Human glucocerebrosidase mediates formation of xylosyl-cholesterol by ß-xylosidase and transxylosidase reactions.

Deficiency of glucocerebrosidase (GBA), a lysosomal ß-glucosidase, causes Gaucher disease. The enzyme hydrolyzes ß-glucosidic substrates and transglucosylates cholesterol to cholesterol-ß-glucoside. Here we show that recombinant human GBA also cleaves ß-xylosides and transxylosylates cholesterol. The xylosyl-cholesterol formed acts as an acceptor for the subsequent formation of di-xylosyl-cholesterol. Common mutant forms of GBA from patients with Gaucher disease with reduced ß-glucosidase activity were similarly impaired in ß-xylosidase, transglucosidase, and transxylosidase activities, except for a slightly reduced xylosidase/glucosidase activity ratio of N370S GBA and a slightly reduced transglucosylation/glucosidase activity ratio of D409H GBA. XylChol was found to be reduced in spleen from patients with Gaucher disease. The origin of newly identified XylChol in mouse and human tissues was investigated. Cultured human cells exposed to exogenous ß-xylosides generated XylChol in a manner dependent on active lysosomal GBA but not the cytosol-facing ß-glucosidase GBA2. We later sought an endogenous ß-xyloside acting as donor in transxylosylation reactions, identifying xylosylated ceramide (XylCer) in cells and tissues that serve as donor in the formation of XylChol. UDP-glucosylceramide synthase (GCS) was unable to synthesize XylChol but could catalyze the formation of XylCer. Thus, food-derived ß-D-xyloside and XylCer are potential donors for the GBA-mediated formation of XylChol in cells. The enzyme GCS produces XylCer at a low rate. Our findings point to further catalytic versatility of GBA and prompt a systematic exploration of the distribution and role of xylosylated lipids.

Inhibition of Fibrotic Contraction by Sirolimus (Rapamycin) in an Ex Vivo Model of Thyroid Eye Disease.

BACKGROUND: Thyroid eye disease (TED) is characterized by orbital inflammation and complicated by extraocular muscle fibrosis. Treatment with rapamycin/sirolimus has been reported to improve ocular motility and disease manifestations in TED. Whether this resulted from a primary antifibrotic effect on fibroblasts or was secondary to immune-suppression is unclear. METHODS: In vitro contractility studies of primary orbital fibroblasts. Cells from patients with TED and controls were treated with rapamycin [mechanistic target of rapamycin an (mTOR) inhibitor] and MHY1485 (an mTOR stimulator) as well as inhibitors upstream in the same signaling cascade (saracatinib and befatinib). RESULTS: At concentrations consistent with the therapeutic dosing range in humans, rapamycin/sirolimus significantly reduces fibrosis in orbital fibroblasts from TED patients and controls in vitro. This effect is separate from, and in addition to, its immune suppressive effect. mTOR-driven fibrotic activity is greater in TED-derived fibroblasts and can be blocked also upstream of mTOR by inhibition of src. There was no adverse effect on cell survival. CONCLUSION: The authors present evidence for a direct antifibrotic effect of rapamycin/sirolimus in primary orbital fibroblasts. Targeting mTOR signaling presents a further and adjunctive treatment of TED alongside other immune-suppressive agents. By acting downstream of IGF1-R, sirolimus may offer a cost-effective alternative to teprotumumab therapy. Clinical case reports, now supplemented by this in vitro evidence, support the initiation of a clinical trial to treat the fibrotic sequelae of TED with this already-approved agent. Such an "off-the-shelf" therapy is a welcome prospect for TED treatment, particularly one available at a low price.

Update on the clinical assessment and management of thyroid eye disease.

PURPOSE OF REVIEW: To offer an update on advances and controversies in the assessment, investigation and treatment of thyroid eye disease (TED), a disfiguring orbital autoimmune disease, which can manifest with diplopia and threaten not only sight - but also life. RECENT FINDINGS: Developments in biomarkers and imaging are helping to tailor the management of patients. Emerging therapies target different pathways in the disease and are informed by studies into TED pathogenesis: the last 2 years has, for example, seen the culmination of a two-decade long bench-to-bedside story in which an original focus on the IGF1 receptor has translated into an effective treatment for proptosis in thyroid eye disease. Whether this will result in a real-world reduction in TED-related morbidity will depend on access; commercial pricing decisions may preclude widespread adoption of novel therapies. SUMMARY: Thyroid eye disease research is enjoying a renaissance with advances in both monitoring and treatment coupled with a renewed emphasis on a holisitic approach, which includes aesthetic care for patients; this is perhaps the most exciting time to be part of the international thyroid eye disease community in decades - for physicians, surgeons and patients. The commercial window for break-through drugs are narrowing with an array of new therapeutic agents in the pipeline over the coming decade.

Periocular hyaluronic acid fillers: applications, implications, complications.

PURPOSE OF REVIEW: The use of dermal filler in the periocular area is increasing - both for functional and aesthetic indications. Hyaluronic acid fillers dominate the market; these treatments offer an alternative to some surgical procedures with the advantage of instant results, minimal healing time and low complication rates. However, success depends on judicious selection of patients, products and procedures to achieve favourable outcomes. This article reviews current understanding of the principal complications in the periocular area and their management. RECENT FINDINGS: Hyaluronic acid is a ubiquitous, biodegradable, nonspecies-specific molecular substrate with limited potential for immunogenic reactions. However, in the periocular area, such products can migrate and last significantly longer than the expected filler lifespan. Contamination or subsequent immune stimulation can trigger delayed-onset inflammatory reactions. Though minor vascular occlusions are not uncommon, cases of blindness secondary to facial filler injections are thought to be rare. Timely enzymatic degradation with injectable hyaluronidase can be effective in the treatment of some such complications. But recent studies demonstrate lack of penetration through arterial walls and optic nerve sheath, casting doubt on the role of retrobulbar hyaluronidase in the management of vision loss because of embolism with hyaluronic acid filler. SUMMARY: Hyaluronic acid fillers represent an emerging and important addition to the armamentarium of the oculofacial plastic surgeon with their use in the aesthetic field also expected continue to rise. The oculoplastic facial surgeon, armed with a thorough knowledge of facial anatomy, safe injection planes and the means of minimizing and treating complications is in the best position to lead clinically in the use of this well tolerated and effective treatment modality.

Heterogeneity in a large pedigree with Danon disease: Implications for pathogenesis and management.

BACKGROUND: Danon disease is an X-linked disturbance of autophagy manifesting with cognitive impairment and disordered heart and skeletal muscle. After a period of relative stability, patients deteriorate rapidly and may quickly become ineligible for elective heart transplantation - the only life-saving therapy. METHODS: We report a large pedigree with diverse manifestations of Danon disease in hemizygotes and female heterozygotes. RESULTS: Malignant cardiac arrhythmias requiring amiodarone treatment induced thyroid disease in two patients; intractable thyrotoxicosis, which enhances autophagy, caused the death of a 21year-old man. Our patients also had striking elevation of serum troponin I during the accelerated phase of their illness (p<0.01) and rising concentrations heralded cardiac decompensation. We argue for changes to cardiac transplantation eligibility criteria. CONCLUSION: Danon disease causes hypertrophic cardiomyopathy - here we propose a common pathophysiological basis for the metabolic and structural effects of this descriptive class of heart disorders. We also contend that troponin I may have prognostic value and merits exploration for clinical decision-making including health warning bracelets. Rapamycin (Sirolimus®), an approved immunosuppressant which also influences autophagy, may prove beneficial. In the interim, while new treatments are developed, a revaluation of cardiac transplantation eligibility criteria is warranted.

Can We Improve the Tolerance of an Ocular Prosthesis by Enhancing Its Surface Finish?

PURPOSE: Patients who wear an ocular prosthesis frequently suffer with dry eye symptoms and socket discharge, often on a daily basis. The aim of the study was to determine whether a smoother, optical quality polish of the prosthesis' surface could improve symptoms and wear tolerance. The study was designed as single-center, single-masked, prospective randomized controlled trial. Eighty-eight consecutive patients undergoing annual ocular prosthesis maintenance review were approached from the prosthesis clinic. Forty-one out of 49 eligible patients were recruited. METHODS: Participants were randomized to either a standard or a higher "optical quality" polish of their prosthesis. At entry to the trial, at 1 month, and 12 months they completed a questionnaire covering cleaning, lubricant use, inflammation, discomfort, and discharge. Lower scores indicated better tolerance of the prosthesis. At each visit, the prosthesis was stained and photographed against a standard background to assess deposit build up. Primary outcome measures were 1) a subjective questionnaire score and 2) an objective assessment of surface deposit build-up on prosthetic eyes by standardized photographic grading. RESULTS: Forty-one patients participated in the study. The median age of their prosthesis was 36 months (range 9 months-40 years). There was no statistically significant difference in questionnaire scores or deposit build up between the 2 groups at baseline. By 12-months, the higher optical quality polish showed a statistically significant reduction in symptoms and frequency of discharge (2.19 vs. 3.85; p = 0.05-lower scores better). Scoring of the prosthesis' deposit build-up showed a significant difference at 1 month, but this was not sustained at 12 months. CONCLUSIONS: Creating an optical quality finish to an ocular prosthesis reduces deposit build up on artificial eyes. The authors found this modification improved patient tolerance at 12 months.

Prolonged mydriasis after inadvertent topical administration of the calcium channel antagonist amlodipine: implications for glaucoma drug development.

CONTEXT: Calcium channel inhibitors are being investigated as potential therapeutic adjuncts to reduce painful ciliary muscle spasm and control intraocular pressure in glaucoma. Relatively little is known about the effect of topical administration of calcium channel blockers in humans. OBJECTIVE: (1) To describe prolonged fixed pupil dilation resulting from exposure to topical amlodipine (2) to review the evidence that links calcium channel blockers with mydriasis and (3) to discuss the implications for glaucoma pharmacotherapy. DESIGN: Single interventional case report, literature review (including human and animal studies) and analysis of reported adverse drug reactions (ADRs) records in the USA and UK. CASE: A 35-year-old female doctor presented to eye casualty with blurred vision and bilateral, fixed, dilated pupils. A history of exposure to liquid amlodipine while preparing a paediatric chemotherapy regimen for a neuroblastoma patient was elicited. The patient was reassured and observed. RESULTS: Pupil function returned to normal within 48 h. A multi-national review of adverse drug reactions reports was conducted, as well as an extensive literature search for case reports and experimental studies. To the authors' knowledge this is the first report of amlodipine causing mydriasis and we discuss the potential molecular mechanism. CONCLUSIONS: This case is the first to suggest that calcium channel blockers can cause prolonged mydriasis. These agents have been investigated as potential adjuncts in glaucoma therapy. As accidental topical exposure to amlodipine can cause prolonged pupil dilation, it could precipitate angle closure in predisposed patients.

A series of pregnancies in women with inherited metabolic disease.

In this case series we report 12 pregnancies, in women treated at four centres, illustrating some of the issues that may be encountered during pregnancy by women with inherited metabolic disease. We discuss how specific pregnancy, labour and delivery issues for mothers with methylmalonic acidemia, homocystinuria, propionic acidemia, glutaric acidemia type 1, ornithine transcarbamylase (OTC) deficiency and 3-hydroxy-3-methylglutaric(HMG)-CoA lyase deficiency were managed and the outcome for the mother and child in each case. Eight of the 12 pregnancies resulted in the successful delivery of a liveborn infant. Several women experienced decompensation of their condition during pregnancy or the post-partum period. There was one maternal death in a women with 3-hydroxy-3-methylglutaric(HMG)-CoA lyase deficiency. Pre-pregnancy counselling and co-management of high risk medical patients by obstetricians and specialist physicians with an understanding of the relationship between pregnancy and inherited metabolic disease is essential.

Necrotizing group A streptococcal periorbital infection following adalimumab therapy for rheumatoid arthritis.

OBJECTIVE: (1) To describe a case of necrotizing group A streptococcal periorbital infection in a patient receiving treatment with adalimumab (Humira, Abbott)-- a fully humanized monoclonal anti-TNF-α agent. (2) To identify bacterial species responsible for infection with different forms of biological therapy. DESIGN: Single interventional case report and literature review. CASE: A 57-year-old woman developed severe right-sided necrotizing periorbital infection whilst receiving treatment with adalimumab for rheumatoid arthritis (RA). Cultures grew Lancefield Group A Streptococcus pyogenes. An extensive literature search for reports of ocular infections associated with biological therapy was conducted. RESULTS: Adalimumab therapy was discontinued and the patient was admitted to an intensive care unit. The patient made a complete recovery after receiving appropriate antibiotic therapy. Overall Gram-positive cocci are the most common infection associated with use of biological therapy. CONCLUSIONS: Anti-TNF-α agents are powerful immune-modulating drugs with potentially serious side effects. This case is the first to link adalimumab to necrotizing periorbital infection. Resolved infection does not preclude reintroduction of anti-TNF therapy however, careful assessment of the risks versus benefits of therapy is required at the individual patient level.

Saccadic latency in hepatic encephalopathy: a pilot study.

Hepatic encephalopathy is a common complication of cirrhosis. The degree of neuro-psychiatric impairment is highly variable and its clinical staging subjective. We investigated whether eye movement response times-saccadic latencies-could serve as an indicator of encephalopathy. We studied the association between saccadic latency, liver function and paper- and pencil tests in 70 patients with cirrhosis and 31 patients after liver transplantation. The tests included the porto-systemic encephalopathy (PSE-) test, critical flicker frequency, MELD score and ammonia concentration. A normal range for saccades was established in 31 control subjects. Clinical and biochemical parameters of liver, blood, and kidney function were also determined. Median saccadic latencies were significantly longer in patients with liver cirrhosis when compared to patients after liver transplantation (244 ms vs. 278 ms p < 0.001). Both patient groups had prolonged saccadic latency when compared to an age matched control group (175 ms). The reciprocal of median saccadic latency (µ) correlated with PSE tests, MELD score and critical flicker frequency. A significant correlation between the saccadic latency parameter early slope (σ(E)) that represents the prevalence of early saccades and partial pressure of ammonia was also noted. Psychometric test performance, but not saccadic latency, correlated with blood urea and sodium concentrations. Saccadic latency represents an objective and quantitative parameter of hepatic encephalopathy. Unlike psychometric test performance, these ocular responses were unaffected by renal function and can be obtained clinically within a matter of minutes by non-trained personnel.

Implications for pharmaceutical companies and clinicians from the Bayer v NHS judgement: an increasing budgetary focus for both.

The English High Court recently dismissed the Bayer pharmaceutical company's challenge against a regional clinical commissioning group's policy allowing NHS Trusts to use a cheaper, but unlicensed, alternative to a sight preserving eye treatment. This makes sober reading for companies marketing "on-label" sales of medicines which are more expensive than off-label or unlicensed alternatives. Unsurprisingly, Bayer has sought to appeal the judgement. The Court has also created legal uncertainty for the NHS: the test for lawfulness is shifted from the Clinical Commission Groups and their policies to individual trusts which must ensure that every unlicensed use is lawful. This could generate legal action against NHS Trusts and ironically drive up costs for the public purse. What is clear is that the Court's conclusions were heavily influenced by fiscal constraints which it accepted as a legitimate counterweight to the commercial interests of pharmaceutical companies. It also appears to establish in law the duty for doctors to have concern for the wider societal costs of prescribed treatments. This article summarises this complex judgement and offers advice for navigating the increasing focus on limited budgets, both for companies and physicians.

Sirolimus (rapamycin) for the targeted treatment of the fibrotic sequelae of Graves' orbitopathy.

BACKGROUND: Rapamycin (alternatively known as sirolimus) is a macrolide immunosuppressant commonly used for organ transplantation. It acts both on lymphocytes through the mechanistic target of rapamycin (mTOR) pathway to reduce their sensitivity to interleukin-2 (IL-2) and, importantly, also has anti-fibrotic properties by acting on myofibroblasts. The latter have been implicated in the pathogenesis of thyroid eye disease (TED). AIM: To describe successful treatment and reversal of extraocular muscle fibrosis in TED with sirolimus. METHODS: Case report and literature review with clinic-pathological correlation. RESULTS: A patient with Graves' orbitopathy (GO) developed significant ocular motility restriction, which was unresponsive to steroids and conventional immunosuppression. Unlike these prior treatments, rapamycin therapy improved the diplopia and fields of binocular single vision over a period of months. There were no adverse effects directly attributable to the treatment. CONCLUSION: With its low renal toxicity and ability to specifically target the underlying fibrotic pathways in GO, rapamycin may prove a useful adjunct to standard immunosuppressive regimes. We encourage further reporting of case series or the instigation of controlled trial.

Serial TSH-receptor antibody levels to guide the management of thyroid eye disease: the impact of smoking, immunosuppression, radio-iodine, and thyroidectomy.

The Thyrotropin receptor antibody (TRAb) is the main driver of Graves' disease (GD) and its most common extra-thyroidal manifestation: thyroid eye disease (TED). Though key to diagnosis, it has not been used routinely as a marker of disease activity or to guide treatment. Here we demonstrate, through a retrospective review of 105 patients with TED, that serial TRAb levels vary with time, correlate with disease activity and are affected by smoking and endocrine control. Such serial measurements can guide the modern management of thyroid eye disease, helping to prevent the more serious manifestations. We show that surgical thyroidectomy is associated with a reduction in antibody levels and a reduced rate of TED reactivation when compared to radio-iodine ablation where the stimulating antigen is not removed. This provides a molecular explanation for epidemiological studies showing radio-ablation being associated with an increased risk of orbitopathy. To demonstrate the effect of our clinical approach on a patient population, we then compared the incidence and severity of TED in a clinic in a period before and after the introduction of serial TRAb measurements. Despite an increase in disease incidence and severity at presentation over the two-decade study period, our approach saw a significant reduction in the need for surgical intervention for this orbital disorder.

Ophthalmic manifestations of Gaucher disease: the most common lysosomal storage disorder.

Gaucher disease (GD) results from a deficiency of glucocerebrosidase activity and the subsequent accumulation of the enzyme's metabolites, principally glucosylsphingosine and glucosylceramide. There are three principal forms: Type I, which is the most common, is usually considered non-neuronopathic. Type II, III and IIIc manifest earlier and have neurological sequelae due to markedly reduced enzyme activity. Gaucher's can be associated with ophthalmological sequelae but these have not been systematically reviewed. We therefore performed a comprehensive literature review of all such ophthalmic abnormalities associated with the different types of Gaucher disease. We systematically searched the literature (1950 - present) for functional and structural ocular abnormalities arising in patients with Gaucher disease and found that all subtypes can be associated with ophthalmic abnormalities; these range from recently described intraocular lesions to disease involving the adnexae, peripheral nerves and brain. In summary, Gaucher can affect most parts of the eye. Rarely is it sight-threatening; some but not all manifestations are amenable to treatment, including with enzyme replacement and substrate reduction therapy. Retinal involvement is rare but patients with ocular manifestations should be monitored and treated early to reduce the risk of progression and further complications. As Gaucher disease is also associated with Parkinsons disease and may also confer an increased risk of malignancy (particularly haematological forms and melanoma), any ocular abnormalities should be fully investigated to exclude these potential underlying conditions.

T2-relaxation mapping and fat fraction assessment to objectively quantify clinical activity in thyroid eye disease: an initial feasibility study.

Imaging in thyroid eye disease (TED) is used to exclude other diagnoses, assess for apical crowding and plan surgery. But to quantify TED activity objectively, subjective clinical scoring assessments remain the norm. Magnetic resonance imaging (MRI) T2-relaxation times correlate with extra-ocular muscle (EOM) inflammation, but are confounded by signal from fat. We investigated whether T2-relaxation mapping in combination with fat fraction (FF) measurements could quantify disease activity in EOMs objectively. Sixty-two TED patients and six controls were enroled for coronal short tau inversion recovery (STIR), T2 multi-echo fast-spin echo and multi-echo fast-gradient echo MRI of the orbits. STIR signal intensity ratios (SIRs), T2-relaxation times and percentage FF were derived for inferior, lateral, superior and medial recti bilaterally. Twelve patients were re-scanned following immunosuppressive treatment. The results found a positive correlation for all subjects between T2 and SIR (p < 0.001), but only mean T2 differed significantly between patients and controls (p < 0.001). We measured FF in EOMs for the first time and found it greater in TED (p < 0.001). There was also a significant reduction in mean T2 after treatment, with a corresponding reduction in the clinical activity score (CAS) in almost all patients. We show that T2-relaxation times differentiate between normal and inflamed EOMs and are responsive to treatment. Combined, uniquely, with FF measurement in EOMs, an objective, quantitative marker of inflammation in TED-affected muscles could be derived. T2-relaxation times mirrored improvements in CAS after treatment, occasionally preceding them. Rarely, they diverged, suggesting limitations in the CAS as a disease burden marker.