The Use of Sirolimus for Treatment of Orbital Lymphatic Malformations: A Systematic Review

Multidisciplinary therapeutic strategy with appropriate timing and modalities for treating cervicofacial lymphatic malformations in children

PURPOSE

The study reviewed a multidisciplinary approach to treating cervicofacial lymphatic malformations (CFLMs) in children.

METHODS

Between 2007 and 2023, 53 children with CFLMs were treated with the median on-set age of 5 months (0-165) at our institute. For infants, airway management, including possible tracheotomy was prioritized, and a "wait-and-see" policy was adopted to expect spontaneous regression. Once children reached one year of age or diagnosed after infancy, OK-432 sclerotherapy and surgical treatment with/without sirolimus were considered for residual lesions.

RESULTS

The median follow-up period was 38 months (0-169). Among 30 infants, tracheostomy was performed in 4 patients, with 3 successfully closed after treatment. Thirteen patients showed excellent improvement without treatment. Sclerotherapy was performed in 15 patients, and partial resection in 5. Six patients were treated with sirolimus and showed moderate shrinkage or cessation of bleeding. Overall, 23 of 30 infants showed moderate to excellent improvement. For the 23 patients diagnosed after infancy, 16 improved without treatment, and 7 showed moderate to excellent improvement with sclerotherapy.

CONCLUSIONS

The study concluded that early sclerotherapy for infants, particularly around the airway, poses risks, and tracheostomy might be necessary. The comprehensive strategy including "wait-and-see," sclerotherapy, sirolimus treatment, and timely surgery significantly improved the patients' quality of life.

Efficacy of Oral Sirolimus Therapy for Adult Orbital Slow-Flow Vascular Malformations: A Volumetric Evaluation

Orbital lymphatic malformations significantly impair visual function, with inflammation contributing to corneal dryness and diplopia due to exophthalmos. Disease progression may lead to blindness, and in severe cases, exenteration may be required. We treated two symptomatic cases of adult orbital slow-flow vascular malformations with oral sirolimus. Although the patients maintained good visual acuity before treatment, prominent exophthalmos posed a substantial risk to visual function. After medication, eyeball proptosis improved significantly in all cases, with magnetic resonance imaging volumetry analysis showing a reduction of 28.5% to 82.1%. This treatment demonstrated minimal side effects and may serve as an initial therapeutic option.

Targeted therapy and immunotherapy for orbital and periorbital tumors: a major review

Traditionally, for patients who are poor candidates for surgery and/or radiotherapy, palliative chemotherapy is often offered but with significant toxic side effects. However, recent advancements in our understanding of tumor biology and molecular genetics have brought new understanding to the molecular pathways of certain tumors and cancers. This has ushered in a new era of precision medicine specific to a tumor or cancer treatment pathway (targeted therapy) or directed to host-tumor responses (immunotherapy). This article will focus on recent updates in the application of available targeted and immunotherapy for managing orbital and periorbital tumors and tumor-like conditions, which include cutaneous basal cell carcinoma, cutaneous squamous cell carcinoma, cutaneous melanoma, Merkel cell carcinoma, sebaceous gland carcinoma, solitary fibrous tumor, dermatofibrosarcoma protuberans, orbital meningioma, neurofibromatosis, Langerhans cell histiocytosis, ocular adnexal lymphoma, orbital lymphatic malformation, and adenoid cystic carcinoma.

Intraorbital lymphatic-venous malformation in an adult patient: is sirolimus the key?

Intraorbital lymphatic-venous malformations are rare lesions that represent a therapeutic challenge given their location and high rate of recurrence, with only a few cases in adult patients having been published in the literature. We present the case of a 30-year-old male with a right intraorbital lymphatic-venous malformation treated with sirolimus at a dose of 4 mg/day with complete clinical and radiologic remission. Mild cold-like symptoms ensued during the first week of treatment and elevation of liver function enzymes and D-dimer occurred in the context of acute SARS-CoV-2 pneumonia. No major adverse effects were documented. After 18 months of treatment, the patient remains asymptomatic and ophthalmologic examinations including optical coherence tomography and visual field test are within normal values.

Immunosuppressants against acute kidney injury: what to prefer or to avoid?

BACKGROUND

Acute kidney injury (AKI) is a critical global health issue associated with high mortality rates, particularly in patients undergoing renal transplants and major surgeries. These individuals often receive immunosuppressants to dampen immune responses, but the impact of these drugs on AKI remains unclear.

OBJECTIVE

This review aims to provide a detailed understanding of the effects of different classes of immunosuppressants against AKI, elucidating their role in either exacerbating or mitigating the occurrence or progression of AKI.

METHODS

Several preclinical and clinical reports were analyzed to evaluate the impact of various immunosuppressants on AKI. Relevant preclinical and clinical studies were reviewed through different databases such as Scopus, PubMed, Google Scholar, and ScienceDirect, and official websites like https://clinicaltrials.gov to understand the mechanisms underlying the effects of immunosuppressants on kidney function.

RESULTS AND DISCUSSION

Specific immunosuppressants have been linked to the progression of AKI, while others demonstrate renoprotective effects. However, there is no consensus on the preferred or avoided immunosuppressants for AKI patients. This review outlines the classes of immunosuppressants commonly used and their impact on AKI, providing guidance for physicians in selecting appropriate drugs to prevent or ameliorate AKI.

CONCLUSION

Understanding the effects of immunosuppressants on AKI is crucial for optimizing patient care. This review highlights the need for further research to determine the most suitable immunosuppressants for AKI patients, considering both their efficacy and potential side effects.

mTOR Pathway Substrates Present High Activation in Vascular Malformations and Significantly Decrease with Age

BACKGROUND

Vascular anomalies often result in aesthetic flaws, pain, and impair the quality of life. They require challenging treatments that frequently do not provide the desired results. The mammalian target of rapamycin (mTOR) is directly involved in the development of these malformations. However, the exact mechanism behind mTOR dysregulation has not been unambiguously defined. The purpose of this study is to investigate the activation of selected substrates of mTOR to partially assess its involvement in the disease process.

METHODS

We analyzed tissue samples collected from patients with vascular anomalies treated in our department. We included patients with histopathological diagnoses of lymphatic, venous, capillary malformations, mixed lesions, and a control group of healthy skin samples. We stained the samples using H and E and immunohistochemistry. We used primary antibodies against p70 S6 Kinase, 4EBP1, and p-4EBP1. We graded their color reactions. The statistical analyses were performed using the FactoMineR and factoextra R v.4.1 packages. p-values < 0.05 were considered statistically significant.

RESULTS

The analysis of 82 patients showed that healthy tissue vessels expressed lower levels of tested mTOR pathway substrates compared to high activation in vascular malformations. Elevated substrate expression in a comparison between sexes revealed higher P-4EBP1 expression in the female malformation group. We observed a decrease in mTOR substrate expression with age.

CONCLUSION

The higher expression of mTOR substrates in vascular malformations compared to healthy tissue confirms their involvement in abnormal vascular development. Age-related changes in mTOR substrate expression highlight the need for timely intervention. Our study contributes to the understanding of the mTOR signaling pathway in vascular malformations and highlights its potential as a therapeutic target, contributing to personalized medicine.

Differences in Efficacy and Safety of Sirolimus and Sildenafil in Pediatric Lymphatic Malformations

OBJECTIVES

To explore the differences in the efficacy and safety of oral sirolimus and sildenafil in the treatment of pediatric intractable lymphatic malformations (LMs).

METHODS

From January 2014 to May 2022, we retrospectively enrolled children with intractable LMs treated with oral drugs (sirolimus or sildenafil) and divided the patients into sirolimus and sildenafil groups from Beijing Children's Hospital (BCH). Clinical features, treatment, and follow-up data were collected and analyzed. The indicators were the ratio of reduction in lesion volume pre and posttreatment, the number of patients with improved clinical symptoms, and adverse reactions to the two drugs.

RESULTS

Twenty-four children in the sildenafil group and 31 children in the sirolimus group were included in the present study. The effective rate in the sildenafil group was 54.2% (13/24), with a median lesion volume reduction ratio of 0.32 (-0.23, 0.89) and clinical symptoms improved in 19 patients (79.2%). On the contrary, the effective rate in the sirolimus group was 93.5% (29/31), with a median lesion volume reduction ratio of 0.68 (0.34, 0.96), and clinical symptoms improved in 30 patients (96.8%). There were significant differences (p < 0.05) between the two groups. Regarding safety, four patients in the sildenafil group and 23 patients in the sirolimus group with mild adverse reactions were reported.

CONCLUSION

Both sildenafil and sirolimus can reduce the volume of LMs and improve clinical symptoms in partial patients with intractable LMs. Sirolimus is more effective than sildenafil and the adverse reactions associated with both drugs are mild and controllable.

LEVEL OF EVIDENCE

III Laryngoscope, 133:3192-3199, 2023.

French national diagnosis and care protocol (PNDS, protocole national de diagnostic et de soins): cystic lymphatic malformations

Cystic lymphatic malformations (LMs) are rare chronic conditions which management differs according to the type (macrocystic LMs, microcystic LMs or both). Studies are lacking due to rarity of the pathology. We aimed to establish a French National Diagnosis and Care Protocol (PNDS: Protocole National de Diagnostic et de Soins), to provide health professionals with free open access synthesis on optimal management and care of patients with LMs ( https://www.has-sante.fr/upload/docs/application/pdf/2021-03/malformations_lymphatiques_kystiques_-_pnds.pdf ). The process included a critical review of the literature and multidisciplinary expert consensus. LMs are congenital but are not always discovered at birth. Nearly 75% of them are located in the head and neck because of the highly dense lymphatic system in this region. Physical examination (showing painless masses with normal skin color and depressible consistency, or cutaneous/mucosal lymphangiectasia) and color Doppler ultrasonography, usually allow for diagnosis. MRI (involving T2 sequences with fat saturation in at least two spatial planes) is the tool of choice for evaluating anatomical extension, characterizing lesions (microcystic and macrocystic), and before considering therapeutic management. A biopsy, coupled to a blood sample, can also be used for molecular biology analyses, to search for activating mutations of the PIK3CA gene, particularly with LM integrating in a syndromic form (CLOVES or Klippel-Trenaunay syndrome) but also in certain isolated (or common) LMs. The spontaneous evolution of LMs, in particular microcystic forms, is often toward progressive aggravation, with an increase in the number of vesicles, thickening, increased oozing and bleeding, while pure macrocystic LMs may regress due to "natural sclerosis", i.e. fibrosis secondary to an inflammatory reorganization after common infantile infections. In case of voluminous LMs or syndromic forms, functional and psychological repercussions can be major, deteriorating the patient's quality of life. LMs must be treated by physicians integrated in multidisciplinary teams, and be personalized. Management is a life-long process that involves one or several of these therapies: conservative management, physical therapy (compression), sclerotherapy, surgery, drugs such as mTOR inhibitors (sirolimus), that has shown efficacy in decreasing the volume of LMs, and, more recently, PI3K-inhibitors in syndromic forms. Psychological and social support is necessary, taking into account the patient and his family.

Sirolimus in the Treatment of Microcystic Lymphatic Malformations: A Systematic Review

Background: Genetic alterations in lymphatic development can lead to microcystic lymphatic malformations (micro LMs). LMs can have both microcystic and macrocytic components or be exclusively one or the other. LMs can result in serious, sometimes life-threatening, sequelae. Absent consensus guidelines, treatment has been largely empiric. Recent advances in our understanding of the pathogenesis of micro LMs have provided a foundation for novel therapeutic approaches. This review examines clinical data over the last 10 years on the role of sirolimus, an inhibitor of the PI3K/AKT/mTOR signaling pathway implicated in micro LM development, in the treatment of micro LM. Methods and Results: Systematic review of published clinical studies from January 1, 2011, to July 15, 2021, using the PubMed, Google Scholar, and Cochrane Reviews databases, and utilizing delimiters to focus specifically on sirolimus in the treatment of micro LM. A total of 16 studies were identified (13 case studies or case reviews; 3 prospective) that included 52 subjects treated with topical (n = 15) or oral (n = 37) sirolimus for micro LM. Clinically meaningful, long-term improvement (up to 3 years) was noted in 92% (46/50), mostly previously treated subjects. Sirolimus yielded improvements in key manifestations such as lymphatic leakage, bleeding, vesicle bulk, pain, and skin discoloration. Some subjects experienced a rapid onset of effect (within 2 weeks). No unexpected adverse events were seen. Conclusion: Sirolimus appears to be an effective and safe option in the management of cutaneous and complex micro LM. However, prospective, controlled trials are clearly needed to accurately elucidate the benefits and risks of sirolimus in the management of micro LM. ClinicalTrials.gov Identifier: NCT05050149.

Orbital Vascular Malformation: Successful Outcome in Two Patients Treated With Rapamycin

Combined vascular malformations are complex vascular anomalies that have high morbidity and therefore, therapeutic strategies are hard to establish. In this report, we aim to present two pediatric cases of ocular combined vascular malformations successfully treated with Rapamycin. This article is protected by copyright. All rights reserved.

Vascular lesions of the pediatric orbit: A radiological walkthrough

Vascular anomalies of the pediatric orbit represent a heterogeneous group that include both vascular tumors and vascular malformations. The disorder may initially be silent and then associated with symptoms and/or function damage, depending on the type of vascular anomaly and its extension. Vascular tumors include benign, locally aggressive (or borderline) and malignant forms while vascular malformations are divided into "simple", "combined" and syndromic, or "low flow" or "high flow". Both entities can arise in isolation or as part of syndromes. In this review, we describe the imaging findings of the vascular lesions of the orbit in the pediatric population, which are key to obtain a correct diagnosis and to guide the appropriate treatment in the light of the new genetic and molecular discoveries, and the role of the radiologist in their multidisciplinary management. We will also touch upon the main syndromes associated with orbital vascular abnormalities.

Novel treatment of recurrent orbital venolymphatic malformation with sirolimus and rivaroxaban

Orbital venolymphatic malformations are rare vascular malformations that typically appear early in life and harbor acute and chronic threats to vision. Historically, there are four categories of management: observation, medication, sclerotherapy, and surgery. Currently, there is neither a gold standard for treatment nor randomized control trials comparing treatments.The authors present a 20-year-old male who presented with spontaneous hemorrhage of an orbital venolymphatic malformation occurring with increased frequency and involving more of the posterior orbit. Surgery and sclerotherapy were not feasible options due to the extensive intraorbital and intracranial involvement of the venolymphatic malformation. Systemic steroids treated symptoms but was not curative. To this end, a combination of sirolimus, an mTOR inhibitor, and rivaroxaban, a factor Xa inhibitor, were used to reduce the size of the lesion and minimize the risk of thromboembolic events. This treatment has successfully kept the patient's symptoms in remission for greater than 2 years.

Development and Validation of a Bioanalytical LC-MS/MS Method for Simultaneous Determination of Sirolimus in Porcine Whole Blood and Lung Tissue and Pharmacokinetic Application with Coronary Stents

Sirolimus is a hydrophobic macrolide compound that has been used for long-term immunosuppressive therapy, prevention of restenosis, and treatment of lymphangioleiomyomatosis. In this study, a simple and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated for the simultaneous determination of sirolimus in both porcine whole blood and lung tissue. Blood and lung tissue homogenates were deproteinized with acetonitrile and injected into the LC-MS/MS system for analysis using the positive electrospray ionization mode. The drug was separated on a C18 reversed phase column with a gradient mobile phase (ammonium formate buffer (5 mM) with 0.1% formic acid and acetonitrile) at 0.2 mL/min. The selected reaction monitoring transitions of m/z 931.5 → 864.4 and m/z 809.5 → 756.5 were applied for sirolimus and ascomycin (the internal standard, IS), respectively. The method was selective and linear over a concentration range of 0.5–50 ng/mL. The method was validated for sensitivity, accuracy, precision, extraction recovery, matrix effect, and stability in porcine whole blood and lung tissue homogenates, and all values were within acceptable ranges. The method was applied to a pharmacokinetic study to quantitate sirolimus levels in porcine blood and its distribution in lung tissue following the application of stents in the porcine coronary arteries. It enabled the quantification of sirolimus concentration until 2 and 14 days in blood and in lung tissue, respectively. This method would be appropriate for both routine porcine pharmacokinetic and bio-distribution studies of sirolimus formulations.

Thrombosed orbital arteriovenous malformation in a patient with lymphangioleiomyomatosis

A 47 year-old female with lymphangioleiomyomatosis developed right periorbital pain worsened while chewing, six months prior. Neuroimaging demonstrated a heterogenous inferotemporal right orbital mass extending through the inferior orbital fissure into the temporalis fossa, with flow voids. Given the patient's past medical history, the lesion was presumed to be a perivascular epithelioid cell tumor, a manifestation of lymphangioleiomyomatosis. A lateral orbitotomy revealed a well-circumscribed bluish-red lesion with areas of hemorrhage that was resected in total. Histopathology, however, was consistent with a thrombosed orbital arteriovenous malformation likely arising from the zygomaticotemporal neurovascular bundle. Lymphangioleiomyomatosis is a rare progressive disease that causes cystic destruction of the lungs and is frequently associated with extrapulmonary tumor infiltration, typically of the kidney and liver. Lymphangiomyoleiomyomatosis cell pathogenesis includes a pro-angiogenic micro-environment, classically expressing vascular endothelial factor-C and -D, which we postulate may have contributed to the development of the orbital arteriovenous malformation.