Functional and Histologic Changes in the Lacrimal Gland After Botulinum Toxin Injection

The Volumetric Effect of Botulinum Toxin Type A Injection on the Parotid Gland: A Randomized Controlled Trial

BACKGROUND

Botulinum neurotoxin type A (BTX-A) to the masseter muscle is a useful tool for the aesthetic narrowing of the width of the lower face. The administration of BTX-A to visible parotid glands is also effective to reduce lower facial width. However, no studies have quantitatively analyzed the effect of BTX-A on the parotid glands.

METHODS

The purpose of this study was to confirm the impact of BTX-A injection on the parotid gland and to suggest the effective dosage of BTX-A in facial slimming. This study was conducted by selecting patients who desired facial slimming from among patients who required surgery for a facial bone fracture. Patients undergoing BTX-A injection were randomized to high-dose, low-dose, and placebo groups, and different doses of BTX-A for each group were injected into both parotid glands during facial bone surgery.

RESULTS

A total of 30 patients were enrolled in this study. Ten patients in the high-dose group, eight in the low-dose group, and nine in the control group completed the clinical trial. There were significant changes in both the high- and low-dose groups compared with the control group ( P < 0.001, P < 0.001), and in interaction of time and group ( P < 0.001). Volume recovery after 3 months was found in 7.6% in the high-dose group and in 4.8% in the low-dose group.

CONCLUSION

BTX-A injection into parotid glands can be an effective treatment option in managing salivary gland enlargement for lower face contouring.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

Current practice trends for lacrimal gland neurotoxin in the management of epiphora-a BOPSS survey

PURPOSE

Injection of botulinum neurotoxin A (BoNTA) to the lacrimal gland (LG) offers a simple and effective treatment in the management of epiphora. However, there is little data on current practice trends or uptake as an alternative to surgery. This study assesses current practice trends of such treatment amongst BOPSS (British Oculoplastic Surgery Society) members.

METHODS

All consultant BOPSS members were invited to participate in a web-based survey which consisted of 5 questions, with a reminder invitation to participate. The role, dose, potential side effects, use as an alternative to surgical intervention, and impact on service delivery were assessed.

RESULTS

Fifty-one BOPSS consultants (43% uptake) completed the survey. Ninety percent of respondents were regularly using LG BoNTA in their management of epiphora. The main indicators for considering BoNTA use were medical comorbidities and elderly patients. The mean first treatment dose of Botox® was 3.6 units (SD 1.5). Diplopia and ptosis complications were always discussed in the consent for treatment in addition to dry eye. Twenty-five percent of surgeons reported doing less conjunctivo-dacryocystorhinostomies (cDCR) due to the availability of LG BoNTA. No respondents felt that the requirement for repeated BoNTA treatments was impacting on their service delivery.

CONCLUSION

Uptake of LG BoNTA in the management of epiphora is at a similar rate to all other available treatments. As a result, respondents are performing less surgical procedures, particularly cDCR in patients at higher surgical morbidity.

MicroRNA-mRNA expression profiles and functional network after injection of botulinum toxin type A into submandibular glands

Botulinum toxin type A (BTXA) is effective for the treatment of sialorrhea. MicroRNAs (miRNAs) have significant functions in salivary diseases, but the role of miRNAs during BTXA-inhibited salivary secretion is not yet clear. A total of 19 differentially expressed (DE) miRNAs and 1072 DE mRNAs were identified following BTXA injected into submandibular glands of rats (n = 4) through miRNA sequencing and microarray analysis. Bioinformatic analysis identified that several pathways may be associated with the inhibition of salivary secretion, such as the MAPK signalling pathway, tight junctions, and cytokine-cytokine receptor interaction. We predicted the target genes of DE miRNAs and established the miRNA-mRNA interaction network. The intersection of DE mRNAs and target genes of DE miRNAs was performed and seven mRNAs were obtained: Egr2, Paqr9, Zkscan1, Usp6n, Cyb561a3, Zfhx4, and Clic5. These findings explore the mechanism of BTXA in inhibiting salivary secretion and probably will provide new ideas for clinical application.

Transconjunctival versus Transcutaneous Injection of Botulinum Toxin into the Lacrimal Gland to Reduce Lacrimal Production: A Randomized Controlled Trial

The purpose of this study was to determine and compare the effects between injecting botulinum toxin A (BTX-A) transconjunctivally into the palpebral lobe and transcutaneously into the orbital lobe of the lacrimal gland in patients with epiphora due to lacrimal outflow obstruction. This randomized controlled study included 53 eyes of 31 patients with unilateral or bilateral epiphora. Patients were randomly allocated to receive an injection of BTX-A (3 units) either transconjunctivally (n = 15, 25 eyes) or transcutaneously (n = 16, 28 eyes). For objective assessments, the tear meniscus height and Schirmer's I test with topical anesthesia were measured at baseline and after 2, 6, 12, and 24 weeks of follow-up. Subjective evaluations were performed using the Munk score. After BTX-A injection, patients in both groups experienced significant objective and subjective reductions in tearing at all follow-up times compared to pre-injection (success rate 86.8%), and the effect lasted for a mean duration of 5.63 months. The two delivery routes showed similar clinical effectiveness for a single injected dose of BTX-A. In conclusion, injecting BTX-A via either a transconjunctival or transcutaneous route helps to reduce normal tear production and results in significant improvements in the symptoms in patients with epiphora.

Repeated injections of botulinum toxin-A for epiphora in lacrimal drainage disorders: qualitative and quantitative assessment

PURPOSE

To report the outcome of repeated botulinum toxin-A (BTA) injections in the lacrimal glands in patients with epiphora.

METHODS

We performed retrospective chart review of patients who were injected with 2.5 units of BTA in the lacrimal gland. Epiphora and tear production were assessed by the Munk score and Schirmer-1 test, respectively, pre-injection and at 1 and 3 months post injection. Regarding repeated injections, the effects of the first were compared to those of the second and third injections.

RESULTS

Forty-six eyes of 35 patients had an average of 2.3 injections per eye (range, 1-6). The mean Munk score significantly decreased from 3.72 to 1.87 at 1 month (p < 0.001) and 2.21 at 3 months (p < 0.001) after injection. The mean Schirmer-1 score also significantly decreased from 15.35 mm to 10.52 mm at 1 month (p < 0.001) and 12.48 mm at 3 months (p < 0.001) after injection. The mean reduction rates of Munk and Schirmer-1 scores after the second (66.1% and 29.8%, respectively) and the third injections (56.1% and 23.3%, respectively) were not significantly different from those after the first injection (63.3% and 26.1%, respectively) (p > 0.05 for each comparison). There was a significant correlation between the difficulty in exposing the lacrimal gland for injection and the risk of complication (p = 0.017).

CONCLUSION

BTA injection in the lacrimal gland showed favourable outcomes; repeated injections did not compromise efficacy. BTA injection can be safely repeated for epiphora, especially in patients whose lacrimal gland can be easily exposed.

A Review of Periocular Botulinum Neurotoxin on the Tear Film Homeostasis and the Ocular Surface Change

Clinical usage of botulinum neurotoxin (BoNT) in ophthalmology has dramatically increased since the 1980s and has become one of the most widely used agents for treating facial movement disorders, autonomic dysfunction and aesthetic wrinkles. Despite its high efficacy, there are some complications with periocular BoNT injections due to its chemodenervation effect. Among these, there is still controversy over the BoNT effect on tear film homeostasis and the ocular surface. A periocular BoNT injection could dry the eye by reducing tear production of the lacrimal gland and increase tear evaporation due to potential eyelid malposition and abnormal blinks. On the contrary, the injection of BoNT in the medial eyelids could treat dry eye disease by impairing lacrimal drainage. Regarding the ocular surface change, corneal astigmatism and high-order aberrations may decrease due to less eyelid tension. In conclusion, the entire awareness of the effect of BoNT and the patients’ ocular condition is crucial for successful and safe results.

A review on use of botulinum toxin for intractable lacrimal drainage disorders

PURPOSE

To review the published literature on botulinum toxin (BTX) for epiphora secondary to refractory lacrimal drainage disorders.

METHODS

The authors performed a Pub Med search of all articles published in English on BTX injection into lacrimal gland for epiphora secondary to lacrimal drainage disorders. Relevant cross-references were obtained from the resultant studies. Data reviewed included demographics, indications, dose of BTX, number of injections, transconjunctival or transcutaneous route, outcomes and complications. Animal experiments of BTX into lacrimal gland were included and analyzed separately.

RESULTS

Botulinum toxin injection into lacrimal gland, in animal studies, has shown to reduce the tear volume significantly lasting for approximately a month without any histological changes. The major indications have been refractory canalicular obstructions and functional epiphora. The commonly used dose was 2.5 U. Outcomes in the few studies published are encouraging with transient ptosis being the most common complication.

CONCLUSIONS

Botulinum toxin into the lacrimal gland is a minimally invasive alternative in cases of refractory epiphora secondary to lacrimal drainage disorders. In these subsets of patients, the reported concentrations, dosage and outcome measures are variable and need larger studies for standardization.

Diabetic retinopathy: Proteomic approaches to help the differential diagnosis and to understand the underlying molecular mechanisms

Diabetic retinopathy is the most common diabetic eye disease and a leading cause of blindness among patients with diabetes. The appearance and the severity of the symptoms correlate with the duration of diabetes and poor blood glucose level management. Diabetic retinopathy is also categorized as a chronic low-level inflammatory disease; the high blood glucose level promotes the accumulation of the advanced glycation end products and leads to the stimulation of monocytes and macrophages. Examination of protein level alterations in tears using state-of the art proteomics techniques have identified several proteins as possible biomarkers for the different stages of the diabetic retinopathy. Some of the differentially expressed tear proteins have a role in the barrier function of tears linking the diabetic retinopathy with another eye complication of diabetes, namely the diabetic keratopathy resulting in impaired wound healing. Understanding the molecular events leading to the eye complications caused by hyperglycemia may help the identification of novel biomarkers as well as therapeutic targets in order to improve quality of life of diabetic patients.

BIOLOGICAL SIGNIFICANCE

Diabetic retinopathy (DR), the leading cause of blindness among diabetic patients can develop without any serious symptoms therefore the early detection is crucial. Because of the increasing prevalence there is a high need for improved screening methods able to diagnose DR as soon as possible. The non-invasive collection and the relatively high protein concentration make the tear fluid a good source for biomarker discovery helping the early diagnosis. In this work we have reviewed the administration of advanced proteomics techniques used in tear biomarker studies and the identified biomarkers with potential to improve the already existing screening methods for DR detection.