Thrombus histology does not predict stroke etiological subtype but influences recanalization.

BACKGROUND: There is conflicting data on whether clot retrieved from mechanical thrombectomy can predict stroke etiology or the success of recanalization. We aimed to analyse the relation between thrombus histology and stroke aetiology as well as recanalization. METHODOLOGY: Histopathological analysis of clots retrieved from patients with acute ischemic stroke and large vessel occlusion was done. Quantification of the amount of fibrin, red blood cells(RBC), platelets and white blood cells (WBC) in the clots were done. The clinical, imaging data and recanalization parameters were collected. The correlation between clot composition and stroke etiology as well as recanalization were analysed. RESULTS: Of the 77 patients, the mean age was 58. 67 ± 12.96 years. The stroke etiology were cardioembolism 44(57.1 %), large artery atherosclerosis 13(16.8 %), other determined aetiology 4(5.1 %) and undetermined in 16(20.7 %) patients. There was no significant correlation between the proportions of RBC-rich, platelet-rich and fibrin-rich thrombi and the stroke etiology. The susceptibility vessel sign was associated with RBC-rich clot(92.3 % vs 7.7 %, p = .03). All RBC-rich clots(100 %) had good recanalization(p = .05). Platelet-rich clots needed less number of passes(64.7 % vs 35.3 %, p = .006) and reduced groin puncture to recanalization time(87.9 % vs 12.1 %, p = .033). WBC-rich clots required lesser number of passes(57.5 % vs 42.5 %, P = .044). In multivariate analysis, WBC-rich clots (OR 0.230, CI 0.07-0.78, p = .018) showed an independent association with reduced recanalization attempts, while platelet-rich clots showed reduced recanalization time(OR 0.09, CI 0.01-0.63, p = .016). CONCLUSION: There was no correlation between thrombus histology and the etiological stroke subtype. However, clot composition predicted the degree of recanalization and number of passes.

CT angiographic patterns predict carotid pseudo-occlusion in acute ischemic stroke.

Background: Identifying carotid pseudo-occlusion (PO) from true occlusion (TO) has implications in determining the candidacy and feasibility of successful endovascular thrombectomy (EVT) in acute ischemic stroke (AIS). Purpose: We reviewed the computed tomography angiographic (CTA) patterns differentiating a PO from a TO and analyzed the rate of successful recanalization after EVT. Materials and Methods: Patients with AIS and proximal internal carotid artery (ICA) occlusion who underwent EVT from 2014 to 2021 were identified. The patterns of carotid occlusion in CTA were classified into beak, dome, and flat patterns and correlated with microcatheter digital subtraction angiography (DSA) as PO and TO. The rates of successful recanalization in PO and TO were analyzed. Results: Of the 24 patients, 16 (66%) had ICA PO and eight (33%) had TO in DSA. A beak pattern of the proximal ICA on CTA was significantly higher among the PO group patients (87.5% vs. 25%, P = 0.005), and a flat pattern was significantly higher among the TO group patients (50% vs. 12%, P = 0.005). A gradual contrast decline of the proximal ICA on CTA images was seen only in PO group patients (85.7% vs. 0%, P = 0.05). There was no significant difference in the rate of successful recanalization between PO and TO group patients (81.25% vs. 62.5%, P = 0.362). Conclusion: Beak pattern and gradual contrast decline at the proximal ICA occlusion site in CTA are suggestive of carotid PO. Identification of PO in CTA can help in planning intervention strategies and prognostication.

Biomarkers predict hemorrhagic transformation and stroke severity after acute ischemic stroke.

OBJECTIVES: Hemorrhagic transformation (HT) is a complication occurring in patients with acute ischemic stroke (AIS) either spontaneously or post-thrombolysis leading to significant morbidity and mortality. We assessed circulating matrix metalloproteinase-9 (MMP-9), Claudin-5, and soluble serum stimulation-2 (sST2) in HT and stroke severity in AIS based on their temporal distribution. MATERIALS AND METHODS: We prospectively enrolled 111 AIS patients within 12 h from onset. Patient demographic, clinical, and imaging details were documented. Follow-up imaging was conducted 24-48 h after admission. Blood samples were taken at three time-points from stroke onset. HT was classified according to the European Co-operative Acute Stroke Study-III(ECASS-III). Stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS). Multiple logistic regression and receiver operating characteristic curve were conducted to determine the discriminative capacity. RESULTS: Mean age was 62.3 ± 11.7 years and median baseline NIHSS was 12[IQR 8.0-18.0]. HT was detected in 30(27%) patients. Biomarker levels at 12 h were elevated with median MMP-9 concentration of 153.9 ng/mL[IQR 110.6-309 ng/mL] indicating a trend toward significant positive correlation with HT(P = 0.05). Claudin-5 levels at 12 h was elevated but was not statistically significant (43.1 pg/mL[IQR:26.7-72.6 pg/mL] vs 59.4 pg/mL[IQR:24.5-100.8 pg/mL];P = 0.4). Multiple logistic regression indicated Claudin-5 levels at 12 h (OR 9.46;95% CI:1.97-64.6;P = 0.010) and baseline low ASPECTS score(OR 20.3;95% CI:3.46-193; P = 0.003) independently predicted HT. MMP-9 at 12 h was significantly elevated in patients with moderate to severe strokes (P = 0.04). CONCLUSIONS: Claudin-5 and low ASPECTS independently predicted HT. MMP-9 was positively correlated with baseline stroke severity.

Does thrombus imaging characteristics predict the degree of recanalisation after endovascular thrombectomy in acute ischaemic stroke?

BACKGROUND: Identification of computed tomography (CT) thrombus imaging characteristics can predict the degree of recanalization and outcome after endovascular thrombectomy (EVT) in patients with acute ischaemic stroke and large vessel occlusion. AIM: We analyzed the thrombus imaging characteristics and procedural factors and correlated with the degree of recanalization and functional outcome after EVT. METHODS: We evaluated the thrombus imaging characteristics (hyperdense MCA sign, thrombus location, length and thrombus permeability) from thin slice CT and CT angiogram. In addition, groin to recanalization time, number of passes, and EVT technique were documented. The primary outcome was degree of recanalization (mTICI score) and secondary outcome was modified Rankin scale (mRS) at 3 months. RESULTS: The mean age of 102 patients was 60.5±11.8 years. Patients with hyperdense MCA sign (90 % vs 75%, p=0.07) and permeable thrombus (86 % vs 70 %, p=0.09) had good recanalization (mTICI grade 2b,2c or 3). The requirement of <3 passes (90 % vs 62 %, p= 0.001) was associated with good recanalization. Multiple logistic regression analysis showed thrombus permeability (OR 5.9; 95% CI 1.3-26.6, p=0.02), use of stent retreiver alone (without aspiration) (OR 5.4; 95% CI 1.3-22.5, p=0.02) and a puncture to recanalization ≤60 minutes (OR 7.9; 95% CI 1.7-36.8; p=0.008) were associated with good recanalization. The requirement of ≥3 passes was associated with poor functional outcome (OR 3.4;95% CI 1.2-9.8; p=0.02). CONCLUSIONS: Thrombus permeability was a predictor of successful recanalization after EVT. The requirement of three or more passes during EVT was associated with poor recanalization and poor functional outcome.

The use of angiogenic-antimicrobial agents in experimental wounds in animals: problems and solutions.

A topical combination (silvathymosin) of natural proangiogeneic protein thymosin ß4 (Tß4) and antimicrobial silver sulfadiazine was hypothesized to promote the healing of large, full-thickness, clean or infected wounds in rats. Silvathymosin showed the fastest wound healing (85%) followed by silver sulfadiazine (84%) and Tß4 (72%). In the infected groups, the healing pattern was different, as Tß4 and silvathymosin groups did not show similar wound healing. Wound histopathology and VEGF and KI67 immunohistochemical assessment of angiogenesis was consistent and correlated well with the tempo of healing of the acute wounds. These preliminary data demonstrate the more rapid acute wound healing properties of the combination formulation of thymosin ß4 and silver sulfadiazine as compared to these agents alone. This novel agent could prove an effective treatment modality for debilitating chronic wounds and decubitus ulcers.

Th2 cell-selective enhancement of human IL13 transcription by IL13-1112C>T, a polymorphism associated with allergic inflammation.

IL-13 is a central mediator of allergic inflammation. The single nucleotide polymorphism IL13-1112C>T (rs1800925) is associated with allergic phenotypes in ethnically distinct populations, but the underlying mechanism(s) remain unknown. Using in vivo, in vitro, and in silico analysis, we show that the IL13-1112T allele enhanced IL13 promoter activity in primary human and murine CD4(+) Th2 lymphocytes. Increased expression of IL13-1112T in Th2 cells was associated with the creation of a Yin-Yang 1 binding site that overlapped a STAT motif involved in negative regulation of IL13 expression and attenuated STAT6-mediated transcriptional repression. Because IL-13 secretion was increased in IL13-1112TT homozygotes, we propose that increased expression of IL13-1112T in vivo may underlie its association with susceptibility to allergic inflammation. Interestingly, IL13-1112T had opposite transcriptional effects in nonpolarized CD4(+) T cells, paralleled by distinct patterns of DNA-protein interactions at the IL13 promoter. Our findings suggest the nuclear milieu dictates the functional outcome of genetic variation.

Role of C-terminal cysteine residues of Aspergillus fumigatus allergen Asp f 4 in immunoglobulin E binding.

Among the several allergens cloned and expressed from Aspergillus fumigatus, Asp f 4 is a major one associated with allergic bronchopulmonary aspergillosis (ABPA). The structure-function relationship of allergens is important in understanding the immunopathogenesis, diagnosis, and treatment of allergic diseases. These include the epitopes, conformational or linear, deletion of the N or C terminus or both N and C termini, and glycosylation or nonglycosylation, all of which affect immune responses. Similarly, the role of cysteine residues present in allergens may yield useful information regarding the conformational structure of allergens and the immunoglobulin E (IgE) epitope interaction. Such information may help in developing new strategies towards immunotherapy. In order to define the role of cysteine in the interaction of the antibody with Asp f 4, we have constructed mutants by selectively deleting cysteine residues from the C-terminal region of the Asp f 4. Immunological evaluation of these engineered recombinant constructs was conducted by using sera from patients with ABPA, Aspergillus skin test-positive asthmatics, and healthy controls. The results demonstrate strong IgE binding with Asp f 4 and two truncated mutants, Asp f 4(1-234) (amino acids [aa] 1 to 234) and Asp f 4(1-241) (aa 1 to 241), while another mutant, Asp f 4(1-196) (aa 1 to 196), showed reactivity with fewer patients. The result suggests that deletion of cysteines and the alteration of IgE epitopes at the C-terminal end resulted in conformational changes, which may have a potential role in the immunomodulation of the disease.

IgE binding conformational epitopes of Asp f 3, a major allergen of Aspergillus fumigatus.

sp f 3 has been identified as one of the major allergens of Aspergillus fumigatus associated with the sensitization and immune responses in allergic bronchopulmonary aspergillosis (ABPA). In order to understand the structure/function relationship of Asp f 3, we studied synthetic peptides and constructed mutants deleted of specific IgE binding regions. The mutated allergens were obtained by expressing the genes and studied by ELISA for their reactivity with IgE from patients with ABPA. Seven linear IgE binding regions spanning the whole Asp f 3 molecule were demonstrated. The results demonstrated strong binding of IgE from ABPA patients with Asp f 3 and one mutant, Asp f 3(1-150), but not with other mutant constructs. The results identified 12 amino acids at the N-terminal end and 8 amino acids (143-150) at the C-terminal end as significant in the conformational constraints for IgE binding. The Fourier transfer spectra showed comparable beta-sheet structure of Asp f 3(1-150) and Asp f 3, indicating the role of secondary structure in IgE binding. The primary and secondary structures may help understanding of the functional role the allergens play in the disease and may have implications in immunodiagnosis and probably immunotherapy.