Clinical Features And Proteomics Of Pyogenic Granuloma In Children

Background Pyogenic granuloma(PG)is a common dermatological condition of acquired vascular hyperplasia of the skin and mucous membranes,accounting for about0.5% of all body swellings in childhood.It accounts for approximately 0.5% of all body surface swellings in childhood.pyogenic granuloma(PG)occurs in exposed areas,such as the head,face,neck,and toes,and begins as a pinpoint-sized red papule that rapidly grows into a smooth-surfaced,lobulated,bright-red to brownish-red nodule in a matter of days to weeks.To date,the clinical features of PG in a large sample size of children have not been reported.As the clinical presentation of PG is similar to many benign and malignant skin tumors,it is prone to misdiagnosis.The application of skin imaging techniques can improve the diagnostic accuracy of PG,reduce the misdiagnosis rate and decrease the number of non-essential tissue biopsies.However,there is no specific skin imaging analysis for PG in children.PG requires prompt treatment because it is prone to ulceration and bleeding and the lesions do not subside on their own.The commonly used treatments include local and systemic treatments,which differ in terms of lesion clearance,adverse effects,and recurrence rate,etc.595 nm pulsed fuel laser is widely used in the treatment of vascular diseases by using the principle of selective photothermal effect.The detailed etiology of PG occurrence is still unclear,and it is usually considered to be the result of an imbalance of angiogenesis-promoting and angiogenesis-suppressing factors due to various causes.Proteomics,which has been rapidly updated in recent years,is a systematic study of disease pathogenesis and is now widely used to investigate the pathogenesis of various complex skin diseases.There are no previous proteomic studies on PG.Object Clinical features,skin imaging characteristics,and laser treatment efficacy of PG in children were summarized through clinical collection of cases and samples,and the proteomic profile of the disease was studied using skin lesion samples.Methods A total of 220 children with PG attending our hospital between December2020 and June 2022 were selected for the study(212 children with PG were studied clinically and another 8 children with PG were studied proteomically).The contents of the study were as follows:(1)Clinical epidemiological study: the designed PG questionnaire was used to collect the basic information of the patients as well as the triggers of the onset of disease and clinical manifestations,including(gender,age of the patient,age of onset of the disease,duration of the lesion,season of onset of the disease,history of traumatic injury or mosquito bite before the onset of the disease,whether or not the lesion had broken down before the clinic visit,the colour of the lesion,the position of the lesion,and the size of the lesion including the diameter and height),and to summarize the clinical characteristics of the patients.patient’s clinical characteristics.(2)Clinical dermatological imaging study: dermoscopic and skin ultrasound imaging were performed on 32 cases of PG lesions,and their dermoscopic and skin ultrasound characteristics were summarised.(3)Clinical laser therapy study: 212 cases of children with PG attending the Department of Dermatology were treated with 595 nm pulsed dye laser,and the safety and efficacy of 595 nm pulsed dye laser in treating PG in children were evaluated.(4)Proteomics study: 4D label-free quantitative proteomics analysis(4D-LFQ)was used to explore the differential proteins expressed in the skin lesions of paediatric PG patients,and the expression levels of the proteins that were different were re-verified in the skin lesions of PG patients.Skin lesion tissues of PG patients(PG group),non-skin lesion normal tissues adjacent to skin lesions(PGC group)and normal skin tissues around pigmented nevi of melanocytic nevus patients(C group)were used as healthy control groups(n=5 cases in each group).The protein expression levels were detected by 4D-LFQ technique to explore the protein expression differences between different groups.Bioinformatics analyses,such as G0 enrichment analysis,KEGG analysis and protein interaction network analysis,were used to screen out the differential proteins that were most likely to be related to the pathogenesis of PG for further quantitative validation of Parallel Reaction Monitoring(PRM)targeted proteomics in skin lesions,paraneoplastic skin lesions,and normal control groups(n=3cases in each group).Results(1)Childhood PG is more common in males,with a median age of 3 years(interquartile spacing: 2.0-5.0 years).The peak season of incidence occurred in summer and autumn in 75.9% of cases.Periorbital area was the high prevalence area(42.5%)followed by cheeks(21.2%).The mean diameter of the lesions was 2.3 ± 0.7 mm,and the mean height was 1.5 ± 0.5 mm.48(22.6%)children with PG had a clear history of trauma or insect bites,and 128(60.4%)had a history of bleeding lesions that had broken prior to consultation.(2)The most common dermatoscopic features were: red or red-white homogeneous areas in 32 cases(100%),white collar sign in 24 cases(75%),linear or bulbous vascular structures in 16 cases(50%),and orbital sign in 8 cases(25%).The combination of structureless red or red-white homogeneous areas + white collar sign was most common in 24 cases(75%).Skin ultrasound images showed that30(94%)lesions were located in the skin layer and 2(6%)in the subcutaneous layer extending to the fat layer.32 lesions showed a regular hypoechoic area protruding outward from the skin.29(91%)lesions had clear borders and 3(9%)had poorly defined borders.Colour Doppler flow imaging(CDFI)showed that 31 cases(94%)had abundant dots and stripes of colourful blood flow signals,and Adler’s blood flow classification was mainly grade 3.(3)Among the 212 cases of PG treated with 595 nm pulsed dye laser,except for 4 cases,the treatment was interrupted due to bleeding of the lesion during the treatment.The remaining 208 children had complete clearance of the lesion,139(66.8%)required only one treatment,and the remaining 69(33.2%)underwent two or three treatments.Male patients responded better than female patients(χ2 = 7.603,p = 0.006),and lesions in non-orbital areas responded better to treatment than lesions in orbital areas(χ2 = 7.445,p = 0.006).Lesion size was inversely related to treatment effect,with smaller diameter and height resulting in better clearance.(4)4D-LFQ found that 499 proteins were significantly up-regulated and 485 proteins were significantly down-regulated in PG lesions compared to normal skin tissues,whereas346 proteins were significantly up-regulated and 357 proteins were significantly down-regulated in PG non-lesions;91 proteins were significantly up-regulated and 37 proteins were significantly down-regulated in PG lesions compared to non-lesions.Up-regulated proteins: Integrin alpha-M(ITGAM),Complement C1 s subcomponent(C1S),C4b-binding protein alpha chain(C4BPA),Complement factor H(CFH),Complement component C8 beta chain(C8B),Complement component C7(C7),von Willebrand factor(VWF),Plasminogen(PLG),and significantly downregulated proteins: succinate dehydrogenase [ ubiquinone] iron-sulfur subunit(SDHB),Succinate dehydrogenase [ubiquinone] flavoprotein subunit(SDHA),Cytochrome b-c1 complex subunit Rieske(UQCRFS1),NADH-ubiquinone oxidoreductase 75 k Da subunit(NDUFS1),and Cytochrome b-c1 complex subunit 1(UQCRC1)are involved in the aberrant expression of hypoxia,complement activation,and coagulation cascade pathways in PG.It also provides a theoretical basis for the next step in functional studies.Conclusions In this study,we summarised for the first time the clinical features of PG in children,such as season of onset,area of skin lesions,size of skin lesions,predisposing factors,and history of bleeding.Meanwhile,it was found that dermoscopy and skin ultrasonography have more typical features of PG in children,which are specific and can be used for the auxiliary and differential diagnosis of PG in children.The 595 nm pulsed dye laser was confirmed to be safe and effective in treating children’s PG,especially for smaller skin lesions at the early stage of onset.Proteomic studies have identified a number of protein factors and pathways that are abnormally expressed in PG,and hypoxia,complement activation,and the coagulation cascade system may contribute to the onset and development of PG by promoting the proliferation of vascular endothelial cells.