IMMUNOHISTOCHEMICAL STUDY OF Ki-67 ANTIGEN EXPRESSION IN DIAGNOSIS OF PSORIASIS

Background: Psoriasis is a common, chronic inflammatory skin disease characterized by scaly white papules and pinpoint bleeding on scratching. Presence of keratinocyte hyperproliferation and abnormal differentiation in the epidermis are some significant features. Histopathologically, it is difficult for the dermatopathologists to differentiate psoriasis from psoriasiform dermatitis when there is a lack of typical features. Aims: To study the Ki-67 antigen expression in the different layers of epidermis of psoriatic skin lesion and its utility in the diagnosis and to differentiate psoriasis from other psoriasiform dermatitis by studying the distribution pattern of Ki-67 immunostaining. Methods: In this cross-sectional study, a total of 91 skin lesions which were clinically labelled as psoriasis and psoriasiform dermatitis were studied, which was confirmed by histopathological examination and followed by Ki-67 immunostaining. The distribution of Ki-67 immunostaining in the supra-basal layer, basal layer and whole epidermis was studied. Results: Ki67 staining was significantly higher in the suprabasal layer and whole epidermis in psoriatic lesions compared to psoriasiform dermatitis. The suprabasal Ki-67 mitotic index was also significantly higher in psoriasis group than psoriasiform dermatitis (p <0.05). We found that in psoriasis > 50% Ki-67 positive keratinocytes are scattered in the suprabasal layer of the epidermis in comparison to the psoriasiform dermatitis which is < 50%. Conclusion: We suggest that Ki-67 labelling index can be used for diagnosing psoriasis and also can differentiate it from other psoriasiform dermatitis.

Decellularized Aortic Scaffold Alleviates H2O2-Induced Inflammation and Apoptosis in CD34+ Progenitor Cells While Driving Neovasculogenesis

Bone marrow-derived stem/progenitor cells have been utilized for cardiac or vascular repair after ischemic injury, but they are subject to apoptosis and immune rejection in the ischemic site. Multiple scaffolds were used as delivery tools to transplant stem/progenitor cells; however, these scaffolds did not show intrinsically antiapoptotic or anti-inflammatory properties. Decellularized aortic scaffolds that facilitate cell delivery and tissue repair were prepared by removing cells of patient-derived aortic tissues. Scanning electron microscopy (SEM) showed cells attached well to the scaffold after culturing for 5 days. Live/dead staining showed most seeded cells survived at day 7 on a decellularized aortic scaffold. Ki67 staining demonstrated that decellularized aortic scaffold promoted proliferation of bone marrow-derived CD34+ progenitor cells. Apoptosis of CD34+ progenitor cells induced by H2O2 at high concentration was significantly alleviated in the presence of decellularized aortic scaffolds, demonstrating a protective effect against oxidative stress-induced apoptosis. Furthermore, decellularized aortic scaffolds significantly reduced the expression of proinflammatory cytokines (IL-8, GM-CSF, MIP-1β, GRO-α, Entoxin, and GRO) concurrently with an increase in anti-inflammatory cytokines (IL-2 and TGF-β) released from CD34+ progenitor cells when exposed to H2O2 at low concentration. Finally, neovascularization was observed by H&E and immunohistochemical staining 14 days after the decellularized aortic scaffolds were subcutaneously implanted in nude mice. This preclinical study demonstrates that the use of a decellularized aortic scaffold possessing antiapoptotic and anti-inflammatory properties may represent a promising strategy for cardiovascular repair after ischemic injury.

Good staining quality ensuring the reproducibility of Ki67 assessment

AimsAlthough Ki67 labelling index (LI) is a prognostic and predictive marker in breast cancer, its accuracy and reproducibility must be validated before its clinical application. We aimed to evaluate the agreement of Ki67 LI in clinical practice in Taiwan.MethodsWe conducted a Ki67 immunohistochemistry (IHC) proficiency test. The participants performed the Ki67 IHC test and measured the Ki67 LI of 10 cases of breast cancer tissue on a microarray slide. The staining quality was centrally reviewed based on the Ki67 staining of the tonsil surface epithelium.ResultsKi67 staining and counting methods are diverse in Taiwan. The reproducibility of Ki67 LI was poor to good (intraclass correlation coefficient: 0.581, 95% CI 0.354 to 0.802). The reproducibility and agreement in the high staining quality group were significantly higher than those in the low staining quality group. The majority of the Ki67 LIs derived from the low staining quality group were underestimated. Different counting methods did not reveal significant differences when determining Ki67 LI with microarray sections.ConclusionsWe suggest using the surface epithelium of the tonsil as external control and achieving optimal staining results that consist of a high positive parabasal layer, a low positive intermediate layer and a negative superficial layer. Good Ki67 staining quality can minimise the staining variations among different laboratories, and it is essential for the reproducibility of Ki67 LI.