Guidelines on the use of gelatin sponge particles in embolotherapy

Effective use of fibrinogen concentrate in a pediatric splenic injury requiring transcatheter arterial embolization

Correction of coagulation is a crucial aspect of trauma care. While there are reports highlighting the effectiveness of fibrinogen concentrate in severe trauma cases with coagulopathic complications, literature on its use in pediatric cases remains limited. This paper discusses the case of a 5-year-old male presenting with a splenic injury and associated coagulopathy. We administered fibrinogen concentrate to enhance his coagulability prior to performing transcatheter arterial embolization utilizing gelatin sponges, aiming for optimal hemostasis. Post-administration, the patient's fibrinogen levels improved significantly, leading to successful hemostasis and a positive clinical outcome.

Feasibility of revascularization after gelatin sponge embolization for hemoptysis during balloon pulmonary angioplasty

BACKGROUND

Vessel injury is a common complication during balloon pulmonary angioplasty (BPA). For persistent hemoptysis, gelatin sponge embolization (GSE) is considered, but its impact on subsequent perfusion in embolized vessels remains unknown. This study explores the feasibility of revascularization in vessels post-GSE.

METHODS

We included 64 vessels from 50 patients with chronic thromboembolic pulmonary hypertension who experienced hemoptysis during BPA in 2012-2023. Twenty-four vessels were treated conservatively (conservative group), while 40 were treated with GSE for persistent hemoptysis or desaturation despite conservative treatment (GSE group). We assessed hemoptysis-related parameters, perfusion of injured vessels pre- and post-treatment, and hemodynamic parameters through multiple BPA sessions.

RESULTS

Hemoptysis resolved immediately after the procedure in 67% of patients, including 70% of those in the GSE group, and all cases resolved by the next day. Of 37 embolized vessels, 41% showed spontaneous perfusion improvement in subsequent sessions. BPA was reperformed in 22 embolized vessels, with 86% showing further improvement, resulting in 70% of all embolized vessels finally showing improvement in perfusion. In both groups, clinical and hemodynamic parameters significantly improved after BPA.

CONCLUSIONS

Perfusion of embolized vessels improved after GSE, suggesting that GSE is safe for the treatment of severe persistent hemoptysis after conservative treatment.

Clinical outcomes and future fertility after uterine artery embolization for postpartum and post-abortion hemorrhage

BACKGROUND

Postpartum hemorrhage (PPH) and post-abortion hemorrhage (PAH) are life-threatening conditions.

PURPOSE

To evaluate the efficacy and safety of uterine arterial embolization (UAE) for PPH and PAH and to investigate future fertility after UAE.

MATERIAL AND METHODS

This study included 57 consecutive patients (mean age = 34 years) who underwent UAE for PPH (n = 46) and PAH (n = 11) at our institution between January 2011 and December 2022. Technical success, non-visualization of the peripheral portion of bilateral uterine arteries on angiography, and clinical success, complete hemostasis after UAE, were assessed. UAE-associated complications and factors related to clinical success were analyzed. Pregnancy outcomes after UAE and complications during subsequent pregnancy were investigated in 16 patients who desired fertility and were followed up for >1 year.

RESULTS

The technical and clinical success rates were 100% and 84.2%, respectively. Sepsis (n = 1) and uterine empyema (n = 1) were observed as severe complications. Placental disorder, bleeding within 24 h after delivery or abortion, ≥1.5 shock index, ≥6 units of transfusion erythrocytes, and ≥8 obstetrical disseminated intravascular coagulation score were significantly associated with unfavorable clinical outcomes. In total, 16 pregnancies were observed in 12 patients after UAE, three of which were miscarriages and 13 were successful live births. During pregnancy, uterine rupture (n = 1) and accreta (n = 1) were observed.

CONCLUSION

UAE is an effective treatment for PPH and PAH. Although UAE could preserve future fertility, careful attention should be paid to perinatal management for unusual complications.

Embolization using both n-butyl cyanoacrylate and gelatin sponges in a patient with a posterior superior pancreaticoduodenal artery pseudoaneurysm that ruptured and bled into the drain tube

Transcatheter arterial embolization is a useful treatment for postpancreatectomy hemorrhage, a severe complication of pancreatic surgery. N-butyl cyanoacrylate is a liquid and permanent embolic material that is widely used in transcatheter arterial embolization. However, its use can lead to the adherence of the catheter to the vessel wall and occlusion of the catheter lumen. This case report presents the case of a 63-year-old man with a postpancreatectomy posterior superior pancreaticoduodenal artery pseudoaneurysm, which ruptured and bled into a drain tube. The patient underwent transcatheter arterial embolization using N-butyl cyanoacrylate and a gelatin sponge without the incidence of adherence or occlusion of the drain tube. Gelatin sponge, which was used as a temporary embolic material, was effective in preventing the drain tube from adhering and occluding.

Comparison of Renal Damage Following Renal Artery Embolization with Three Different Embolic Mixtures in Swine

Purpose

Renal artery embolization is a minimally invasive and effective procedure for renal ablation, a complete necrosis of the renal parenchyma. This study aims to compare the extent of renal damage in swine following renal artery embolization with ethanol and N-butyl-2-cyanoacrylate, commonly used as embolic materials in renal ablation.

Material and Methods

Three different embolic mixtures were prepared for renal artery embolization in swine: 33% ethanol-Lipiodol mixture (ethanol:Lipiodol = 1:2; Group A), 67% ethanol-Lipiodol mixture (ethanol:Lipiodol = 2:1; Group B), and 10% N-butyl-2-cyanoacrylate-Lipiodol mixture (N-butyl-2-cyanoacrylate:Lipiodol = 1:9; Group C). Three swine were assigned to each group and underwent embolization of the unilateral renal artery. Renal arteriography was performed before, immediately after, and two days after renal artery embolization. After two days, the kidneys were removed to determine the macroscopic necrosis rate and for histologic examination. Dark tissue regions were considered necrotic.

Results

The macroscopic necrosis rate of the kidneys was 50.3%±7.4%, 100%±0%, and 100%±0% in Groups A, B, and C, respectively. The necrosis rates were higher in Groups B and C than in Group A. Histologically, the renal tubules were damaged in the necrotic areas. In addition, the glomeruli were damaged in Groups A and B but were preserved in Group C.

Conclusions

Sixty-seven percent ethanol-Lipiodol mixture and 10% N-butyl-2-cyanoacrylate-Lipiodol mixture are effective embolic materials in renal artery embolization for renal ablation in swine. Also, ethanol caused partial glomerular necrosis, whereas N-butyl-2-cyanoacrylate preserved the glomeruli. Therefore, ethanol should be used for renal ablation.

Evaluating the Safety and Effectiveness of Quick-Soluble Gelatin Sponge Particles for Genicular Artery Embolization for Chronic Knee Pain Associated with Osteoarthritis

PURPOSE

To evaluate the effectiveness and safety of genicular artery embolization (GAE) using quick-soluble gelatin sponge particles (QS-GSPs) to alleviate chronic knee pain associated with osteoarthritis.

MATERIALS AND METHODS

This retrospective study included 71 patients (97 procedures, including 26 patients for both knees) who underwent GAE to treat osteoarthritic knee pain between August 2019 and January 2022. QS-GSPs were used for all the procedures. Technical success was defined as the embolization of at least 1 feeding artery. Clinical outcomes were evaluated using a 10-point visual analog scale (VAS). Clinical success was defined as a decrease in the VAS score of >50%.

RESULTS

The technical success rate was 100% (97 of 97). The mean VAS scores at baseline, immediately after TAE, and at 1 day, 1 week, 1 month, 3 months, and 6 months after TAE were 6.3, 4.3, 5.0, 3.0, 2.9, 2.9, and 2.8, respectively. The clinical success rate was 72% (70 of 97 patients) at 6 months. No major adverse events were reported, and temporary skin color change (50.5%, 49 of 97) and hematoma at the puncture site (10.3%, 10 of 97) were observed.

CONCLUSIONS

GAE using QS-GSPs had a high technical success rate and was considered safe. Clinical outcomes using QS-GSPs were comparable with those of existing materials.

Rare case of pediatric trauma with hepatic injury managed using gel-foam embolization: a case report

Nonoperative management for hepatic injuries requires observation and supportive care in the case of hemodynamically stable patients. If there is active bleeding on presentation, hepatic artery embolization is an option to achieve hemostasis in the acute setting. Although interventional radiology procedures are well documented in adults, there is limited literature regarding these procedures in the pediatric population. In this report, we present a case of a pediatric patient who sustained blunt abdominal trauma, resulting in a grade IV liver injury. Treatment involved fluoroscopically guided right hepatic segmental arterial gel-foam embolization.

Treatment of Vascular Injury During Balloon Pulmonary Angioplasty in Patients With Chronic Thromboembolic Pulmonary Hypertension

Background

Treatment strategy for vascular injury during balloon pulmonary angioplasty (BPA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) was uncertain.

Objectives

This study aimed to identify an optimal therapeutic strategy for vascular injury during BPA in patients with CTEPH.

Methods

This study reviewed 207 patients with CTEPH and 956 BPA procedures between November 1, 2012 and November 30, 2015. Patients who were diagnosed with vascular injury during BPA, which was defined as angiographic signs or sudden respiratory and hemodynamic defects were included in this study. The study investigated the safety and efficacy of the hierarchically systematic treatment strategy including gelatin sponge embolization (GSE).

Results

More than one-half of the 79 patients and 133 procedures with vascular injury were improved by general treatment with reversal of heparin and high-flow oxygen administration. The investigators performed conventional treatment of proximal vessel occlusion using a guiding or balloon catheter in 47 procedures (35%) in which the culprit vessels could be detected under patients' stable conditions. In 32 procedures (24%) without detected culprit lesions or improvement by conventional treatment, GSE could significantly improve patient condition. The treatment strategy obtained successful bailout in 98% of procedures with vascular injury. No patients who underwent GSE died within 30 days after the treatment. There was no significant difference in cumulative mortality rate (median follow-up: 6.6 years) between groups with or without GSE (15.6% vs 8.2%; adjusted HR: 1.47; 95% CI: 0.25-8.69; P = 0.67).

Conclusions

Treatment strategy including GSE would be promising for vascular injury during BPA in patients with CTEPH.

Emerging Polymer Materials in Trackable Endovascular Embolization and Cell Delivery: From Hype to Hope

Minimally invasive endovascular embolization is a widely used clinical technique used for the occlusion of blood vessels to treat various diseases. Different occlusive agents ranging from gelatin foam to synthetic polymers such as poly(vinyl alcohol) (PVA) have been commercially used for embolization. However, these agents have some drawbacks, such as undesired toxicity and unintended and uncontrolled occlusion. To overcome these issues, several polymer-based embolic systems are under investigation including biocompatible and biodegradable microspheres, gelling liquid embolic with controlled occlusive features, and trackable microspheres with enhanced safety profiles. This review aims to summarize recent advances in current and emerging polymeric materials as embolization agents with varying material architectures. Furthermore, this review also explores the potential of combining injectable embolic agents and cell therapy to achieve more effective embolization with the promise of outstanding results in treating various devastating diseases. Finally, limitations and challenges in developing next-generation multifunctional embolic agents are discussed to promote advancement in this emerging field.

Shape-Anisotropic Microembolics Generated by Microfluidic Synthesis for Transarterial Embolization Treatment

Particulate embolic agents with calibrated sizes, which employ interventional procedures to achieve endovascular embolization, have recently attracted tremendous interest in therapeutic embolotherapies for a wide plethora of diseases. However, the particulate shape effect, which may play a critical role in embolization performances, has been rarely investigated. Here, polyvinyl alcohol (PVA)-based shape-anisotropic microembolics are developed using a facile droplet-based microfluidic fabrication method via heat-accelerated PVA-glutaraldehyde crosslinking reaction at a mild temperature of 38 ^° C. Precise geometrical controls of the microembolics are achieved with a nearly capsule shape through regulating surfactant concentration and flow rate ratio between dispersed phase and continuous phase in the microfluidics. Two specific models are employed, i.e., in vitro decellularized rabbit liver embolization model and in vivo rabbit ear embolization model, to systematically evaluate the embolization behaviors of the nonspherical microembolics. Compared to microspheres of the same volume, the elongated microembolics demonstrated advantageous endovascular navigation capability, penetration depth and embolization stability due to their comparatively smaller radial diameter and their central cylindrical part providing larger contact area with distal vessels. Such nonspherical microembolics present a promising platform to apply shape anisotropy to achieve distinctive therapeutic effects for endovascular treatments.

A preliminary animal study of thermal rheology fluid as a new temperature-dependent liquid intravascular embolic material

Purpose

Thermal rheology (TR) fluid, which comprises polyethylene (PE) particles, their dispersant, and solvent, is a material that increases in viscosity to various degrees depending on the type and ratio of these constituents when its temperature rises. The viscosity of type 1 (TRF-1) increases more than that of type 2 (TRF-2) near rabbit body temperature. This preliminary animal study aimed to determine the basic characteristics and embolic effect of TR fluid by comparing TRF-1 and TRF-2.

Materials and methods

Twenty-four Japanese white rabbits underwent unilateral renal artery embolization using TRF-1 or TRF-2 and follow-up angiography at 7 or 28 days (4 subgroups, n = 6 each). Subsequently, the rabbits were euthanized, and the embolized kidneys were removed for pathological examination. The primary and final embolization rates were defined as the ratio of renal artery area not visible immediately after embolization and follow-up angiography, respectively, to visualized renal artery area before embolization. The final embolization rate and maximum vessel diameter filled with PE particles were compared between materials. Moreover, the embolic effect was determined to be persistent when a two-sided 95% confidence interval (CI) for the difference in means between the embolization rates was < 5%.

Results

The final embolization rate was significantly higher for the TRF-1 than for the TRF-2 at both 7 (mean 80.7% [SD 18.7] vs. 28.4% [19.9], p = 0.001) and 28 days (94.0% [3.5] vs. 37.8% [15.5], p < 0.001). The maximum occluded vessel diameter was significantly larger for TRF-1 than for TRF-2 (870 µm [417] vs. 270 µm [163], p < 0.001). The embolic effect of TRF-1 was persistent until 28 days (difference between rates − 3.3 [95% CI − 10.0–3.4]).

Conclusion

The embolic effect of TRF-1 was more persistent than that of TRF-2, and the persistency depended on the type and ratio of TR fluid constituents.

Preoperative Arterial Embolization to Avoid Intraoperative Bleeding during Endoscopic Sinus Surgery for Organized Hematoma of the Maxillary Sinus: A Case Series and Literature Review

Purpose:

This study aimed to evaluate the safety and efficacy of preoperative arterial embolization of organized hematoma of the maxillary sinus.

Material and Methods:

Seven patients who were pathologically diagnosed with an organized hematoma of the maxillary sinus and who underwent endoscopic sinus surgery following preoperative arterial embolization for the same from July 2013 to April 2020 at our hospital were included. A literature review of the PubMed database was performed to identify 13 cases on organized hematomas of the maxillary sinuses. The embolization and nonembolization groups comprised patients who underwent preoperative embolization (n = 10, seven from this study and three from literature) and those who did not undergo preoperative embolization (n = 10, from literature), respectively. Outcomes of embolization including embolization-related complications and postoperative bleeding were assessed, and volumes of intraoperative blood loss and duration of surgery were compared between the groups.

Results:

No preoperative embolization-related complications were observed in our cases. The volume of surgical blood loss in the seven cases varied from 0 to 100 mL with a median of 30 mL, and the duration of surgery ranged from 45 to 166 minutes with a median of 112 minutes. The volume of blood loss was significantly lower for the embolization group than that for the nonembolization group (p = 0.0031). There was no statistically significant difference regarding duration of surgery between the groups (p > 0.10).

Conclusions:

Preoperative embolization of an organized hematoma of the maxillary sinus is a safe and effective method that helps prevent serious intraoperative hemorrhage.

The Emergent Pelvic Artery Embolization in the Management of Postpartum Hemorrhage: A Systematic Review and Meta-analysis

Importance

Postpartum hemorrhage (PPH) is an emergent obstetric complication and the leading cause of maternal mortality. Pelvic arterial embolization (PAE) is an effective treatment for intractable PPH. However, a unique protocol has not been accepted in obstetrical practice.

Objective

To evaluate its efficiency, safety, complications, and outcomes, we conducted a systematic review and meta-analysis of PAE for PPH in the literature.

Evidence Acquisition

The Medline, the database of abstract of reviews, the index to allied health literature, and the Chinese database Sino-Med were searched on March 31, 2020, for studies on PAE for PPH. The data for PAE indication, agents, arteries, success rate, complications, and outcomes were extracted and syncretized for meta-analysis.

Results

From 1075 identified articles, 113 abstracts or full articles were retrieved and 43 studies were finally identified as meeting the including criteria. The results demonstrated that the indications for PAE were as follows: uterine atony, placental abnormality, delivery tract injury, disseminated intravascular coagulation, arteriovenous malformation, and vaginal hematoma. The embolization agents mostly in order were gelatin sponge particles, polyvinyl alcohol particles, Gelfoam, N-butyl cyanoacrylate, microcoil, and glue; for arteries, they were mostly uterine artery and internal iliac artery. The clinical success rate was 90.5%, whereas the technical success rate was 99.3%. The most common complications of PAE were postembolization syndrome and menstrual abnormality.

Conclusions and Relevance

The emergent PAE is a safe and effective method with high success rate in life-threatening PPH management. Gelatin sponge granules measuring 500 to 1000 μm in diameter have safe results. Pelvic arterial embolization may affect the recovery of menses and increase PPH in the subsequent pregnancy, but there was no noted correlation with fetal growth restriction.

Pelvic arterial embolisation with cyanoacrylate during caesarean hysterectomy for placenta accreta

PURPOSE

To compare n-butyl cyanoacrylate (NBCA) and gelatine sponge (GS) as embolic materials for prophylactic pelvic arterial embolisation during caesarean hysterectomy for placenta accreta spectrum (PAS).

MATERIAL AND METHODS

This retrospective study comprised 12 women (age range, 23-42 years; mean, 34.1 years) who underwent caesarean hysterectomy for PAS. Following caesarean delivery, bilateral uterine and non-uterine parasitic arteries were embolized with GS in the first four cases (GS group) and primarily with NBCA mixed with iodized oil in the subsequent eight cases (NBCA group). Procedure time for embolisation and hysterectomy and total blood loss were compared between the two groups using Welch's t-test.

RESULTS

Although procedure time for embolisation tended to be longer in the NBCA group than in the GS group (111 ± 47 min versus 71 ± 32 min, p=.11), that for hysterectomy was significantly reduced in the NBCA group when compared to the GS group (158 ± 42 min versus 236 ± 39 min, p=.02). Total blood loss was significantly lower in the NBCA group than in the GS group (1375 ± 565 mL versus 2668 ± 587 mL, p=.01).

CONCLUSION

Procedure time for hysterectomy and total blood loss during caesarean hysterectomy can be reduced by using NBCA instead of GS in prophylactic pelvic arterial embolisation for PAS.

Hepatic Artery Embolization Enhances Expression of Programmed Cell Death 1 Ligand 1 in an Orthotopic Rat Hepatocellular Carcinoma Model: In Vivo and in Vitro Experimentation

PURPOSE

To evaluate the effects of hepatic artery embolization (HAE) on the expression of programmed cell death 1 ligand 1 (PD-L1) in an orthotopic rat hepatocellular carcinoma (HCC) model.

MATERIALS AND METHODS

A rat HCC model was established in Sprague-Dawley rats with the RH7777 cell line. Six animals each were assigned to receive HAE or sham treatment. Liver tissues were harvested 24 h after the procedure. Immunohistochemistry (IHC) was used to compare expression of PD-L1 and hypoxia-inducible factor (HIF)-1α in the intratumoral and peritumoral regions and normal liver tissue. In vitro cell culture study was performed for 24 h under normoxic and hypoxic conditions, and protein expression of PD-L1 and HIF-1α and the effects of HIF-1α inhibitors were assessed.

RESULTS

IHC showed that PD-L1- and HIF-1α-positive areas were significantly larger in the HAE group vs the sham group in intratumoral (P = .006 and P < .001, respectively) and peritumoral regions (both P < .001). The expression of PD-L1 positively correlated with HIF-1α expression in the intratumoral region (r² = 0.551; P < .001). In vitro cell culture study revealed that protein expression of PD-L1 and HIF-1α were significantly higher when cells were incubated under hypoxic vs normoxic conditions (P = .028 and P = .010, respectively). PD-L1 expression was suppressed significantly when the HIF-1α inhibitor rapamycin was added to the culture medium (P = .024).

CONCLUSIONS

HAE enhances intratumoral and peritumoral PD-L1 expression in a rat HCC model. The HIF-1α pathway is a possible mechanism underlying increased intratumoral PD-L1 expression after HAE.

Utility of low-dose gelatin sponge particles and 5% ethanolamine oleate iopamidol mixture in retrograde transvenous obliteration (GERTO) for gastric varices

OBJECTIVE

To determine the utility of low-dose gelatin sponge particles and 5% ethanolamine oleate iopamidol (EOI) mixture in retrograde transvenous obliteration (GERTO) for gastric varices (GV).

METHODS

57 consecutive patients who underwent balloon-occluded retrograde transvenous obliteration (B-RTO) for GV were divided into three groups with Hirota's grade by balloon-occluded retrograde transvenous venography. Hirota's Grade 1 patients were assigned to G1 group and underwent treatment with 5% EOI. Grade ≥ 2 patients prior to August 2015 were G ≥ 2 group treated with 5% EOI, and those treated thereafter were GERTO group. The amount of EOI used per unit GV volume (EOI/GV ratio), the times to embolization and recurrence rate of GV were evaluated.

RESULTS

The EOI/GV ratio was 0.66 ± 0.19 in G1, 1.5 ± 0.8 in G ≥ 2, and 0.58 ± 0.23 in GERTO (G ≥ 2 vs GERTO, p < 0.0001). The times to embolization were 26.5 ± 10.5 min for G1, 39.2 ± 26.8 for G ≥ 2, and 21.4 ± 9.4 for GERTO (G ≥ 2 vs GERTO, p = 0.005). The recurrence rate was not significantly different in any of the groups.

CONCLUSION

GERTO was performed in lower amount of sclerosants and in less time compared to conventional B-RTO in Hirota's grade ≥2.

ADVANCES IN KNOWLEDGE

Feasibility of low-dose gelatin sponge particles and 5% EOI mixture as sclerosants for GV.

Effect of transcatheter arterial embolisation in normal canine liver using trisacryl gelatine microspheres (Embosphere)

The effect of selective transcatheter arterial embolisation (TAE) using trisacryl gelatine microspheres (TGMs) in the normal canine liver was investigated. Selective embolisation was achieved by injecting TGMs into the left hepatic artery through a microcatheter in four healthy dogs. After embolisation, computed tomography (CT), biochemical analysis and histological examination were performed during a 12-week observation period. Embolisation was successful in all four dogs. Postoperative CT revealed consistent embolisation of the artery within the experimental period in three dogs. Hepatic enzyme levels slightly increased after embolisation but tapered to normal ranges. Histological examinations revealed no abnormal changes. Thus, selective TAE with TGMs was well tolerated in normal dogs and may be applicable to canine hepatocellular carcinoma.

Advances in Biomaterials and Technologies for Vascular Embolization

Minimally invasive transcatheter embolization is a common nonsurgical procedure in interventional radiology used for the deliberate occlusion of blood vessels for the treatment of diseased or injured vasculature. A wide variety of embolic agents including metallic coils, calibrated microspheres, and liquids are available for clinical practice. Additionally, advances in biomaterials, such as shape-memory foams, biodegradable polymers, and in situ gelling solutions have led to the development of novel preclinical embolic agents. The aim here is to provide a comprehensive overview of current and emerging technologies in endovascular embolization with respect to devices, materials, mechanisms, and design guidelines. Limitations and challenges in embolic materials are also discussed to promote advancement in the field.

Characterization of Calibrated Gelatin Sponge Particles in a Rabbit Renal Embolization Model

PURPOSE

To evaluate the level of artery occlusion, degradation periods, tissue response and vessel recanalization of calibrated gelatin sponge particles after segmental renal artery embolization.

MATERIALS AND METHODS

Superselective embolization of 14 adult rabbits was performed with calibrated gelatin sponge particles (150-350 μm). Two rabbits were killed immediately after the procedure (day 0). One pair of rabbits was killed on each of the following days: 1, 3, 7, 14, 28 and 56. One rabbit from each pair underwent CT angiography before embolization and killing. The pathologic changes of the embolized renal parenchyma and embolic characteristics of calibrated gelatin sponge particles were evaluated histologically and angiographically.

RESULTS

Calibrated gelatin sponge particles were distally located in interlobular artery with a dense packing on day 0. The level of occlusion paralleled the size of the particles. Partial degradation of the particles was observed on day 3, and complete degradation was observed on day 14. Vessel recanalization was observed through both CTA and histological analysis starting on day 3. Vascular inflammation responding to gelatin sponge particles was mild and subsided with the degradation of the particles. On day 28 and day 56, attenuation of embolized vessels occurred due to marked intimal proliferation, and vascular occlusion developed.

CONCLUSIONS

Gelatin sponge particles of 150-350 μm produced dense and distal embolization, and were resorbed before day 14 with a mild tissue reaction. Vessel recanalization occurred secondary to the resorption of gelatin sponge particles, but permanent vascular occlusion developed due to marked intimal hyperplasia after day 28.

Sustained Release SDF-1α/TGF-β1-Loaded Silk Fibroin-Porous Gelatin Scaffold Promotes Cartilage Repair

Continuous delivery of growth factors to the injury site is crucial to creating a favorable microenvironment for cartilage injury repair. In the present study, we fabricated a novel sustained-release scaffold, stromal-derived factor-1α (SDF-1α)/transforming growth factor-β1 (TGF-β1)-loaded silk fibroin-porous gelatin scaffold (GSTS). GSTS persistently releases SDF-1α and TGF-β1, which enhance cartilage repair by facilitating cell homing and chondrogenic differentiation. Scanning electron microscopy showed that GSTS is a porous microstructure and the protein release assay demonstrated the sustainable release of SDF-1α and TGF-β1 from GSTS. Bone marrow-derived mesenchymal stem cells (MSCs) maintain high in vitro cell activity and excellent cell distribution and phenotype after seeding into GSTS. Furthermore, MSCs acquired enhanced chondrogenic differentiation capability in the TGF-β1-loaded scaffolds (GSTS or GST: loading TGF-β1 only) and the conditioned medium from SDF-1α-loaded scaffolds (GSTS or GSS: loading SDF-1α only) effectively promoted MSCs migration. GSTS was transplanted into the osteochondral defects in the knee joint of rats, and it could promote cartilage regeneration and repair the cartilage defects at 12 weeks after transplantation. Our study shows that GSTS can facilitate in vitro MSCs homing, migration, chondrogenic differentiation and SDF-1α and TGF-β1 have a synergistic effect on the promotion of in vivo cartilage forming. This SDF-1α and TGF-β1 releasing GSTS have promising therapeutic potential in cartilage repair.

Polyethylenimine-alginate nanocomposites based bone morphogenetic protein 2 gene-activated matrix for alveolar bone regeneration

The repair and treatment of lost or damaged alveolar bone is of great significance in dentistry. Gene-activated matrix (GAM) technology provides a new way for bone regeneration. It is a local gene delivery system, which can not only recruit cells, but also influence their fate. For this purpose, we fabricated a bone morphogenetic protein 2 (BMP-2) gene-loaded absorbable gelatin sponge (AGS) and studied its effect on promoting alveolar bone formation and preventing resorption following tooth extraction in rats. In order to obtain better transfection efficiency, polyethylenimine-alginate (PEI-al) nanocomposites were synthesized and used as gene vectors to deliver BMP-2 cDNA plasmids (PEI-al/pBMP-2). The transfection efficiency, BMP-2 protein expression and osteogenic differentiation of the cells were investigated in vitro. In vivo, we established an alveolar bone regeneration model by extracting the rats' left mandibular incisors. The rats were randomly assigned into 3 groups: control group, unfilled sockets; AGS group, sockets filled with PEI-al solution-loaded gelatin sponges; AGS/BMP group, sockets filled with PEI-al/pBMP-2 solution-loaded gelatin sponge. Radiological and histological assays were performed at 4 and 8 weeks later. In vitro transfection assays indicated that PEI-al/pBMP-2 complexes could effectively transfect MC3T3-E1 cells, promoting the secretion of BMP-2 protein for at least 14 days, as well as increasing the expression of osteogenesis-related gene, ALP activity and calcium deposition. In vivo, western blot analysis showed BMP-2 protein was expressed in bone tissues of AGS/BMP group. The relative height of the residual alveolar ridge and bone mineral density (BMD) of the AGS/BMP group were significantly greater than those in the AGS and control groups at 4 and 8 weeks, respectively. Histological examination showed that, at 4 weeks, osteoblasts had grown in a cubic shape around the new bone in the AGS/BMP group, suggesting new bone formation. In conclusion, the combination of PEI-al/pBMP-2 complexes and gelatin sponge could promote alveolar bone regeneration, which may provide an easy and valuable method for alveolar ridge preservation and augmentation.

Polyethylenimine-alginate nanocomposites based bone morphogenetic protein 2 gene-activated matrix may provide an easy and valuable method for alveolar ridge regeneration.

Efficacy and prognostic factors of transarterial embolization as initial treatment for spontaneously ruptured hepatocellular carcinoma: a single-center retrospective analysis in 57 patients

PURPOSE

To evaluate the efficacy and prognostic factors following transarterial embolization (TAE) as initial treatment for spontaneously ruptured hepatocellular carcinoma (HCC).

METHODS

From June 2012 to June 2016, a total of 57 spontaneously ruptured HCC patients who received TAE as initial therapy were retrospectively studied at our institution. Patients were followed until October 2016. Survival rates were estimated using the Kaplan-Meier method, and prognostic factors related to survival were evaluated using Cox regression analysis.

RESULTS

Among them, 8 (14.0%) patients died within 30 days after initial TAE. The median overall survival time was 208 days. The 6-month, 1-year, and 2-year cumulative overall survival rates were 50.3%, 35.9%, and 14.7%, respectively. Multivariate analysis indicated that tumor size [HR (hazard ratio) 1.12; 95% CI (confidence interval) 1.02-1.23, P = 0.022] Child-Pugh class (HR 1.78; 95% CI 1.13-2.80; P = 0.013), absence of shock on admission (HR 0.40; 95% CI 0.17-0.95; P = 0.039), and embolization with lipiodol and gelatin sponge particles (HR 0.33; 95% CI 0.16-0.70; P = 0.004) were independent prognostic factors for survival.

CONCLUSION

TAE appeared to be an effective initial treatment for spontaneously ruptured HCC. The results indicated that large tumors, poor Child-Pugh class, and shock on admission were associated with poor prognosis. For these patients, embolization with lipiodol and gelatin sponge particles could achieve better survival than PVA particles used.

Preoperative transcatheter arterial embolization using a gelatin sponge for head and neck tumors

Purpose: To evaluate the usefulness of preoperative transcatheter arterial embolization using a gelatin sponge for hypervascular head and neck tumors to reduce intraoperative blood loss (IBL).　　　　 Material and methods: Nineteen patients underwent preoperative transcatheter arterial embolization for hypervascular head and neck tumors using a gelatin sponge. The technical success rate, devascularization rate, IBL, and complications were evaluated. Angiography images obtained before and after preoperative embolization were compared in all patients, and the devascularization rate was assessed from the relative reduction rate of contrast agent volumes. Results: The technical success rate was 100%. The median devascularization rate was 95% (range, 75-100%). The median period between embolization and surgical resection was one day (range, 1-12 days). The median IBL was 122 ml (range, 0-3780 ml). Blood transfusions were required in three cases, and their IBL and devascularization rates were 850, 1959, and 3780 ml, and 75%, 90%, and 80%, respectively. There was a complication of cerebral embolism in one out of 19 cases (5%). Conclusions: Preoperative transcatheter arterial embolization using a gelatin sponge was feasible and may contribute to decreasing IBL.

Isolated Arteries Originating from the Intrahepatic Arteries: Anatomy, Function, and Importance in Intervention

Isolated hepatic arteries are defined as hepatic terminal arterioles that are not accompanied by portal venules or bile ductules and penetrate the liver parenchyma and distribute to the hepatic capsule and intrahepatic hepatic veins. Abundant communications exist between intra- and extrahepatic arteries through isolated arteries and capsular arterial plexus. They play a principal role in the development of subcapsular hemorrhage and arterial collateral formation following transcatheter arterial chemoembolization for liver cancers. The anatomy, function, and clinical importance of isolated hepatic arteries in interventional radiology, especially regarding subcapsular hemorrhage and arterial collateral formation, are highlighted in this article.

Angle-tipped guidewire-induced vascular perforation at branch of superior thoracic artery during sheath insertion: Case report

An 84-year-old woman was admitted to our hospital because of congestive heart failure, rapid atrial fibrillation, and ischemic heart disease. Percutaneous coronary intervention (PCI) via the left radial artery was performed, and a stent was deployed successfully into left anterior descending coronary artery (LAD). She got into shock state one hour after PCI. Chest X-ray and computed tomography scan revealed increase of soft tissue around the left axilla and implied the existence of hematoma. Hemoglobin level decreased from 13.3 g/dL to 8.2 g/dL and hemorrhagic shock was suspected. Angiography of the left axillary artery demonstrated contrast extravasation, and selective angiography using a micro-catheter identified bleeding from a branch of the superior thoracic artery. Hemostasis was performed successfully by embolization using a gelatin sponge, and improvement of the general condition was obtained. Aberration of 0.025-in. angle tipped guidewire was considered to induce arterial perforation during sheath insertion. <Learning objective: Guidewire-induced perforation is a known rare and sometimes fatal complication of percutaneous interventional procedures. The incidence of angiographic-evident peripheral artery perforation has been reported to be 0.9%. In particular, a guidewire advanced into a small branch artery can potentially cause perforation. This risk suggests that clinicians should use caution when manipulating a guidewire during sheath insertion.>.

Comparison of the wound healing efficacy of polyglycolic acid sheets with fibrin glue and gelatin sponge dressings in a rat cranial periosteal defect model

Oral surgical procedures occasionally require removal of the periosteum due to lesions, and these raw bone surfaces are prone not only to infection but also to scar formation during secondary healing. The objective of this study was to identify successful methods for reconstruction using periosteal defect dressings. We created 1-cm2 defects in the skin and cranial periosteum of 10-week-old male Wistar rats under isoflurane anesthesia. The animals were assigned to three defect treatment groups: (1) polyglycolic acid sheets with fibrin glue dressing (PGA-FG), (2) Spongel® gelatin sponge dressing (GS), and (3) open wound (control). Postoperative wound healing was histologically evaluated at 2, 4, and 6 weeks. The moist conditions maintained by the GS and PGA-FG treatments protected the bone surface from the destructive effects of drying and infection. Complete wound healing was observed in the GS group but not for all animals in the PGA-FG and control groups. Histologically, osteoblast proliferation on bone surfaces and complete epithelialization with adnexa were observed in the GS group at 6 weeks after surgery. In contrast, PGA sheets that had not been absorbed inhibited osteoblast proliferation and delayed wound healing in the PGA-FG group. Wound surface dressings maintain a moist environment that promotes wound healing, but PGA materials may not be suitable for cases involving exposed periosteum or bone surfaces due to the observed scar formation and foreign-body reaction.

Functional polymer-dependent 3D culture accelerates the differentiation of HepaRG cells into mature hepatocytes

AIM

The hepatoma-derived cell line HepaRG is regarded as an in vitro model of drug metabolism because fully differentiated HepaRG cells demonstrate functional metabolic responses comparable to those of primary human hepatocytes. Recently, it was demonstrated that the 3D culture of HepaRG cells enhanced their metabolic functions and toxicological responses. We approached the mechanisms underlying these enhancement effects.

METHODS

We compared 2D-cultured HepaRG cells with 3D-cultured HepaRG spheroids in the gene expression patterns and the metabolic functions. In the present study, we performed 3D culture of HepaRG cells using functional polymers (FP). To reveal the in vivo differentiation ability, we transplanted the 3D-cultured HepaRG spheroids into TK-NOG mice.

RESULTS

A comparison between 2D and 3D cultures revealed that 3D-cultured HepaRG spheroids demonstrated reductions in bile duct marker expression, accelerated expression of cytochrome P450 3A4, and increases in the ratio of albumin-expressing hepatocytes. Furthermore, catalytic activities of cytochrome P450 3A4 were modified by omeprazole and rifampicin in the 3D-cultured HepaRG spheroids. Transplantation analysis revealed that 3D-cultured HepaRG spheroids formed hepatocyte-like colonies rather than cholangiocytes in vivo.

CONCLUSION

Our results indicated that the enhancement of hepatic functions in 3D-cultured HepaRG cells was induced by selective hepatocyte differentiation and accelerated hepatocyte maturation. HepaRG spheroids reproduced the metabolic responses of human hepatocytes. Therefore, FP-dependent 3D-cultured HepaRG cells may serve as an excellent in vitro model for evaluating the hepatic metabolism and toxicity.

Superselective Conventional Transarterial Chemoembolization for Hepatocellular Carcinoma: Rationale, Technique, and Outcome

Conventional transarterial chemoembolization with ethiodized oil and gelatin sponge (GS) particles is a standard technique for hepatocellular carcinoma. Ethiodized oil can temporarily block tumor sinusoids, portal venules, hepatic sinusoids, and arterial microcommunications. By adding GS embolization, strong ischemic effects not only on the tumor but also on the surrounding liver parenchyma can be achieved. Superselective conventional transarterial chemoembolization is mainly indicated for patients with Child-Pugh scores of 5-8, tumors ≤ 7 cm, and ≤ 5 lesions. According to a Japanese nationwide survey, the 5-year survival rate of patients with Child-Pugh class A and a single tumor was 52%.

Diameter of main tumor feeding artery of a hepatocellular carcinoma: Measurement at the entry site into the nodule

AIM

To measure the diameter of the main tumor feeding artery (TFA) of a hepatocellular carcinoma (HCC) nodule at the entry site into the nodule.

METHODS

Fifty-seven HCC nodules in 43 patients were analyzed using a 3-D workstation and picture archiving system (PACS). TFA was defined as an artery connected to a HCC nodule on catheter-assisted multidetector computed tomography angiography (CAMDCTA). The entry site of the main TFA into the nodule was identified on CAMDCTA, and the corresponding portion was measured on digital angiography (DA) or digital subtracted angiography (DSA). The measuring scale of the PACS was calibrated using the platinum tip of microballoon catheters 0.68 mm in diameter. We investigated the relationship between diameters of the nodule and its main TFA.

RESULTS

The diameters of the nodule and its main TFA ranged 7-63 mm (20.3 ± 12.7) and 0.12-1.79 mm (0.41 ± 0.32), respectively. Simple regression analysis revealed a relationship between diameters of the nodule and its main TFA (P < 0.0001). The diameter of the main TFA was less than 1 mm in 53 of 57 nodules (93.0%), and less than 0.5 mm in 42 (73.7%).

CONCLUSION

The diameter of main TFA was thicker in the larger nodule. The size of commercially available porous gelatin particles (1 or 2 mm in diameter) seems too large for embolization of most of HCC nodules.

Creation of small gelatin particles by pumping method for transarterial chemoembolization of hepatocellular carcinoma: analysis of particle size and reproducibility

PURPOSE

Spherical porous gelatin particles (Gelpart(®), Nippon Kayaku, Tokyo) were crushed by a pumping method to create small gelatin particles for transarterial chemoembolization of hepatocellular carcinoma. The aim of this study was to analyze crushed particle size.

MATERIALS AND METHODS

To minimize the size of crushed particles, we used the pumping method using two 2.5-mL syringes connected by a 3-way stopcock. Sixteen samples created by 3 operators were examined. The crushed particles were stained with hematoxylin-eosin, images magnified by a microscope were captured using a digital camera, and the maximum length of each particle was measured. The differences in particle size within the same operator and among the 3 operators were examined by an ANOVA test.

RESULTS

The particle sizes created by each operator were 139.0 ± 58.8, 201.1 ± 90.9, and 158.4 ± 72.0 µm, respectively. There was a statistically significant difference in particle size among the 3 operators (p < 0.01). With one operator, there was no statistically significant difference in the particle size among the 4 samples (p = 0.93). With 2 operators, there were statistically significant differences among 5, or 7 samples, respectively (p < 0.01).

CONCLUSION

Small gelatin particles can be created with Gelpart(®) by the pumping method, but mean particle size was different among samples and not reproducible.