NF1 tumor suppressor in epidermal wound healing with special focus on wound healing in patients with type 1 neurofibromatosis

Altered actin dynamics is possibly implicated in the inhibition of mechanical stimulation-induced dermal fibroblast differentiation into myofibroblasts

The formation of hypertrophic scars and keloids is strongly associated with mechanical stimulation, and myofibroblasts are known to play a major role in abnormal scar formation. Wounds in patients with neurofibromatosis type 1 (NF1) become inconspicuous and lack the tendency to form abnormal scars. We hypothesized that there would be a unique response to mechanical stimulation and subsequent scar formation in NF1. To test this hypothesis, we investigated the molecular mechanisms of differentiation into myofibroblasts in NF1-derived fibroblasts and neurofibromin-depleted fibroblasts and examined actin dynamics, which is involved in fibroblast differentiation, with a focus on the pathway linking LIMK2/cofilin to actin dynamics. In normal fibroblasts, expression of α-smooth muscle actin (α-SMA), a marker of myofibroblasts, significantly increased after mechanical stimulation, whereas in NF1-derived and neurofibromin-depleted fibroblasts, α-SMA expression did not change. Phosphorylation of cofilin and subsequent actin polymerization did not increase in NF1-derived and neurofibromin-depleted fibroblasts after mechanical stimulation. Finally, in normal fibroblasts treated with Jasplakinolide, an actin stabilizer, α-SMA expression did not change after mechanical stimulation. Therefore, when neurofibromin was dysfunctional or depleted, subsequent actin polymerization did not occur in response to mechanical stimulation, which may have led to the unchanged expression of α-SMA. We believe this molecular pathway can be a potential therapeutic target for the treatment of abnormal scars.

Dermatologic Manifestations of Neurofibromatosis Type 1 and Emerging Treatments

Neurofibromatosis type 1 (NF1) is an autosomal dominant tumor predisposition syndrome that increases one's risk for both benign and malignant tumors. NF1 affects every organ in the body, but the most distinctive symptoms that are often the most bothersome to patients are the cutaneous manifestations, which can be unsightly, cause pain or pruritus, and have limited therapeutic options. In an effort to increase awareness of lesser-known dermatologic associations and to promote multidisciplinary care, we conducted a narrative review to shed light on dermatologic associations of NF1 as well as emerging treatment options. Topics covered include cutaneous neurofibromas, plexiform neurofibromas, diffuse neurofibromas, distinct nodular lesions, malignant peripheral nerve sheath tumors, glomus tumors, juvenile xanthogranulomas, skin cancer, and cutaneous T-cell lymphoma.

Treatment of cutaneous neurofibromas with carbon dioxide laser: Technique and patient experience

Cutaneous neurofibromas (cNF) are one of the hallmarks of neurofibromatosis 1 (NF1). The number of cNFs varies between individuals from a few to hundreds or even thousands and increases throughout adult life. cNFs cause a significant disease burden to adult patients and constitute an unmet need for therapy, since they may cause itch and pain and, being conspicuous and unsightly, stigmatize the patient. There is a lack of reports on how the outcome of various treatment options are perceived by the patients. Here we describe a technique for cNF removal using CO₂ laser, and report how patients experience the procedure. Questionnaires were sent to patients who had had CO₂ laser surgery in the French Referral Center for Neurofibromatoses, and in the Turku University Hospital, Finland, to retrospectively evaluate the patients' global satisfaction of the procedure, treatment indications, and reasons for withdrawal from treatment, if this was the case. The number of returned questionnaires was 233/473 in France and 23/27 in Finland. The results showed that the most important indications for cNF removal were esthetic, and pain and itch caused by the tumors. In general, the procedure was well tolerated, and the degree of satisfaction was 8-10 on a scale from 0 to 10. For those 30% who discontinued the tumor removal program, the main reasons were organizational constraints, a non-satisfactory esthetic result, too many cNFs to treat, or problems with healing. Thus, the CO₂ laser method is well tolerated but does not fully answer to the needs of the patients. Since medical treatment is not yet available, we encourage the use of laser removal of cNFs as a feasible method to decrease the tumor burden of the patients.

Ruptured tibial artery in neurofibromatosis type 1: A case report

Introduction

Neurofibromatosis type 1 (NF-1) or von Recklinghausen's disease, an autosomal dominant genetic disorder, is characterized by a café au lait spot and cutaneous neurofibromas. It typically involves the skin, nerves, bones, muscles, and eyes, and occasionally involves vascular complications and can lead to life-threatening hemorrhage.

Case presentation

We present the case of a 77-year-old female with a posterior tibial artery rupture with NF-1. She presented with sudden right lower leg swelling, pain, paresthesia, and paralysis; computed tomography images revealed popliteal artery aneurysm with surrounding hematoma, expanding from the posterior aspect of the knee to the calf. Diagnosed with compartment syndrome, due to a ruptured right popliteal artery aneurysm, she underwent prosthetic replacement of the popliteal aneurysm. Intraoperatively, the fragility of the popliteal artery was noted, although no perforation site was recognized despite the aneurysm; active bleeding originated from the hematoma between the calf muscles. Intraoperative digital subtraction angiography revealed an extravasation at the branch of the posterior tibial artery that was managed by coil embolization of the posterior tibial artery.

Clinical discussion

Although the frequency of NF-1 vasculopathy is unknown, vasculopathy is the second most common cause of mortality in patients with NF-1, after malignancy. The less invasive endovascular approach might be preferable for treating NF-1-related aneurysm. The NF-related vasculopathy lesion sites are diverse, and intraoperative angiography would help confirm the diagnosis.

Conclusion

NF-1-related vasculopathy may be associated with vascular fragility, and the endovascular approach might be preferable. Endovascular-first approach could have helped in correct diagnosis in the present case.

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Vasculopathy in neurofibromatosis type1 (NF-1) occurs in any blood vessels and preoperative diagnosis is sometimes difficult

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Open surgery for NF-1 vasculopathy is sometimes difficult due to vascular fragility

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Endovascular approach is not only less invasive, but also useful for diagnosis

Peripheral nerve sheath tumors of the upper extremity and hand in patients with neurofibromatosis type 1: topography of tumors and evaluation of surgical treatment in 62 patients

Objective: Neurofibromatosis type 1 (NF1) is an autosomal dominant tumor predisposition syndrome with a tendency to develop peripheral nerve sheath tumors (PNST). Plexiform neurofibromas (PNF) are detected in a high proportion of affected patients. The tumors can lead to severe disfigurement and are classified as precancerous. This study examines the surgical procedures that have been performed on large PNST of the upper limb and hand, and investigates whether a specific distribution pattern of the tumors can be detected in surgically treated cases.

Methods: Surgical procedures on the upper extremity and hand performed on patients with NF1 were evaluated at an interval of 25 years (1992–2016). Topography of the tumors was classified according to dermatomes. The number of interventions per patient, duration of operations, and complications of the interventions were registered. An overview of the surgical treatment of PNST of the upper limb and hand was obtained from the literature, with special consideration of the genetic background of treated tumors.

Results: One hundred and sixty-three surgical interventions on the upper limb and hand were performed in 62 patients with NF1 for the treatment of large PNST, predominantly PNF (age: mean value: 27.33 years, male: 33, female: 29; right side: 25, left side: 26, bilateral: 7). Surgical procedures lasted an average of 72.47 minutes. In approximately half of the patients, one surgical procedure was sufficient. Duration of stay in hospital was on average 7–11 days. Neurological complications were rarely noted and occurred only temporarily. There were no dermatomes affected by PNF with particular frequency. However, some dermatomes were more often simultaneously affected by a PNF at the same time as others.

Conclusion: Although the distribution pattern shows some accumulation of tumor localization, tumors are distributed evenly and show very variable size and extent in individual cases. Surgical treatment of PNF of the upper limb and hand helps alleviate the physical discomfort that these patients have from their disfiguring disease. Repeated interventions are necessary relatively often in order to adapt the tumorous region to the outline of the limb and to improve its function.

Proteomic and transcriptomic analyses to explain the pleiotropic effects of Ankaferd blood stopper

Ankaferd blood stopper is a standardized mixture of the plants Thymus vulgaris, Glycyrrhiza glabra, Vitis vinifera, Alpinia officinarum, and Urtica dioica and has been used as a topical hemostatic agent and with its clinical application established in randomized controlled trials and case reports. Ankaferd has been successfully used in gastrointestinal endobronchial mucosal and cutaneous bleedings and also in abdominal, thoracic, dental and oropharyngeal, and pelvic surgeries. Ankaferd’s hemostatic action is thought to form a protein complex with coagulation factors that facilitate adhesion of blood components. Besides its hemostatic action, Ankaferd has demonstrated pleiotropic effects, including anti-neoplastic and anti-microbial activities and tissue-healing properties; the underlying mechanisms for these have not been well studied. Ankaferd’s individual components were determined by proteomic and chemical analyses. Ankaferd also augments transcription of some transcription factors which is shown with transcriptomic analysis. The independent effects of these ingredients and augmented transcription factors are not known precisely. Here, we review what is known of Ankaferd blood stopper components from chemical, proteomic, and transcriptomic analyses and propose that individual components can explain some pleiotropic effects of Ankaferd. Certainly more research is needed focusing on individual ingredients of Ankaferd to elucidate their precise and effects.

Surgical care burden in orbito-temporal neurofibromatosis: Multiple procedures and surgical care duration analysis in 47 consecutive adult patients

Patients with orbito-temporal neurofibromatosis (OTNF) bear a heavy burden of surgical care. We studied 47 consecutive patients with OTNF from the French Neurofibromatosis 1 Referral Center cohort (n > 900), over a 15-year period to determine the clinical features most likely to predict repeat surgery and longer duration of surgical care. Forty-seven patients (5.2% of the NF1 patients' cohort) underwent 79 procedures with a 4.8 years average follow-up. Soft-tissue surgery had a high revision rate (19/45 patients), skeletal surgery did not (2/13 patients). Transosseous wire canthopexy and facial aesthetic unit remodeling were associated with stable outcome. Ptosis repair carried an unfavorable outcome, particularly in the presence of sphenoid dysplasia. Stable skeletal remodeling was achieved with polyethylene implants and/or cementoplasty. Multiple procedures were undertaken in 70% of patients and were predicted by the NF volume, canthopexy, skeletal dysplasia, or a Jackson's classification 2 and/or 3; but not by declining visual acuity. A classification based upon predictive risk of repeated procedures is proposed: Group 1: Isolated soft tissue infiltration not requiring levator palpebrae or canthal surgery; Group 2: Soft tissue involvement requiring ptosis repair or canthopexy, or NF great axis over 4.5 cm; Group 3: Presence of sphenoid dysplasia with pulsatile proptosis, regardless of visual acuity.

Hyperactive RAS/PI3-K/MAPK Signaling Cascade in Migration and Adhesion of Nf1 Haploinsufficient Mesenchymal Stem/Progenitor Cells

Neurofibromatosis type 1 (NF1) is an autosomal dominant disease caused by mutations in the NF1 tumor suppressor gene, which affect approximately 1 out of 3000 individuals. Patients with NF1 suffer from a range of malignant and nonmalignant manifestations such as plexiform neurofibromas and skeletal abnormalities. We previously demonstrated that Nf1 haploinsufficiency in mesenchymal stem/progenitor cells (MSPCs) results in impaired osteoblastic differentiation, which may be associated with the skeletal manifestations in NF1 patients. Here we sought to further ascertain the role of Nf1 in modulating the migration and adhesion of MSPCs of the Nf1 haploinsufficient (Nf1^+/−) mice. Nf1^+/− MSPCs demonstrated increased nuclear-cytoplasmic ratio, increased migration, and increased actin polymerization as compared to wild-type (WT) MSPCs. Additionally, Nf1^+/− MSPCs were noted to have significantly enhanced cell adhesion to fibronectin with selective affinity for CH271 with an overexpression of its complimentary receptor, CD49e. Nf1^+/− MSPCs also showed hyperactivation of phosphoinositide 3-kinase (PI3-K) and mitogen activated protein kinase (MAPK) signaling pathways when compared to WT MSPCs, which were both significantly reduced in the presence of their pharmacologic inhibitors, LY294002 and PD0325901, respectively. Collectively, our study suggests that both PI3-K and MAPK signaling pathways play a significant role in enhanced migration and adhesion of Nf1 haploinsufficient MSPCs.

Poor wound healing after pial synangiosis in 2 children with moyamoya vasculopathy associated with neurofibromatosis type 1

Wound healing is a key component of recovery for children with neurologic conditions undergoing neurosurgical procedures. Understanding factors that can impair wound healing aids in planning long-term clinical care. Children with neurofibromatosis type 1 are at risk for vasculopathies in the brain (including moyamoya vasculopathy) and in other organs, including the heart, lung, and skin. Neurofibromatosis 1 is caused by mutations in the gene for neurofibromin, a protein that plays a role in tissue maintenance and repair as well as tumor suppression. The authors report 2 children with neurofibromatosis 1-associated moyamoya vasculopathy who developed significant wound healing complications after pial synangiosis surgery. They discuss possible contributors to these complications, including the role of neurofibromin and the possibility of vasculopathy affecting the skin, and the implications of poor wound healing in pediatric neurology patients.

Tumors perturbing extracellular matrix biosynthesis. The case of von Recklinghausen's disease

This is a short review of neurofibromatosis-1 or von Recklinghausen's disease, due to a loss of function mutation of the gene neurofibromin-1, which normally inhibits the Ras MAPK-pathways. Among its symptoms, the strong oversynthesis of several collagen types designates this disease as producing a deregulation of extracellular matrix biosynthesis involved in tumor formation. Up to about 40% of the skin tumors consist of collagens. A short summary of the clinical manifestations and pathological and genetic mechanisms are also described.

Vasculopathy in two cases of NF1-related congenital pseudarthrosis

Neurofibromatosis type 1 (NF1) is a common dominantly inherited disease. More than half of NF1 patients suffer from skeletal manifestations, of which congenital pseudarthrosis of tibia (CPT) is one of the most incapacitating lesions. Two NF1 patients with CPT were operated, and the resected tissues were analyzed using immunohistochemistry and/or in situ hybridization for NF1 protein and mRNA, p-p44/42 MAPK, and S100 protein. Both patients displayed thick-walled arteries and veins with a small lumen within the fibrotic tissue in the vicinity of pseudarthrosis. Endothelial cells were highly positive for p-p44/42 MAPK. A subpopulation of cells surrounding the blood vessels was S100 protein-positive. However, the exact identity of the S100-positive cells remains to be elucidated. Neurofibromin mRNA and protein labeling was detected in both cell types. In conclusion, decreased NF1 function as a RAS-GAP in the endothelium may contribute to vascular thickening in CPT.