γD318Y fibrinogen shows no fibrin polymerization due to defective "A-a" and "B-b" interactions, whereas that of γK321E fibrinogen is nearly normal

ArticleThrombosis research. 182: 150-158. (2019)journal articl

Differences in the function and secretion of congenital aberrant fibrinogenemia between heterozygous gamma D320G (Okayama II) and gamma Delta N319-Delta D320 (Otsu I)

Background: We encountered two patients with hypodysfibrinogenemia and designated them as Okayama II and Otsu I. Although the affected residue(s) in Okayama II and Otsu I overlapped, functionally determined fibrinogen levels and the ratio of functionally to immunologically determined plasma fibrinogen levels were markedly different.Methods: DNA sequence and functional analyses were performed for purified plasma fibrinogen. A recombinant protein was synthesized in Chinese hamster ovary (CHO) cells to determine the secretion of variant fibrinogens.Results: A heterozygous A>G in FGG, resulting in gamma 320Asp>Gly for Okayama II, and a heterozygous deletion of AATGAT in FGG, resulting in the deletion of gamma Asn319 and gamma Asp320 (gamma Delta N319-Delta D320) for Otsu I, were obtained. SDS-PAGE and Coomassie staining revealed that the variant gamma-chain was not clear in Okayama II, but was clearly present in Otsu I. The lag period for the fibrin polymerization of Okayama II was slightly slower than that of the normal control, whereas Otsu I fibrinogen indicated no polymerization within 30 min. Both variant gamma-chains were synthesized in CHO cells and assembled into fibrinogen; however, the fibrinogen concentration ratio of the medium/cell lysate of gamma 320Gly was six-fold lower than that of gamma Delta N319-Delta D320.Conclusions: We concluded that the plasma fibrinogen of Okayama II, constituted by a lower ratio of the variant gamma-chain, led to the almost normal functioning of fibrin polymerization. However, the plasma fibrinogen of Otsu I, with a higher ratio of the variant gamma-chain, led to marked reductions in fibrin polymerization. (C) 2015 Elsevier Ltd. All rights reserved.THROMBOSIS RESEARCH. 136(6):1318-1324 (2015)journal articl

Novel heterozygous dysfibrinogenemia, Sumida (A alpha C472S), showed markedly impaired lateral aggregation of protofibrils and mildly lower functional fibrinogen levels

Introduction: We encountered a 6-year-old girl with systemic lupus erythematosus. Although no bleeding or thrombotic tendency was detected, routine coagulation screening tests revealed slightly lower plasma fibrinogen levels, as determined by functional and antigenic measurements (functional/antigenic ratio=0.857), suggesting hypodysfibrinogenemia. Materials and methods: DNA sequence and functional analyses were performed on purified plasma fibrinogen, and recombinant variant fibrinogen was synthesized in Chinese hamster ovary cells based on the results obtained. Results: DNA sequencing revealed a heterozygous A alpha C472S substitution (mature protein residue number) in the alpha C-domain. A alpha C472S fibrinogen indicated the presence of additional disulfide-bonded molecules, and markedly impaired lateral aggregation of protofibrils in spite of slightly lower functional plasma fibrinogen levels. Scanning electron microscopic observations showed a thin fiber fibrin clot, and t-PA and plasminogen-mediated clot lysis was similar to that of a normal control. Recombinant variant fibrinogen-producing cells demonstrated that destruction of the A alpha 442C-472C disulfide bond did not prevent the synthesis or secretion of fibrinogen, whereas the variant A alpha chain of the secreted protein was degraded faster than that of the normal control. Conclusion: Our results suggest that A alpha C472S fibrinogen may cause dysfibrinogenemia, but not hypofibrinogenemia. The destruction and steric hindrance of the alpha C-domain of variant fibrinogen led to the impaired lateral aggregation of protofibrils and t-PA and plasminogen-mediated fibrinolysis, as well as several previously reported variants located in the alpha C-domain, and demonstrated the presence of disulfide-bonded molecules.ArticleTHROMBOSIS RESEARCH. 135(4):710-717 (2015)journal articl

Recombinant gamma T305A fibrinogen indicates severely impaired fibrin polymerization due to the aberrant function of hole 'a' and calcium binding sites

Introduction: We examined a 6-month-old girl with inherited fibrinogen abnormality and no history of bleeding or thrombosis. Routine coagulation screening tests showed a markedly low level of plasma fibrinogen determined by functional measurement and also a low level by antigenic measurement (functional/antigenic ratio = 0.295), suggesting hypodysfibrinogenemia. Materials and methods: DNA sequence analysis was performed, and gamma T305A fibrinogen was synthesized in Chinese hamster ovary cells based on the results. We then functionally analyzed and compared with that of nearby recombinant gamma N308K fibrinogen. Results: DNA sequence analysis revealed a heterozygous gamma T305A substitution (mature protein residue number). The gamma T305A fibrinogen indicated markedly impaired thrombin-catalyzed fibrin polymerization both in the presence or absence of 1 mM calcium ion compared with that of gamma N308K fibrinogen. Protection of plasmin degradation in the presence of calcium ion or Gly-Pro-Arg-Pro peptide (analogue for so-called knob 'A') and factor XIIIa-catalyzed fibrinogen crosslinking demonstrated that the calcium binding sites, hole 'a' and D:D interaction sites were all markedly impaired, whereas gamma N308K was impaired at the latter two sites. Molecular modeling demonstrated that gamma T305 is localized at a shorter distance than gamma N308 from the high affinity calcium binding site and hole 'a'. Conclusion: Our findings suggest that gamma T305 might be important for construction of the overall structure of the. module of fibrinogen. Substitution of gamma T305A leads to both dysfibrinogenemic and hypofibrinogenemic characterization, namely hypodysfibrinogenemia. We have already reported that recombinant gamma T305A fibrinogen was synthesized normally and secreted slightly, but was significantly reduced.ArticleTHROMBOSIS RESEARCH. 134(2):518-525 (2014)journal articl

The fibrous form of intracellular inclusion bodies in recombinant variant fibrinogen-producing cells is specific to the hepatic fibrinogen storage disease-inducible variant fibrinogen

Fibrinogen storage disease (FSD) is a rare disorder that is characterized by the accumulation of fibrinogen in hepatocytes and induces liver injury. Six mutations in the γC domain (γG284R, γT314P, γD316N, the deletion of γG346-Q350, γG366S, and γR375W) have been identified for FSD. Our group previously established γ375W fibrinogen-producing Chinese hamster ovary (CHO) cells and observed aberrant large granular and fibrous forms of intracellular inclusion bodies. The aim of this study was to investigate whether fibrous intracellular inclusion bodies are specific to FSD-inducible variant fibrinogen. Thirteen expression vectors encoding the variant γ-chain were stably or transiently transfected into CHO cells expressing normal fibrinogen Aα- and Bβ-chains or HuH-7 cells, which were then immunofluorescently stained. Six CHO and HuH-7 cell lines that transiently produced FSD-inducible variant fibrinogen presented the fibrous (3.2?22.7 and 2.1?24.5%, respectively) and large granular (5.4?25.5 and 7.7?23.9%) forms of intracellular inclusion bodies. Seven CHO and HuH-7 cell lines that transiently produced FSD-non-inducible variant fibrinogen only exhibit the large granular form. These results demonstrate that transiently transfected variant fibrinogen-producing CHO cells and inclusion bodies of the fibrous form may be useful in non-invasive screening for FSD risk factors for FSD before its onset.ArticleINTERNATIONAL JOURNAL OF HEMATOLOGY.105:758-768(2017)journal articl

Genetic analyses of novel compound heterozygous hypodysfibrinogenemia, Tsukuba I: FGG c.1129+62_65 del AATA and FGG c.1299+4 del A

Epub 2016 Nov 5Introduction: Wefound a novel hypodysfibrinogenemia designated Tsukuba I caused by compound heterozygous nucleotide deletionswith FGG c. 1129+ 62_ 65 del AATA and FGG c. 1299+ 4 del A on different alleles. The former was deep in intron 8 of FGG (IVS-8 deletion) and the latter in exon 9 of FGG (Ex-9 deletion), which is translated for the gamma'-chain, but not the.A-chain. AWestern blot analysis of plasma fibrinogen from our patient revealed an aberrant gamma-chain that migrated slightly faster than the normal B beta-chain. Materials andmethods: To clarify the complex genetic mechanismunderlying Tsukuba I's hypodysfibrinogenemia induced by nucleotide deletions in two regions, we generated two minigenes incorporating each deletion region, transfected them into Chinese Hamster Ovary (CHO) cells, and analyzed RT-PCR products. We also established CHO cells producing the recombinant variant fibrinogen,gamma' 409.A (Ex-9 deletion). Results and conclusions: Minigene I incorporating the IVS-8 deletion showed two products: a normal splicing product and the unspliced product. Minigene II incorporating the Ex-9 deletion only produced the unspliced product. The established gamma' 409.A-CHOcells secreted variant fibrinogenmore effectively than normal fibrinogen. Therefore, the aberrant splicing products derived from the IVS-8 deletion cause hypofibrinogenemia most likely due to nonsense-mediated mRNA decay and the partial production of normal.A-and gamma'-chains; moreover, the Ex-9 deletion causes hypodysfibrinogenemia due to the absence of normal.A-and gamma'-chain production (hypofibrinogenemia) and augmented aberrant.'-chain production (dysfibrinogenemia). (C) 2016 Elsevier Ltd. All rights reserved.ArticleTHROMBOSIS RESEARCH. 148:111-117 (2016)journal articl

Evaluation of the effects of a combination of Japanese honey and hydrocolloid dressing on cutaneous wound healing in male mice

The aim of this study was to evaluate the effect of the combined use of Japanese honey and hydrocolloid dressing (HCD) on cutaneous wound healing. Mice were divided into four groups: the Acacia (Japan) + HCD, Manuka (New Zealand) + HCD, Chinese milk vetch (Japan) + HCD, and HCD (control) groups. The mice received two full-thickness wounds. The wounds of the HCD group were covered with HCD, whereas those of the other groups were treated with 0.1 mL of the relevant type of honey, before being covered with HCD. Wound area was significantly smaller in the HCD group than in the Acacia + HCD and Manuka + HCD groups on day 13 and days 8-14, respectively. Moreover, compared with the HCD group, reepithelialization was delayed in the Acacia + HCD group and reepithelialization and collagen deposition were delayed in the Chinese milk vetch + HCD and Manuka + HCD groups. These results indicate that the combined use of Japanese honey and HCD does not promote cutaneous wound healing compared with the use of HCD alone. Thus, this method is probably not useful for promoting healing. © 2015 Kanae Mukai et al

Cricotracheostomy for patients with severe COVID-19: A case control study

BackgroundTracheostomy is an important procedure for the treatment of severe coronavirus disease-2019 (COVID-19). Older age and obesity have been reported to be associated with the risk of severe COVID-19 and prolonged intubation, and anticoagulants are often administered in patients with severe COVID-19; these factors are also related to a higher risk of tracheostomy. Cricotracheostomy, a modified procedure for opening the airway through intentional partial cricoid cartilage resection, was recently reported to be useful in cases with low-lying larynx, obesity, stiff neck, and bleeding tendency. Here, we investigated the usefulness and safety of cricotracheostomy for severe COVID-19 patients.Materials and methodsFifteen patients with severe COVID-19 who underwent cricotracheostomy between January 2021 and April 2022 with a follow-up period of ≥ 14 days were included in this study. Forty patients with respiratory failure not related to COVID-19 who underwent traditional tracheostomy between January 2015 and April 2022 comprised the control group. Data were collected from medical records and comprised age, sex, body mass index, interval from intubation to tracheostomy, use of anticoagulants, complications of tracheostomy, and decannulation.ResultsAge, sex, and days from intubation to tracheostomy were not significantly different between the COVID-19/cricotracheostomy and control/traditional tracheostomy groups. Body mass index was significantly higher in the COVID-19 group than that in the control group (P = 0.02). The rate of use of anticoagulants was significantly higher in the COVID-19 group compared with the control group (P < 0.01). Peri-operative bleeding, subcutaneous emphysema, and stomal infection rates were not different between the groups, while stomal granulation was significantly less in the COVID-19 group (P = 0.04).ConclusionsThese results suggest that cricotracheostomy is a safe procedure in patients with severe COVID-19