Malawer type I/V proximal humerus reconstruction after tumor resection: a systematic review.

BACKGROUND: Several reconstruction methods exist for Malawer type I/V proximal humerus reconstruction after bone tumor resection; however, no consensus has been reached regarding the preferred methods. METHODS: We conducted a literature search on various types of proximal humerus oncologic reconstruction methods. We collected data on postoperative functional outcomes assessed based on Musculoskeletal Tumor Society (MSTS) scores, 5-year reconstruction survival rates, and complications. We calculated each reconstruction's weighted mean based on the sample size and standard errors. Complications were categorized based on the Henderson classification. Based on these integrated data, our primary objective is to propose an optimal strategy for proximal humerus reconstruction after bone tumor resection. RESULTS: We examined various reconstruction techniques, including modular prosthesis (752 patients in 21 articles), osteoarticular allograft (142 patients in six articles), allograft prosthesis composites (236 patients in 12 articles), reverse shoulder total arthroplasty (141 patients in 10 articles), composite reverse shoulder total arthroplasty (33 patients in four articles), claviculo-pro-humero technique (51 patients in six articles), and cement spacer (207 patients in four articles). Weighted mean MSTS scores were: modular prosthesis (73.8%), osteoarticular allograft (74.4%), allograft prosthesis composites (79.2%), reverse shoulder total arthroplasty (77.0%), composite reverse shoulder total arthroplasty (76.1%), claviculo-pro-humero technique (75.1%), and cement spacer (69.1%). Weighted 5-year reconstruction survival rates were modular prosthesis (85.4%), osteoarticular allograft (67.6%), allograft prosthesis composites (85.2%), reverse shoulder total arthroplasty (84.1%), and cement spacer (88.0%). Reconstruction survival data was unavailable for composite reverse shoulder total arthroplasty and claviculo-pro-humero technique. Major complications included shoulder joint instability: modular prosthesis (26.2%), osteoarticular allograft (41.5%), allograft prosthesis composites (33.9%), reverse shoulder total arthroplasty (17%), composite reverse shoulder total arthroplasty (6.1%), claviculo-pro-humero technique (2.0%), and cement spacer (8.7%). Aseptic loosening of the prosthesis occurred: modular prosthesis (3.9%) and reverse shoulder total arthroplasty (5.7%). Allograft fracture was observed in 54.9% of patients with osteoarticular allograft. CONCLUSION: The complication profiles differed among reconstruction methods. Weighted mean MSTS scores exceeded 70% in all methods except cement spacer, and the 5-year reconstruction survival rate surpassed 80% for all methods except osteoarticular allograft. Proximal humerus reconstruction after bone tumor resection should consider potential complications and patients' individual factors.

The dipeptide prolyl-hydroxyproline promotes cellular homeostasis and lamellipodia-driven motility via active ß1-integrin in adult tendon cells.

Collagen-derived hydroxyproline (Hyp)-containing peptides have a variety of biological effects on cells. These bioactive collagen peptides are locally generated by the degradation of endogenous collagen in response to injury. However, no comprehensive study has yet explored the functional links between Hyp-containing peptides and cellular behavior. Here, we show that the dipeptide prolyl-4-hydroxyproline (Pro-Hyp) exhibits pronounced effects on mouse tendon cells. Pro-Hyp promotes differentiation/maturation of tendon cells with modulation of lineage-specific factors and induces significant chemotactic activity in vitro. In addition, Pro-Hyp has profound effects on cell proliferation, with significantly upregulated extracellular signal-regulated kinase phosphorylation and extracellular matrix production and increased type I collagen network organization. Using proteomics, we have predicted molecular transport, cellular assembly and organization, and cellular movement as potential linked-network pathways that could be altered in response to Pro-Hyp. Mechanistically, cells treated with Pro-Hyp demonstrate increased directional persistence and significantly increased directed motility and migration velocity. They are accompanied by elongated lamellipodial protrusions with increased levels of active ß1-integrin-containing focal contacts, as well as reorganization of thicker peripheral F-actin fibrils. Pro-Hyp-mediated chemotactic activity is significantly reduced (p < 0.001) in cells treated with the mitogen-activated protein kinase kinase 1/2 inhibitor PD98059 or the α5ß1-integrin antagonist ATN-161. Furthermore, ATN-161 significantly inhibits uptake of Pro-Hyp into adult tenocytes. Thus, our findings document the molecular basis of the functional benefits of the Pro-Hyp dipeptide in cellular behavior. These dynamic properties of collagen-derived Pro-Hyp dipeptide could lead the way to its application in translational medicine.

Conditional targeting in mice reveals that hepatic homogentisate 1,2-dioxygenase activity is essential in reducing circulating homogentisic acid and for effective therapy in the genetic disease alkaptonuria.

Alkaptonuria is an inherited disease caused by homogentisate 1,2-dioxygenase (HGD) deficiency. Circulating homogentisic acid (HGA) is elevated and deposits in connective tissues as ochronotic pigment. In this study, we aimed to define developmental and adult HGD tissue expression and determine the location and amount of gene activity required to lower circulating HGA and rescue the alkaptonuria phenotype. We generated an alkaptonuria mouse model using a knockout-first design for the disruption of the HGD gene. Hgd tm1a -/- mice showed elevated HGA and ochronosis in adulthood. LacZ staining driven by the endogenous HGD promoter was localised to only liver parenchymal cells and kidney proximal tubules in adulthood, commencing at E12.5 and E15.5 respectively. Following removal of the gene trap cassette to obtain a normal mouse with a floxed 6th HGD exon, a double transgenic was then created with Mx1-Cre which conditionally deleted HGD in liver in a dose dependent manner. 20% of HGD mRNA remaining in liver did not rescue the disease, suggesting that we need more than 20% of liver HGD to correct the disease in gene therapy. Kidney HGD activity which remained intact reduced urinary HGA, most likely by increased absorption, but did not reduce plasma HGA nor did it prevent ochronosis. In addition, downstream metabolites of exogenous 13C6-HGA, were detected in heterozygous plasma, revealing that hepatocytes take up and metabolise HGA. This novel alkaptonuria mouse model demonstrated the importance of targeting liver for therapeutic intervention, supported by our observation that hepatocytes take up and metabolise HGA.

Roles of fibronectin isoforms in neonatal vascular development and matrix integrity.

Fibronectin (FN) exists in two forms-plasma FN (pFN) and cellular FN (cFN). Although the role of FN in embryonic blood vessel development is well established, its function and the contribution of individual isoforms in early postnatal vascular development are poorly understood. Here, we employed a tamoxifen-dependent cFN inducible knockout (cFN iKO) mouse model to study the consequences of postnatal cFN deletion in smooth muscle cells (SMCs), the major cell type in the vascular wall. Deletion of cFN influences collagen deposition but does not affect life span. Unexpectedly, pFN translocated to the aortic wall in the cFN iKO and in control mice, possibly rescuing the loss of cFN. Postnatal pFN deletion did not show a histological aortic phenotype. Double knockout (dKO) mice lacking both, cFN in SMCs and pFN, resulted in postnatal lethality. These data demonstrate a safeguard role of pFN in vascular stability and the dispensability of the individual FN isoforms in postnatal vascular development. Complete absence of FNs in the dKOs resulted in a disorganized tunica media of the aortic wall. Matrix analysis revealed common and differential roles of the FN isoforms in guiding the assembly/deposition of elastogenic extracellular matrix (ECM) proteins in the aortic wall. In addition, we determined with two cell culture models that that the two FN isoforms acted similarly in supporting matrix formation with a greater contribution from cFN. Together, these data show that pFN exerts a critical role in safeguarding vascular organization and health, and that the two FN isoforms function in an overlapping as well as distinct manner to maintain postnatal vascular matrix integrity.

Transcription factor scleraxis vitally contributes to progenitor lineage direction in wound healing of adult tendon in mice.

Tendon is a dense connective tissue that transmits high mechanical forces from skeletal muscle to bone. The transcription factor scleraxis (Scx) is a highly specific marker of both precursor and mature tendon cells (tenocytes). Mice lacking scx exhibit a specific and virtually complete loss of tendons during development. However, the functional contribution of Scx to wound healing in adult tendon has not yet been fully characterized. Here, using ScxGFP-tracking and loss-of-function systems, we show in an adult mouse model of Achilles tendon injury that paratenon cells, representing a stem cell antigen-1 (Sca-1)-positive and Scx-negative progenitor subpopulation, display Scx induction, migrate to the wound site, and produce extracellular matrix (ECM) to bridge the defect, whereas resident tenocytes exhibit a delayed response. Scx induction in the progenitors is initiated by transforming growth factor ß (TGF-ß) signaling. scx-deficient mice had migration of Sca-1-positive progenitor cell to the lesion site but impaired ECM assembly to bridge the defect. Mechanistically, scx-null progenitors displayed higher chondrogenic potential with up-regulation of SRY-box 9 (Sox9) coactivator PPAR-γ coactivator-1α (PGC-1α) in vitro, and knock-in analysis revealed that forced expression of full-length scx significantly inhibited Sox9 expression. Accordingly, scx-null wounds formed cartilage-like tissues that developed ectopic ossification. Our findings indicate a critical role of Scx in a progenitor-cell lineage in wound healing of adult mouse tendon. These progenitor cells could represent targets in strategies to facilitate tendon repair. We propose that this lineage-regulatory mechanism in tissue progenitors could apply to a broader set of tissues or biological systems in the body.

Molecular Mechanism Responsible for Fibronectin-controlled Alterations in Matrix Stiffness in Advanced Chronic Liver Fibrogenesis.

Fibrosis is characterized by extracellular matrix (ECM) remodeling and stiffening. However, the functional contribution of tissue stiffening to noncancer pathogenesis remains largely unknown. Fibronectin (Fn) is an ECM glycoprotein substantially expressed during tissue repair. Here we show in advanced chronic liver fibrogenesis using a mouse model lacking Fn that, unexpectedly, Fn-null livers lead to more extensive liver cirrhosis, which is accompanied by increased liver matrix stiffness and deteriorated hepatic functions. Furthermore, Fn-null livers exhibit more myofibroblast phenotypes and accumulate highly disorganized/diffuse collagenous ECM networks composed of thinner and significantly increased number of collagen fibrils during advanced chronic liver damage. Mechanistically, mutant livers show elevated local TGF-ß activity and lysyl oxidase expressions. A significant amount of active lysyl oxidase is released in Fn-null hepatic stellate cells in response to TGF-ß1 through canonical and noncanonical Smad such as PI3 kinase-mediated pathways. TGF-ß1-induced collagen fibril stiffness in Fn-null hepatic stellate cells is significantly higher compared with wild-type cells. Inhibition of lysyl oxidase significantly reduces collagen fibril stiffness, and treatment of Fn recovers collagen fibril stiffness to wild-type levels. Thus, our findings indicate an indispensable role for Fn in chronic liver fibrosis/cirrhosis in negatively regulating TGF-ß bioavailability, which in turn modulates ECM remodeling and stiffening and consequently preserves adult organ functions. Furthermore, this regulatory mechanism by Fn could be translated for a potential therapeutic target in a broader variety of chronic fibrotic diseases.

A thyroid hormone receptor/KLF9 axis in human hepatocytes and pluripotent stem cells.

Biological processes require close cooperation of multiple transcription factors that integrate different signals. Thyroid hormone receptors (TRs) induce Krüppel-like factor 9 (KLF9) to regulate neurogenesis. Here, we show that triiodothyronine (T3) also works through TR to induce KLF9 in HepG2 liver cells, mouse liver, and mouse and human primary hepatocytes and sought to understand TR/KLF9 network function in the hepatocyte lineage and stem cells. Knockdown experiments reveal that KLF9 regulates hundreds of HepG2 target genes and modulates T3 response. Together, T3 and KLF9 target genes influence pathways implicated in stem cell self-renewal and differentiation, including Notch signaling, and we verify that T3 and KLF9 cooperate to regulate key Notch pathway genes and work independently to regulate others. T3 also induces KLF9 in human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSC) and this effect persists during differentiation to definitive endoderm and hiPSC-derived hepatocytes. Microarray analysis reveals that T3 regulates hundreds of hESC and hiPSC target genes that cluster into many of the same pathways implicated in TR and KLF9 regulation in HepG2 cells. KLF9 knockdown confirms that TR and KLF9 cooperate to regulate Notch pathway genes in hESC and hiPSC, albeit in a partly cell-specific manner. Broader analysis of T3 responsive hESC/hiPSC genes suggests that TRs regulate multiple early steps in ESC differentiation. We propose that TRs cooperate with KLF9 to regulate hepatocyte proliferation and differentiation and early stages of organogenesis and that TRs exert widespread and important influences on ESC biology.

Transforming growth factor-ß-independent role of connective tissue growth factor in the development of liver fibrosis.

We previously identified transforming growth factor (TGF)-ß signaling as a fibronectin-independent mechanism of type I collagen fibrillogenesis following adult liver injury. To address the contribution of TGF-ß signaling during the development of liver fibrosis, we generated adult mice lacking TGF-ß type II receptor (TGF-ßIIR) from the liver. TGF-ßIIR knockout livers indeed showed a dominant effect in reducing fibrosis, but fibrosis still remained approximately 45% compared with control and fibronectin knockout livers. Unexpectedly, this was accompanied by significant up-regulation of connective tissue growth factor mRNA levels. Organized type I collagen networks in TGF-ßIIR knockout livers colocalized well with fibronectin. We provide evidence that elimination of TGF-ßIIR is not sufficient to completely prevent liver fibrosis. Our results indicate a TGF-ß-independent mechanism of type I collagen production and suggest connective tissue growth factor as its potent mediator. We advocate combined elimination of TGF-ß signaling and connective tissue growth factor as a potential therapeutic target by which to attenuate liver fibrosis.

Keratin 5-Cre-driven excision of nonmuscle myosin IIA in early embryo trophectoderm leads to placenta defects and embryonic lethality.

In studies initially focused on roles of nonmuscle myosin IIA (NMIIA) in the developing mouse epidermis, we have discovered that a previously described cytokeratin 5 (K5)-Cre gene construct is expressed in early embryo development. Mice carrying floxed alleles of the nonmuscle myosin II heavy chain gene (NMHC IIA(flox/flox)) were crossed with the K5-Cre line. The progeny of newborn pups did not show a Mendelian genotype distribution, suggesting embryonic lethality. Analysis of post-implantation conceptuses from embryonic day (E)9.5 to E13.5 revealed poorly developed embryos and defective placentas, with significantly reduced labyrinth surface area and blood vessel vascularization. These results suggested the novel possibility that the bovine K5 promoter-driven Cre-recombinase was active early in trophoblast-lineage cells that give rise to the placenta. To test this possibility, K5-Cre transgenic mice were crossed with the mT/mG reporter mouse in which activation of GFP expression indicates Cre transgene expression. We observed activation of K5-Cre-driven GFP expression in the ectoplacental cone, in the extraembryonic ectoderm, and in trophoblast giant cells in the E6.5 embryo. In addition, we observed GFP expression at E11.5 to E13.5 in both the labyrinth of the placenta and the yolk sac. NMIIA expression was detected in these same cell types in normal embryos, as well as in E13.5 yolk sac and labyrinth. These findings taken together suggest that NMHC IIA may play critical roles in the early trophoblast-derived ectoplacental cone and extraembryonic ectoderm, as well as in the yolk sac and labyrinth tissues that form later. Our findings are consistent with phenotypes of constitutive NMIIA knockout mice made earlier, that displayed labyrinth and yolk sac-specific defects, but our findings extend those observations by suggesting possible NMIIA roles in trophoblast lineages as well. These results furthermore demonstrate that K5-Cre gene constructs, previously reported to be activated starting at approximately E12.5 in the forming epidermis, may be widely useful as drivers for activation of cre/lox based gene excision in early embryo extraembronic trophoblast tissues as well.

Thrombospondin-1 is a novel negative regulator of liver regeneration after partial hepatectomy through transforming growth factor-beta1 activation in mice.

UNLABELLED: The matricellular protein, thrombospondin-1 (TSP-1), is prominently expressed during tissue repair. TSP-1 binds to matrix components, proteases, cytokines, and growth factors and activates intracellular signals through its multiple domains. TSP-1 converts latent transforming growth factor-beta1 (TGF-ß1) complexes into their biologically active form. TGF-ß plays significant roles in cell-cycle regulation, modulation of differentiation, and induction of apoptosis. Although TGF-ß1 is a major inhibitor of proliferation in cultured hepatocytes, the functional requirement of TGF-ß1 during liver regeneration remains to be defined in vivo. We generated a TSP-1-deficient mouse model of a partial hepatectomy (PH) and explored TSP-1 induction, progression of liver regeneration, and TGF-ß-mediated signaling during the repair process after hepatectomy. We show here that TSP-1-mediated TGF-ß1 activation plays an important role in suppressing hepatocyte proliferation. TSP-1 expression was induced in endothelial cells (ECs) as an immediate early gene in response to PH. TSP-1 deficiency resulted in significantly reduced TGF-ß/Smad signaling and accelerated hepatocyte proliferation through down-regulation of p21 protein expression. TSP-1 induced in ECs by reactive oxygen species (ROS) modulated TGF-ß/Smad signaling and proliferation in hepatocytes in vitro, suggesting that the immediately and transiently produced ROS in the regenerating liver were the responsible factor for TSP-1 induction. CONCLUSIONS: We have identified TSP-1 as an inhibitory element in regulating liver regeneration by TGF-ß1 activation. Our work defines TSP-1 as a novel immediate early gene that could be a potential therapeutic target to accelerate liver regeneration.

Fibronectin is essential for survival but is dispensable for proliferation of hepatocytes in acute liver injury in mice.

UNLABELLED: Acute liver injury causes massive hepatocyte apoptosis and/or fatal liver damage. Fibronectin, an extracellular matrix glycoprotein, is prominently expressed during adult tissue repair. However, the extent of fibronectin dependence on hepatocyte response to acute liver damage remains to be defined. Because identification of hepatic survival factors is critical for successful therapeutic intervention in liver failure, this relationship has been investigated using a fibronectin-deficient mouse model of acute liver injury. Here, we show that lack of fibronectin induces significantly increased hepatocyte apoptosis, which is accompanied by significant down-regulation of the antiapoptotic protein, B-cell lymphoma-extra large (Bcl-xL). Furthermore, fibronectin deficiency leads to a significantly elevated production of hepatocyte growth factor in hepatic stellate cells postinjury, which, in turn, results in an earlier onset and acceleration of hepatocyte regeneration. Primary hepatocytes on fibronectin are protected from reactive oxygen species-induced cellular damage, retaining the expression of Bcl-xL, whereas those on type I collagen are not. This retained expression of Bcl-xL is inhibited by the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. CONCLUSION: We provide evidence that fibronectin-mediated matrix survival signals for hepatocytes are transduced through the PI3K/Bcl-xL-signaling axis in response to injury. This work defines fibronectin as a novel antiapoptotic factor for hepatocytes after acute liver injury, but demonstrates that fibronectin is not essential for subsequent hepatocyte proliferation.

Outcomes of Window Therapy with Carboplatin and Ifosfamide for Pediatric Osteosarcoma: A Case Series.

For the treatment of osteosarcoma, cisplatin (CDDP) can be substituted by carboplatin (CBDCA) to reduce toxicity. We report a single institution experience of CBDCA-based regimen. Two to three cycles of CBDCA + ifosfamide (IFO) therapy (window therapy) were administered as neoadjuvant therapy for osteosarcoma. Depending on the response of window therapy, the subsequent protocols were determined; for good responders, surgery is performed, and postoperative therapies with CBDCA + IFO, adriamycin (ADM) and high-dose methotrexate (MTX) were administered; for stable disease, the postoperative regimens were advanced before surgery, and the remaining amount of postoperative chemotherapy is deduced; for progressive disease, CBDCA-based regimen is changed to CDDP-based regimen. From 2009 to 2019, seven patients were treated with this protocol. During the window therapy, two patients (28.6%) were assessed as good responders and completed the regimen as planned. Four patients (57.1%) had stable disease, and the chemotherapy schedules were modified. One patient (14.2%) with progressive disease was shifted to the CDDP-based regimen. At final follow-up, four patients showed no evidence of disease and three patients died of the disease. Since the efficacy during window therapy was limited, a CBDCA-based regimen in the neoadjuvant setting was considered insufficient for performing adequate surgery.

Pericellular fibronectin is required for RhoA-dependent responses to cyclic strain in fibroblasts.

To test the hypothesis that the pericellular fibronectin matrix is involved in mechanotransduction, we compared the response of normal and fibronectin-deficient mouse fibroblasts to cyclic substrate strain. Normal fibroblasts seeded on vitronectin in fibronectin-depleted medium deposited their own fibronectin matrix. In cultures exposed to cyclic strain, RhoA was activated, actin-stress fibers became more prominent, MAL/MKL1 shuttled to the nucleus, and mRNA encoding tenascin-C was induced. By contrast, these RhoA-dependent responses to cyclic strain were suppressed in fibronectin knockdown or knockout fibroblasts grown under identical conditions. On vitronectin substrate, fibronectin-deficient cells lacked fibrillar adhesions containing alpha5 integrin. However, when fibronectin-deficient fibroblasts were plated on exogenous fibronectin, their defects in adhesions and mechanotransduction were restored. Studies with fragments indicated that both the RGD-synergy site and the adjacent heparin-binding region of fibronectin were required for full activity in mechanotransduction, but not its ability to self-assemble. In contrast to RhoA-mediated responses, activation of Erk1/2 and PKB/Akt by cyclic strain was not affected in fibronectin-deficient cells. Our results indicate that pericellular fibronectin secreted by normal fibroblasts is a necessary component of the strain-sensing machinery. Supporting this hypothesis, induction of cellular tenascin-C by cyclic strain was suppressed by addition of exogenous tenascin-C, which interferes with fibronectin-mediated cell spreading.

Defective granulation tissue formation in mice with specific ablation of integrin-linked kinase in fibroblasts - role of TGFß1 levels and RhoA activity.

Wound healing crucially relies on the mechanical activity of fibroblasts responding to TGFß1 and to forces transmitted across focal adhesions. Integrin-linked kinase (ILK) is a central adapter recruited to integrin ß1 tails in focal adhesions mediating the communication between cells and extracellular matrix. Here, we show that fibroblast-restricted inactivation of ILK in mice leads to impaired healing due to a severe reduction in the number of myofibroblasts, whereas inflammatory infiltrate and vascularization of the granulation tissue are unaffected. Primary ILK-deficient fibroblasts exhibit severely reduced levels of extracellular TGFß1, α-smooth muscle actin (αSMA) production and myofibroblast conversion, which are rescued by exogenous TGFß1. They are further characterized by elevated RhoA and low Rac1 activities, resulting in abnormal shape and reduced directional migration. Interference with RhoA-ROCK signaling largely restores morphology, migration and TGFß1 levels. We conclude that, in fibroblasts, ILK is crucial for limiting RhoA activity, thus promoting TGFß1 production, which is essential for dermal repair following injury.

A fibronectin-independent mechanism of collagen fibrillogenesis in adult liver remodeling.

BACKGROUND & AIMS: Fibrosis is an abnormal extension of the wound healing process that follows tissue damage; it is involved in pathogenesis in a variety of chronic diseases. The formation of extracellular matrix is an essential response in wound healing. Although it has been proposed that collagen organization and assembly depend on the fibronectin matrix in culture, the contribution of fibronectin to these processes remains to be defined in vivo. METHODS: We generated a conditional, fibronectin-deficient mouse model of liver injury and explored whether fibronectin would be a suitable target for preventing extensive collagen deposits and scar formation that could lead to liver fibrosis. RESULTS: The lack of fibronectin did not interfere with reconstruction of collagen fibril organization in response to liver injury. Signaling by transforming growth factor-ß and type V collagen were required for collagen fibrillogenesis during remodeling of adult liver tissue. CONCLUSIONS: Transforming growth factor-ß and type V collagen are targets for regulating the initial fibrogenic response to liver damage.

Critical role of factor XIII in the initial stages of carbon tetrachloride-induced adult liver remodeling.

The transglutaminase-mediated, covalent cross-linking of proteins is an essential step in tissue remodeling after injury. This process provides tissues with extra rigidity and resistance against proteolytic degradation. Plasma coagulation factor XIII (FXIII) is a transglutaminase that promotes cross-linking of the extracellular matrix (ECM) components fibrin and fibronectin to form a provisional matrix in response to tissue damage. However, the functional requirement for this FXIII-mediated cross-linked provisional matrix in adult tissue remodeling remains to be defined. Although it has been proposed that the formation FXIII-mediated fibrin-fibronectin provisional matrix is a critical step for ECM remodeling, we show in an FXIII subunit A-deficient murine model of acute liver injury that the lack of FXIII subunit A did not interfere with collagen reconstruction and resolution after liver injury. Furthermore, FXIIIA deficiency caused significantly increased hepatocyte apoptosis and a delay in hepatocyte regeneration after injury, which were accompanied by a significantly high induction of p53 expression. These findings suggest novel functions of FXIII that the FXIII-mediated covalently cross-linked matrix could promote survival signals for hepatocytes in adult tissue remodeling.

Integrin-linked kinase is required for epidermal and hair follicle morphogenesis.

Integrin-linked kinase (ILK) links integrins to the actin cytoskeleton and is believed to phosphorylate several target proteins. We report that a keratinocyte-restricted deletion of the ILK gene leads to epidermal defects and hair loss. ILK-deficient epidermal keratinocytes exhibited a pronounced integrin-mediated adhesion defect leading to epidermal detachment and blister formation, disruption of the epidermal-dermal basement membrane, and the translocation of proliferating, integrin-expressing keratinocytes to suprabasal epidermal cell layers. The mutant hair follicles were capable of producing hair shaft and inner root sheath cells and contained stem cells and generated proliferating progenitor cells, which were impaired in their downward migration and hence accumulated in the outer root sheath and failed to replenish the hair matrix. In vitro studies with primary ILK-deficient keratinocytes attributed the migration defect to a reduced migration velocity and an impaired stabilization of the leading-edge lamellipodia, which compromised directional and persistent migration. We conclude that ILK plays important roles for epidermis and hair follicle morphogenesis by modulating integrin-mediated adhesion, actin reorganization, and plasma membrane dynamics in keratinocytes.

Bone Metastases from Gastric Cancer Resembling Paget's Disease: A Case Report.

Systemic osteosclerotic lesions are frequently caused by multiple bone metastases or systemic metabolic disorders. However, bone metastasis from gastric cancer is rare. Herein, we describe such a case, with radiographic and clinical findings resembling Paget's disease. The patient was an 80-year-old Japanese woman with a history of early gastric cancer, treated by partial gastrectomy 2 years prior. The patient sought medical care for chronic low back pain. On imaging, systemic sclerotic lesions were observed throughout the spine and pelvis, with an increase in bone mineral density from 0.86 g/cm3 (2 years prior) to 1.38g/cm3 (current visit) in the lumbar spine. Elevated serum levels of osteoblastic and osteolytic markers were identified. A bone biopsy was used to confirm the diagnosis of metastatic gastric cancer. The patient was treated with TS-1 and denosumab, with normalization of abnormal metabolic markers and alleviation of the back pain. Bone metastasis is reported in only 10% of cases of gastric cancer and, thus, is relatively rare. Therefore, our case of gastric cancer recurrence presenting with mixed osteoblastic and osteolytic bone lesions similar to Paget's disease is relevant to the report. Bone biopsy is necessary for an accurate diagnosis.

Animal models for the study of liver fibrosis: new insights from knockout mouse models.

Fibrosis arises as part of a would-healing response that maintains organ structure and integrity following tissue damage but also contributes to a variety of human pathologies such as liver fibrosis. Liver fibrosis is an abnormal response of the liver to persistent injury with the excessive accumulation of collagenous extracellular matrices. Currently there is no effective treatment, and many patients end up with a progressive form of the disease, eventually requiring a liver transplant. The clarification of mechanisms underlying pathogenesis of liver fibrosis and the development of effective therapy are of clinical importance. Experimental animal models, in particular targeted gene knockouts (loss of function) in mice, have become a powerful resource to address the molecular mechanisms or significance of the targeted gene in hepatic functions and diseases. This review will focus on the recent advances in knowledge obtained from genetically engineered mice that provide novel insights into the pathophysiology of liver fibrosis.

Musculoskeletal diseases--tendon.

INTRODUCTION: Tendons establish specific connections between muscles and the skeleton by transferring contraction forces from skeletal muscle to bone thereby allowing body movement. Tendon physiology and pathology are heavily dependent on mechanical stimuli. Tendon injuries clinically represent a serious and still unresolved problem since damaged tendon tissues heal very slowly and no surgical treatment can restore a damaged tendon to its normal structural integrity and mechanical strength. Understanding how mechanical stimuli regulate tendon tissue homeostasis and regeneration will improve the treatment of adult tendon injuries that still pose a great challenge in today's medicine. SOURCE OF DATA: This review summarizes the current status of tendon treatment and discusses new directions from the point of view of cell-based therapy and regenerative medicine approach. We searched the available literature using PubMed for relevant original articles and reviews. GROWING POINTS: Identification of tendon cell markers has enabled us to study precisely tendon healing and homeostasis. Clinically, tissue engineering for tendon injuries is an emerging technology comprising elements from the fields of cellular source, scaffold materials, growth factors/cytokines and gene delivering systems. AREAS TIMELY FOR DEVELOPING RESEARCH: The clinical settings to establish appropriate microenvironment for injured tendons with the combination of these novel cellular- and molecular-based scaffolds will be critical for the treatment.