Leukemic Stem Cells and Hematological Malignancies.

The association between leukemic stem cells (LSCs) and leukemia development has been widely established in the context of genetic alterations, epigenetic pathways, and signaling pathway regulation. Hematopoietic stem cells are at the top of the bone marrow hierarchy and can self-renew and progressively generate blood and immune cells. The microenvironment, niche cells, and complex signaling pathways that regulate them acquire genetic mutations and epigenetic alterations due to aging, a chronic inflammatory environment, stress, and cancer, resulting in hematopoietic stem cell dysregulation and the production of abnormal blood and immune cells, leading to hematological malignancies and blood cancer. Cells that acquire these mutations grow at a faster rate than other cells and induce clone expansion. Excessive growth leads to the development of blood cancers. Standard therapy targets blast cells, which proliferate rapidly; however, LSCs that can induce disease recurrence remain after treatment, leading to recurrence and poor prognosis. To overcome these limitations, researchers have focused on the characteristics and signaling systems of LSCs and therapies that target them to block LSCs. This review aims to provide a comprehensive understanding of the types of hematopoietic malignancies, the characteristics of leukemic stem cells that cause them, the mechanisms by which these cells acquire chemotherapy resistance, and the therapies targeting these mechanisms.

Fish Collagen Peptides Enhance Thymopoietic Gene Expression, Cell Proliferation, Thymocyte Adherence, and Cytoprotection in Thymic Epithelial Cells via Activation of the Nuclear Factor-κB Pathway, Leading to Thymus Regeneration after Cyclophosphamide-Induced Injury.

Prolonged thymic involution results in decreased thymopoiesis and thymic output, leading to peripheral T-cell deficiency. Since the thymic-dependent pathway is the only means of generating fully mature T cells, the identification of strategies to enhance thymic regeneration is crucial in developing therapeutic interventions to revert immune suppression in immunocompromised patients. The present study clearly shows that fish collagen peptides (FCPs) stimulate activities of thymic epithelial cells (TECs), including cell proliferation, thymocyte adhesion, and the gene expression of thymopoietic factors such as FGF-7, IGF-1, BMP-4, VEGF-A, IL-7, IL-21, RANKL, LTß, IL-22R, RANK, LTßR, SDF-1, CCL21, CCL25, CXCL5, Dll1, Dll4, Wnt4, CD40, CD80, CD86, ICAM-1, VCAM-1, FoxN1, leptin, cathepsin L, CK5, and CK8 through the NF-κB signal transduction pathway. Furthermore, our study also revealed the cytoprotective effects of FCPs on TECs against cyclophosphamide-induced cellular injury through the NF-κB signaling pathway. Importantly, FCPs exhibited a significant capability to facilitate thymic regeneration in mice after cyclophosphamide-induced damage via the NF-κB pathway. Taken together, this study sheds light on the role of FCPs in TEC function, thymopoiesis, and thymic regeneration, providing greater insight into the development of novel therapeutic strategies for effective thymus repopulation for numerous clinical conditions in which immune reconstitution is required.

Decellularized Extracellular Matrix-based Bioinks for Engineering Tissue- and Organ-specific Microenvironments.

Biomaterials-based biofabrication methods have gained much attention in recent years. Among them, 3D cell printing is a pioneering technology to facilitate the recapitulation of unique features of complex human tissues and organs with high process flexibility and versatility. Bioinks, combinations of printable hydrogel and cells, can be utilized to create 3D cell-printed constructs. The bioactive cues of bioinks directly trigger cells to induce tissue morphogenesis. Among the various printable hydrogels, the tissue- and organ-specific decellularized extracellular matrix (dECM) can exert synergistic effects in supporting various cells at any component by facilitating specific physiological properties. In this review, we aim to discuss a new paradigm of dECM-based bioinks able to recapitulate the inherent microenvironmental niche in 3D cell-printed constructs. This review can serve as a toolbox for biomedical engineers who want to understand the beneficial characteristics of the dECM-based bioinks and a basic set of fundamental criteria for printing functional human tissues and organs.

The Quinazoline Otaplimastat (SP-8203) Reduces the Hemorrhagic Transformation and Mortality Aggravated after Delayed rtPA-Induced Thrombolysis in Cerebral Ischemia.

Acute ischemic stroke is the leading cause of morbidity and mortality worldwide. Recombinant tissue plasminogen activator (rtPA) is the only agent clinically approved by FDA for patients with acute ischemic stroke. However, delayed treatment of rtPA (e.g., more than 3 h after stroke onset) exacerbates ischemic brain damage by causing intracerebral hemorrhage and increasing neurotoxicity. In the present study, we investigated whether the neuroprotant otaplimastat reduced delayed rtPA treatment-evoked neurotoxicity in male Sprague Dawley rats subjected to embolic middle cerebral artery occlusion (eMCAO). Otaplimastat reduced cerebral infarct size and edema and improved neurobehavioral deficits. In particular, otaplimastat markedly reduced intracerebral hemorrhagic transformation and mortality triggered by delayed rtPA treatment, consequently extending the therapeutic time window of rtPA. We further found that ischemia-evoked extracellular matrix metalloproteases (MMPs) expression was closely correlated with cerebral hemorrhagic transformation and brain damage. In ischemic conditions, delayed rtPA treatment further increased brain injury via synergistic expression of MMPs in vascular endothelial cells. In oxygen-glucose-deprived endothelial cells, otaplimastat suppressed the activity rather than protein expression of MMPs by restoring the level of tissue inhibitor of metalloproteinase (TIMP) suppressed in ischemia, and consequently reduced vascular permeation. This paper shows that otaplimastat under clinical trials is a new drug which can inhibit stroke on its own and extend the therapeutic time window of rtPA, especially when administered in combination with rtPA.

Advanced Strategies for 3D Bioprinting of Tissue and Organ Analogs Using Alginate Hydrogel Bioinks.

Alginate is a natural polysaccharide that typically originates from various species of algae. Due to its low cost, good biocompatibility, and rapid ionic gelation, the alginate hydrogel has become a good option of bioink source for 3D bioprinting. However, the lack of cell adhesive moieties, erratic biodegradability, and poor printability are the critical limitations of alginate hydrogel bioink. This review discusses the pivotal properties of alginate hydrogel as a bioink for 3D bioprinting technologies. Afterward, a variety of advanced material formulations and biofabrication strategies that have recently been developed to overcome the drawbacks of alginate hydrogel bioink will be focused on. In addition, the applications of these advanced solutions for 3D bioprinting of tissue/organ mimicries such as regenerative implants and in vitro tissue models using alginate-based bioink will be systematically summarized.

3D Cell Printing of Tissue/Organ-Mimicking Constructs for Therapeutic and Drug Testing Applications.

The development of artificial tissue/organs with the functional maturity of their native equivalents is one of the long-awaited panaceas for the medical and pharmaceutical industries. Advanced 3D cell-printing technology and various functional bioinks are promising technologies in the field of tissue engineering that have enabled the fabrication of complex 3D living tissue/organs. Various requirements for these tissues, including a complex and large-volume structure, tissue-specific microenvironments, and functional vasculatures, have been addressed to develop engineered tissue/organs with native relevance. Functional tissue/organ constructs have been developed that satisfy such criteria and may facilitate both in vivo replenishment of damaged tissue and the development of reliable in vitro testing platforms for drug development. This review describes key developments in technologies and materials for engineering 3D cell-printed constructs for therapeutic and drug testing applications.

Stimulus-Responsive Anti-Oxidizing Drug Crystals and their Ecological Implication.

Various antioxidants are being used to neutralize the harmful effects of reactive oxygen species (ROS) overproduced in diseased tissues and contaminated environments. Polymer-directed crystallization of antioxidants has attracted attention as a way to control drug efficacy through molecular dissolution. However, most recrystallized antioxidants undertake continuous dissolution independent of the ROS level, thus causing side-effects. This study demonstrates a unique method to assemble antioxidant crystals that modulate their dissolution rate in response to the ROS level. We hypothesized that antioxidants recrystallized using a ROS-labile polymer would be triggered to dissolve when the ROS level increases. We examined this hypothesis by using catechin as a model antioxidant. Catechin was recrystallized using polyethylenimine cross-linked with ROS-labile diselanediylbis-(ethane-2,1-diyl)-diacrylate. Catechin crystallized with the ROS-labile polymer displays accelerated dissolution proportional to the H2 O2 concentration. The ROS-responsive catechin crystals protect vascular cells from oxidative insults by activating intracellular glutathione peroxidase expression and, in turn, inhibiting an increase in the intracellular oxidative stress. In addition, ROS-responsive catechin crystals alleviate changes in the heart rate of Daphnia magna in oxidative media. We propose that the results of this study would be broadly useful for improving the therapeutic efficacy of a broad array of drug compounds.

Thiostrepton: A Novel Therapeutic Drug Candidate for Mycobacterium abscessus Infection.

Mycobacterium abscessus is a rapid-growing, multidrug-resistant, non-tuberculous mycobacterial species responsible for a variety of human infections, such as cutaneous and pulmonary infections. M. abscessus infections are very difficult to eradicate due to the natural and acquired multidrug resistance profiles of M. abscessus. Thus, there is an urgent need for the development of effective drugs or regimens against M. abscessus infections. Here, we report the activity of a US Food and Drug Administration approved drug, thiostrepton, against M. abscessus. We found that thiostrepton significantly inhibited the growth of M. abscessus wild-type strains, subspecies, clinical isolates, and drug-resistant mutants in vitro and in macrophages. In addition, treatment of macrophages with thiostrepton significantly decreased proinflammatory cytokine production in a dose-dependent manner, suggesting an inhibitory effect of thiostrepton on inflammation induced during M. abscessus infection. We further showed that thiostrepton exhibits antimicrobial effects in vivo using a zebrafish model of M. abscessus infection.

Suppression of influenza B virus replication by sakuranetin and mode of its action.

This study aimed to investigate in vitro the anti-influenza B/Lee/40 virus effect of sakuranetin and mode of its action. The sakuranetin exhibited potent antiviral activity against influenza B/Lee/40 virus, reducing the formation of a visible cytopathic effect, with a 50% inhibitory concentration (IC50 ) of 7.21 µg/ml and no cytotoxicity at a concentration of 100 µg/ml, and the derived therapeutic index (TI) was >13.87. Oseltamivir showed weak anti-influenza B/Lee/40 virus activity with IC50 of 80.74 µg/ml, 50% cytotoxicity concentration of >100 µg/ml, and TI of >1.24. Sakuranetin also showed effective inhibitory effects when added at the viral attachment, entry, and postentry steps. Moreover, sakuranetin effectively inactivated influenza B/Lee/40 virus infection in dose- and temperature-dependent manners. Sakuranetin indicated an inhibitory effect in viral RNA synthesis in the presence of 100 µg/ml of sakuranetin. Overall, this research revealed that sakuranetin could inhibit influenza B/Lee/40 virus replication and that sakuranetin may be involved in the virus attachment, entry, and postentry. Therefore, sakuranetin is a good candidate for a chemopreventive agent for influenza virus-related diseases.

Development of Liver Decellularized Extracellular Matrix Bioink for Three-Dimensional Cell Printing-Based Liver Tissue Engineering.

The liver is an important organ and plays major roles in the human body. Because of the lack of liver donors after liver failure and drug-induced liver injury, much research has focused on developing liver alternatives and liver in vitro models for transplantation and drug screening. Although numerous studies have been conducted, these systems cannot faithfully mimic the complexity of the liver. Recently, three-dimensional (3D) cell printing technology has emerged as one of a number of innovative technologies that may help to overcome this limitation. However, a great deal of work in developing biomaterials optimized for 3D cell printing-based liver tissue engineering remains. Therefore, in this work, we developed a liver decellularized extracellular matrix (dECM) bioink for 3D cell printing applications and evaluated its characteristics. The liver dECM bioink retained the major ECM components of the liver while cellular components were effectively removed and further exhibited suitable and adjustable properties for 3D cell printing. We further studied printing parameters with the liver dECM bioink to verify the versatility and fidelity of the printing process. Stem cell differentiation and HepG2 cell functions in the liver dECM bioink in comparison to those of commercial collagen bioink were also evaluated, and the liver dECM bioink was found to induce stem cell differentiation and enhance HepG2 cell function. Consequently, the results demonstrate that the proposed liver dECM bioink is a promising bioink candidate for 3D cell printing-based liver tissue engineering.

MTF performance verification of an athermalized large-aperture IR optical system for space environment.

We develop an athermalized IR optical system operating in the temperature range of 10°C-30°C in vacuum. As large defocus errors can occur in IR optical systems in such an environment, we estimate the amount of defocus induced by the thermoelastic effect, thermo-optic effect, and air-to-vacuum transition. Furthermore, we measure the modulation transfer function (MTF) performance of our IR optical system in a thermal vacuum chamber. Our athermal system design and accurate estimation of the air-to-vacuum transition effect enable the realization of a stable IR optical system for a space environment, which exhibits an MTF value greater than 18%.

Translational possibility of [18 F]Mefway to image serotonin 1A receptors in humans: Comparison with [18 F]FCWAY in rodents.

PURPOSE: To compare the cerebral uptake and binding potential of [18 F]FCWAY and [18 F]Mefway in the rodent to assess their potential for imaging serotonin 1A (5-HT1A ) receptors. MATERIALS AND METHODS: In vitro liver microsomal studies were performed to evaluate the degree of defluorination. Dynamic positron emission tomography (PET) studies were then conducted for 2 h with or without an anti-defluorination agent. The regions of interest were the hippocampus and frontal cortex (5-HT1A target regions) and the cerebellum (5-HT1A nontarget region). The in vivo kinetics of the radioligands were compared based on the brain uptake values and target-to-nontarget ratio. We also performed a comparison of binding potential (BPND ) as a steady-state binding parameter. Finally, binding affinities to 5-HT1A receptors were assessed in Chinese hamster ovary cells (CHO-K1) cells expressing human recombinant 5-HT1A receptors. RESULTS: The radiochemical yield of [18 F]Mefway was slightly higher than that of [18 F]FCWAY (19 vs. 15%). With regard to metabolic stability against defluorination, both compounds exhibited similar stability in rat liver microsomes, but [18 F]Mefway displayed higher stability in the human microsome (defluorination ratio at 30 min: 32 vs. 29 in rat liver microsomes, 31 vs. 64 in human liver microsomes for [18 F]Mefway and [18 F]FCWAY, respectively). There were no significant differences in brain uptake, the target-to-nontarget ratios, and the BPND (at hippocampus, peak brain uptakes: 6.9 vs. 8.5, target-to-nontarget ratios: 6.9 vs. 8.5, BPND : 5.2 vs. 6.2 for [18 F]Mefway and [18 F]FCWAY). The binding affinity of [18 F]Mefway was considerably higher than that of [18 F]FCWAY (IC50 : 1.5 nM vs. 2.2 nM). CONCLUSION: [18 F]Mefway exhibits favorable characteristics compared to [18 F]FCWAY in rodents, and may be a promising radioligand for use in human subjects. Synapse 68:595-603, 2014. © 2014 Wiley Periodicals, Inc.

Genomic organization and functional diversification of two warm-temperature-acclimation-associated 65-kDa protein genes in rockbream (Oplegnathus fasciatus; Perciformes).

Two paralogue genes of warm-temperature-acclimation-associated 65-kDa protein were characterized and their mRNA expression patterns during various experimental stimulations were examined in the rockbream (Oplegnathus fasciatus; Perciformes). Rockbream Wap65 isoforms (rbWap65-1 and rbWap65-2) share basically common structural features with other teleostean orthologues and human hemopexin (HPX) at both amino acid (conserved cysteine and histidine residues) and genomic levels (ten-exon structure), although the rbWap65-2 reveals more homologous characteristics to human HPX than does rbWap65-1 isoform. Southern blot analysis indicates that each rbWap65 isoform exists as a single copy gene in the rockbream genome. Both rbWap65 genes were predicted to possess various transcription factor (TF) binding motifs related with stress and innate immunity in their 5ʹ-upstream regions, in which inflammation-related motifs were more highlighted in the rbWap65-2 than in rbWap65-1. Based on the RT-PCR assay, the liver-predominant expression pattern was more apparent in rbWap65-1 than rbWap65-2 isoform. During thermal elevation, clear upregulation was found only for the rbWap65-1. In contrast, immune stimulations (bacterial challenges, viral infection and iron overload) activated more preferentially the rbWap65-2 isoform in overall, although the inducibility was affected by the kinds of stimulators and tissue types. Taken together, our data suggest that the two paralogue rbWap65 isoforms have experienced subfunctionalization and/or neofunctionalization during their evolutionary history, in which the rbWap65-2 has retained closer, functional orthology to the human HPX while the rbWap65-1 have been diversified to be more related with thermal acclimation physiology.

Isolation and mRNA expression analysis of aquaporin isoforms in marine medaka Oryzias dancena, a euryhaline teleost.

We have identified six putative aquaporin (AQP) genes from marine medaka Oryzias dancena (named odAQPs 1, 3, 8, 10, 11 and 12). The marine medaka AQP cDNAs encode polypeptides of 259-298 amino acids, respectively. Topology predictions showed six transmembrane domains, five connecting loops, and cytoplasmic N- and C-terminal domains, all of which is conserved among AQP molecules. Although asparagine-proline-alanine (NPA) motifs are highly conserved in most odAQP isoforms, several AQPs revealed variant types of motifs such as asparagine-proline-proline (NPP), asparagine-proline-valine (NPV) or/and asparagine-proline-serine (NPS) motifs. The phylogenic analysis showed that marine medaka AQPs had closet relationship with Japanese ricefish (medaka; Oryzias latipes) counterparts. Reverse transcription (RT)-PCR analyses showed that marine medaka AQP transcripts would be expressed in not only osmoregulatory tissues but also nonosmoregulatory tissues, and also that the expression levels of certain AQP isoforms in nonosmoregulatory tissues were readily comparable or even higher than those in typically known osmoregulatory organs. Although the overall tissue distribution patterns of AQPs were not significantly different between 0- and 30-ppt acclimated fish, the expression levels under different salinities were largely variable among isoforms and tissues. This is the first report to investigate tissue expression profiles of teleostean AQPs 11 and 12 during the long-term acclimation to freshwater and salted water.

Advancement in Cancer Vasculogenesis Modeling through 3D Bioprinting Technology.

Cancer vasculogenesis is a pivotal focus of cancer research and treatment given its critical role in tumor development, metastasis, and the formation of vasculogenic microenvironments. Traditional approaches to investigating cancer vasculogenesis face significant challenges in accurately modeling intricate microenvironments. Recent advancements in three-dimensional (3D) bioprinting technology present promising solutions to these challenges. This review provides an overview of cancer vasculogenesis and underscores the importance of precise modeling. It juxtaposes traditional techniques with 3D bioprinting technologies, elucidating the advantages of the latter in developing cancer vasculogenesis models. Furthermore, it explores applications in pathological investigations, preclinical medication screening for personalized treatment and cancer diagnostics, and envisages future prospects for 3D bioprinted cancer vasculogenesis models. Despite notable advancements, current 3D bioprinting techniques for cancer vasculogenesis modeling have several limitations. Nonetheless, by overcoming these challenges and with technological advances, 3D bioprinting exhibits immense potential for revolutionizing the understanding of cancer vasculogenesis and augmenting treatment modalities.

Decellularized matrix bioink with gelatin methacrylate for simultaneous improvements in printability and biofunctionality.

Gelatin methacrylate (GelMA) bioink has been widely used in bioprinting because it is a printable and biocompatible biomaterial. However, it is difficult to print GelMA bioink without any temperature control because it has a thermally-sensitive rheological property. Therefore, in this study, we developed a temperature-controlled printing system in real time without affecting the viability of the cells encapsulated in the bioink. In addition, a skin-derived decellularized extracellular matrix (SdECM) was printed with GelMA to better mimic the native tissue environment compared with solely using GelMA bioink with the enhancement of structural stability. The temperature setting accuracy was calculated to be 98.58 ± 1.8 % for the module and 99.48 ± 1.33 % for the plate from 5 °C to 37 °C. The group of the temperature of the module at 10 °C and the plate at 20 °C have 93.84 % cell viability with the printable range in the printability window. In particular, the cell viability and proliferation were increased in the encapsulated fibroblasts in the GelMA/SdECM bioink, relative to the GelMA bioink, with a morphology that significantly spread for seven days. The gene expression and growth factors related to skin tissue regeneration were relatively upregulated with SdECM components. In the bioprinting process, the rheological properties of the GelMA/SdECM bioink were successfully adjusted in real time to increase printability, and the native skin tissue mimicked components providing tissue-specific biofunctions to the encapsulated cells. The developed bioprinting strategies and bioinks could support future studies related to the skin tissue reconstruction, regeneration, and other medical applications using the bioprinting process.

Mycobacterium marinum infection in Drosophila melanogaster for antimycobacterial activity assessment.

OBJECTIVES: The major advantages of Drosophila melanogaster are a well-characterized immune system and high degree of susceptibility to tuberculosis caused by Mycobacterium marinum. The D. melanogaster-M. marinum infection model is gaining momentum as a screening tool because it is genetically amenable, low priced, rapid, technically convenient and ethically acceptable. In this context, the aim of this study was to develop a new, effective D. melanogaster-M. marinum in vivo efficacy model for antimycobacterial drug discovery. METHODS: D. melanogaster were challenged with intra-abdominal injections of M. marinum and infected flies were fed with a fly medium containing isoniazid, rifampicin, ethambutol, pyrazinamide, amikacin, dinitrobenzamide or ampicillin dissolved in DMSO at different concentrations (0, 100 and 500 mg/L). Bacterial dissemination in flies was monitored by fluorescence microscopy/cfu counts and a fly survival curve was plotted. RESULTS: The D. melanogaster-M. marinum model allowed assessment of the effectiveness of antibiotic treatment not only with conventional drugs, but also with newly discovered antimycobacterial agents. Rifampicin, dinitrobenzamide, amikacin and isoniazid effectively extended the life span of infected flies and ethambutol showed slightly improved survival. However, M. marinum infection was not cured by ampicillin or pyrazinamide. CONCLUSIONS: This D. melanogaster-M. marinum infection/curing methodology may be valuable in the rapid evaluation of the activity of new antimycobacterial agents in drug discovery.

Pore size reduction in directional crystallization processing of porous polymeric membranes.

Although various prep technologies of porous polymeric materials have evolved, the versatile control of pore morphology still remains as the most demanding subject. Herein, we applied the engineering principles of crystal habit by directional crystallization to the fabrication of porous PVDF (polyvinylidene fluoride) membranes. Pores of low tortuosity and relatively high porosity (80-90%) were successfully fabricated by the directional crystallization of DMSO (dimethyl sulfoxide) under a temperature gradient imposed by the controlled movement of a sample toward a liquid nitrogen reservoir followed by subsequent solvent removal. Pore size was controlled across a wide range by mixing DMSO with dioxane. Notably, nanoporous structures could be prepared at a 1:1 mixing ratio, in which the multi-step crystallization of solvents restricted by highly concentrated solutes enabled the preparation of nanomembranes. The homogeneous dispersion of TiO2 nanoparticles into PVDF, which are often used to improve hydrophilicity and antifouling performance, was easily achieved by this method. This novel prep technology based on the directional crystallization of solvent mixtures is a potentially viable solution to the limitations of current porous materials research.

Three-dimensional printing of smart constructs using stimuli-responsive biomaterials: A future direction of precision medicine.

Three-dimensional (3D) printing, which is a valuable technique for the fabrication of tissue-engineered constructs and biomedical devices with complex architectures, has brought about considerable progress in regenerative medicine, drug delivery, and diagnosis of diseases. However, because of the static and inanimate properties of conventional 3D-printed structures, it is difficult to use them in therapies for active and precise medicine, such as improved tissue regeneration, targeted or controlled drug delivery, and advanced pathophysiological monitoring. The integration of stimuli-responsive biomaterials into 3D printing provides a potential strategy for designing and building smart constructs that exhibit programmed functions and controllable changes in properties in response to exogenous and autogenous stimuli. These features make 3D-printed smart constructs the next generation of tissue-engineered products. In this review, we introduce the prevalent 3D printing techniques (with an emphasis on the differences between 3D printing and bioprinting, and biomaterials and bioink), the working principle of each technique, and the advantages of using 3D printing for the fabrication of smart constructs. Stimuli-responsive biomaterials that are widely used for 3D printing of smart constructs are categorized, followed by a summary of their applications in tissue regeneration, drug delivery, and biosensors. Finally, the challenges and future perspectives of 3D-printed smart constructs are discussed.

A comparative study of rubber band ligation versus BANANA-Clip in grade 1 to 3 internal hemorrhoids.

PURPOSE: Rubber band ligation (RBL) for grade 1 to 3 internal hemorrhoids is a well-established modality of choice. But RBL is also a kind of surgical treatment; it is not free from complications (e.g., delayed bleeding [DB], rectal stenosis). This study aimed to investigate the results of the comparative treatment of RBL and BANANA-Clip (BC; Endovision). METHODS: Study participants were 632 consecutive patients with grade 1 to 3 internal hemorrhoids attended to Department of Colorectal Surgery at Wellness Hospital between January 2010 and May 2019. We retrospectively reviewed the incidence rate of complications, including DB between RBL and BC. RESULTS: There were 304 male and 328 female patients, whose ages ranged from 15 to 84 years, with a mean age of 45.7 years. The common symptom and cause of treatment was prolapse (70.1%). The number of ligated sites was 1.49±0.57 in the RBL group and 1.99±0.77 in the BC group. RBL showed a significantly higher incidence of DB (3.5%) compared to BC (0%) (P=0.001). The 1-year success rate was 95.9% in the RBL group and 99.7% in the BC group (P=0.005). CONCLUSION: In our study, BC was more reliable in treating grade 1 to 3 internal hemorrhoids with higher success rates and less post-ligation complications, especially DB, compared to RBL.