DS-7300a, a DNA Topoisomerase I Inhibitor, DXd-Based Antibody-Drug Conjugate Targeting B7-H3, Exerts Potent Antitumor Activities in Preclinical Models

B7-H3 is overexpressed in various solid tumors and has been considered as an attractive target for cancer therapy. Here, we report the development of DS-7300a, a novel B7-H3-targeting antibody-drug conjugate with a potent DNA topoisomerase I inhibitor, and its in vitro profile, pharmacokinetic profiles, safety profiles, and in vivo antitumor activities in nonclinical species. The target specificity and species cross-reactivity of DS-7300a were assessed. Its pharmacologic activities were evaluated in several human cancer cell lines in vitro and xenograft mouse models, including patient-derived xenograft (PDX) mouse models in vivo. Pharmacokinetics was investigated in cynomolgus monkeys. Safety profiles in rats and cynomolgus monkeys were also assessed. DS-7300a specifically bound to B7-H3 and inhibited the growth of B7-H3-expressing cancer cells, but not that of B7-H3-negative cancer cells, in vitro. Additionally, treatment with DS-7300a and DXd induced phosphorylated checkpoint kinase 1, a DNA damage marker, and cleaved PARP, an apoptosis marker, in cancer cells. Moreover, DS-7300a demonstrated potent in vivo antitumor activities in high-B7-H3 tumor xenograft models, including various tumor types of high-B7-H3 PDX models. Furthermore, DS-7300a was stable in circulation with acceptable pharmacokinetic profiles in monkeys, and well tolerated in rats and monkeys. DS-7300a exerted potent antitumor activities against B7-H3-expressing tumors in in vitro and in vivo models, including PDX mouse models, and showed acceptable pharmacokinetic and safety profiles in nonclinical species. Therefore, DS-7300a may be effective in treating patients with B7-H3-expressing solid tumors in a clinical setting.

Cell therapy for medication-related osteonecrosis of the jaw: update on treatment strategies

Bioactive glasses (BAG) are used as bone-graft substitutes in orthopaedic surgery. A specific BAG scaffold was developed by sintering BAG-S53P4 granules. It is hypothesised that this scaffold can be used as a bone substitute to fill bone defects and induce a bioactive membrane (IM) around the defect site. Beyond providing the scaffold increased mechanical strength, that the initial inflammatory reaction and subsequent IM formation can be enhanced by coating the scaffolds with poly(DL-lactide-co-glycolide) (PLGA) is also hypothesised. To study the immunomodulatory effects, BAG-S53P4 (± PLGA) scaffolds were placed on monolayers of primary human macrophage cultures and the production of various pro- and anti-inflammatory cytokines was assessed using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) and ELISA. To study the osteogenic effects, BAG-S53P4 (± PLGA) scaffolds were cultured with rabbit mesenchymal stem cells and osteogenic differentiation was evaluated by RT-qPCR and matrix mineralisation assays. The scaffold ion release was quantified and the BAG surface reactivity visualised. Furthermore, the pH of culture media was measured. BAG-S53P4 scaffolds had both anti-inflammatory and osteogenic properties that were likely attributable to alkalinisation of the media and ion release from the scaffold. pH change, ion release, and immunomodulatory properties of the scaffold could be modulated by the PLGA coating. Contrary to the hypothesis, the coating functioned by attenuating the BAG surface reactions and subsequent anti-inflammatory properties, rather than inducing an elevated inflammatory response compared to BAG-S53P4 alone. These results further validated the use of BAG-S53P4 (± PLGA) scaffolds as bone substitutes and indicate that scaffold properties can be tailored to a specific clinical need.

Real-world clinical impact of external elastic lamina-based stent sizing criteria using optical coherence tomography

Introduction

ILUMIEN III trial has reported that non-inferiority of optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) to intravascular ultrasound-guided PCI for postprocedural minimum stent area. In the trial, external elastic lamina (EEL)-based stent sizing criteria was introduced, however OCT has limitations including incomplete visualization of EEL in severale lesions.

Purpose

The aim of the study is to investigate real-world clinical impact of EEL-based stent sizing criteria.

Methods

The study included consecutive patients who underwent OCT-guided percutaneous coronary intervention (PCI) for de novo lesions in our institution between September 2016 and April 2018. EEL visibility, mean EEL diameter, mean lumen diameter and plaque morphology were assessed at proximal and distal references. The plaque morphology at references was categorized according to its most prevalent component as follows: normal, fibrous plaque, lipid plaque, and calcified plaque. Both references were divided into 3 groups according to visibility of EEL.

Results

Among 205 lesions, 31 lesions had artifacts at references (16 proximal and 17 distal references). EEL visibility was summarized in a table. Out of 174 lesions with both analyzable references, 111 lesions (63.8%) had >180-degree EEL visibility at both references. Proportion of plaque morphology were significantly different among 3 groups at proximal and distal references as shown in a figure.

Conclusions

EEL-based stent sizing criteria was usable for 63.8% of all the lesions. Vessel size and plaque morphology were significantly associated with EEL visibility.

Proportion of plaque morphology

Funding Acknowledgement

Type of funding source: None

Difference of myocardial injury, inflammation and early recurrence after pulmonary vein isolation among laser balloon ablation, radiofrequency catheter ablation and cryoballoon ablation

Background

Pulmonary vein isolation (PVI) has become well-established as the main therapy for patients with drug-refractory paroxysmal atrial fibrillation (PAF) and various isolation methods including radiofrequency ablation (RFA), cryoballoon ablation (CBA) and laser balloon ablation (LBA) were available. Pathological findings in each ablation methods such as myocardial injury and inflammation are thought to be different. High sensitive cardiac troponin I (hs-TnI), subunit of cardiac troponin complex, is a sensitive and specific marker of myocardium injury. High-sensitive C-reactive protein (hs-CRP) is a biomarker of inflammation and is elevated following cardiomyocyte necrosis. Relationship between myocardial injury and inflammation after ablation using RFA, CBA and LBA and early recurrence of atrial fibrillation (ERAF) remains unclear.

Methods

We enrolled consecutive PAF patients from Osaka Rosai Atrial Fibrillation (ORAF) registry who underwent PVI from January 2019 to October 2019. We compared the clinical characteristics including age, gender, hypertension, diabetes mellitus, history of heart failure, CHADS2Vasc score, renal function, serum BNP level and echocardiographic parameters including left ventricular dimensions, left atrial diameter (LAD) and left ventricular ejection fraction (LVEF) between RFA, CBA and LBA groups. We investigated the difference of relationship between myocardial injury marker (hs-TnI), inflammation markers (white blood cell change (DWBC) from post to pre PVI, neutrophil-to-lymphocyte ratio change (DNLR) from after to before PVI and hs-CRP) at 36–48 hours after PVI and ERAF (<3 months after PVI) between each group.

Results

We enrolled 187 consecutive PAF patients who underwent PVI. RFA, CBA and LBA groups comprised 108, 57 and 22 patients, respectively. There were no significant differences of age, gender, hypertension, diabetes mellitus, history of heart failure, CHADS2Vasc score, renal function, serum BNP level and echocardiographic parameters between each group. Serum hs-TnI in RFA group and LBA group were significantly lower than in CBA group (2.643 ng/ml vs 5.240ng/ml, 1.344 ng/ml vs 5.240 ng/ml, p<0.001, p=0.002, respectively, Figure). DWBC was significantly higher in LBA group than CBA group (1157.3/μl vs 418.4/μl, p=0.045). DNLR did not differ between each group. Hs-CRP in RFA group and LBA group were significantly higher than in CBA group (1.881 mg/dl vs 1.186 mg/dl, 2.173 mg/dl vs 1.186 mg/dl, p=0.010, p=0.003, respectively, Figure). Incidence of ERAF was significantly higher in LBA group than RFA group (36.4% vs 16.7%, p=0.035). Incidence of ERAF tended to be higher in LBA group than CBA group (36.4% vs 19.3%, p=0.112).

Conclusion

LBA may cause less myocardial injury than RFA and CBA, on the contrary LBA may cause more inflammation than CBA. Incidence of ERAF in LBA was highest between each procedure.

Inflammation markers and ERAF

Funding Acknowledgement

Type of funding source: None

Not only power and energy but also balloon size is correlated with lesion formation in laser ablation model in vitro study

Background

Power and total energy were known to correlate with lesion formation during laser balloon ablation for atrial fibrillation. However, it is unclear whether balloon size can influence lesion formation. The aim of this study was to evaluate the impact of balloon size on lesion formation during laser balloon procedure in vitro model.

Methods

Laser energy was applied to chicken muscles using first generation laser balloon. Laser ablation was performed with different 2 balloon size (18mm and 32mm) using 2 different power settings (12W/20sec and 8.5W/20sec). Forty lesions were evaluated for each setting. We compared maximum lesion width, maximum lesion depth, depth at maximum width and endocardial lesion width between 18mm and 32mm balloon groups at 12W/20sec and 8.5W/20sec, respectively.

Results

At 8.5W/20sec, inadequate lesion formation to assess lesion size was observed in 1/40 lesion of 18mm balloon group and in 5/40 lesions of 32mm balloon group. Thus, at 8.5W/20sec 18 mm balloon group consisted of 39 lesions and 32 mm balloon group consisted of 35 lesions. At 12W/20sec 18 mm balloon group consisted of 40 lesions and 32 mm balloon group consisted of 40 lesions. At both power settings, maximum lesion depth was larger in 18mm balloon than in 32mm balloon group. At 12W/20sec setting, maximum lesion width and endocardial width were larger in 32mm balloon group than in 18mm balloon group. At 12W/20sec setting, depth at maximum width was smaller in 32mm balloon group than in 18mm balloon group. Lesion morphologies were summarized in a figure.

Conclusion

Balloon size could affect lesion formation during laser balloon ablation in addition to laser power and energy. Laser ablation lesion were wider but shallower in 32mm balloon group compared with in 18mm balloon group.

Funding Acknowledgement

Type of funding source: None

Clinical characteristics and outcomes after pulmonary vein isolation in atrial fibrillation patients with complete right bundle branch block

Background

Complete right bundle branch block (CRBBB) is one of the most frequent alterations of the electrocardiogram (ECG). Several studies have shown that CRBBB was a risk factor for cardiovascular diseases and the appearance of CRBBB in patients hospitalized for exacerbated heart failure (HF) was associated with a worse prognosis. Various alternations of ECG such as early repolarization pattern and intraventricular conduction disturbance were associated with high recurrence ratio of atrial fibrillation (AF) after pulmonary vein isolation (PVI). However clinical outcome after PVI in patients with CRBBB remains unclear.

Methods

We enrolled consecutive AF patients who underwent PVI from September 2014 to November 2018 rom Osaka Rosai Atrial Fibrillation (ORAF) registry. We excluded patients with other wide QRS (left bundle branch block, ventricular pacing and unclassified intraventricular conduction disturbance) and divided into 2 groups; CRBBB (QRS duration ≥120msec) group and no-CRBBB (QRS duration <120) group. We compared the clinical characteristics including age, gender, hypertension, diabetes mellitus, history of heart failure, history of stroke, CHADS2Vasc score, paroxysmal AF (PAF), renal function, plasma brain natriuretic peptide (BNP) level and echocardiographic parameters including left ventricular end-diastolic diameter (LVDd), left ventricular end-systolic diameter (LVDs), left atrial diameter (LAD) and left ventricular ejection fraction (LVEF) between the 2 groups. We also compared the incidence of late recurrence of AF/atrial tachycardia (AT) between the 2 groups. We investigated whether CRBBB was an independent predictor of late recurrence of AF/AT after PVI by multivariate Cox analysis.

Results

We enrolled 736 consecutive AF patients who underwent PVI. CRBBB patients comprised 55 patients (7.5%). There were no significant differences of age, gender, hypertension, diabetes mellitus, history of heart failure, history of stroke, CHADS2Vasc score, PAF, renal function, plasma BNP level and echocardiographic parameters (LVDd, LVDs, LVEF and LAD) between the 2 groups. Incidence of AF/AT recurrence after PVI was significantly higher in CRBBB group than no-CRBBB group (Figure). CRBBB was an independently and significantly associated with late recurrence of AF/AT after PVI by multivariate Cox analysis (hazard ratio: 1.923, 95% CI: 1.190–2.961, p=0.009) in addition to female (p<0.001), no-PAF (p=0.005) and left atrial diameter (p=0.042).

Conclusion

CRBBB may be a strong predictor of AF/AT late recurrence after PVI.

AF/Ar recurrence after PVI

Funding Acknowledgement

Type of funding source: None

Clinical outcome of non-use of touch-up focal ablation catheters strategy during cryoballoon atrial fibrillation ablation

Background

It has been reported that frequent use of touch-up focal ablation catheters was related to worse outcomes after cryoballoon (CB) atrial fibrillation (AF) ablation. It is unknown whether non-use of touch-up focal ablation catheters strategy affects the outcome of AF ablation. Therefore, this study aimed to assess whether non-use of touch-up focal ablation catheters strategy improve clinical outcome after AF ablation using CB.

Methods

A total of 151 consecutive patients who received CB ablation from February 2017 to August 2019 were enrolled. Non-use of a touch-up focal ablation catheters strategy was started from February 2018. Patients were divided into 2 groups according to the type of strategy. In the non-touch-up group, pulmonary veins were isolated without touch-up focal ablation catheters as much as possible and in conventional group, touch-up focal ablation catheters were used as required. The 1-year atrial tachyarrhythmia free survival without class 1 or 3 antiarrhythmic drugs after a 90-day blanking period was assessed between the 2 groups.

Results

The conventional group consisted of 76 patients and the non-touch-up group consisted of 75 patients. Baseline characteristics were comparable between 2 groups. Touch-up focal ablation catheters were used more in the conventional group (11 patients, 14%) than non-touch-up group (0 patients, 0%) (p<0.001). Pulmonary isolation was achieved in all patients of both groups. Atrial tachyarrhythmia recurrence occurred more frequently in the non-touch-up group (15/75 patients, 20%) than conventional group (7/76 patients, 9%) (p=0.045).

Conclusion

Non-use of a touch-up focal ablation catheters strategy may be related to worse outcome after CB AF ablation.

Funding Acknowledgement

Type of funding source: None

Ablation index guide pulmonary vein isolation can reduce early recurrence of atrial fibrillation: a propensity score-matched analysis

Background

Ablation index (AI) is a novel marker of ablation lesion quality for radiofrequency ablation (RFA). It has been reported that AI guided pulmonary vein isolation (PVI) reduced pulmonary vein reconnection and late recurrence of atrial fibrillation (AF). However, little is known about the impact of AI guided PVI on early recurrence of AF (ERAF).

Purpose

The aim of this study is to clarify whether AI guided PVI can reduce ERAF.

Methods

From September 2014 to August 2019, consecutive AF patients who underwent 1st session PVI were enrolled. We compared prevalence of ERAF between AI guided PVI group (AI group) and conventional contact force guided PVI group (CF group) using propensity score-matched analysis, which adjusted patient backgrounds (age, sex, and body mass index (BMI)), type of AF, the history of heart failure, hypertension, diabetes and stroke, laboratory findings including estimated glomerular filtration rate (eGFR) and b-type natriuretic peptide (BNP), and echocardiographic parameters including left ventricular ejection fraction (LVEF) and left atrial diameter.

Results

Total 711 patients were enrolled. AI group comprised 233 patients and CF group comprised 233 patients. Prevalence of ERAF were significantly lower in AI group than in CF group significantly (21.5% vs 36.1%, p=0.001, Table).

Conclusions

AI guided PVI can reduce ERAF as compared to conventional method.

Funding Acknowledgement

Type of funding source: None

Multicenter study of novel mapping technique to detect non-pulmonary vein triggers excluding the origin from left atrial posterior wall and superior vena cava

Background

It has been reported that elimination of non-pulmonary vein (PV) triggers after PV isolation is a good predictor of atrial tachyarrhythmia free survival. However, precise mapping of triggers outside from superior vena cava (SVC) or left atrial posterior wall (LAPW) are difficult. The aim of this study is to assess the efficacy of self-reference mapping technique to eliminate non-PV triggers originated from outside of primordial pulmonary vein area.

Methods

Total of 431 patients (446 procedures) underwent atrial fibrillation (AF) ablation in a hospital and in a medical center from January 2017 to March 2019. After isolation of PV, non-PV triggers were induced with isoproterenol and/or adenosine triphosphate. Reproducible non-PV triggers were targeted to ablate using following self-reference mapping technique: A trigger conducts centrifugally and the earliest site should be distinguished from other later activated sites. Using a PentaRay multipolar catheter, the operators annotated the earliest site of local activation and a reference tag was placed. The multipolar catheter was then moved to the reference tag and the process repeated. Ultimately, we identified clusters of early circumferential activation and ablated.

Results

A total of 32 non-PV triggers excluding the origin from LAPW and SVC were induced in 23 patients. Nineteen triggers (59%) were located in the right atrium and 13 triggers (41%) in the left atrium (Figure 1). All triggers were eliminated with ablation and AF was non-inducible in all patients at the end of the procedure. During the follow-up (529±270 days), 18 patients (77%) were free from atrial tachyarrhythmias after a 3-month blanking period. Three patients received additional ablation procedures for recurrent atrial arrhythmias. No non-PV triggers ablated during the previous procedure were observed.

Conclusion

A novel self-reference mapping technique is useful for eliminating non-PV triggers in terms of the short- and long-term success.

Figure 1. Distribution of non-PV triggers

Funding Acknowledgement

Type of funding source: None

P2691Excimer laser coronary angioplasty can achieve favorable clinical outocomes for in-stent restenosis lesion with neoatherosclerosis

Background

Recent reports revealed that residual area stenosis (% AS) ≤30% after lesion preparation is a suitable predictor for target lesion revascularization (TLR) after drug-coated balloon (DCB) treatment for in-stent restenosis (ISR). Excimer laser coronary angioplasty (ELCA) can obtain larger lumen area and may be more useful for lesion preparation than plain old ballooning (POBA). On the other hands, it has been reported that in-stent neoatherosclerosis (NA) is major cause of restenosis. It is unclear the correlation between NA of ISR and the effect of ELCA. Thus, we compared the influence of NA which was evaluated by optical coherence tomography (OCT) on % AS for ISR treatment between ELCA and DCB (ELCA) group and POBA and DCB (non-ELCA) group and their clinical outcome.

Methods

We enrolled 58 consecutive ISR lesions which were treated by OCT guidance between July 2014 and July 2018 in our hospital. The lesions were divided into NA and non-NA lesions according to OCT findings. In each lesion, we compared post procedural % AS and % AS change which was calculated by the difference between pre and post procedural % AS between ELCA and non-ELCA groups. In addition, we compared 8-month major advance cardiac events (MACE) defined by composite of binary restenosis and target lesion revascularization (TLR) between ELCA and non-ELCA group in NA lesions.

Results

There were 19 NA (33.3%) and 39 non-NA lesions. In NA lesions, ELCA group can obtain significantly lower % AS (p=0.02) and significantly larger % AS change (p<0.01) than non-ELCA group, but in non-NA lesions, % AS and %AS change were similar between ELCA and non-ELCA groups (table). In 8-month clinical outcome, non-ELCA group experienced MACE twice as much as ELCA group did. (31% vs 17%)

Results of %AS NA lesions (n=19) P value non-NA lesions (n=39) P value ELCA group (n=6) non-ELCA group (n=13) ELCA group (n=17) non-ELCA group (n=22) Post %AS (%) 2±21 26±25 0.02 7±29 23±19 0.07 %AS change (%) 71±15 38±19 <0.01 56±29 44±17 0.11

Conclusion

Although neoatherosclerosis is correlated with refractory restenosis, ELCA can improve residual area stenosis in neoatherosclerosis lesions and can achieve better clinical outcomes for in-stent neoatherosclerosis.

P3385Difference of vascular healing after percutaneous coronary intervention between 4 kinds of new generation drug-eluting stents: an optical coherence tomography analysis

Background

New generation drug eluting stents (DES) have improved target vessel failure as compared with early generation DES and bare metal stent. Contemporary several new generation DES are different each other regarding strut thickness and drug and polymer type. A little is known about which stent induces a more favorable vascular healing at follow up.

Purpose

In this study, we compared the vascular healing at 8-month follow up by optical coherence tomography (OCT) between 4 different kinds of new generation DES.

Methods

We enrolled 112 consecutive patients (121 lesions) who underwent PCI using 4 kinds of new generation DES including biodegradable-polymer everolimus-eluting stents (BP-EES), biodegradable-polymer sirolimus-eluting stents (BP-SES), durable-polymer everolimus-eluting stents (DP-EES) and durable-polymer zotarolimus-eluting stents (DP-ZES) and who underwent 8-month follow up angiogram and OCT between July 2016 and April 2018. We compared the OCT parameters including percentage of covered struts, uncovered struts, well-apposed and uncovered struts, malapposed strut and mean neointimal hyperplasia (NIH) thickness between them.

Results

BP-EES consisted of 29 lesions, BP-SES consisted of 25 lesions, DP-EES consisted of 38 lesions and DP-ZES consisted of 29 lesions. A total of 734 frames with 5163 struts in BP-EES, 481 frames with 4214 struts in BP-SES, 783 frames with 6119 struts in DP-EES and 583 frames with 4708 struts in DP-ZES were analyzed. As shown in a table, mean NIH thickness was significantly higher in BP-EES and BP-SES. Thus, we compared the OCT parameters between durable-polymer (DP) group including DP-ZES and DP-EES and biodegradable-polymer (BP) group including BP-EES and BP-SES. The percentage of uncovered struts was significantly lower and mean NIH thickness was significantly higher in BP group than DP group.

Results of OCT parameters BP-EES (n=29) BP-SES (n=25) DP-EES (n=38) DP-ZES (n=29) P value BP group (n=54) DP group (n=67) P value Covered struts (%) 89.5±13.6 92.4±8.6 85.5±17.5 85.0±17.7 0.29 90.9±11.6 85.3±17.4 0.08 Uncovered struts (%) 8.8±10.8 7.1±8.7 14.5±17.5 15.0±17.7 0.14 8.0±9.9 14.7±17.4 0.03 Well-apposed and uncovered struts (%) 7.9±9.9 5.9±7.7 11.7±13.1 12.3±14.0 0.15 7.0±8.9 11.9±13.4 0.04 Malapposed struts (%) 0.8±1.6 1.3±2.2 2.7±5.8 2.7±4.7 0.33 1.0±1.9 2.7±5.3 0.07 Mean NIH thickness (μm) 102±57 121±48 78±28 88±33 <0.01 111±53 82±31 <0.01

Conclusion

The present OCT study demonstrated that delayed neointimal healing characterized by the presence of uncovered struts and lower mean NIH thickness was less common in BP group than DP gruop. Biodegradable-polymer may be more favorable than durable-polymer from the point of view of vascular healing.

103Maximum calcium thickness is a useful predictor for under expansion after post dilatation in calcified lesions: optical coherence tomographic study

Background

Several reports have revealed that stent under expansion is associated with target lesion failure and calcified lesions usually induced inadequate stent expansion. Contemporary debulking devices such as rotational/orbital atherectomy can modify severe calcified lesions before stenting. However, it is uclear which calcium parameter is most useful predictor for stent expansion in the calcified lesions. Thus, we investigated useful calcium parameters correlating with stent expansion in the calcified lesions.

Methods

We enrolled 43 consecutive calcified lesions (43 patients) who underwent optical coherence tomography (OCT) guided percutaneous coronary intervention (PCI) between September 2016 and January 2019. We evaluated the lesions treated with post dilatation by non-compliant balloon due to stent under expansion after stenting. Exclusion criteria included acute coronary syndrome, in-stent restenosis and lesions without any calcium or treated with rotational atherectomy. If there were several calcium lesions in one patient, we selected maximum calcium angle lesion. Stent expansion defined as post-PCI lumen area divided by the values predicted by the manufactures compliance charts. We compared mean reference area, pre lesion area stenosis, calcium parameters including calcium arc, maximum thickness, area and longitudinal length in pre-PCI OCT evaluations with post-PCI stent expansion at that site.

Results

Maximum calcium thickness showed significant correlation with stent expansion, while the others did not show a significant correlation with stent expansion (table). The optimal thresholds of maximum calcium thickness for the prediction of acceptable stent expansion defined by 80% of the values predicted by the manufactures compliance charts was 870mm (area under curve (AUC): 0.65) (figure).

Results of OCT parameters Univariate analysis P value Mean reference area 0.41 Pre % area stenosis 0.16 Calcium parameters   Calcium arc 0.37   Calcium maximum thickness 0.04   Calcium area 0.20   Calcium longitudinal length 0.43

Conclusion

A maximum calcium thickness<870mm is a useful predictor for acceptable stent expansion after post dilatation in calcified lesions.

P3393Comparison of intermediate-term vascular response to new-generation biodegradable polymer and durable polymer-based drug-eluting stents: optical coherence tomographic study

Background

Over the last decade, drug-eluting stents (DES) have undergone substantial modifications with thinner struts and more biocompatible durable polymer (DP) or biodegradable polymer (BP). In DP-based DES, after drug elusion has been completed, DP remnants may trigger of local inflammatory vascular reactions and promote delayed healing, leading to accelerated neoatherosclerosis (NA). Thus, BPs have been developed to reduce the above-mentioned risks. Recently, poor strut coverage and in-stent NA are increasingly recognized the cause of late stent failure, but it is unclear whether BPs can reduce the incidence of NA and the poor stent coverage as compared to DPs.

Objectives

The purpose of this study was to compare the incidence of NA and the stent coverage using optical coherence tomography (OCT) between the DPs and the BPs.

Methods

Between July 2016 and April 2018, 127 consecutive patients with new-generation DES who underwent 8-month follow up OCT imaging were enrolled. Patients were divided into the two groups: DP group who had the new-generation durable polymer everolimus-eluting and zotarolimus-eluting stents and BP group who had the new-generation biodegradable polymer sirolimus-eluting and everolimus-eluting stents. We compared patient characteristics including hypertension, dyslipidemia and diabetes mellitus and 8-month follow up OCT findings including NA, uncovered struts and malapposed struts between the two groups.

Results

The DP group comprised 64 patients (50.4%. The incidence of NA, uncovered struts and malapposed struts were similar between the two groups (DPs vs BPs, 1.56% vs 7.94%, P=0.11; 7.80% vs 5.88%, P=0.16 and 2.76% vs 2.01%, P=0.43, respectively) (table). The other parameters were also similar between the two groups.

Table 1 DP group (n=64) BP group (n=63) P value Hypertension 44 (68.8%) 50 (79.4%) 0.2251 Dyslipidemia 39 (60.9%) 37 (58.7%) 0.8573 Diabetes mellitus 25 (39.1%) 30 (47.6%) 0.3731 8 month OCT follow up findings   Neoatherosclerosis 1 (1.6%) 5 (7.9%) 0.1147   Uncovered struts 7.8% (2.8–20.4) 5.9% (0.7–16.7) 0.1616   Malapposed struts 0.2% (0–2.8) 0% (0–2.8) 0.4392

Conclusions

The new-generation DP based-DES may have similar effects on vascular response compared to the new-generation BP-based DES during 8-month follow-up period.

P2689Irregular protrusion area is associated with incidence of cardiac events after implantation of new generation drug-eluting stents - optical coherence tomography study

Background

Several studies using optical coherence tomography (OCT) have shown that the prevalence of irregular protrusion was associated with the incidence of adverse cardiac events. However, the correlation between cardiac events and protrusion area is not well investigated.

Method

One hundred twenty-nine consecutive patients with 138 clesions with 2nd and 3rd generation drug-eluting stents (DES) which had pre-stenting and post-stenting OCT imaging between April 2016 and April 2018 were evaluated. We compared baseline characteristics, procedure findings and OCT findings including minimum stent area, protrusion type and maximum protrusion area between target lesion revascularization (TLR) group and non-TLR group.

Results

TLR occurred in 12 (9.3%) in 129 patients. The baseline characteristics and procedure findings were similar between TLR group and non-TLR group. Univariate analysis revealed that maximum irregular protrusion area was significantly larger (0.51 [0.00–0.63] vs 0.00 [0.00–0.27], p=0.036) in TLR group than non-TLR group. Receiver operating characteristic curve analysis revealed that the suitable cutoff value of maximum irregular protrusion area were 0.43mm2 for TLR. In multivariate analysis using the parameters with p value<0.10 determined by univariate analysis, maximum irregular protrusion (≥0.43mm2) and minimum stent area (MSA) were independently correlated with TLR (table).

Odd's ratio (95% CI) P value Major irregular protrusion (≥0.43mm2) 17.3 (3.63–82.6) <0.001 MSA 2.13 (1.15–3.93) 0.002

Conclusion

Major irregular protrusion (>0.43mm2) in post-stenting OCT findings may be a powerful predictor of TLR in the patients with new generation DES.

P1914Relationship between myocardial injury, inflammation and early, late recurrence after pulmonary vein isolation may be different between radiofrequency catheter ablation and cryoballoon ablation

Background

High sensitive cardiac troponin I (hs-TnI), subunit of cardiac troponin complex, is a sensitive and specific marker of myocardium injury as troponin T. Several studies showed hs-TnI was associated with worse cardiovascular outcomes but relationship between serum hs-TnI level in patients with atrial fibrillation (AF) after pulmonary vein isolation (PVI) and AF recurrence remains unclear.

Methods

We enrolled 444 consecutive AF patients who underwent PVI from May 2017 to September 2018. We investigated the difference of relationship between serum hs-TnI, inflammation markers at 48 hours after PVI and early or late recurrence of AF (ERAF, <3 months and LRAF, during 1 year after PVI in patients with AF) between radiofrequency ablation (RFA) group and cryoballoon ablation (CBA) group.

Results

RFA and CBA were performed in 328 and 116 patients, respectively. There were no significant differences in patient characteristics between RFA group and CBA group. Serum hs-TnI in RFA group was significantly lower than in CBA group (1.93 ng/ml±3.28 vs 5.08 ng/ml±4.29, p<0.001), while hs-CRP was significantly higher in RFA group than CB group (1.97±2.38 mg/dl vs 1.10±0.84 mg/dl, p<0.001). The incidence of ERAF was similar between the two groups (RFA group: 26.8% and CBA group: 21.6%, p=0.262). There was no significant difference of hs-TnI and hs-CRP between patients with ERAF and without ERAF (table). In 213 patients who were followed during 1 year (PVIs were performed from May 2017 to January 2018, RFA 149 and CBA 64 patients), there was no significant association between hs-TnI, hs-CRP and incidence of LRAF (table).

TnI and CRP between RFA and CBA RFA (n=328) CBA (n=116) P value hs-TnI 1.93±3.28 5.08±4.29 <0.001 hs-CRP 1.97±2.38 1.10±0.84 <0.001 3 months follow-up RFA (n=328) CBA (n=116) ERAF (+) ERAF (−) P value ERAF (+) ERAF (−) P value hs-TnI 1.68±1.90 2.02±3.66 0.410 5.03±3.17 5.10±4.56 0.943 hs-CRP 2.23±2.65 1.88±2.27 0.238 1.01±0.84 1.13±0.85 0.524 1 year follow-up RFA (n=149) CBA (n=64) LRAF (+) LRAF (−) P value LRAF (+) LRAF(−) P value hs-TnI 1.61±1.77 1.87±2.69 0.570 4.71±2.14 5.60±5.69 0.664 hs-CRP 2.18±2.24 1.92±2.24 0.550 1.12±0.64 1.12±0.98 0.991

Conclusion

CBA may cause more myocardial injury than RFA, on the contrary RFA may cause more inflammation than CBA. These markers did not affect ERAF and LRAF after PVI.

P1736A novel calcium parameter, calcium ratio, can predict minimum lumen area in calcified lesions: optical coherence tomographic study

Background

Several reports have revealed that minimum lumen area (MLA) is associated with target lesion failure even with newer-generation drug-eluting stents, and calcified lesions usually induced inadequate lumen area because of stent under expansion. Contemporary debulking devices such as rotational/orbital atherectomy can modify severe calcified lesions before stenting. However, there are no optimal criteria to indicate necessity for calcium modification to obtain adequate acute gain. Therefore, we investigated useful calcium parameters correlating with MLA in the calcified lesions after stenting.

Methods

We enrolled 71 consecutive calcified lesions (71 patients) who underwent optical coherence tomography (OCT) guided percutaneous coronary intervention (PCI) between September 2016 and January 2019. Exclusion criteria included acute coronary syndrome, in-stent restenosis and lesions without any calcium or treated with rotational atherectomy. If there were several calcium lesions in one patient, we selected maximum calcium angle lesion. We compared mean reference area, pre lumen area and various calcium parameters including calcium arc, maximum thickness, depth, area, longitudinal length and calcium ratio that was maximum calcium thickness divided by nearest reference diameter in disease-free segments as much as possible in pre-PCI OCT evaluation with post-PCI lumen area at that site by simple and multiple regression analysis.

Results

Calcium ratio was an independent predictor for post-PCI lumen area in addition to mean reference area, while the others were not associated with post-PCI lumen area (table).

Results of OCT parameters Univariate analysis Multivariate analysis P value P value β Mean reference area <0.01 <0.01 0.69 Pre lumen area <0.01 0.08 0.15 Cacium arc <0.01 0.58 −0.06 Calcium maximum thickness 0.62 Calcium ratio <0.01 0.01 −0.21 Calcium area 0.02 0.64 0.05 Calcium longitudinal length 0.60 Calcium depth 0.09

Conclusion

The novel calcium measurement, calcium ratio, may be a useful predictor for post-PCI lumen area for calcified lesions.

B7-H3 Negatively Modulates CTL-Mediated Cancer Immunity

Purpose: Anti-programmed-death-1 (PD-1) immunotherapy improves survival in non-small cell lung cancer (NSCLC), but some cases are refractory to treatment, thereby requiring alternative strategies. B7-H3, an immune-checkpoint molecule, is expressed in various malignancies. To our knowledge, this study is the first to evaluate B7-H3 expression in NSCLCs treated with anti-PD-1 therapy and the therapeutic potential of a combination of anti-PD-1 therapy and B7-H3 targeting.Experimental Design: B7-H3 expression was evaluated immunohistochemically in patients with NSCLC (n = 82), and its relationship with responsiveness to anti-PD-1 therapy and CD8⁺ tumor-infiltrating lymphocytes (TILs) was analyzed. The antitumor efficacy of dual anti-B7-H3 and anti-programmed death ligand-1 (PD-L1) antibody therapy was evaluated using a syngeneic murine cancer model. T-cell numbers and functions were analyzed by flow cytometry.Results: B7-H3 expression was evident in 74% of NSCLCs and was correlated critically with nonresponsiveness to anti-PD-1 immunotherapy. A small number of CD8⁺ TILs was observed as a subpopulation with PD-L1 tumor proportion score less than 50%, whereas CD8⁺ TILs were still abundant in tumors not expressing B7-H3. Anti-B7-H3 blockade showed antitumor efficacy accompanied with an increased number of CD8⁺ TILs and recovery of effector function. CD8⁺ T-cell depletion negated antitumor efficacy induced by B7-H3 blockade, indicating that improved antitumor immunity is mediated by CD8⁺ T cells. Compared with a single blocking antibody, dual blockade of B7-H3 and PD-L1 enhanced the antitumor reaction.Conclusions: B7-H3 expressed on tumor cells potentially circumvents CD8⁺-T-cell-mediated immune surveillance. Anti-B7-H3 immunotherapy combined with anti-PD-1/PD-L1 antibody therapy is a promising approach for B7-H3-expressing NSCLCs. Clin Cancer Res; 24(11); 2653-64. ©2018 AACR.

Novel anti-EPHA2 antibody, DS-8895a for cancer treatment

Overexpression of EPHA2 has been observed in multiple cancers and reported to be associated with poor prognosis. Here, we produced an afucosylated humanized anti-EPHA2 monoclonal antibody (mAb), DS-8895a for cancer treatment. The antibody recognizes the extracellular juxtamembrane region of EPHA2 and therefore can bind to both full-length and truncated forms of EPHA2, which are anchored to cell membranes and recently reported to be produced by post-translational cleavage in tumors. DS-8895a exhibited markedly increased antibody dependent cellular cytotoxicity (ADCC) in vitro and also inhibited tumor growth in EPHA2-positive human breast cancer MDA-MB-231 and human gastric cancer SNU-16 xenograft mouse models. Moreover, DS-8895a in combination with cisplatin (CDDP) showed better efficacy than each of the monotherapies did in the human gastric cancer model. These results suggest that a novel antibody, DS-8895a has therapeutic potential against EPHA2-expressing tumors.

Development of DS-5573a: A novel afucosylated mAb directed at B7-H3 with potent antitumor activity

B7‐H3 is highly overexpressed in a variety of human clinical tumors, and its expression is significantly associated with poor outcomes. In our study, we aimed to develop new antitumor mAbs by employing cancer cell immunization, and succeeded in generating a mouse anti‐human B7‐H3 antibody (M30) that shows antitumor activity. M30 was humanized (Hu‐M30), and an afucosylated Hu‐M30 (DS‐5573a) was also generated. To assess the potency of DS‐5573a as a therapeutic mAb, we characterized this mAb and evaluated its antitumor activity in vitro and in vivo. Flow cytometry analysis showed that B7‐H3 proteins were expressed on various types of cancer cell lines broadly, and DS‐5573a binds to IgC1 and IgC2 domains of human B7‐H3. Antibody‐dependent cellular cytotoxicity activity of DS‐5573a was drastically enhanced against medium to high B7‐H3‐expressing cancer cell lines MDA‐MB‐231 and NCI‐H322. DS‐5573a also induced high antibody‐dependent cellular cytotoxicity activity against low B7‐H3‐expressing cancer cell line COLO205, whereas Hu‐M30 induced little activity against it. In addition, DS‐5573a was found to be a novel anti‐B7‐H3 antibody which showed antibody‐dependent cellular phagocytosis activity. Furthermore, DS‐5573a showed dose‐dependent and significant antitumor efficacy (0.03–3 mg/kg) in MDA‐MB‐231‐bearing SCID mice (which have functional natural killer cells and macrophages), but little antitumor efficacy in NOG mice (which lack natural killer cells and have reduced macrophage function). These results suggest that antitumor activity of DS‐5573a is mediated by effector cells, and this mAb could be a promising antitumor therapy for patients with a wide range of B7‐H3‐expressing tumors.

Great Ears: Low-Frequency Sensitivity Correlates in Land and Marine Leviathans

Like elephants, baleen whales produce low-frequency (LF) and even infrasonic (IF) signals, suggesting they may be particularly susceptible to underwater anthropogenic sound impacts. Analyses of computerized tomography scans and histologies of the ears in five baleen whale and two elephant species revealed that LF thresholds correlate with basilar membrane thickness/width and cochlear radii ratios. These factors are consistent with high-mass, low-stiffness membranes and broad spiral curvatures, suggesting that Mysticeti and Proboscidea evolved common inner ear adaptations over similar time scales for processing IF/LF sounds despite operating in different media.

Brain imaging in methamphetamine-treated mice using a nitroxide contrast agent for EPR imaging of the redox status and a gadolinium contrast agent for MRI observation of blood-brain barrier function

Methamphetamine (METH)-induced neurotoxicity is associated with mitochondrial dysfunction and enhanced oxidative stress. The aims of the present study conducted in the mouse brain repetitively treated with METH were to (1) examine the redox status using the redox-sensitive imaging probe 3-methoxycarbonyl-2,2,5,5-tetramethylpiperidine-1-oxyl (MCP) and (2) non-invasively visualize the brain redox status with electron paramagnetic resonance (EPR) imaging. The rate of reduction of MCP was measured from a series of temporal EPR images of mouse heads, and this rate was used to construct a two-dimensional map of rate constants called a "redox map." The obtained redox map clearly illustrated the change in redox balance in the METH-treated mouse brain that is a known result of oxidative damage. Biochemical assays also showed that the level of thiobarbituric acid-reactive substance, an index of lipid peroxidation, was increased in mouse brains by METH. The enhanced reduction in MCP observed in mouse brains was remarkably suppressed by treatment with the dopamine synthase inhibitor, α-methyl-p-tyrosine, suggesting that enhancement of the reduction reaction of MCP resulted from enzymatic reduction in the mitochondrial respiratory chain. Furthermore, magnetic resonance imaging (MRI) of METH-treated mice using a blood-brain barrier (BBB)-impermeable paramagnetic contrast agent revealed BBB dysfunction after treatment with METH for 7 days. MRI also indicated that the impaired BBB recovered after withdrawal of METH. EPR imaging and MRI are useful tools not only for following changes in the redox status and BBB dysfunction in mouse brains repeatedly administered METH, but also for tracing the drug effect after withdrawal of METH.

Surgical procedure of extracting teeth for obtaining dental pulp for regenerative medicine in swine

Dental pulp is a potential source of cells that can be used in cell replacement therapy for various nerve disorders, including stroke, spinal cord injury, and peripheral nerve defect. However, the validation of an animal model closely related to humans is needed in translational research. The miniature pig is a suitable experimental model in maxillofacial surgery, because its anatomical structure and size are similar to those of humans. However, the swine tooth is extremely long. The routine closed extraction procedure for harvesting dental pulp tissue causes root fracture. This report describes the details of a surgical procedure for tooth extraction. Four healthy 7-8-month-old male NIBS miniature pigs were used. Two mandibular deciduous right incisors (Di1 and Di2) were extracted in order to obtain dental pulp tissue. Gingival envelope incision with vertical-releasing incision was performed, and a full-thickness mucoperiosteal flap was made. The buccal alveolar bone was exposed and removed by osteotomy. Di1 and Di2 were extracted. Dental pulp tissue was obtained from these extracted teeth by splitting hard tissue. In this procedure, 9.8 ± 2.5 × 10(5) cells were obtained from the mandibular Di1 and Di2 (n = 4).

Studies of the humoral factors produced by layered chondrocyte sheets

The authors aimed to repair and regenerate articular cartilage with layered chondrocyte sheets, produced using temperature-responsive culture dishes. The purpose of this study was to investigate the humoral factors produced by layered chondrocyte sheets. Articular chondrocytes and synovial cells were harvested during total knee arthroplasty. After co-culture, the samples were divided into three groups: a monolayer, 7 day culture sheet group (group M); a triple-layered, 7 day culture sheet group (group L); and a monolayer culture group with a cell count identical to that of group L (group C). The secretion of collagen type 1 (COL1), collagen type 2 (COL2), matrix metalloproteinase-13 (MMP13), transforming growth factor-β (TGFβ), melanoma inhibitory activity (MIA) and prostaglandin E2 (PGE2) were measured by enzyme-linked immunosorbent assay (ELISA). Layered chondrocyte sheets produced the most humoral factors. PGE2 expression declined over time in group C but was significantly higher in groups M and L. TGFβ expression was low in group C but was significantly higher in groups M and L (p<0.05). Our results suggest that the humoral factors produced by layered chondrocyte sheets may contribute to cartilaginous tissue repair and regeneration.

Requirement of integrin β3 for iron transportation during enamel formation

Rodent incisors exhibit pigmentation on their labial surfaces. Although previous studies have shown that this pigment is composed of iron, the existence of other elements has not been investigated. This study found that the lower incisors of CD61, also known as integrin β3, null mice (CD61(-/-)) lacked pigmentation. Although ameloblasts differentiated and formed enamel normally, no ferric ion accumulation was observed in maturation-stage ameloblasts in CD61(-/-) mice. Surface elements of control and CD61-/- lower incisors were compared by x-ray photoelectron spectroscopy (XPS). XPS analysis detected C, Ca, N, O, and P on the labial surfaces of lower incisors of both mice, whereas Fe was detected only in control samples. No peak of non-ferrous metal or other element was detected in either group. Quantitative RT-PCR analysis of 18 iron-transportation-related genes with mRNA from maturation-stage ameloblasts and ALC, a pre-ameloblastic cell line, was performed. The results suggested that CD61 regulates the expressions of Slc11a2 and Slc40a1, both of which are involved in iron transportation in epithelial tissues. These results suggested that the pigment on the labial surface of mouse incisors is composed of Fe and that both anemia and reduction of iron-transporting proteins may cause the loss of pigmentation in CD61(-/-) mice.

Cell sheet engineering: a unique nanotechnology for scaffold-free tissue reconstruction with clinical applications in regenerative medicine

Cell sheet technology (CST) is based on the use of thermoresponsive polymers, poly(N-isopropylacrylamide) (PIPAAm). The surface of PIPAAms is formulated in such a way as to make its typical thickness <100 nm. In this review, we first focus on how the methods of PIPAAm-grafted surface preparations and functionalization are important to be able to harvest a functional cell sheet, to be further transplanted. Then, we present aspects of tissue mimics and three-dimensional reconstruction of a tissue in vitro. Finally, we give an overview of clinical applications and clinically relevant animal experimentations of the technology, such as cardiomyopathy, visual acuity, periodonty, oesophageal ulcerations and type 1 diabetes.

Analysis of soluble vascular endothelial growth factor receptor-1 secreted from cultured corneal and oral mucosal epithelial cell sheets in vitro

BACKGROUND

In clinical trials, eyes transplanted with cultured oral mucosal epithelial cell sheets have shown increased neovascularisation compared with eyes treated with cultured corneal epithelial cell sheets. As reported recently, soluble vascular endothelial growth factor receptor-1 (soluble VEGFr-1) is a main factor to maintain a corneal avascularity.

AIM

To investigate soluble VEGFr-1 of cultured corneal epithelial cells (CCE) and cultured oral mucosal epithelial cells (COE) in vitro.

METHODS

Rabbit corneal and oral mucosal epithelial cells were co-cultured with mitomycin C-treated NIH/3T3 cells on culture plates. After CCE and COE were multilayered, culture medium was replaced by basal medium and incubated. Protein secretion of soluble VEGFr-1 was assessed in conditioned medium from CCE and COE by ELISA. Angiogenic potential was examined by invasion, migration assays with human umbilical vein endothelial cells (HUVECs) in addition to recombinant soluble VEGFr-1.

RESULTS

CCE secreted a significantly higher amount of soluble VEGFr-1 than did COE. Recombinant soluble VEGFr-1 significantly suppressed HUVEC migration induced by COE, without suppression in CCE. In conclusion, these findings suggest that low protein levels of soluble VEGFr-1 may lead to corneal neovascularisation after COE sheet transplantation.

Cementum-periodontal ligament complex regeneration using the cell sheet technique

BACKGROUND AND OBJECTIVE

In the present study we evaluated if a multilayered human periodontal ligament cell sheet could reconstruct the physiological architecture of a periodontal ligament-cementum complex.

MATERIAL AND METHODS

Human periodontal ligament cells were isolated and then cultured in dishes coated with a temperature-responsive polymer to allow cell detachment as a cell sheet. In the control group, human periodontal ligament cells were cultured in Dulbecco's modified Eagle's minimal essential medium containing 10% fetal bovine serum and 1% antibiotics. In the experimental group, human periodontal ligament cells were cultured in Dulbecco's modified Eagle's minimal essential medium and osteodifferentiation medium containing dexamethasone, ascorbic acid and beta-glycerophosphate. After 3 wk, scanning electron microscopy was carried out, in addition to staining for alkaline phosphatase activity and for calcium (using the Von Kossa stain). Then human periodontal ligament cell sheets were multilayered and placed onto dentin blocks. The constructs were transplanted subcutaneously into the back of immunodeficient rats. At 1 and 6 wk after transplantation, the animals were killed. Demineralized tissue sections were stained using hematoxylin and eosin, and Azan, and then analyzed.

RESULTS

After 3 wk of culture in osteodifferentiation medium, human periodontal ligament cells produced mineral-like nodules and also showed positive staining for alkaline phosphatase, calcium (Von Kossa) and mRNA expression of type I collagen. By contrast, in the control group only weak alkaline phosphatase staining was observed, the Von Kossa stain was negative and there was no mRNA expression of type I collagen. Six weeks after transplantation with human periodontal ligament cells cultured in osteodifferentiation medium, most of the dentin surfaces showed a newly immature cementum-like tissue formation and periodontal ligament with perpendicular orientation inserted into the newly deposited cementum-like tissue.

CONCLUSION

This study suggests that the multilayered temperature-responsive culture system can be used as a novel strategy for periodontal regeneration. The human periodontal ligament cell sheet technique may be applicable for regeneration of the clinical periodontal ligament-cementum complex.

Mesothelial cells from tunica vaginalis, a practical source for mesothelial transplantation

Transplantation of mesothelial cells is used to repair peritoneum that is damaged by surgery, peritonitis, and peritoneal dialysis. The largest obstacle for clinical application of mesothelial cell transplantation is the lack of a reliable source of mesothelial cells. So far, they are isolated from omentum, mesentery, parietal wall and ascites. Procedures used to obtain mesothelial cells from the omentum or mesentery are invasive, however, especially in pre-operative situations. Sufficient amounts of ascites for aspiration can not be obtained under physiological conditions. We have developed a novel method of isolating mesothelial cells from the tunica vaginalis. The tunica vaginalis originates from the peritoneum and descends into the scrotum along with the testis during fetal development. This region provides a source of mesothelial cells that is convenient to approach and free from abdominal complications. Transplantation of autologous mesothelial cells that were isolated from tunica vaginalis was effective in preventing post-operative adhesions. In this review, we summarize mesothelial cell transplantation trials and describe the method of isolating mesothelial cells form the tunica vaginalis. Mesothelial cell transplantation might be widely accepted for clinical use in the near future.

Treatment of oesophageal ulcerations using endoscopic transplantation of tissue-engineered autologous oral mucosal epithelial cell sheets in a canine model

BACKGROUND

With the recent development of endoscopic submucosal dissection (ESD), large oesophageal cancers can be removed with a single procedure, with few limits on the resectable range. However, after aggressive ESD, a major complication that arises is postoperative inflammation and stenosis that can considerably affect the patient's quality of life.

AIMS

To examine a novel treatment combining ESD and the endoscopic transplantation of tissue-engineered cell sheets created using autologous oral mucosal epithelial cells, in a clinically relevant large animal model.

METHODS

Oral mucosal epithelial cells, harvested from beagle dogs, were cultured under normal conditions at 37 degrees C, on temperature-responsive dishes. After ESD (5 cm in length, 180 degrees in range), cell sheets were harvested by a simple reduction in temperature to 20 degrees C, and transplanted by endoscopy.

RESULTS

The transplanted cell sheets were able to adhere to and survive on the underlying muscle layers in the ulcer sites, providing an intact, stratified epithelium. Four weeks after surgery, complete wound healing, with no observable stenosis, was seen in the animals receiving autologous cell sheet transplantation. By contrast, noticeable fibrin mesh and host inflammation, consistent with the intermediate stages of wound healing, were observed in the control animals that received only ESD.

CONCLUSIONS

These findings in a clinically relevant canine model show the effectiveness of a novel combined endoscopic approach for the potential treatment of oesophageal cancers that can effectively enhance wound healing and possibly prevent postoperative oesophageal stenosis.

Potent and selective cathepsin K inhibitors

A novel series of cathepsin K inhibitors derived from Novartis compound I is described. Optimization of the P1, P3, and P1' units led to the identification of 4-aminophenoxyacetic acid 24b with an IC(50) value of 4.8 nM, which possessed an excellent selectivity over other human cathepsins and good pharmacokinetic (PK) properties. Oral administration of compound 24b to ovariectomized (OVX) rats showed a trend toward an improvement of bone mineral density (BMD) in the femur bone.

Arylamine based cathepsin K inhibitors: investigating P3 heterocyclic substituents

A modification of novel cathepsin K inhibitors I was carried out. The structural design was aimed at reducing the lipophilic character of compounds I for obtaining better pharmacokinetic profiles. This modification afforded several less lipophilic compounds with good inhibitory activities and pharmacokinetic profiles, although the enzyme selectivity over cathepsin S was left at issue.

In vivo engineering of metabolically active hepatic tissues in a neovascularized subcutaneous cavity

Recent success in clinical hepatocyte transplantation therapy has encouraged further investigation into bioengineering hepatic tissues in vivo. Engineering tissues in the subcutaneous space is an attractive method; however, hepatocyte survival has been transient due to insufficient vascular network formation. To establish a vascularized cavity, we created a polyethylene terephthalate mesh device coated with poly(vinylalcohol) that allowed for the gradual release of basic fibroblast growth factor (bFGF), a potent angiogenic factor. The efficacy of the bFGF-releasing device in inducing vascular network formation in the subcutaneous space was observed in mouse and rat studies. Isolated mouse hepatocytes transplanted into newly vascularized subcutaneous cavities allowed for persistent survival up to 120 days. In the absence of a vascularized compartment, the survival of the transplanted hepatocytes was markedly diminished. Functional maintenance of the engineered hepatic tissues was confirmed by high expression of liver-specific mRNAs and proteins. These engineered hepatic tissues have the ability to take up inoculated compounds and express strong induction of drug-metabolizing enzymes, demonstrating functional relevance as a metabolic tissue. In conclusion, we have created a novel technology to engineer functionally active hepatic tissues in the subcutaneous space, which will likely facilitate hepatocyte-based therapies.

Serological Diversity Demonstrable by a Set of Monoclonal Antibodies to Eight Serotypes of the Mutans Streptococci

A set of monoclonal antibodies were prepared by the conventional cell fusion of myeloma cells (SP2/0-Ag14) with spleen cells from BALB/c mice immunised with whole cells of a strain of mutans streptococci. Their specificities were examined against 35 reference strains of mutans streptococci, 34 reference strains of other oral streptococci and 8 reference strains of other microorganisms often inhabiting the oral cavity. Specificity was examined by enzyme immunoassay using whole cells. A total of 52 strains, consisting of 19 strains isolated in Japan, 19 strains isolated in Italy and 14 strains isolated in England, were characterised by conventional physiological and biochemical tests and then serotyped by the use of 8 monoclonal antibodies with different specificities. They were also confirmed by guanine-plus-cytosine contents of their nucleic acid and DNA-DNA hybridisation test. The results indicated that all monoclonal antibodies are useful for identification of 8 serotypes of the mutans streptococci responsible for dental caries. They also suggest the existence of more serological varieties among mutans species.