Propranolol responsiveness in vascular tumors is not determined by qualitative differences in adrenergic receptors

Topical timolol: An effective treatment option for agminated pyogenic granuloma

We present three patients with agminated pyogenic granulomas who experienced significant decrease in size and bleeding with treatment with topical timolol solution with minimal side effects. One patient had complete clinical resolution. For patients with agminated pyogenic granuloma who may otherwise have limited treatment options, timolol is an effective potential solution.

Medical Management of Vascular Anomalies

PURPOSE OF REVIEW

This chapter will summarize the most recent literature regarding the current state of medical treatment for vascular anomalies.

RECENT FINDINGS

Research into the biology of these anomalies has strengthened our understanding of each anomaly and has helped to pave the way for more tailored treatment options involving molecular and/or genetic targets.

SUMMARY

While there is still a role for surgical intervention, medical therapies that target the etiology of vascular anomalies may represent an alternative or adjunctive approach in the management of these lesions.

Expression of β-Adrenergic Receptor Subtypes in Proliferative, Involuted, and Propranolol-Responsive Infantile Hemangiomas

Importance

Propranolol hydrochloride has become the primary medical treatment for problematic infantile hemangioma; however, the expression of propranolol's target receptors during growth, involution, and treatment of hemangioma remains unclear.

Objective

To measure and compare the expression of β1-, β2-, and β3-adrenergic receptors (ADBR1, ADBR2, and ADBR3, respectively) in proliferative (n = 10), involuted (n = 11), and propranolol-responsive (n = 12) hemangioma tissue.

Design, Setting, and Participants

Infantile hemangioma specimens were harvested for molecular investigation. Messenger RNA (mRNA) expression of the ADBR1, ADBR2, and ADBR3 genes was detected by real-time polymerase chain reaction. Protein level expression was measured by Western blot and standardized with densitometry. A total of 33 specimens were collected from patients in a tertiary pediatric hospital who underwent excision of problematic hemangiomas. This study was conducted from January 18, 2011, to September 24, 2013, and data analysis was performed from February 25, 2015, to June 25, 2016.

Results

Of the 33 patients included, 21 were female (64%). The mean (SD) patient age at the time of excision was 7 (2.5) months for the proliferative group lesions, 23.5 (10) months for the involuted group, and 16 (10) months for the propranolol group. The mean level of ADBR1 mRNA expression was significantly higher in proliferative hemangioma than in propranolol-responsive hemangioma (1.05 [0.56] vs 0.52 [0.36]; P = .01; 95% CI, 0.12-0.94). There was no difference in ADBR2 expression among the groups. Protein expression of ADBR3 was significantly higher in involuted (0.64 [0.12] vs 0.26 [0.04]; P < .01; 95% CI, 0.26-0.49) and propranolol-responsive hemangioma (0.66 [0.31] vs 0.26 [0.04]; P = .01; 95% CI, 0.16-0.68) compared with proliferative hemangioma.

Conclusions and Relevance

These data demonstrate the variable expression of ADBR subtypes among infantile hemangiomas during growth, involution, and response to treatment. These findings may have clinical implications regarding the use of selective vs nonselective β-blockade.

Level of Evidence

2.

Sympathetic nervous system regulation of the tumour microenvironment

The peripheral autonomic nervous system (ANS) is known to regulate gene expression in primary tumours and their surrounding microenvironment. Activation of the sympathetic division of the ANS in particular modulates gene expression programmes that promote metastasis of solid tumours by stimulating macrophage infiltration, inflammation, angiogenesis, epithelial-mesenchymal transition and tumour invasion, and by inhibiting cellular immune responses and programmed cell death. Haematological cancers are modulated by sympathetic nervous system (SNS) regulation of stem cell biology and haematopoietic differentiation programmes. In addition to identifying a molecular basis for physiologic stress effects on cancer, these findings have also identified new pharmacological strategies to inhibit cancer progression in vivo.

Multicenter Evaluation of the Effectiveness of Systemic Propranolol in the Treatment of Airway Hemangiomas

Objective

To evaluate the effectiveness of systemic propranolol in airway infantile hemangioma (AIH) treatment.

Design

Case series with chart review.

Participants

Patients with AIH treated with propranolol between 2009 and 2012 with at least a 1-year follow-up.

Outcomes

Presenting age, treating institution, syndrome presence, presenting AIH stage, endoscopy status, propranolol initiation location/dose/duration, time to stridor resolution, adjunctive medical and surgical therapy, and treatment-associated complications.

Results

Twenty-seven patients met inclusion criteria. Average age of diagnosis was 2.3 months (range, 1-5 months). The AIHs were stage 1 in 7 of 27 (26%), stage 2 in 12 of 27 (44%), and stage 3 in 8 of 27 (30%). Propranolol initiation was inpatient in 25 of 27 (93%) and outpatient in 2 of 27 (7%). Propranolol dose was maintained at 2 mg/kg/d in all patients for a minimum of 7 months (range, 7-34 months; median, 15 months). Stridor was eliminated within 24 hours or less of propranolol initiation in 23 of 27 (85%). At diagnosis, staging and propranolol initiation in 11 of 27 (41%) were managed with propranolol alone; the remaining 16 of 27 (59%) also had a steroid injection. The use of adjuvant therapy at the time of propranolol initiation and the size of the AIH were not statistically correlated. Twelve patients had additional treatments after the initiation of propranolol due to recurrence of respiratory symptoms, 1 of 27 (4%) of whom was considered a nonresponder. No complications related to propranolol use were noted.

Conclusions

This multisite study of AIH treatment with propranolol demonstrates similar effectiveness to surgical treatment modalities. Propranolol therapy for AIH had no complications, had potentially lower resource utilization, and should be considered a first-line AIH treatment.

Mechanisms of propranolol action in infantile hemangioma

Infantile hemangioma is a common tumor of infancy. Although most hemangiomas spontaneously regress, treatment is indicated based on complications, risk to organ development and function, and disfigurement. The serendipitous discovery of propranolol, a non-selective β-adrenergic receptor blocker, as an effective means to regress hemangiomas has made this a first-line therapy for hemangioma patients. Propranolol has shown remarkable response rates. There are, however, some adverse effects, which include changes in sleep, acrocyanosis, hypotension, and hypoglycemia. Over the last few years, researchers have focused on understanding the mechanisms by which propranolol causes hemangioma regression. This has entailed study of cultured vascular endothelial cells including endothelial cells isolated from hemangioma patients. In this article, we review recent studies offering potential mechanisms of how various cell types found in hemangioma may respond to propranolol.