Radiomics analysis of myocardial perfusion SPECT images in patients with cardiomyopathy and heart failure

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): JSPS KAKENHI Grants

Background

Although myocardial perfusion heterogeneity due to focally damaged cardiomyocytes is observed in single−photon emission computed tomography (SPECT) imaging, a current perfusion defect scoring system does not allow us to provide sufficient diagnostic information for heterogeneity.

Purpose

The aim of this study was to perform radiomics analysis of myocardial perfusion SPECT (MPS) images to investigate the potential to detect myocardial perfusion heterogeneity.

Methods

Patients with hypertrophic cardiomyopathy (n = 3), heart failure (n = 9), and with a low likelihood of coronary artery disease (n =15) (Figure 1), who underwent a rest 99mTc-MIBI myocardial perfusion SPECT, were assessed using a LIFEx software. Four shape−based features, 6 histogram−based features, and 32 textural features were computed. The relevant features for the classification of the patients were selected using the Boruta algorithm, and hierarchical clustering of the selected features using the Spearman correlation coefficient was also performed for the feature reduction. The receiver operating characteristics (ROC) analysis was performed by the support vector machine to calculate the area under the ROC curve (AUC) for the selected features.

Results

Of 40 features, 17 were selected by the classification analysis, and these features were classified into 7 classes by the correlation analysis (Figure 2). The ROC AUCs for 7 features extracted from each class were 0.99, 0.97, 0.96, 0.92, 0.90, 0.86, and 0.83 for the contrast of NDGLDM, the entropy of histogram, ZLNU of GLZLM, the energy of GLCM, the energy of histogram, SZLGE of GLZLM, and the correlation of GLCM, respectively, as compared to 0.39 for a summed rest score.

Conclusions

Radiomics analysis successfully determined the myocardial perfusion heterogeneity in patients with cardiomyopathy and heart failure. It might be promising for the evaluation of myocardial damages that cannot be analyzed by the conventional scoring method.

Impact of Local Drug Delivery of Minocycline on the Subgingival Microbiota during Supportive Periodontal Therapy: A Randomized Controlled Pilot Study

The aim of this study was to examine the effect of adjunct local minocycline administration on the microbiological parameters of subgingival plaque samples in the residual periodontal pockets. Ten chronic periodontitis patients under a supportive periodontal therapy regimen were recruited. After subgingival debridement, either 2% minocycline gel, Periocline™, (Test Group) or a placebo (Control Group) was administered to the selected sites once a week for three weeks. Subgingival plaque was collected at baseline, and at four weeks and eight weeks. The microbiological composition was analyzed by 16S ribosomal RNA sequencing. In the Test Group, α-diversity (evenness) decreased compared to the baseline (p = 0.005) and was lower compared to the control group at four weeks (p = 0.003). The microbial community composition between the two groups was significantly different at four weeks (p = 0.029). These changes were attributable to a decrease in the bacteria associated with periodontitis and an increase in the bacteria associated with periodontal health. Additionally, the improvement in bleeding on probing continued at eight weeks; however, there were little microbial effects of 2% minocycline gel observed at eight weeks. The control group demonstrated no change throughout the eight-week experimental period. Thus, local minocycline administration can change the subgingival microbial community of residual periodontal pockets.

Quantitative Near-Infrared Imaging of Platelets in Platelet-Rich Fibrin (PRF) Matrices: Comparative Analysis of Bio-PRF, Leukocyte-Rich PRF, Advanced-PRF and Concentrated Growth Factors

Platelet-rich fibrin (PRF) is a fibrin matrix enriched with platelets. The PRF matrix is thought to form a steep gradient of platelet density around the region corresponding to the buffy coat in anticoagulated blood samples. However, this phenomenon has not yet been proven. To visualize platelet distribution in PRF in a non-invasive manner, we utilized near-infrared (NIR) imaging technology. In this study, four types of PRF matrices, bio-PRF, advanced-PRF (A-PRF), leukocyte-rich PRF (L-PRF), and concentrated growth factors (CGF) were compared. Blood samples collected from healthy, non-smoking volunteers were immediately centrifuged using four different protocols in glass tubes. The fixed PRF matrices were sagittally divided into two equal parts, and subjected to modified immunohistochemical examination. After probing with NIR dye-conjugated secondary antibody, the CD41⁺ platelets were visualized using an NIR imager. In L-PRF and CGF, platelets were distributed mainly on and below the distal surface, while in bio-PRF and A-PRF, platelet distribution was widespread and homogenous. Among three regions of the PRF matrices (upper, middle, and lower), no significant differences were observed. These findings suggest that platelets aggregate on polymerizing fibrin fibers and float up as a PRF matrix into the plasma fraction, amending the current “gradient” theory of platelet distribution.

Effect of proinflammatory cytokines on endometrial collagen and metallopeptidase expression during the course of equine endometrosis

Equine endometrosis (endometrial fibrosis) is a degenerative chronic process that occurs in the uterus of the mare and disturbs proper endometrial function. Fibrosis is attributed to excessive deposition of extracellular matrix (ECM) components. The turnover of ECM is mediated by matrix metallopeptidases (MMP). Previously, it was shown that cytokines modulate MMP expression in other tissues and may regulate fibrosis indirectly by attracting inflammatory cells to the site of inflammation and directly on various tissues. However, the regulation of MMP expression in equine endometrosis is still relatively unknown. Thus, our aim was to determine if interleukin (IL)-1β and IL-6 regulate ECM, MMPs, or their inhibitors (TIMPs) and whether this regulation differs during endometrosis in the mare. Endometrial fibrosis was divided into four categories according to severity: I (no degenerative changes), IIA (mild degenerative changes), IIB (moderate degenerative changes) and III (severe degenerative changes) according to Kenney and Doig classification. Endometrial explants (n = 5 for category I, IIA, IIB and III according to Kenney and Doig) were incubated with IL-1β (10 ng/ml) or IL-6 (10 ng/ml) for 24 h. Secretion and mRNA transcription of collagen type 1 (Col1a1) and type 3 (Col3a1), fibronectin (Fn1), Mmp-1, -2, -3, -9, -13, Timp-1, -2 were analyzed by real-time PCR and ELISA, respectively. IL-1β treatment up-regulated secretion of COL1, MMP-2, TIMP1, and TIMP2 in category I endometrial fibrosis tissues (P < 0.05). IL-6 treatment up-regulated secretion of ECM, MMP-2, and MMP-3 and down-regulated secretion of MMP-9 in category I tissues (P < 0.05). In category IIA tissues, IL-1β and IL-6 treatment up-regulated secretion of COL3 (P < 0.05; P < 0.05), and IL-6 treatment also down-regulated secretion of MMP-9 (P < 0.05). In category IIB tissues, IL-1β treatment down-regulated secretion of COL3 (P < 0.05) and up-regulated secretion of MMP-3 (P < 0.01), while IL-6 treatment up-regulated secretion of MMP-3, MMP-9, and MMP-13 (P < 0.05). In category III tissues, IL-1β treatment up-regulated secretion of COL1, MMP-1, MMP-9 and TIMP-2 (P < 0.05), and IL-6 up-regulated secretion of all investigated ECM components, MMPs and TIMPs. These results reveal that the effect of IL-1β and IL-6 on equine endometrium differs depending on the severity of endometrial fibrosis. Our findings indicate an association between inflammation and development of endometrosis through the effect of IL-1β and IL-6 on expression of ECM components, MMPs, and TIMPs in the mare.

Postoperative changes in serum creatine kinase in paediatric orthopaedic patients with preoperative hyperCKaemia: review of three cases

An elevated serum creatine kinase (CK) level is commonly known as hyperCKaemia, and anaesthesiologists must take into account the potential susceptibility of hyperCKaemia patients to develop malignant hyperthermia during general anaesthesia as well as acute onset of rhabdomyolysis postoperatively. Three paediatric patients with hyperCKaemia were scheduled for orthopaedic surgery. With the consent of their parents, their CK changes were monitored for seven days postoperatively to detect rhabdomyolysis. The results showed that the postoperative CK change patterns were almost the same as those for patients whose CK levels were within reference range. Maximum CK levels tended to be higher in these patients than in the CK reference-range patients studied previously, although the reason remains unclear. This experience and previous studies suggest that measuring CK levels at least on postoperative days 1 and 2 might be better for detecting early signs of rhabdomyolysis, even in paediatric patients with hyperCKaemia.

Quantitative evaluation of morphological changes in activated platelets in vitro using digital holographic microscopy

Platelet activation and aggregation have been conventionally evaluated using an aggregometer. However, this method is suitable for short-term but not long-term quantitative evaluation of platelet aggregation, morphological changes, and/or adhesion to specific materials. The recently developed digital holographic microscopy (DHM) has enabled the quantitative evaluation of cell size and morphology without labeling or destruction. Thus, we aim to validate its applicability in quantitatively evaluating changes in cell morphology, especially in the aggregation and spreading of activated platelets, thus modifying typical image analysis procedures to suit aggregated platelets. Freshly prepared platelet-rich plasma was washed with phosphate-buffered saline and treated with 0.1% CaCl₂. Platelets were then fixed and subjected to DHM, scanning electron microscopy (SEM), atomic force microscopy, optical microscopy, and flow cytometry (FCM). Tightly aggregated platelets were identified as single cells. Data obtained from time-course experiments were plotted two-dimensionally according to the average optical thickness versus attachment area and divided into four regions. The majority of the control platelets, which supposedly contained small and round platelets, were distributed in the lower left region. As activation time increased, however, this population dispersed toward the upper right region. The distribution shift demonstrated by DHM was essentially consistent with data obtained from SEM and FCM. Therefore, DHM was validated as a promising device for testing platelet function given that it allows for the quantitative evaluation of activation-dependent morphological changes in platelets. DHM technology will be applicable to the quality assurance of platelet concentrates, as well as diagnosis and drug discovery related to platelet functions.

Comprehensive Quality Control of the Regenerative Therapy Using Platelet Concentrates: The Current Situation and Prospects in Japan

Platelet concentrates (PCs), represented by platelet-rich plasma (PRP), have been widely applied in the fields of regenerative and aesthetic therapies. PCs' mechanisms of action, however, are too complicated, and it is not easy to present the whole picture; besides, clinical outcomes are hardly reproducible in many cases. Therefore, several medically advanced countries seemingly intend to regulate PC therapies weakly or strictly because of the increasing popularity. Japan established laws and regulations for PC therapy in the "Act on the Safety of Regenerative Medicine" along with the "Pharmaceuticals, Medical Devices and Other Therapeutic Products Act" in 2014, which, to our knowledge, represent the strictest regulatory framework for production and therapeutic use of PCs in the world. According to these laws and regulations, PCs produced for topical use should be prepared as cell-based medicinal products, essentially as should stem cells, in accordance with their registered ("licensed" under actual conditions) standard operating procedures. Nonetheless, criteria for their quality are not standardized. In this review, we discuss the quality of PC preparations by focusing on the basic concept and regulatory framework of regenerative medicine in Japan. Within the new framework, PC therapy is regulated by a specific notification and registration system, as is stem cell therapy. In comparison with the latter, however, risk factors that hamper successful PC therapy are much fewer. Via appropriate evaluation of patients' conditions and whole-blood samples by simple and sensitive but not yet fully standardized assays, it is theoretically possible that PC quality will be controlled nearly completely. In addition to or instead of standardization of preparation protocols, standardization of preoperative examination of individual PC preparations is an urgent task for improving and guaranteeing the safety and efficacy of PC therapy.

Abstract P3-08-11: The prognostic impact of retinoic acid-induced 2 (RAI2) expression in ERα-positive breast cancer patients

Background: Breast cancer cells disseminate to the bone marrow and form bone metastases in a large majority of late-stage patients. Retinoic Acid-Induced 2 (RAI2) was reported as a putative suppressor of early hematogenous dissemination of tumor cells to the bone marrow in breast cancer, particularly in estrogen receptor α (ERα)-positive breast cancer. Here, we investigated mRNA expression of RAI-2 in breast cancer patients during long-term follow-up.

Materials and methods: A total of 451 invasive breast cancer tissues was available for analysis of RAI2 mRNA using a TaqMan PCR system. We also sought correlations between clinicopathological factors and levels of RAI2 expression in these samples. The expression of markers associated with tumor-initiating capacity, such as SNAI1, SNAI2 and VIM was also analyzed. The median follow-up period was 9.0 years. Survival curves were analyzed using the Kaplan-Meier method. Cox proportional hazards regression analysis was used for univariate and multivariate analyses of prognostic values.

Results: We found positive correlations between low expression of RAI2 mRNA and shorter disease-free survival and overall survival in breast cancer patients (P=0.003, P&lt;0.0001, respectively), which was limited to ERα-positive patients (P=0.04, P=0.0009, respectively), and not seen in ERα-negative patients (P=0.52, P=0.27, respectively). Low RAI2 mRNA levels were positively correlated with high grade, ERα-negativity and PgR negativity. Multivariate analysis indicated that low level RAI2 mRNA expression was an independent factor for survival both overall in breast cancer and in ERα-positive breast cancer patients

Multivariate analysis (ERα-positive breast cancer patients)  OS  Multivariate patientsp valueHR(95%CI)Tumor size≤2cm1390.83691 (Reference) &gt;2cm207 1.08(0.54-2.28)Node statusNegative176&lt;0.00011 (Reference) Positive144 4.72(2.33-10.34)Grade11240.95921 (Reference) 2•3218 0.98(0.50-2.14)RAI2 mRNA expressionhigh140&lt;0.00011 (Reference) middle•low206 4.79(2.14-12.78)

.

Conclusion:We show that low expression of RAI2 is an independent factor predictive of a poor prognosis in ERα-positive breast cancer patients. RAI2 could be a promising candidate biomarker and therapeutic target in ERα-positive breast cancer to prevent dissemination to the bone marrow.

Citation Format: Nishikawa S, Kondo N, Endo Y, Hato Y, Hisada T, Nishimoto M, Dong Y, Okuda K, Kato H, Takahashi S, Nakanishi R, Toyama T. The prognostic impact of retinoic acid-induced 2 (RAI2) expression in ERα-positive breast cancer patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-08-11.

Platelet Counts in Insoluble Platelet-Rich Fibrin Clots: A Direct Method for Accurate Determination

Platelet-rich fibrin (PRF) clots have been used in regenerative dentistry most often, with the assumption that growth factor levels are concentrated in proportion to the platelet concentration. Platelet counts in PRF are generally determined indirectly by platelet counting in other liquid fractions. This study shows a method for direct estimation of platelet counts in PRF. To validate this method by determination of the recovery rate, whole-blood samples were obtained with an anticoagulant from healthy donors, and platelet-rich plasma (PRP) fractions were clotted with CaCl2 by centrifugation and digested with tissue-plasminogen activator. Platelet counts were estimated before clotting and after digestion using an automatic hemocytometer. The method was then tested on PRF clots. The quality of platelets was examined by scanning electron microscopy and flow cytometry. In PRP-derived fibrin matrices, the recovery rate of platelets and white blood cells was 91.6 and 74.6%, respectively, after 24 h of digestion. In PRF clots associated with small and large red thrombi, platelet counts were 92.6 and 67.2% of the respective total platelet counts. These findings suggest that our direct method is sufficient for estimating the number of platelets trapped in an insoluble fibrin matrix and for determining that platelets are distributed in PRF clots and red thrombi roughly in proportion to their individual volumes. Therefore, we propose this direct digestion method for more accurate estimation of platelet counts in most types of platelet-enriched fibrin matrix.

Mechanical and degradation properties of advanced platelet-rich fibrin (A-PRF), concentrated growth factors (CGF), and platelet-poor plasma-derived fibrin (PPTF)

BACKGROUND

Fibrin clot membranes prepared from advanced platelet-rich fibrin (A-PRF) or concentrated growth factors (CGF), despite their relatively rapid biodegradability, have been used as bioactive barrier membranes for alveolar bone tissue regeneration. As the membranes degrade, it is thought that the growth factors are gradually released. However, the mechanical and degradable properties of these membranes have not well been characterized. The purpose of this study was to mechanically and chemically characterize these membranes.

METHODS

A-PRF and CGF clots were prepared from blood samples collected from non-smoking, healthy donors and were compressed to form 1-mm-thick membranes. Platelet-poor plasma-derived fibrin (PPTF) clots were prepared by adding bovine thrombin to platelet-poor plasma. A tensile test was performed at the speed of 1 mm/min. Morphology of the fibrin fibers was examined by SEM. A digestion test was performed in PBS containing trypsin and EDTA.

RESULTS

In the tensile test, statistical difference was not observed in Young's modulus, strain at break, or maximum stress between A-PRF and CGF. In strain at break, PPTF was significantly weaker than CGF. Likewise, fibrin fiber thickness and crosslink density of PPTF were less than those of other membranes, and PPTF degraded faster than others.

CONCLUSIONS

Although the centrifugal conditions are different, A-PRF and CGF are prepared by essentially identical mechanisms. Therefore, it is conceivable that both membranes have similar mechanical and chemical properties. Only PPTF, which was prepared by a different mechanism, was characterized as mechanically weaker and enzymatically more degradable.

Synergistic effects of the combined use of human-cultured periosteal sheets and platelet-rich fibrin on bone regeneration: An animal study

A human-cultured alveolar bone-derived periosteal (hCP) sheet is an osteogenic grafting material used clinically in periodontal regenerative therapy, while platelet-rich fibrin (PRF), a platelet concentrate with fibrin clot, is considered to augment the wound healing process. Therefore, whether the combined use of hCP-PRF complex could facilitate bone regeneration synergistically was evaluated in animal models. Human periosteal segments (1 × 1 mm) were cultured initially on plastic dishes and formed an hCP sheet. The hCP sheet was implanted with freshly prepared human PRF into subcutaneous tissue (hCP: n = 4, hCP + PRF: n = 4) and 4 mm diameter calvarial bone defect models (hCP: n = 4, hCP + PRF: n = 4, control [defect-only]: n = 4) that prepared in nude mice. At 4 weeks postimplantation, new bone formation was evaluated by using μCT. Cell growth and neovascularization were evaluated by histochemical and immunohistological methods. In the subcutaneous tissue, mineral deposit formation, collagen deposition, and number of vessels were higher in the hCP + PRF group than in the hCP alone group. In the calvarial defect models, new bone formation was significantly higher in the hCP + PRF group than in the hCP alone group and defect-only control group. The numbers of vessels and PCNA-positive cells in calvarial defects were also increased in the hCP + PRF group more than in the hCP alone group. Platelet-rich fibrin preparations support the proliferation and the growth of periosteal cells to form well-combined active biological materials. Platelet-rich fibrin also stimulates the local angiogenesis in the implantation site. Therefore, the combined use of hCP and PRF could be clinically applicable in bone regeneration therapy.

Perfusion MR Imaging Using a 3D Pulsed Continuous Arterial Spin-Labeling Method for Acute Cerebral Infarction Classified as Branch Atheromatous Disease Involving the Lenticulostriate Artery Territory

BACKGROUND AND PURPOSE

Branch atheromatous disease is a stroke subtype considered a risk factor for early neurologic deterioration. Meanwhile, crossed cerebellar diaschisis is thought to be influenced by the degree and location of supratentorial perfusion abnormalities and is associated with the clinical outcome in the case of an ischemic stroke. In this article, our aim was to clarify the utility of using a whole-brain 3D pulsed continuous arterial spin-labeling method as an imaging biomarker for predicting neurologic severity in branch atheromatous disease.

MATERIALS AND METHODS

Twenty-three patients with branch atheromatous disease in the lenticulostriate artery territory were enrolled. All patients underwent MR imaging, including DWI, 3D-TOF-MRA, and 3D-arterial spin-labeling. We measured the asymmetry index of CBF in the affected area (branch atheromatous disease), the asymmetry index of the contralateral cerebellar hemisphere (crossed cerebellar diaschisis), and the DWI infarct volume in the lenticulostriate artery territory. We also compared each parameter with the initial NIHSS score with the Pearson correlation coefficient.

RESULTS

Among the 23 patients, we found no correlation between NIHSS score and the asymmetry index of CBF in the affected area (branch atheromatous disease) (r = -0.027, P = .724), whereas the asymmetry index of the contralateral cerebellar hemisphere (crossed cerebellar diaschisis) and DWI infarct volumes were significantly correlated with NIHSS score (r = 0.515, P = .012; r = 0.664, P = .001, respectively).

CONCLUSIONS

In patients with branch atheromatous disease, 3D-arterial spin-labeling can detect crossed cerebellar diaschisis, which is correlated with the degree of neurologic severity.

Constitutively active ABL family kinases, TEL/ABL and TEL/ARG, harbor distinct leukemogenic activities in vivo

ABL (ABL1) and ARG (ABL2) are highly homologous to each other in overall domain structure and amino-acid sequence, with the exception of their C termini. As with ABL, translocations that fuse ARG to ETV6/TEL have been identified in patients with leukemia. To assess the in vivo leukemogenic activity of constitutively active ABL and ARG, we generated a bone marrow (BM) transplantation model using the chimeric forms TEL/ABL and TEL/ARG, which have comparable kinase activities. TEL/ABL rapidly induced fatal myeloid leukemia in recipient mice, whereas recipients of TEL/ARG-transduced cells did not develop myeloid leukemia, instead, they succumbed to a long-latency infiltrative mastocytosis that could be adoptively transferred to secondary recipients. Swapping of the C termini of ABL and ARG altered disease latency and phenotypes. In a detailed in vitro study, TEL/ARG strongly promoted mast cell differentiation in response to stem cell factor or interleukin-3, whereas TEL/ABL preferentially induced myeloid differentiation of hematopoietic stem/progenitor cells. These results indicate that ABL and ARG kinase activate distinct differentiation pathways to induce specific diseases in vivo, that is, myeloid leukemia and mastocytosis, respectively. Further elucidation of the differences in their properties should provide important insight into the pathogenic mechanisms of oncogenes of the ABL kinase family.

An Evaluation of the Accuracy of the Subtraction Method Used for Determining Platelet Counts in Advanced Platelet-Rich Fibrin and Concentrated Growth Factor Preparations

Platelet concentrates should be quality-assured of purity and identity prior to clinical use. Unlike for the liquid form of platelet-rich plasma, platelet counts cannot be directly determined in solid fibrin clots and are instead calculated by subtracting the counts in other liquid or semi-clotted fractions from those in whole blood samples. Having long suspected the validity of this method, we herein examined the possible loss of platelets in the preparation process. Blood samples collected from healthy male donors were immediately centrifuged for advanced platelet-rich fibrin (A-PRF) and concentrated growth factors (CGF) according to recommended centrifugal protocols. Blood cells in liquid and semi-clotted fractions were directly counted. Platelets aggregated on clot surfaces were observed by scanning electron microscopy. A higher centrifugal force increased the numbers of platelets and platelet aggregates in the liquid red blood cell fraction and the semi-clotted red thrombus in the presence and absence of the anticoagulant, respectively. Nevertheless, the calculated platelet counts in A-PRF/CGF preparations were much higher than expected, rendering the currently accepted subtraction method inaccurate for determining platelet counts in fibrin clots. To ensure the quality of solid types of platelet concentrates chairside in a timely manner, a simple and accurate platelet-counting method should be developed immediately.

Non-invasive, quantitative assessment of the morphology of γ-irradiated human mesenchymal stem cells and periosteal cells using digital holographic microscopy

PURPOSE

To assure the quality of cells to be used in cell therapy, we examined the applicability of digital holographic microscopy (DHM) for non-invasive, quantitative assessment of changes in cell morphology.

MATERIALS AND METHODS

Mesenchymal stem cells derived from adipose tissue (MSC-AT) and bone marrow (MSC-BM), in addition to human alveolar periosteal cells (PC) as a reference, were γ-ray irradiated (1 and 4 Gy), and their morphological changes were quantified without fixation using holographic microscopy. After detachment and fixation with ethanol, cell number and surface antigen expression were determined using an automated cell counter kit and flow-cytometry, respectively.

RESULTS

Among various indexes, only indexes related to cell size were significantly changed after γ-irradiation. Both BMC-AT and BMC-BM were enlarged and more sensitive to a low dose of γ-irradiation than PC. In contrast to PC, proteins related to DNA damage repair (γ-H2AX, p21^waf1, p53 and Rb) were not substantially upregulated or sustained for a week in either MSC-AT or MSC-BM.

CONCLUSION

Instead of DNA damage markers, we suggest that cell morphological parameters (e.g. cell volume) that are monitored by DHM could be a useful and more stable marker of MSC quality.

Evaluating the Safety of Somatic Periosteal Cells by Flow-Cytometric Analysis Monitoring the History of DNA Damage

In preparing cell-based products for regenerative therapy, cell quality should be strictly controlled. Methodologies for evaluating cell viability, identity, and purity are established and used routinely, whereas current methodologies for evaluating cell safety, particularly genetic integrity or tumorigenicity, are time-consuming and relatively insensitive. As part of developing a more practical screening system, the authors previously demonstrated that γ-H2AX and p53 were useful markers for evaluating the history of DNA damage. To validate these markers further and develop a more quantitative methodology, single cell-based expression of these markers and two additional candidates have now been examined using flow cytometry (FCM). FCM analysis and immunofluorescent staining demonstrated that γ-ray-irradiation suppressed proliferation, enlarged cells, and cell nuclei, and immediately upregulated γ-H2AX and p21(waf1) in large numbers of cells for up to 12 days. Gamma-H2AX foci were formed in the nuclei of many affected cells. An initial sharp increase in p53 expression declined slowly over 12 days, while Rb expression increased linearly. The present findings suggest that this high-throughput, cell-based, combinational evaluation of protein markers and cell size enables a small number of cells with a history of DNA damage to be detected quickly and routinely from within a very large cell population. Using this screening methodology will improve the ability to verify the quality of cell-based products used in regenerative therapy.

In vitro immunological and biological evaluations of the angiogenic potential of platelet-rich fibrin preparations: a standardized comparison with PRP preparations

Background

Platelet-rich fibrin (PRF), a platelet-rich plasma (PRP) derivative mainly composed of fibrin networks, has been increasingly demonstrated to be effective in wound healing in clinical and pre-clinical animal studies. However, there has still been a concern that major growth factors may significantly be loss from PRF during its preparation through the slow clotting process. To address this concern, we compared the angiogenic potential of PRF and PRP by standardization of procedures based on volume ratios.

Methods

PRP, PRF, and platelet-poor plasma (PPP) were prepared from the peripheral blood of healthy donors. PRF preparations were squeezed or homogenized to produce exudate (PRFexu) or extract (PRFext), respectively. Concentrations of the angiogenic factors and their bioactivities were determined using ELISA kits, a scratch assay using endothelial cells and a chicken chorioallantoic membrane (CAM) assay.

Results

In PRP and PRF preparations, both VEGF and PDGF-BB were significantly more concentrated than PPP. In the scratch assay, PRFexu and PRFext were the most effective for wound closure. In the CAM assay, PRF membranes were the most effective for neovascularization.

Conclusions

It is suggested that PRF preparations efficiently preserve the angiogenic factors and function not only as a scaffolding material but as a reservoir of angiogenic factors in wound healing.

X-Ray-Induced Damage to the Submandibular Salivary Glands in Mice: An Analysis of Strain-Specific Responses

Radiation therapy for head and neck cancers often causes xerostomia (dry mouth) by acutely damaging the salivary glands through the induction of severe acute inflammation. By contrast, the mechanism underlying the X-ray-induced delayed salivary dysfunction is unknown and has attracted increasing attention. To identify and develop a mouse model that distinguishes the delayed from the acute effects, we examined three different mouse strains (C57BL/6, ICR, and ICR-nu/nu) that showed distinct T-cell activities to comparatively analyze their responses to X-ray irradiation. Three strains were irradiated with X-rays (25 Gy), and functional changes of the submandibular glands were examined by determining pilocarpine-induced saliva secretion. Structural changes were evaluated using histopathological and immunohistochemical examinations of CD3, cleaved poly (ADP-ribose) polymerase (PARP), and Bcl-xL. In C57BL/6 mice, the X-ray irradiation induced acute inflammation accompanied by severe inflammatory cell infiltration at 4 days postirradiation, causing substantial destruction and significant dysfunction at 2 weeks. Fibrotic repair was observed at 16 weeks. In ICR-nu/nu mice, the inflammation and organ destruction were much milder than in the other mice strains, but increased apoptotic cells and a significant reduction in salivary secretion were observed at 4 and 8 weeks and beyond, respectively. These results suggest that in C57BL/6 mice, X-ray-induced functional and structural damage to the salivary glands is caused mainly by acute inflammation. By contrast, although neither acute inflammation nor organ destruction was observed in ICR-nu/nu mice, apoptotic cell death preceded the dysfunction in salivary secretion in the later phase. These data suggest that the X-ray-irradiated ICR-nu/nu mouse may be a useful animal model for developing more specific therapeutic methods for the delayed dysfunction of salivary glands.

Heat devices in nonlinear irreversible thermodynamics

We present results obtained by using nonlinear irreversible models for heat devices. In particular, we focus on the global performance characteristics, the maximum efficiency and the efficiency at maximum power regimes for heat engines, and the maximum coefficient of performance (COP) and the COP at maximum cooling power regimes for refrigerators. We analyze the key role played by the interplay between irreversibilities coming from heat leaks and internal dissipations. We also discuss the relationship between these results and those obtained by different models.

Quantitative single-cell motility analysis of platelet-rich plasma-treated endothelial cells in vitro

Platelet-rich plasma (PRP) has been widely applied in regenerative therapy due to its high concentration of growth factors. Previous in vitro and in vivo studies have provided evidence supporting the angiogenic activity of PRP. To more directly demonstrate how PRP acts on endothelial cells, we examined the PRP-induced changes in the motility of human umbilical vein endothelial cells by examining the involvement of VEGF. Time-lapse quantitative imaging demonstrated that in the initial phase (∼2 h) of treatment, PRP substantially stimulated cell migration in a wound-healing assay. However, this effect of PRP was not sustained at significant levels beyond the initial phase. The average net distance of cell migration at 10 h was 0.45 ± 0.16 mm and 0.82 ± 0.23 mm in control and PRP-stimulated cells, respectively. This effect was also demonstrated with recombinant human VEGF and was significantly attenuated by a neutralizing anti-VEGF antibody. Immunofluorescent examination of paxillin and actin fibers demonstrated that PRP concomitantly up-regulated focal adhesion and cytoskeletal formation. Western blotting analysis of phosphorylated VEGFR2 demonstrated that PRP mainly stimulated the phosphorylation of immature VEGFR2 in a dose- and time-dependent manner, an action that was completely blocked by the neutralizing antibody. Taken together, these data suggest that PRP acts directly on endothelial cells via the activation of VEGFR2 to transiently up-regulate their motility. Thus, the possibility that PRP desensitizes target endothelial cells for a relatively long period of time after short-term activation should be considered when the controlled release system of PRP components is designed.

A short-term preservation of human cultured periosteal sheets, osteogenic grafting materials, using a commercial preservation solution containing epigallocatechin-3-gallate (Theliokeep(®)) under hypothermic conditions

In the past decade, it has increasingly been reported that epigallocatechin-3-gallate (EGCG), a major catechin derivative extracted from Green tea, has various bioactivities, including a cell-protective action on mammalian cells and tissues. In this study, we have tested a commercial preservation solution containing EGCG (Theliokeep(®)) in both two- and three-dimensional cultures of human periosteal sheets, which have been used as an osteogenic grafting material for periodontal regenerative therapy. When periosteal sheets were 3D-cultured on collagen mesh, cell viability was maintained for 2 days using the hypothermic EGCG preservation solution. Replenishment of EGCG solution with 2-day intervals prevented the time-dependent decline in cell viability at 3 days and later. As observed in nonpreserved control cultures, most cells were positive for proliferating cell-nuclear antigen (PCNA) in the cultures preserved at 4°C in the EGCG solution, whereas PCNA-negative cells were increased in the cultures preserved at 4°C in the MesenPRO medium. In periosteal sheets 2D-cultured in plastic dishes, the EGCG solution occasionally was associated with vacuole formation in the cytoplasm, but cells could again expand in the culture medium at 37°C. As observed in the nonpreserved periosteal sheets control, the osteogenic induction upregulated alkaline phosphatase in those cells and tissues preserved in the EGCG solution. The EGCG solution protected cells from the cold shock-induced membrane phospholipid peroxidation. Our data suggest that the EGCG solution acts as an antioxidant to protect periosteal cells from cold shock and preserves cells under chilled conditions. The limited period of preservation time could be expanded by repeating replenishment of the EGCG solution or by optimizing the formula to be more favorable for human periosteal sheets without sacrificing cell viability. This methodology of preserving human cultured periosteal sheets with EGCG would be expected to support and spread the clinical use of regenerative therapy with autologous periosteal sheets.

104 EXPRESSION OF ACTIVIN A AS A LOCAL REGULATOR IN THE BOVINE OVIDUCT

Activin (ACV) is known as a local regulator of several reproductive functions including follicular development and implantation in mammals. ACVA is a glycopeptide belonging to the transforming growth factor β superfamily, and is a homodimer of inhibin ßA (INHBA) subunits. Follistatin (FST), an ACV-specific binding protein, inhibits ligand-receptor binding. ACV receptor (ACVR) is a hetero-tetramer consisting of 2 kinds of protein, ACVR1 or ACVR1B and ACVR2A or ACVR2B. The oviduct provides an optimal environment for sperm capacitation, fertilization, and early embryonic development. Previous reports have demonstrated that ACVRs were expressed in bovine oocytes and embryos, and that early embryonic development is facilitated by ACVA in vitro. ACVA produced by the bovine oviduct may affect gametes and embryos as well as oviductal cells as a local regulator in cow. Bovine oviductal samples were classified into 6 stages of the oestrous cycle (day of ovulation; Days 2–3 after ovulation; Days 5–6; Days 8–12; Days 15–17; Days 19–21). We examined (1) protein expression of ACVA and FST in oviductal fluid collected from the ampulla and isthmus, (2) mRNA expression of INHBA and FST in the ampullary and isthmic oviductal tissues during the oestrous cycle, (3) the effects of oestradiol-17β (E2: 0.1, 1, 10 nM) and progesterone (P4: 1, 10, 100 nM) on mRNA expressions of INHBA and FST in cultured oviductal epithelial cells isolated from the ampulla and isthmus, and (4) mRNA expression of ACVRs in tissues and in cultured epithelial and stromal cells. The main findings were as follows: (1) Both ACVA and FST were detected throughout the oestrous cycle in the oviductal fluid of the ampulla and isthmus. (2) INHBA expression was higher in the isthmus than in the ampulla. FST expression in the ampulla was lowest at peri-ovulation, INHBA expression in the isthmus was highest on the day of ovulation and FST in the isthmus during Days 2–6 was highest. Because an increase of ACVA production and a decrease of FST production raise ACVA bioactivity, ACVA seems to be most active at peri-ovulation in both the ampulla and isthmus. (3) In the cultured isthmic oviductal epithelial cells, 10 nM E2 significantly stimulated INHBA expression, but tended to suppress FST expression. Therefore, the bioactivity of ACVA seems to be controlled by E2 during the oestrous cycle in the isthmus. (4) The expression of ACVR1B and ACVR2A was clearly detected in the tissues as well as in cultured epithelial and stromal cells. The overall findings suggest that ACVA secreted into oviductal fluid plays an important role in oviductal functions, including fertilization in the ampulla and sperm motility and viability in the isthmus. It is also suggested that ACVA acts on both epithelial and stromal cells as a local regulator of cellular functions, such as cellular proliferation and secretion in the cow.

105 EFFECT OF LYSOPHOSPHATIDIC ACID ON PROSTAGLANDIN PRODUCTION IN THE BOVINE OVIDUCT

The oviduct is an essential organ for successful pregnancy in mammals. The transport of gametes and early embryos is mainly induced by contraction and relaxation of smooth muscle. The contraction and relaxation of bovine oviductal smooth muscle are induced by prostaglandin (PG) F2α and PGE2, respectively. Lysophosphatidic acid (LPA), a type of phospholipid, is involved in various physiological actions such as promoting inflammation and cellular proliferation in various organs. LPA acts through at least 6 G protein-coupled receptors. Both LPA and LPA receptors are expressed in endometrium and, moreover, LPA affects PG production by the endometrium in cow. Based on the above findings, we hypothesised that LPA is locally involved in PG production by oviductal cells to promote motility of oviductal smooth muscle in cow. Oviductal samples ipsilateral to a corpus luteum or a dominant follicle at peri-ovulation (0–6 and 19–21 days after ovulation) were collected in abattoir. Messenger RNA expression of LPA receptors (LPAR1–6) and LPA-producing enzymes (ATX, PLA1α, PLA1β) was examined in ampullary and isthmic tissues. Expression in cultured epithelial and stromal cells isolated from the bovine oviduct were also examined to determine the cells possessing LPA receptors and LPA-producing enzymes. In addition, the effect of LPA (0.1, 1, 10 μM) on the expression of cyclooxygenase (COX)-1 and COX-2 (PG-synthesising enzymes) and on PGE2 and PGF2α production by cultured epithelial and stromal cells was investigated. The significant differences (P < 0.05) were determined by Student's t-test for 2 groups, and by one-way ANOVA followed by Tukey's multiple comparison test for more than 3 groups. LPAR1–6, ATX, PLA1α, and PLA1β were expressed in both ampullary and isthmic tissues as well as in both cultured epithelial and stromal cells. The expression of LPAR1–3 was significantly lower in the isthmic tissues than in the ampullary tissues, whereas the expression of LPAR4–6 was significantly higher in the isthmic tissues than in the ampullary tissues. The expression of COX-2 was significantly stimulated by 10 μM LPA in cultured isthmic stromal cells. In addition, LPA significantly stimulated both PGE2 and PGF2α production by cultured isthmic stromal cells. In the isthmus of the oviduct, LPA produced by epithelial and stromal cells may stimulate the expression of COX-2 in the stromal cells, followed by increased PG production. Because the mRNA expression of LPAR4–6 is higher in the isthmus than in the ampulla, those effects of LPA might be mediated by activation of LPAR4–6. The overall findings suggest that LPA is one of the regulating factors for transport of gametes and early embryos by controlling the motility of smooth muscle in the bovine oviduct.

X-ray and ultraviolet C irradiation-induced γ-H2AX and p53 formation in normal human periosteal cells in vitro: markers for quality control in cell therapy

BACKGROUND AIMS

For successful cell transplantation therapy, the quality of cells must be strictly controlled. Unfortunately, to exclude inappropriate cells that possess structurally abnormal chromosomes, currently only karyotyping functions as an assessment. Unfortunately, this methodology is time-consuming and only effective for metaphasic cells. To develop a more efficient, inclusive and sensitive methodology, we examined the phosphorylation of histone H2AX and the p53 levels in normal human periosteal cells exposed to x-rays or other oxidative stressors.

METHODS

Periosteal cells were obtained from human alveolar bone before being exposed to x-rays, ultraviolet C or hydrogen peroxide. The cell cycle, electric nuclear volume and CD44 expression were evaluated using flow cytometry, and the phosphorylated H2AX (γ-H2AX), p53, p21 and proliferating cell nuclear antigen (PCNA) levels were evaluated by Western blot analyses.

RESULTS

Each oxidative stress dose-dependently arrested cell growth and partially induced premature cellular senescence. In parallel, each oxidative stress rapidly phosphorylated H2AX and stabilized p53, and intense stress sustained these high levels for at least 8 days.

CONCLUSIONS

Intensive oxidative stress induces sustained high levels of γ-H2AX and p53, which force cells toward senescence or non-apoptotic cell death. Lower doses of oxidative stress induced more modest and transient increases in γ-H2AX and p53, and these cells eventually survive. However, because DNA is repaired without a template in the majority of these cells, G1 mutations accumulate. Therefore, we recommend that any cell population expressing elevated γ-H2AX and p53 levels be excluded from cell transplantation therapy.

The heat-compression technique for the conversion of platelet-rich fibrin preparation to a barrier membrane with a reduced rate of biodegradation

Platelet-rich fibrin (PRF) was developed as an advanced form of platelet-rich plasma to eliminate xenofactors, such as bovine thrombin, and it is mainly used as a source of growth factor for tissue regeneration. Furthermore, although a minor application, PRF in a compressed membrane-like form has also been used as a substitute for commercially available barrier membranes in guided-tissue regeneration (GTR) treatment. However, the PRF membrane is resorbed within 2 weeks or less at implantation sites; therefore, it can barely maintain sufficient space for bone regeneration. In this study, we developed and optimized a heat-compression technique and tested the feasibility of the resulting PRF membrane. Freshly prepared human PRF was first compressed with dry gauze and subsequently with a hot iron. Biodegradability was microscopically examined in vitro by treatment with plasmin at 37°C or in vivo by subcutaneous implantation in nude mice. Compared with the control gauze-compressed PRF, the heat-compressed PRF appeared plasmin-resistant and remained stable for longer than 10 days in vitro. Additionally, in animal implantation studies, the heat-compressed PRF was observed at least for 3 weeks postimplantation in vivo whereas the control PRF was completely resorbed within 2 weeks. Therefore, these findings suggest that the heat-compression technique reduces the rate of biodegradation of the PRF membrane without sacrificing its biocompatibility and that the heat-compressed PRF membrane easily could be prepared at chair-side and applied as a barrier membrane in the GTR treatment.