Bioactive fiber-reinforced hydrogel to tailor cell microenvironment for structural and functional regeneration of myotendinous junction

Myotendinous junction (MTJ) injuries are prevalent in clinical practice, yet the treatment approaches are limited to surgical suturing and conservative therapy, exhibiting a high recurrence rate. Current research on MTJ tissue engineering is scarce and lacks in vivo evaluation of repair efficacy. Here, we developed a three-dimensional-printed bioactive fiber-reinforced hydrogel containing mesenchymal stem cells (MSCs) and Klotho for structural and functional MTJ regeneration. In a rat MTJ defect model, the bioactive fiber-reinforced hydrogel promoted the structural restoration of muscle, tendon, and muscle-tendon interface and enhanced the functional recovery of injured MTJ. In vivo proteomics and in vitro cell cultures elucidated the regenerative mechanisms of the bioactive fiber-reinforced hydrogel by modulating oxidative stress and inflammation, thus engineering an optimized microenvironment to support the survival and differentiation of transplanted MSCs and maintain the functional phenotype of resident cells within MTJ tissues, including tendon/muscle cells and macrophages. This strategy provides a promising treatment for MTJ injuries.

Assembly of Metal-Phenolic Networks onto Microbubbles for One-Step Generation of Functional Microcapsules

The one-step assembly of metal-phenolic networks (MPNs) onto particle templates can enable the facile, rapid, and robust construction of hollow microcapsules. However, the required template removal step may affect the refilling of functional species in the hollow interior space or the in situ encapsulation of guest molecules during the formation of the shells. Herein, a simple strategy for the one-step generation of functional MPNs microcapsules is proposed. This method uses bovine serum albumin microbubbles (BSA MBs) as soft templates and carriers, enabling the efficient pre-encapsulation of guest species by leveraging the coordination assembly of tannic acid (TA) and FeIII ions. The addition of TA and FeIII induces a change in the protein conformation of BSA MBs and produces semipermeable capsule shells, which allow gas to escape from the MBs without template removal. The MBs-templated strategy can produce highly biocompatible capsules with controllable structure and size, and it is applicable to produce other MPNs systems like BSA-TA-CuII and BSA-TA-NiII . Finally, those MBs-templated MPNs capsules can be further functionalized or modified for the loading of magnetic nanoparticles and the pre-encapsulation of model molecules through covalence or physical adsorption, exhibiting great promise in biomedical applications.

Muscle-bone crosstalk via endocrine signals and potential targets for osteosarcopenia-related fracture

Background

Osteosarcopenia is a syndrome coexisting sarcopenia and osteopenia/osteoporosis, with a high fracture risk. Recently, skeletal muscle and bone have been recognized as endocrine organs capable of communication through secreting myokines and osteokines, respectively. With a deeper understanding of the muscle-bone crosstalk, these endocrine signals exhibit an important role in osteosarcopenia development and fracture healing.

Methods

This review summarizes the role of myokines and osteokines in the development and treatment of osteosarcopenia and fracture, and discusses their potential for osteosarcopenia-related fracture treatment.

Results

Several well-defined myokines (myostatin and irisin) and osteokines (RANKL and SOST) are found to not only regulate skeletal muscle and bone metabolism but also influence fracture healing processes. Systemic interventions targeting these biochemical signals has shown promising results in improving the mass and functions of skeletal muscle and bone, as well as accelerating fracture healing processes.

Conclusion

The regulation of muscle-bone crosstalk via biochemical signals presents a novel and promising strategy for treating osteosarcopenia and fracture by simultaneously enhancing bone and muscle anabolism. We propose that myostatin, irisin, RANKL, and SOST may serve as potential targets to treat fracture patients with osteosarcopenia.

The translational potential of this article

Osteosarcopenia is an emerging geriatric syndrome where sarcopenia and osteoporosis coexist, with high fracture risk, delayed fracture healing, and increased mortality. However, no pharmacological agent is available to treat fracture patients with osteosarcopenia. This review summarizes the role of several myokines and osteokines in the development and treatment of osteosacropenia and fracture, as well as discusses their potential as intervention targets for osteosarcopenia-related fracture, which provides a novel and promising strategy for future osteosarcopenia-related fracture treatment.

Material Stiffness in Cooperation with Macrophage Paracrine Signals Determines the Tenogenic Differentiation of Mesenchymal Stem Cells

Stiffness is an important physical property of biomaterials that determines stem cell fate. Guiding stem cell differentiation via stiffness modulation has been considered in tissue engineering. However, the mechanism by which material stiffness regulates stem cell differentiation into the tendon lineage remains controversial. Increasing evidence demonstrates that immune cells interact with implanted biomaterials and regulate stem cell behaviors via paracrine signaling; however, the role of this mechanism in tendon differentiation is not clear. In this study, polydimethylsiloxane (PDMS) substrates with different stiffnesses are developed, and the tenogenic differentiation of mesenchymal stem cells (MSCs) exposed to different stiffnesses and macrophage paracrine signals is investigated. The results reveal that lower stiffnesses facilitates tenogenic differentiation of MSCs, while macrophage paracrine signals at these stiffnesses suppress the differentiation. When exposed to these two stimuli, MSCs still exhibit enhanced tendon differentiation, which is further elucidated by global proteomic analysis. Following subcutaneous implantation in rats for 2 weeks, soft biomaterial induces only low inflammation and promotes tendon-like tissue formation. In conclusion, the study demonstrates that soft, rather than stiff, material has a greater potential to guide tenogenic differentiation of stem cells, which provides comprehensive evidence for optimized bioactive scaffold design in tendon tissue engineering.

Silk Fibroin and Sericin Differentially Potentiate the Paracrine and Regenerative Functions of Stem Cells Through Multiomics Analysis

Silk fibroin (SF) and sericin (SS), the two major proteins of silk, are attractive biomaterials with great potential in tissue engineering and regenerative medicine. However, their biochemical interactions with stem cells remain unclear. In this study, multiomics are employed to obtain a global view of the cellular processes and pathways of mesenchymal stem cells (MSCs) triggered by SF and SS to discern cell-biomaterial interactions at an in-depth, high-throughput molecular level. Integrated RNA sequencing and proteomic analysis confirm that SF and SS initiate widespread but distinct cellular responses and potentiate the paracrine functions of MSCs that regulate extracellular matrix deposition, angiogenesis, and immunomodulation through differentially activating the integrin/PI3K/Akt and glycolysis signaling pathways. These paracrine signals of MSCs stimulated by SF and SS effectively improve skin regeneration by regulating the behavior of multiple resident cells (fibroblasts, endothelial cells, and macrophages) in the skin wound microenvironment. Compared to SS, SF exhibits better immunomodulatory effects in vitro and in vivo, indicating its greater potential as a carrier material of MSCs for skin regeneration. This study provides comprehensive and reliable insights into the cellular interactions with SF and SS, enabling the future development of silk-based therapeutics for tissue engineering and stem cell therapy.

Stiffness-dependent dynamic effect of inflammation on keratocyte phenotype and differentiation

Although extensive studies have evaluated the regulation effect of microenvironment on cell phenotype and cell differentiation, further investigations in the field of the cornea are needed to gain sufficient knowledge for possible clinical translation. This study aims to evaluate the regulation effects of substrate stiffness and inflammation on keratocyte phenotype of corneal fibroblasts, as well as the differentiation from stem cells towards keratocytes. Soft and stiff substrates were prepared based on polydimethylsiloxane (PDMS). HTK and stem cells were cultured on these substrates to evaluate the effects of stiffness. The possible synergistic effects between substrate stiffness and inflammatory factor IL-1β were examined by qPCR and immunofluorescence staining. In addition, macrophages were cultured on soft and stiff substrates to evaluate the effect of substrate stiffness on the synthesis of inflammatory factors. The conditioned medium of macrophages (Soft-CM and Stiff-CM) was collected to examine the effects on HTK and stem cells. It was found that inflammatory factor IL-1β promoted keratocyte phenotype and differentiation when cells were cultured on soft substrate (~130 kPa), which were different from cells cultured on stiff substrate (~2×103 kPa) and TCP (∼106 kPa). Besides, macrophages cultured on stiff substrates had significantly higher expression of IL-1β and Tnf-α as compared to the cells cultured on soft substrates. And Stiff-CM decreased the expression of keratocyte phenotype markers as compared to Soft-CM. The results of our study indicate a stiffness-dependent dynamic effect of inflammation on keratocyte phenotype and differentiation, which is of significance not only in gaining a deeper knowledge of corneal pathology and repair, but also in being instructive for scaffold design in corneal tissue engineering and ultimate regeneration.

Biointerfacial giant capsules with high paclitaxel loading and magnetic targeting for breast tumor therapy

High drug loading, targeted delivery, prolonged drug release, and low systemic toxicity are effective weapons for hydrophobic drug delivery systems to solve serious concerns in poor water-solubility and toxicity of paclitaxel (PTX). Herein, we reported that biointerfacial giant multilayer microcapsules (BGMs) with the feature of high-density drug loading and high-efficiency magnetic delivery were fabricated templated by PTX-liposome-microbubble complex using the layer-by-layer self-assembly (LbL) technique. The drug loading capacity of BGMs was improved by optimizing the structure of microbubbles and capsules to increase the PTX-contained layers, and the resultant BGMs exhibited high drug loading content (50.56 ± 0.09 %) and sustained drug release properties. The BGMs with an average diameter of 74.1 ± 12.1 µm and an average thickness of 275.5 ± 48.4 nm contained abundant magnetic nanoparticles (MNPs) in their cavity, which endowed these capsules with outstanding magnetic properties and fast magnetophoretic velocity in the blood (∼0.3 mm/s, ▽B = 1 T/mm). Moreover, both in vitro and in vivo studies demonstrated that the biocompatible PTX-loaded magnetic BGMs (Capsule@PLMPPL) caused notable death (71.3 ± 2.9 %) of 4 T1 breast cancer cells through PTX diffusion, capsules degradation, and subsequent endocytosis by cancer cells, and ultimately effectively inhibited tumor growth. In general, the developed BGM with good deformability and degradation was the first reported giant polyelectrolyte capsule to be used in tumor therapy, which could notably improve the therapeutic efficacy of PTX while reducing its side effects.

Hydroxycamptothecin and Substratum Stiffness Synergistically Regulate Fibrosis of Human Corneal Fibroblasts

Corneal fibrosis is a common outcome of inappropriate repair associated with trauma or ocular infection. Altered biomechanical properties with increased corneal stiffness is a feature of fibrosis that cause corneal opacities, resulting in severe visual impairment and even blindness. The present study aims to determine the effect of hydroxycamptothecin (HCPT) and matrix stiffness on transforming growth factor-β1 (TGF-β1)-induced fibrotic processes in human corneal fibroblasts (HTK cells). HTK cells were cultured on substrates with different stiffnesses ("soft", ∼261 kPa; "stiff", ∼2.5 × 10³ kPa) and on tissue culture plastic (TCP, ∼10⁶ kPa) and simultaneously treated with or without 1 μg/mL HCPT and 10 ng/mL TGF-β1. We found that HCPT induced decreased cell viability and antiproliferative effects on HTK cells. TGF-β1-induced expression of fibrosis-related genes (FN1, ACTA2) was reduced if the cells were simultaneously treated with HCPT. Substrate stiffness did not affect the expression of fibrosis-related genes. The TGF-β1 induced expression of FN1 on both soft and stiff substrates was reduced if cells were simultaneously treated with HCPT. However, this trend was not seen for ACTA2, i.e., the TGF-β1 induced expression of ACTA2 was not reduced by simultaneous treatment of HCPT in either soft or stiff substrate. Instead, HCPT treatment in the presence of TGF-β1 resulted in increased gene expression of keratocyte phenotype makers (LUM, KERA, AQP1, CHTS6) on both substrate stiffnesses. In addition, the protein expression of keratocyte phenotype makers LUM and ALDH3 was increased in HTK cells simultaneously treated with TGF-β1 and HCPT on stiff substrate as compared to control, i.e., without HCPT. In conclusion, we found that HCPT can reduce TGF-β1-induced fibrosis and promote the keratocyte phenotype in a substrate stiffness dependent manner. Thus, HCPT stimulation might be an approach to stimulate keratocytes in the appropriate healing stage to avoid or reverse fibrosis and achieve more optimal corneal wound healing.

Nanosilicate-Reinforced Silk Fibroin Hydrogel for Endogenous Regeneration of Both Cartilage and Subchondral Bone

Osteochondral defects are characterized by injuries to both cartilage and subchondral bone, which is a result of trauma, inflammation, or inappropriate loading. Due to the unique biological properties of subchondral bone and cartilage, developing a tissue engineering scaffold that can promote dual-lineage regeneration of cartilage and bone simultaneously remains a great challenge. In this study, a microporous nanosilicate-reinforced enzymatically crosslinked silk fibroin (SF) hydrogel is fabricated by introducing montmorillonite (MMT) nanoparticles via intercalation chemistry. In vitro studies show that SF-MMT nanocomposite hydrogel has improved mechanical properties and hydrophilicity, as well as the bioactivities to promote the osteogenic differentiation of bone marrow mesenchymal stem cells and maintain chondrocyte phenotype compared with SF hydrogel. Global proteomic analysis verifies the dual-lineage bioactivities of SF-MMT nanocomposite hydrogel, which are probably regulated by multiple signaling pathways. Furthermore, it is observed that the biophysical interaction of cells and SF-MMT nanocomposite hydrogel is partially mediated by clathrin-mediated endocytosis and its downstream processes. In vivo, the SF-MMT nanocomposite hydrogel effectively promotes osteochondral regeneration as evidenced by macroscopic, micro-CT, and histological evaluation. In conclusion, a functionalized SF-MMT nanocomposite hydrogel is developed with dual-lineage bioactivity for osteochondral regeneration, indicating its potential in osteochondral tissue engineering.

Single-Cell Transcriptomic Atlas of Gingival Mucosa in Type 2 Diabetes

The oral gingival barrier is a constantly stimulated and dynamic environment where homeostasis is often disrupted, resulting in inflammatory periodontal diseases. Type 2 diabetes (T2D) has been reported to be associated with gingival barrier dysfunction, but the effect and underlying mechanism are inconclusive. Herein, we performed single-cell RNA sequencing (scRNA-seq) of gingiva from leptin receptor-deficient mice (db/db) to examine the gingival heterogeneity in the context of T2D. Periodontal health of control mice is characterized by populations of Krt14⁺-expressing epithelial cells and Col1a1⁺-fibroblasts mediating immune homeostasis primarily through the enrichment of innate lymphoid cells. The db/db gingiva exhibited decreased epithelial/stromal ratio and dysfunctional barrier. We further observed stromal, particularly fibroblast immune hyperresponsiveness, linked to the recruitment of myeloid-derived cells at the db/db gingiva. Both scRNA-seq and histological analysis suggested the inflammatory signaling between fibroblasts and neutrophils as a potential driver of diabetes-induced periodontal damage. Notably, the "immune-like" stromal cells were wired toward the induction of gingival γδ T hyperresponsiveness in db/db mice. Our work reveals that the "immune-like" fibroblasts with transcriptional diversity are involved in the innate immune homeostasis at the diabetic gingiva. It highlights a potentially significant role of these cell types in its pathogenesis.

Multifunctional polyphenol-based silk hydrogel alleviates oxidative stress and enhances endogenous regeneration of osteochondral defects

In osteochondral defects, oxidative stress caused by elevated levels of reactive oxygen species (ROS) can disrupt the normal endogenous repair process. In this study, a multifunctional hydrogel composed of silk fibroin (SF) and tannic acid (TA), the FDA-approved ingredients, was developed to alleviate oxidative stress and enhance osteochondral regeneration. In this proposed hydrogel, SF first interacts with TA to form a hydrogen-bonded supramolecular structure, which is subsequently enzymatically crosslinked to form a stable hydrogel. Furthermore, TA had multiple phenolic hydroxyl groups that formed interactions with the therapeutic molecule E7 peptide for controlled drug delivery. In vitro investigations showed that SF-TA and SF-TA-E7 hydrogels exhibited a multitude of biological effects including scavenging of ROS, maintaining cell viability, and promoting the proliferation of bone marrow mesenchymal stem cells (BMSCs) against oxidative stress. The proteomic analysis indicated that SF-TA and SF-TA-E7 hydrogels suppressed oxidative stress, which in turn improved cell proliferation in multiple proliferation and apoptosis-related pathways. In rabbit osteochondral defect model, SF-TA and SF-TA-E7 hydrogels promoted enhanced regeneration of both cartilage and subchondral bone as compared to hydrogel without TA incorporation. These findings indicated that the multifunctional SF-TA hydrogel provided a microenvironment suitable for the endogenous regeneration of osteochondral defects.

The application of human periodontal ligament stem cells and biomimetic silk scaffold for in situ tendon regeneration

Background

With the development of tissue engineering, enhanced tendon regeneration could be achieved by exploiting suitable cell types and biomaterials. The accessibility, robust cell amplification ability, superior tendon differentiation potential, and immunomodulatory effects of human periodontal ligament stem cells (hPDLSCs) indicate their potential as ideal seed cells for tendon tissue engineering. Nevertheless, there are currently no reports of using PDLSCs as seed cells. Previous studies have confirmed the potential of silk scaffold for tendon tissue engineering. However, the biomimetic silk scaffold with tendon extracellular matrix (ECM)-like structure has not been systematically studied for in situ tendon regeneration. Therefore, this study aims to evaluate the effects of hPDLSCs and biomimetic silk scaffold on in situ tendon regeneration.

Methods

Human PDLSCs were isolated from extracted wisdom teeth. The differentiation potential of hPDLSCs towards osteo-, chondro-, and adipo-lineage was examined by cultured in different inducing media. Aligned and random silk scaffolds were fabricated by the controlled directional freezing technique. Scaffolds were characterized including surface structure, water contact angle, swelling ratio, degradation speed and mechanical properties. The biocompatibility of silk scaffolds was evaluated by live/dead staining, SEM observation, cell proliferation determination and immunofluorescent staining of deposited collagen type I. Subsequently, hPDLSCs were seeded on the aligned silk scaffold and transplanted into the ruptured rat Achilles tendon. Scaffolds without cells served as control groups. After 4 weeks, histology evaluation was carried out and macrophage polarization was examined to check the repair effects and immunomodulatory effects.

Results

Human PDLSCs were successfully isolated, and their multi-differentiation potential was confirmed. Compared with random scaffold, aligned silk scaffold had more elongated and aligned pores and promoted the proliferation and ordered arrangement of hPDLSCs. After implantation into rat Achilles tendon defect, hPDLSCs seeded aligned silk scaffold enhanced tendon repair with more tendon-like tissue formation after 4 weeks, as compared to the scaffold-only groups. Higher expression of CD206 and lower expression of iNOS, IL-1β and TNF-α were found in the hPDLSCs seeded aligned silk scaffold group, which revealed its modulation effect of macrophage polarization from M1 to M2 phenotype.

Conclusions

In summary, this study demonstrates the efficacy of hPDLSCs as seed cells and aligned silk scaffold as a tendon-mimetic scaffold for enhanced tendon tissue engineering, which may have broad implications for future tendon tissue engineering and regenerative medicine researches.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02661-7.

Enzymatically crosslinked silk-nanosilicate reinforced hydrogel with dual-lineage bioactivity for osteochondral tissue engineering

Osteochondral defects are characterized by damage to both articular cartilage and subchondral bone. Various tissue engineering strategies have been developed for osteochondral defect repair. However, strong mechanical properties and dual-lineage (osteogenesis and chondrogenesis) bioactivity still pose challenges for current biomaterial design. Silicate nanoclay has been reported to improve the mechanical properties and biofunctionality of polymer systems, but its effect on in vitro dual-lineage differentiation or in vivo osteochondral regeneration has not been extensively investigated before. Here, a novel enzymatically crosslinked silk fibroin (SF)-Laponite (LAP) nanocomposite hydrogel was fabricated and evaluated for osteochondral regeneration. The incorporation of a small amount of LAP (1% w/v) accelerated the gelation process of SF and greatly enhanced the mechanical properties and hydrophilicity of the hydrogel. In vitro investigations showed that the developed SF-LAP hydrogel was biocompatible and was able to induce osteogenic and chondrogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs), validated by Alizarin red/Alcian blue staining, qPCR, and immunofluorescent staining. During an 8-week implantation into rabbit full-thickness osteochondral defects, the SF-LAP hydrogel promoted the simultaneous and enhanced regeneration of cartilage and subchondral bone. The repaired tissue in the chondral region was constituted mainly of hyaline cartilage with typical chondrocyte morphology and cartilaginous extracellular matrix (ECM). These findings suggested that the SF-LAP nanocomposite hydrogel developed in this study served as a promising biomaterial for osteochondral regeneration due to its mechanical reinforcement and dual-lineage bioactivity.

Cell-Free Biomimetic Scaffold with Cartilage Extracellular Matrix-Like Architectures for In Situ Inductive Regeneration of Osteochondral Defects

The development of a biomimetic scaffold designed to provide a native extracellular matrix (ECM)-like microenvironment is a potential strategy for cartilage repair. The ECM in native articular cartilage is structurally composed of three different architectural zones, i.e., horizontally aligned, randomly arranged, and vertically aligned collagen fibers. However, the effects of scaffolds with these three different ECM-like architectures on in vivo cartilage regeneration are not clear. In this study, we aim to systematically investigate and compare their in situ inductive regenerative efficacy on cartilage defects. ECM-mimetic silk fibroin scaffolds with horizontally aligned, vertically aligned, and random pore architectures are fabricated using the controlled directional freezing technique. All of these scaffolds exhibit similar pore area, swelling ratio, and in vitro degradation behavior. Nevertheless, the aligned scaffolds have a higher pore aspect ratio and hydrophilicity, and increase the proliferation of bone marrow-derived mesenchymal stem cells (BMSCs) in vitro. When implanted into rabbit osteochondral defects, the scaffold with vertically aligned pore architectures provides a more cell-favorable microenvironment conducive to endogenous BMSCs than other scaffolds and supports the simultaneous regeneration of cartilage and subchondral bone. These findings indicate that scaffolds with vertically aligned ECM-like architectures serve as an effective cell-free and growth factor-free scaffold for enhanced endogenous osteochondral regeneration.

LepR-Expressing Stem Cells Are Essential for Alveolar Bone Regeneration

Stem cells play a critical role in bone regeneration. Multiple populations of skeletal stem cells have been identified in long bone, while their identity and functions in alveolar bone remain unclear. Here, we identified a quiescent leptin receptor–expressing (LepR+) cell population that contributed to intramembranous bone formation. Interestingly, these LepR+ cells became activated in response to tooth extraction and generated the majority of the newly formed bone in extraction sockets. In addition, genetic ablation of LepR+ cells attenuated extraction socket healing. The parabiosis experiments revealed that the LepR+ cells in the healing sockets were derived from resident tissue rather than peripheral blood circulation. Further studies on the mechanism suggested that these LepR+ cells were responsive to parathyroid hormone/parathyroid hormone 1 receptor (PTH/PTH1R) signaling. Collectively, we demonstrate that LepR+ cells, a postnatal skeletal stem cell population, are essential for alveolar bone regeneration of extraction sockets.

An all-silk-derived functional nanosphere matrix for sequential biomolecule delivery and in situ osteochondral regeneration

Endogenous repair of osteochondral defect is usually limited by the insufficient number of cells in the early stage and incomplete cell differentiation in the later stage. The development of drug delivery systems for sequential release of pro-migratory and pro-chondrogenic molecules to induce endogenous bone marrow-derived mesenchymal stem cells (BMSCs) recruitment and chondrogenic differentiation is highly desirable for in situ osteochondral regeneration. In this study, a novel, all-silk-derived sequential delivery system was fabricated by incorporating the tunable drug-loaded silk fibroin (SF) nanospheres into a SF porous matrix. The loading efficiency and release kinetics of biomolecules depended on the initial SF/polyvinyl alcohol (PVA) concentrations (0.2%, 1% and 5%) of the nanospheres, as well as the hydrophobicity of the loaded molecules, resulting in controllable and programmed delivery profiles. Our findings indicated that the 5% nanosphere-incorporated matrix showed a rapid release of E7 peptide during the first 120 h, whereas the 0.2% nanosphere-incorporated matrix provided a slow and sustained release of Kartogenin (KGN) longer than 30 days. During in vitro culture of BMSCs, this functional SF matrix incorporated with E7/KGN nanospheres showed good biocompatibility, as well as enhanced BMSCs migration and chondrogenic differentiation through the release of E7 and KGN. Furthermore, when implanted into rabbit osteochondral defect, the SF nanosphere matrix with sequential E7/KGN release promoted the regeneration of both cartilage and subchondral bone. This work not only provided a novel all-silk-derived drug delivery system for sequential release of molecules, but also a functional tissue-engineered scaffold for osteochondral regeneration.

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An all-silk-derived sequential biomolecule delivery system is developed.

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The release profiles of both hydrophilic and hydrophobic molecules from the SF nanosphere matrix can be easily tuned.

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This SF nanosphere matrix induces BMSCs recruitment and chondrogenic differentiation by programmed release of E7 and KGN.

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The SF nanosphere matrix with sequential E7/KGN release improves the regeneration of cartilage and subchondral bone in vivo..

Photoluminescence characterisations of a dynamic aging process of organic-inorganic CH3NH3PbBr3 perovskite

After unprecedented development of organic-inorganic lead halide perovskite solar cells over the past few years, one of the biggest barriers towards their commercialization is the stability of the perovskite material. It is thus important to understand the interaction between the perovskite material and oxygen and/or humidity and the associated degradation process in order to improve device and encapsulation design for better durability. Here we characterize the dynamic aging process in vapour-assisted deposited (VASP) CH3NH3PbBr3 perovskite thin films using advanced optical techniques, such as time-resolved photoluminescence and fluorescence lifetime imaging microscopy (FLIM). Our investigation reveals that the perovskite grains grow spontaneously and the larger grains are formed at room temperature in the presence of moisture and oxygen. This crystallization process leads to a higher density of defects and a shorter carrier lifetime, specifically in the larger grains. Excitation-intensity-dependent steady-state photoluminescence shows both N2 stored and aged perovskite exhibit a super-linear increase of photoluminescence intensity with increasing excitation intensity; and the larger slope in aged sample suggests a larger density of defects is generated, consistent with time-resolved PL measurements.

Synthesis and cytotoxic activity of 3-phenyl-2-thio-quinoxaline 1,4-dioxide derivatives in hypoxia and in normoxia

A series of novel 3-phenyl-2-ethylthio/ethylsulfinyl/ethylsulfonyl/phenylthio/ phenylsulfonyl-quinoxaline 1,4-dioxide derivatives were synthesized and screened for their cytotoxicity in vitro on human leukaemia cell line HL-60, human esophagus cancer cell line ECA-109, human prostate cancer cell line PC-3, human gastric carcinoma cell line SGC-7901, and human breast cancer cell line MCF-7 in hypoxia and in normoxia. Half of tested compounds showed higher cytotoxic activity both in hypoxia and in normoxia. The mechanism of one potent compound, 67, in hypoxia showed that the mitochondria pathway is involved in the antitumor activity of this class of compounds.

[The expression and clinical significance of proliferative antigen Ki-67 and apoptosis-antagonizing antigen Bcl-2 in non-Hodgkin's lymphoma]

OBJECTIVE

To evaluate the expression of proliferative antigen Ki-67 and apoptosis-antagonizing protein Bcl-2 as well as their clinical significance in non-Hodgkin's lymphoma (NHL).

METHODS

Ki-67 antigen and Bcl-2 protein were measured by immunohistochemistry on paraffin -embedded slices in 35 cases of NHL.

RESULTS

(1) The level of Ki-67 expression in low grade NHL was lower than that in high grade NHL (P < 0.01),while Bcl-2 expression in lower grade NHL was higher than that in high grade (P < 0.01). (2) The level of Bcl-2 expression in B cell NHL was higher than that in T cell NHL (P < 0.02), but there was no difference in the expression of Ki-67. (3) The level of Bcl-2 expression in remission group was lower than that in non-remission group after the first course of chemotherapy, but there was no significant difference in Ki-67 expression. (4) The survival time was longer in the group with Ki-67 < or = 20% than that in the group with Ki-67 > 20%, but there was no significant difference of survival time between the high and low expression group of Bcl-2.

CONCLUSIONS

The level of Ki-67 and Bcl-2 expression was closely related with the grade of malignant and the prognosis of NHL. They were a pair of useful markers for understanding the generation and prognosis of NHL.

[Ultrastructure changes of the olfactory epithelium of the patients suffering from dysosmia caused by the chronic sinusitis]

OBJECTIVE

To observe the ultrastructural changes of olfactory epithelium (OE) in patients suffering from dysosmia caused by chronic sinusitis.

METHODS

The specimens of olfactory epithelium were obtained from 35 patients operated for chronic sinusitis accompanied by dysosmia. According to the results of light microscope (LM) examination, the OE was divided into three groups by the types of pathological changes: normal, atrophic and respiratory epithelium metaplasia(REM). Transmission electron microscope was used to observe the ultrastructural changes of each group.

RESULTS

Under the LM, the surface ultrastructure of the OE showed some abnormal changes: (1) surface microvillus of the supporting cells disappeared; (2) olfactory vesicle changed their shape due to vacuolization; (3) disappearance of canaliculus structure in the olfactory vesicle; (4) the olfactory cilia changed the shape or reduced; some of the reduced cilia underwent metaplasia. The ultrastructural changes of atrophic OE included: (1) minor and moderate atrophy: the organelles and the membrane-limited electron dense vesicles on the upper section of the supporting cells obviously decreased or disappeared, even underwent vacuolization. The basic cell degenerated; (2) serious atrophy: the turbidity of the cell structure, even double cell structure, the nuclei of the cell aggregated as the plaque and vesiculose change or karyopyknosis. As for the cytoplasm, there were the dilation of the ERs, turgidity of the mitochondrion, the disarrangement, diminution and vacuolization. Fasciculate cilia were distributed separately in the REM group.

CONCLUSION

There is a positive relationship between the atrophy degree and the degree of the abnormal ultrastructural changes of the OE. The ultrastructural changes of OE in patients suffering from dysosmia caused by chronic sinusitis may provide reference for assessment of the treatment of dysosmia.

Production of no-carrier-added 186Re via deuteron induced reactions on isotopically enriched 186W

Rhenium-186 was produced from the reaction induced by 16 MeV deuterons on isotopically enriched 186W metal powder target. Following its separation from 187W, 183Ta and the bulk of target materials 186W through an acid alumina column, the 186Re was converted to HNO3 solution through an anion exchange column, or to ammonia solution by extracting with N-235-dimethylbenzene, and finally the no-carrier-added 186Re saline solution was obtained. The radionuclidic purity of 186Re was >99.9% and the isotopic impurities were mainly 183Re (5.0 x 10(-3)%) and 184gRe (4.6 x 10(-2)%). The experimental thick-target yield of 186Re was determined to be approximately 529 microCi/microA h and the overall chemical recovery yield was > 80%.

[The diagnosis and treatment of Lyme disease: a report of six cases]

We retrospectively analyzed the clinical features, diagnosis, treatment, and prognosis of 6 cases of Lyme disease from November, 1994 to December, 1998. According to our report, doxycycline, penicillin, and ceftriaxone are effective drugs for Lyme disease. The shorter the disease course is, the better the treatment effect will be. Patients in phase III usually need repeated treatment.

[Study of 6 cases of AIDS with pulmonary complication]

OBJECTIVE

To improve and to increase the awareness of pulmonary complications of AIDS.

METHODS

Six cases of confirmed AIDS from may 1992 to August 1997 were analyzed.

RESULTS

Of the six cases, there were five complicated with pneumocysitis carinii pneumonia (PCP) (in which one had PCP as the first occurred manifestation). The clinical presentations of PCP were fever(5/5), dyspnea on exertion or at rest(4/5), and hypoxemi with mean PaO2 of 58.1 mm Hg. Chest X-ray showed bilateral diffuse interstitial or alveolar infiltrates. Pulmonary tuberculosis, tuberculous lymphadenities (fast-acid staining positive but PPD negative) and bronchial fungal infection were found in three cases.

CONCLUSIONS

AIDS patients are at high risk of suffering from pulmonary complications, of which PCP is more common. If young pateints who were healthy in the past suddenly suffered from pneumonia and respiratory failure, PCP should be considered. When opportunistic pulmonary infections are diagnosed under special circumstances, one should be alert to the possibility of AIDS. In these cases serum HIV antibodies should be checked immediately.

[Lyme neuroborreliosis with acute meningitis as the presenting manifestation: report of a case]

To enhance the understanding of Lyme disease, a case of Lyme neuroborreliosis with acute meningitis as the presenting manifestation was reported. The diagnosis was confirmed by elevated serum antibody response to B. burgdorferi using both ELISA and Western blotting, excluding other causes of neurological abnormalities and the typical response of our patient to antibiotics. This case indicates the existence of Lyme disease in Beijing area. If the etiology of a meningitis with lymphocytic pleocytosis is not known, it is important that Lyme neuroborreliosis should be considered as one of the differential diagnoses and detection of antibody to B. burgdorferi in serum and cerebrospinal fluid performed in time. A brief review of the literature including epidemiology, clinical menifestations, diagnosis and treatment of Lyme disease was made.

[The technology of processing carbonized Cirsium japonicum and quality standards of its prepared pieces]

The technology of processing carbonized Cirsium japonicum was selected by using orthogonal experiment design. The result shows that the best way is to bake of 10 min at 220 degrees C. The contents of macro and trace elements in the prepared pieces significantly increased.

[Investigation of the genetic instability of tumor cells by transfection of RER+ cell lines with exogenous microsatellite sequence]

OBJECTIVE

Frequent alterations of microsatellite sequence of cancer cells were found recently in a substantial fraction of human cancers including hereditary non-polyposis colon cancer. This paper aimed to investigate the genetic instability of tumor cells by using microsatellite instability(MI) as the marker in vitro.

METHODS

Two RER+ cell lines (replication error phenotype), RKO and HCT116 and one RER- cell line, sw480, were used as the hosts for transfection with an episomal plasmid, pCMV-CAR, containing an exogenous (CA)14 repeat which was inserted within the coding sequence of lacZ reporter gene and thus made lacZ misreading. The transfectant clones were selected and established by hygromicin. Expression and production of lacZ reporter gene of restored reading frame were detected with X-gal staining assay.

RESULTS

After hygromicin selection, stable pCMV-CAR transfectant clones were established. It was shown that mutation of deletion of insertion within(CA)14 occurred in the transfectant RER+ cells but not in the RER-cells. The mutation restored normal reading frame of lacZ gene, and resulted in expression and production of bio-active beta galactosidase which was detected with X-gal staining. This feature of the transfectant clones was maintained during culture passages.

CONCLUSION

The alterations of the exogenous(CA)14 repeat in the transfectant RER+ clones revealed genetic instability and complicated mutation status of cancer cells. It is suggested that the exogenous (CA)14 in transfectant clones could be a useful target sequence for monitoring the effects of environmental agents on MI of human cancer cells.

Hypervascular liver metastases: do unenhanced and hepatic arterial phase CT images affect tumor detection?

PURPOSE

To evaluate the relative roles of unenhanced and hepatic arterial phase (HAP) computed tomographic (CT) imaging in the detection of hypervascular liver metastases.

MATERIALS AND METHODS

Eighty-four patients with biopsy-proved liver metastases from hypervascular primary tumors other than hepatocellular carcinoma underwent unenhanced and HAP and portal venous phase (PVP) helical CT studies. Three blinded radiologists evaluated each series of images separately for the number, size, and enhancement characteristics of lesions. Sixty-nine patients had follow-up imaging proof of tumor burden.

RESULTS

The three readers detected 381-402 lesions on the PVP images and 397-416 lesions on the unenhanced images. Unenhanced images allowed detection of 72%-80% of the lesions seen on PVP images. They detected 94-137 additional lesions on unenhanced but not PVP images. On the HAP images, 375-395 lesions were identified. HAP images allowed detection of 81%-90% of the lesions seen on PVP images. Forty-five to 78 additional lesions were detected on HAP but not on PVP images. In the 69-patient subset, maximal detection of tumor foci occurred in 94% of patients with unenhanced plus PVP images and in 78% with HAP plus PVP images. Unenhanced plus PVP images allowed detection of 96% of the 322 tumors in the subset population.

CONCLUSION

Unenhanced plus PVP CT images allow detection of statistically significantly more hypervascular liver metastases than do HAP plus PVP images or imaging only in the PVP.

[Absorption spectra study for fullerene-doped in polystyrene film]

The absorption spectra of C60 and C70-doped in polystyrene film and in solution were studied. The experiment results showed that the positions of the absorption peaks for C60-doped in polystyrene film moved a little toward longer wavelength than in n-hexane, and regular solid material appeared while the ratio of C60-doped in the film increased; The absorption peaks for C70-doped in polystyrene film were almost in consistent with that in solution. We suggest that C60 molecules may be connected as "microcrystalline" in polystyrene film, while C70 may be exist as single molecule or particle less than C60 in it. The preliminary model for the growth of "microcrystslline" in polystyrene film has been proposed.

[Hepatitis C virus infection among long-term hemodialysis patients]

We determined the prevalence and incidence of hepatitis C virus (HCV) infection among hemodialysis patients and evaluate their risk factors. 80 patients on maintenance hemodialysis in Peking Union Medical College Hospital Dialysis Center from December 1994 to June 1995 were studied. 30 medical students were used as health controls. Serum samples were tested for HCV antibodies by a second-generation enzyme-linked immunosorbent assay (ELISA) and for HCV RNA using nested polymerase chain reaction (PCR) and retested for anti-HCV and HCV RNA three months later. 24 (30%) of 80 hemodialysis patients were anti-HCV positive, and 2 (3.6%) of 56 anti-HCV negative cases were found HCV RNA positive. By combined assessment, the HCV infection rate of hemodialysis patient was 32.5% (26/80). Mantel-Haenszel analysis showed that HCV infection was associated with multi-transfusions, dialysis over a long period, renal transplantation, history of operation. Samples of dialysate in 9 serum HCV RNA positive cases were directly detected for HCV RNA, and 3 were found HCV RNA detectable. HCV infection rate in hemodialysis patients is higher than that of general population. The main risk factors for HCV transmission is transfusion of unscreened blood but is not an independent factor, hemodialysis itself plays an important role, the length of time on dialysis, renal transplantation, blood-contaminated material and contaminated dialysis equipment are also the risk factors. Infected hemodialysis patients should be isolated.

[Study on the clinical and biological characteristics of 20 cases of chronic lymphoid leukemias]

OBJECTIVE

To further define the chronic lymphoid leukemia (CLL).

METHODS

Tweenty cases of CLL classified after the FAB proposals (1989) were retrospectively analyzed.

RESULTS

Based on the clinical features, cell/tissue morphology, immunophenotype, IgH and TCR gamma gene rearrangement serum or urine immunoglobulin levels, 16 cases of B-lymphoid leukemia (12 of CLL, 1 of PLL, 2 of leukemia/lymphoma, and 1 of WM) as well as 4 cases of T-lymphoid leukemia (2 of leukemia/lymphoma, 1 of T-LGLL, and 1 of NK-LGLL) were identified. The diagnostic criteria,cell morphology,biological characteristics and prognosis for CLL were discussed.

CONCLUSION

T-leukemia/lymphoma should be incorporated in the classification of CLL.

[A prospective study on post-transfusion hepatitis C]

A cooperative prospective study on the clinical epidemiology of post-transfusion hepatitis C virus (HCV) infection was carried out from April 1993 to November 1994 in four medical schools in China, namely, Peking Union Medical College (PUMC), Western China Medical University (WCMU), Shanghai Medical University (SMU) and Beijing Medical University (BMU). A screen test on anti-HCV was done for the healthy donors of four groups. Anti-HCV positive rate was found to be 14.49% in professional blood donors, 5.60% in rural donors and 0.42% in urban volunteer donors. The positive rate of anti-HCV in blood recipients followed more than three months after transfusion was quite different in the four institutes, being 15.34% (14/91) in PUMC, 24.59% (15/61) in WCMU, 13.18% (12/91) in SMU and 1.53% (1/65) in BMU. During the same period post-transfusion hepatitis B virus infection rate decreased as compared with that in the past. It is concluded that the screen test on anti-HCV in blood donors can not completely rule out post-transfusion HCV infection.

Assessment of clinical and communication skills: operationalizing Benner's model

The introduction of ward-based clinical assessment of nursing skills in the 1970s meant a more realistic method of assessment, but still essentially a 'snapshot' of the student's practical abilities. This now being replaced by continuous clinical assessment which requires that student nurses meet the expected level of competence in a range of nursing skills in each clinical placement. Benner's (1984) model of skill acquisition is currently receiving considerable attention by nurse educationalists and is providing the framework for many curricula (English 1993). The model identifies five stages of development in nursing: novice; advanced beginner; competent; proficient; and expert. What is needed, however, is a more detailed description of what those stages mean in terms of the component parts of nursing, especially the clinical and communication skills. This paper describes a framework for the assessment of clinical and communication skills, a framework which seeks to operationalize Benner's model by defining the level of performance expected in clinical and communication skills at each stage.

Cholangiographic features of biliary strictures after liver transplantation for primary sclerosing cholangitis: evidence of recurrent disease

OBJECTIVE

Biliary strictures occur more frequently after liver transplantation for primary sclerosing cholangitis (PSC) than for other diseases. A hypothesized cause is recurrence of PSC in the liver graft. In our study, we compared cholangiographic features of biliary strictures after transplantation for PSC to those after transplantation for other diseases.

MATERIALS AND METHODS

A study group of 32 PSC grafts in adults with biliary strictures was compared with a control group of 32 non-PSC grafts with strictures. Both groups were matched for the type of biliary anastomosis (choledochojejunostomy) and for the time interval between transplantation and stricture diagnosis. We then performed a blind retrospective review of cholangiograms in these 64 cases to evaluate for features of PSC.

RESULTS

Location, number, and length of strictures and ductal dilatation were similar in the PSC and non-PSC groups. Mural irregularities of bile ducts were present in 15 of 32 (47%) PSC grafts compared with four of 32 (13%) in the control group (p=.005). Diverticulum-like outpouchings occurred in six of 32 (19%) PSC graft compared with one of 32 (3%) in the control group. An overall resemblance to PSC was observed in eight of 32 (25%) grafts in the PSC group compared with two of 32 (6%) in the control group.

CONCLUSION

Mural irregularity and diverticulum-like outpouchings--findings suggestive of PSC--and an overall appearance resembling PSC occur more frequently in PSC transplants than in transplants for other diseases. These findings are consistent with the hypothesis that PSC may recur in liver transplants.

Biliary stones and sludge in liver transplant patients: a 13-year experience

PURPOSE

To determine the prevalence, radiologic features, and clinical significance of bile duct filling defects (BDFDs) in liver transplant recipients studied with cholangiography.

MATERIALS AND METHODS

During 13 years, 4,100 cholangiograms were obtained in 1,650 patients. All studies showing BDFD suggestive of stones, sludge, cast, or necrotic debris were retrospectively evaluated.

RESULTS

The prevalence of BDFD was 5.7% (n = 94). On the basis of cholangiographic appearance, BDFDs were categorized as sludge or cast in 53 grafts (56%), stones in 32 (34%), and necrotic debris in nine (10%). Forty-three patients (46%) underwent surgical biliary reconstruction, while 14 (15%) underwent interventional radiologic treatments. Twenty-four of 32 stones (75%) were treated with surgical reconstruction, compared with 31% (19 of 62 grafts) of other BDFDs (P < .0001). Necrotic debris and sludge were associated with hepatic artery occlusion in seven of nine (78%) and 16 of 53 (30%) grafts, respectively.

CONCLUSION

Stones and sludge are relatively infrequent after liver transplantation but are associated with high morbidity. Surgical or interventional radiologic treatments are usually performed. Bile duct stones are usually treated with surgical biliary reconstruction. While debris and bile duct necrosis are due to ischemia from hepatic artery occlusion, sludge may also have an ischemic pathogenesis in some cases.

Hepatic artery stenosis in liver transplant recipients: prevalence and cholangiographic appearance of associated biliary complications

OBJECTIVE

The occurrence of biliary strictures or bile duct necrosis in liver transplant recipients with hepatic artery stenosis has been well documented. This study was done to determine the prevalence and cholangiographic appearance of biliary complications in liver transplant recipients with hepatic artery stenosis and to determine if such complications occur with increased frequency compared with transplant recipients with patent hepatic arteries.

MATERIALS AND METHODS

The study population consisted of 33 patients (17 male, 16 female; 1-65 years old) with angiographically proven significant hepatic artery stenosis after liver transplantation. All patients had T-tube or percutaneous transhepatic cholangiography performed within 4 months of hepatic arteriography. A retrospective review of radiographs was done to determine the prevalence and appearance of biliary complications in the study group compared with a control group of 58 patients with angiographically patent hepatic arteries who had liver transplants during the same period.

RESULTS

Biliary complications were significantly more prevalent in patients with hepatic artery stenosis, with 22 (67%) showing cholangiographic abnormal findings compared with 16 (28%) in the control group (p = .001). The most significant abnormalities in patients with arterial stenosis were nonanastomotic biliary strictures seen in 16 (49%), compared with 13 (22%) in the control group (p = .04). Other findings (intraductal filling defects, anastomotic biliary stricture, and anastomotic bile leak) showed no statistically significant difference between the study and control groups.

CONCLUSION

Biliary complications are significantly more prevalent in liver transplant recipients with hepatic artery stenosis. The most common complication seen on cholangiography was nonanastomotic biliary stricture.

Dissecting pseudoaneurysm of the hepatic artery: a delayed complication of angioplasty in a liver transplant

We report a 59-year-old female with a dissecting pseudoaneurysm of the allograft hepatic artery, as a delayed complication of percutaneous transluminal angioplasty (PTA). PTA of a severe anastomotic stenosis was successful, but complicated by a dissection involving the allograft hepatic artery. A large dissecting pseudoaneurysm developed and was incidentally detected during routine sonographic evaluation 14 months after PTA. Because of the extent of the pseudoaneurysm, percutaneous repair or surgical reconstruction was considered impossible. The patient underwent successful retransplantation 1 week after diagnosis.

Transhepatic balloon dilation of biliary strictures in liver transplant patients: a 10-year experience

PURPOSE

The authors report their initial and long-term results using transhepatic balloon dilation to treat biliary strictures in liver transplant patients.

PATIENTS AND METHODS

Over a 10-year period, 72 liver transplant patients with biliary strictures underwent 81 balloon dilation treatments. Anastomotic strictures were present in 56 patients; nonanastomotic strictures were present in 16.

RESULTS

Initial technical success was achieved in 64 of 72 patients (89%). Balloon dilation failed in eight patients (11%), and they were treated surgically. Complications occurred in nine (12%) patients, and all were successfully treated. Within the first 6 months, five patients (6.9%) required surgical revision. Three patients (4.2%) underwent repeated liver transplantation; and five patients (6.9%) died. Fifty-one patients in whom balloon dilation was initially successful were available for at least a 6-month follow-up. Life-table analysis showed an overall 81% +/- 4.8 success rate at 6 months; it dropped to 70% +/- 6.2 at 6 years. For anastomotic strictures, it was 77% +/- 5.8 at 6 months and 66% +/- 7.3 at 6 years. For nonanastomotic strictures, it was 94% +/- 6.2 at 6 months, which dropped to 84% +/- 10 at 5 years.

CONCLUSION

Transhepatic balloon dilation represents an effective and relatively safe treatment for biliary stricture in liver transplant recipients.

Bile leak after hepatic transplantation: cholangiographic features, prevalence, and clinical outcome

PURPOSE

To evaluate cholangiographic features and prevalence of bile duct leaks in liver transplant recipients and correlate the different types of leaks with clinical outcomes.

MATERIALS AND METHODS

For 6 years, 3,242 cholangiograms were obtained in 1,363 liver allografts in 1,306 patients. All cholangiograms with definite or suspected bile duct leaks, per the radiology reports, were retrospectively reviewed.

RESULTS

Leaks were diagnosed in 59 allografts in 59 patients. The prevalence of leaks after liver transplantation, as depicted on cholangiograms, was 4.3% (59 of 1,363 grafts). Sixteen of 21 patients with anastomotic leaks needed 17 surgical repairs, four leaks were surgically drained without repair, and one was treated with percutaneous biliary catheter drainage. Twelve of 21 patients with T-tube exit-site leaks underwent T-tube drainage. Seven underwent surgical repair or drainage, one died, and one underwent retransplantation. Nine of 13 patients with leaks from bile duct necrosis required retransplantation.

CONCLUSION

Bile duct leaks at biliary anastomoses and those resulting from bile duct necrosis have high morbidity, mortality, and graft loss rates and usually require surgical intervention. Most T-tube exit-site leaks heal with conservative treatment.

Intrahepatic biliary strictures after liver transplantation

PURPOSE

To evaluate the prevalence, cholangiographic features, causes, and management of intrahepatic biliary strictures in hepatic transplants.

MATERIALS AND METHODS

Over a 12-year period, cholangiography was performed in 1,590 liver allografts. Confirmed cases of stricture were evaluated and correlated with clinical variables.

RESULTS

Intrahepatic biliary strictures occurred in 130 of 1,590 grafts (8.2%). Strictures were multiple in 99 grafts (76.2%) and single in 31 (23.8%). Locations were the common hepatic duct bifurcation in 46 grafts (35.4%), the peripheral ducts in 44 (33.8%), and both in 40 (30.8%). Strictures caused mild to moderate bile duct dilatation in 72 grafts (55.4%), marked dilatation in 11 (8.5%), and obstruction in four (3.1%). Hepatic artery occlusion, pretransplantation primary sclerosing cholangitis, choledochojejunostomy, use of Euro-Collins organ preservation solution, cholangitis at liver biopsy, and young age were statistically significantly associated with strictures (P < .001).

CONCLUSION

Strictures have multiple causes and may be an important indicator of underlying abnormalities. They often require interventional radiologic or surgical treatment.

Percutaneous transluminal angioplasty of venous anastomotic stenoses complicating liver transplantation: intermediate-term results

PURPOSE

The authors evaluated the safety and efficacy of percutaneous transluminal angioplasty (PTA) for the treatment of venous stenoses in liver transplant recipients.

PATIENTS AND METHODS

Over a 5-year period, 15 venous stenoses were treated with PTA in 12 patients with liver transplants (seven children and five adults). PTA was performed for portal vein stenoses in five patients, inferior vena cava (IVC) stenoses (n = 6) in five patients, combined superior mesenteric vein-portal vein graft anastomosis and hepatic vein-IVC anastomosis in one patient, and combined IVC and hepatic vein-IVC anastomosis in one patient. PTA was repeated in three patients (five procedures) for recurrent IVC stenoses.

RESULTS

Initial technical and clinical success of PTA was achieved in 11 patients (92%); failure occurred in one patient (8%) with a portal vein anastomotic stenosis. No complications occurred in the immediate post-procedure period (up to 7 days). Nine patients (75%) are clinically well, with follow-up ranging from 7 to 33 months (mean, 18 months). Two of them required one or more repeated PTA procedures to maintain vessel patency. One patient required retransplantation for chronic rejection at 3 months, and another died of gastrointestinal tract bleeding from a gastric ulcer at 2 months after initially successful IVC PTA.

CONCLUSIONS

PTA is a safe procedure for the treatment of venous anastomotic stenoses in liver transplant recipients. PTA of portal vein anastomotic stenosis has favorable intermediate-term results. Repeat PTA may be necessary in some cases of IVC anastomotic stenoses to maintain vessel patency and avoid surgical revision or retransplantation.

Biliary strictures in hepatic transplants: prevalence and types in patients with primary sclerosing cholangitis vs those with other liver diseases

OBJECTIVE

The purpose of this study was to determine the prevalence and types of biliary strictures seen in liver allografts transplanted for primary sclerosing cholangitis and other end-stage liver diseases and to determine if such strictures occur more often in the allografts transplanted for primary sclerosing cholangitis than in the others.

MATERIALS AND METHODS

During a 10-year period, 643 liver transplantation patients (687 allografts) with choledochojejunostomy biliary anastomoses underwent 1728 cholangiographic studies. Three hundred six cholangiograms were obtained in 100 transplant recipients who had primary sclerosing cholangitis (112 allografts) and 1422 cholangiograms were obtained in 543 recipients who had other liver diseases (575 allografts). We retrospectively reviewed all cholangiograms of transplant recipients who had primary sclerosing cholangitis and 909 cholangiograms of the recipients who had other liver diseases and a diagnosis of biliary strictures, possible biliary strictures, or duct irregularity based on radiologic reports. The presence, number, and locations of strictures were recorded. The remaining 513 cholangiograms of recipients with other liver diseases without strictures were not reviewed. Biliary strictures were classified as intrahepatic (including bifurcation), anastomotic, and nonanastomotic extrahepatic.

RESULTS

Cholangiograms showed intrahepatic biliary strictures in 105 allografts (15%), anastomotic strictures in 105 allografts (15%), and nonanastomotic extrahepatic biliary strictures in 17 allografts (2%). Intrahepatic biliary strictures were diagnosed in 27% (30/112) of the allografts transplanted for primary sclerosing cholangitis and in 13% (75/575) of the allografts transplanted for other end-stage liver diseases (p = .0005). Anastomotic strictures developed in 18% (20/112) of the allografts transplanted for primary sclerosing cholangitis and in 15% (85/575) of the others (p = .381). Nonanastomotic extrahepatic strictures were seen in 6% (7/112) of the allografts transplanted for primary sclerosing cholangitis and in 2% (10/575) of the others (p = .008).

CONCLUSION

Intrahepatic and nonanastomotic extrahepatic biliary strictures are significantly more common in patients who have liver transplantation for primary sclerosing cholangitis than in patients who receive allografts for other end-stage liver diseases. However, strictures at the choledochojejunostomy anastomosis occur with equal frequency in both groups of patients.