxianus Separates Dairy and Non-dairy Isolates.

Kluyveromyces marxianus is traditionally associated with fermented dairy products, but can also be isolated from diverse non-dairy environments. Because of thermotolerance, rapid growth and other traits, many different strains are being developed for food and industrial applications but there is, as yet, little understanding of the genetic diversity or population genetics of this species. K. marxianus shows a high level of phenotypic variation but the only phenotype that has been clearly linked to a genetic polymorphism is lactose utilisation, which is controlled by variation in the LAC12 gene. The genomes of several strains have been sequenced in recent years and, in this study, we sequenced a further nine strains from different origins. Analysis of the Single Nucleotide Polymorphisms (SNPs) in 14 strains was carried out to examine genome structure and genetic diversity. SNP diversity in K. marxianus is relatively high, with up to 3% DNA sequence divergence between alleles. It was found that the isolates include haploid, diploid, and triploid strains, as shown by both SNP analysis and flow cytometry. Diploids and triploids contain long genomic tracts showing loss of heterozygosity (LOH). All six isolates from dairy environments were diploid or triploid, whereas 6 out 7 isolates from non-dairy environment were haploid. This also correlated with the presence of functional LAC12 alleles only in dairy haplotypes. The diploids were hybrids between a non-dairy and a dairy haplotype, whereas triploids included three copies of a dairy haplotype.