Prognostic implications of preoperative, postoperative, and dynamic changes of alpha-fetoprotein and des-gamma (γ)-carboxy prothrombin expression pattern for hepatocellular carcinoma after hepatic resection: a multicenter observational study.

Background: The utility of pre- and post-operative alpha-fetoprotein (AFP) and des-gamma (γ)-carboxy prothrombin (DCP) expression patterns and their dynamic changes as predictors of the outcome of hepatic resection for hepatocellular carcinoma (HCC) has yet to be well elucidated. Methods: From a multicenter database, AFP and DCP data during the week prior to surgery and the first post-discharge outpatient visit (within 1-2 months after surgery) were collected from patients with HCC who underwent hepatectomy. AFP-DCP expression patterns were categorized according to the number of positive tumor markers (AFP ≥ 20ng/mL, DCP ≥ 40mAU/mL), including double-negative, single-positive, and double-positive. Changes in the AFP-DCP expression patterns were delineated based on variations in the number of positive tumor markers when comparing pre- and post-operative patterns. Results: Preoperatively, 53 patients (8.3%), 337 patients (52.8%), and 248 patients (38.9%) exhibited double-negative, single-positive, and double-positive AFP-DCP expression patterns, respectively. Postoperatively, 463 patients (72.6%), 130 patients (20.4%), and 45 patients (7.0%) showed double-negative, single-positive, and double-positive AFP-DCP expression patterns, respectively. Survival analysis showed a progressive decrease in recurrence-free (RFS) and overall survival (OS) as the number of postoperative positive tumor markers increased (both P < 0.001). Multivariate analysis showed that postoperative AFP-DCP expression pattern, but not preoperative AFP-DCP expression pattern, was an independent risk factor for RFS and OS. Further analysis showed that for patients with positive preoperative markers, prognosis gradually improves as positive markers decrease postoperatively. In particular, when all postoperative markers turned negative, the prognosis was consistent with that of preoperative double-negative patients, regardless of the initial number of positive markers. Conclusions: AFP-DCP expression patterns, particularly postoperative patterns, serve as vital sources of information for prognostic evaluation following hepatectomy for HCC. Moreover, changes in AFP-DCP expression patterns from pre- to post-operation enable dynamic prognostic risk stratification postoperatively, aiding the development of individualized follow-up strategies.

Association of Pringle maneuver with postoperative recurrence and survival following hepatectomy for hepatocellular carcinoma: a multicenter propensity score and competing-risks regression analysis.

Background: The application of Pringle maneuver (PM) during hepatectomy reduces intraoperative blood loss and the need for perioperative transfusion, but its effect on long-term recurrence and survival for patients with hepatocellular carcinoma (HCC) remains controversial. We sought to determine the association between the application of PM and post-hepatectomy oncologic outcomes for patients with HCC. Methods: Patients who underwent curative hepatectomy for HCC at 9 Chinese hospitals from January 2010 to December 2018 were identified. Using two propensity score methods [propensity score matching (PSM) and inverse probability of treatment weight (IPTW)], cumulative recurrence rate and cancer-specific mortality (CSM) were compared between the patients in the PM and non-PM groups. Multivariate competing-risks regression models were performed to adjust for the effect of non-cancer-specific mortality and other prognostic risk factors. Results: Of the 2,798 included patients, 2,404 and 394 did and did not adopt PM (the PM and non-PM groups), respectively. The rates of intraoperative blood transfusion, postoperative 30-day mortality and morbidity were comparable between the two groups (all P>0.05). In the PSM cohort by the 1:3 ratio, compared to 382 patients in the non-PM group, 1,146 patients in the PM group also had the higher cumulative 5-year recurrence rate and CSM (63.9% and 39.1% vs. 55.3% and 31.6%, both P<0.05). Similar results were also yielded in the entire cohort and the IPTW cohort. Multivariate competing-risks regression analyses demonstrated that no application of the PM was independently associated with lower recurrence rate and CSM based on various analytical cohorts [hazard ratio (HR), 0.82 and 0.77 in the adjusted entire cohort, HR 0.80 and 0.73 in the PSM cohort, and HR 0.80 and 0.76 in the IPTW cohort, respectively]. Conclusions: The findings suggested that no application of PM during hepatectomy for patients with HCC reduced the risk of postoperative recurrence and cancer-specific death by approximately 20-25%.

Serum alpha-fetoprotein response as a preoperative prognostic indicator in unresectable hepatocellular carcinoma with salvage hepatectomy following conversion therapy: a multicenter retrospective study.

Background: This study evaluates the efficacy of alpha-fetoprotein (AFP) response as a surrogate marker for determining recurrence-free survival (RFS) in patients with unresectable hepatocellular carcinoma (uHCC) who undergo salvage hepatectomy following conversion therapy with tyrosine kinase inhibitor (TKI) and anti-PD-1 antibody-based regimen. Methods: This multicenter retrospective study included 74 patients with uHCC and positive AFP (>20 ng/mL) at diagnosis, who underwent salvage hepatectomy after treatment with TKIs and anti-PD-1 antibody-based regimens. The association between AFP response-defined as a ≥ 80% decrease in final AFP levels before salvage hepatectomy from diagnosis-and RFS post-hepatectomy was investigated. Results: AFP responders demonstrated significantly better postoperative RFS compared to non-responders (P<0.001). The median RFS was not reached for AFP responders, with 1-year and 2-year RFS rates of 81.3% and 70.8%, respectively. In contrast, AFP non-responders had a median RFS of 7.43 months, with 1-year and 2-year RFS rates at 37.1% and 37.1%, respectively. Multivariate Cox regression analysis identified AFP response as an independent predictor of RFS. Integrating AFP response with radiologic tumor response facilitated further stratification of patients into distinct risk categories: those with radiologic remission experienced the most favorable RFS, followed by patients with partial response/stable disease and AFP response, and the least favorable RFS among patients with partial response/stable disease but without AFP response. Sensitivity analyses further confirmed the association between AFP response and improved RFS across various cutoff values and in patients with AFP ≥ 200 ng/mL at diagnosis (all P<0.05). Conclusion: The "20-80" rule based on AFP response could be helpful for clinicians to preoperatively stratify the risk of patients undergoing salvage hepatectomy, enabling identification and management of those unlikely to benefit from this procedure.

STING Agonist-Loaded Nanoparticles Promotes Positive Regulation of Type I Interferon-Dependent Radioimmunotherapy in Rectal Cancer.

Hypoxia-associated radioresistance in rectal cancer (RC) has severely hampered the response to radioimmunotherapy (iRT), necessitating innovative strategies to enhance RC radiosensitivity and improve iRT efficacy. Here, a catalytic radiosensitizer, DMPtNPS, and a STING agonist, cGAMP, are integrated to overcome RC radioresistance and enhance iRT. DMPtNPS promotes efficient X-ray energy transfer to generate reactive oxygen species, while alleviating hypoxia within tumors, thereby increasing radiosensitivity. Mechanistically, the transcriptomic and immunoassay analysis reveal that the combination of DMPtNPS and RT provokes bidirectional regulatory effects on the immune response, which may potentially reduce the antitumor efficacy. To mitigate this, cGAMP is loaded into DMPtNPS to reverse the negative impact of DMPtNPS and RT on the tumor immune microenvironment (TiME) through the type I interferon-dependent pathway, which promotes cancer immunotherapy. In a bilateral tumor model, the combination treatment of RT, DMPtNPS@cGAMP, and αPD-1 demonstrates a durable complete response at the primary site and enhanced abscopal effect at the distant site. This study highlights the critical role of incorporating catalytic radiosensitizers and STING agonists into the iRT approach for RC.

Prognostic implications of alpha-fetoprotein and C-reactive protein elevation in hepatocellular carcinoma following resection (PACE): a large cohort study of 2770 patients.

BACKGROUND: Routine clinical staging for hepatocellular carcinoma (HCC) incorporates liver function, general health, and tumor morphology. Further refinement of prognostic assessments and treatment decisions may benefit from the inclusion of tumor biological marker alpha-fetoprotein (AFP) and systemic inflammation indicator C-reactive protein (CRP). METHODS: Data from a multicenter cohort of 2770 HCC patients undergoing hepatectomy were analyzed. We developed the PACE risk score (Prognostic implications of AFP and CRP Elevation) after initially assessing preoperative AFP and CRP's prognostic value. Subgroup analyzes were performed in BCLC cohorts A and B using multivariable Cox analysis to evaluate the prognostic stratification ability of the PACE risk score and its complementary utility for BCLC staging. RESULTS: Preoperative AFP ≥ 400ng/mL and CRP ≥ 10 mg/L emerged as independent predictors of poorer prognosis in HCC patients who underwent hepatectomy, leading to the creation of the PACE risk score. PACE risk score stratified patients into low, intermediate, and high-risk groups with cumulative 5-year overall (OS) and recurrence-free survival (RFS) rates of 59.6%/44.9%, 43.9%/38.4%, and 20.6%/18.0% respectively (all P < 0.001). Increased PACE risk scores correlated significantly with early recurrence and extrahepatic metastases frequency (all P < 0.001). The multivariable analysis identified intermediate and high-risk PACE scores as independently correlating with poor postoperative OS and RFS. Furthermore, the PACE risk score proficiently stratified the prognosis of BCLC stages A and B patients, with multivariable analyses demonstrating it as an independent prognostic determinant for both stages. CONCLUSION: The PACE risk score serves as an effective tool for postoperative risk stratification, potentially supplementing the BCLC staging system.

Systemic delivery of glycosylated-PEG-masked oncolytic virus enhances targeting of antitumor immuno-virotherapy and modulates T and NK cell infiltration.

Rationale: Immuno-virotherapy has emerged as a promising approach for cancer treatment, as it directly and cytotoxically eliminates tumors with systemic immune stimulation. However, the clinical efficacy of this approach remains limited by inappropriate delivery routes, robust antiviral responses, and the tumor immunosuppressive microenvironment. Methods: To address these challenges, we propose a surface engineering strategy that masks oncolytic herpes simplex virus (oHSV) with a galactose-polyethylene-glycol (PEG) polymer chain to minimize host antiviral responses and selectively targets tumors by limiting exposure to circulation upon systemic administration. We evaluated the antitumor efficacy of glycosylated-PEG-oHSV by examining tumor growth in animal models and analyzing tumor-infiltrating CD8+T cells and NK cells in the tumor microenvironment (TME). To assess the neutralizing antibody levels after systemic administration of glycosylated-PEG-oHSV, we utilized a mouse model and measured oHSV-specific IgG. Results: We demonstrate that the glycosylated-PEG modified oHSV does not affect the replication of oHSV yet exhibits high specificity to the asialoglycoprotein receptor (ASGPR) overexpressed in hepatocellular carcinoma cells. This results in selectively targeting cancer cells and deep penetration into tumors while avoiding spreading into the brain. Our approach also effectively reduces oHSV-specific neutralizing antibody levels to mitigate host antiviral immune response. Notably, our glycosylated-PEG-oHSV alleviates the immunosuppressive microenvironment within tumors by reducing regulatory T cells, augmenting the infiltration of activated CD8+T cells and NK cells with increasing release of anti-tumor cytokines, to impede tumor progression. Conclusion: Our findings offer a widely applicable and universal strategy to enhance cancer immuno-virotherapy through systemic administration of non-genetically engineered oncolytic viruses. This approach has the potential to overcome the limitations of current immune-virotherapy strategies and may improve clinical outcomes for cancer patients.

Association of hepatitis B virus DNA levels with efficacy and safety outcomes in patients with hepatitis B virus-associated advanced hepatocellular carcinoma receiving tyrosine kinase inhibitor plus anti-PD-1 antibody: a multicenter propensity-matched study.

BACKGROUND: The efficacy and safety of tyrosine kinase inhibitors (TKIs) combined with anti-PD-1 antibodies (α-PD-1) in advanced hepatocellular carcinoma (HCC) with high hepatitis B virus (HBV) DNA levels (>500 IU/mL) remain unclear. METHODS: We retrospectively assessed patients from seven medical institutions diagnosed with HBV-related HCC, undergoing treatment with TKIs and α-PD-1 in conjunction with antiviral therapies. Based on HBV-DNA levels, patients were categorized into either high (HHBV-DNA, >500 IU/mL) or low HBV-DNA (LHBV-DNA, ≤500 IU/mL) cohorts Propensity score matching (PSM) was used to minimize baseline imbalance between groups. RESULTS: 149 patients were included, with 66 patients exhibiting HBV-DNA > 500 IU/mL and 83 patients presenting HBV-DNA ≤ 500 IU/mL. Compared with the LHBV-DNA cohort, the HHBV-DNA cohort had a greater incidence of serum HBeAg positivity, tumor diameter ≥ 10 cm, and vascular invasion. Following PSM, 57 individuals were enrolled in each group. Oncological outcomes were comparable between HHBV-DNA and LHBV-DNA cohorts before and after PSM. Before PSM, the median PFS and OS were 6.1 months and 17.5 months in the HHBV-DNA cohort and 6.7 months and 19.3 months in the LHBV-DNA cohort (all P > 0.05). After PSM, the median PFS and OS were 6.0 months and 19.5 months in the HHBV-DNA cohort and 6.0 months and 17.1 months in the LHBV-DNA cohort, respectively (all P > 0.05). Safety profiles were equivalent across cohorts with no fatal incidents reported. Seven patients (4.7 %) had HBV reactivation. 1 (0.7 %) from HHBV-DNA and 6 (4.0 %) from LHBV-DNA (P = 0.134). Only one patient developed HBV-related hepatitis. CONCLUSIONS: The effectiveness and safety of TKIs plus α-PD-1 in advanced HCC with HBV-DNA > 500 IU/mL were not compromised in the context of concomitant antiviral therapy.

Caveolin-mediated cytosolic delivery of spike nanoparticle enhances antitumor immunity of neoantigen vaccine for hepatocellular carcinoma.

Rationale: Although neoantigen-based cancer vaccines have shown promise in various solid tumors, limited immune responses and clinical outcomes have been reported in patients with advanced disease. Cytosolic transport of neoantigen and adjuvant is required for the activation of intracellular Toll-like receptors (TLRs) and cross-presentation to prime neoantigen-specific CD8+T cells but remains a significant challenge. Methods: In this study, we aimed to develop a virus-like silicon vaccine (V-scVLPs) with a unique spike topological structure, capable of efficiently co-delivering a hepatocellular carcinoma (HCC)-specific neoantigen and a TLR9 agonist to dendritic cells (DCs) to induce a robust CD8+T cell response to prevent orthotopic tumor growth. We evaluated the antitumor efficacy of V-scVLPs by examining tumor growth and survival time in animal models, as well as analyzing tumor-infiltrating CD8+T cells and cytokine responses in the tumor microenvironment (TME). To evaluate the synergistic efficacy of V-scVLPs in combination with α-TIM-3 in HCC, we used an orthotopic HCC mouse model, a lung metastasis model, and a tumor rechallenge model after hepatectomy. Results: We found that V-scVLPs can efficiently co-deliver the hepatocellular carcinoma (HCC)-specific neoantigen and the TLR9 agonist to DCs via caveolin-mediated endocytosis. This advanced delivery strategy results in efficient lymph node draining of V-scVLPs to activate lymphoid DC maturation for promoting robust CD8+T cells and central memory T cells responses, which effectively prevents orthotopic HCC tumor growth. However, in the established orthotopic liver tumor models, the inhibitory receptor of TIM-3 was significantly upregulated in tumor-infiltrating CD8+T cells after immunization with V-scVLPs. Blocking the TIM-3 signaling further restored the antitumor activity of V-scVLPs-induced CD8+T cells, reduced the proportion of regulatory T cells, and increased the levels of cytokines to alter the tumor microenvironment to efficiently suppress established orthotopic HCC tumor growth, and inhibit lung metastasis as well as recurrence after hepatectomy. Conclusion: Overall, the developed novel spike nanoparticles with efficient neoantigen and adjuvant intracellular delivery capability holds great promise for future clinical translation to improve HCC immunotherapy.

Perioperative safety, oncologic outcome, and risk factors of salvage liver resection for initially unresectable hepatocellular carcinoma converted by transarterial chemoembolization plus tyrosine kinase inhibitor and anti-PD-1 antibody: a retrospective multicenter study of 83 patients.

BACKGROUND: To assess the perioperative safety, oncological outcomes, and determinants influencing the oncological outcomes of salvage liver resection for initially unresectable hepatocellular carcinoma (HCC) rendered resectable through transarterial chemoembolization (TACE) combined with tyrosine kinase inhibitors (TKIs) and anti-PD-1 antibodies (α-PD-1). METHODS: We retrospectively reviewed data from 83 consecutive patients across six tertiary hospitals who underwent salvage liver resection for initially unresectable HCC following conversion by TACE combined with TKIs and α-PD-1, emphasizing perioperative and oncological outcomes. Multivariate Cox regression analysis was employed to discern independent risk factors for postoperative recurrence-free survival (RFS). RESULTS: The median operative duration was 200 min, with a median blood loss of 400 ml. Intraoperative blood transfusions were necessitated for 27 patients. The overall perioperative complication rate was 48.2%, with a major complication rate of 16.9%. One patient died during the perioperative period due to postoperative liver failure. During the median follow-up period of 15.1 months, 24 patients experienced recurrence, with early and intrahepatic recurrence being the most common. Seven patients died during follow-up. Median RFS was 25.4 months, with 1- and 2-year RFS rates of 68.2% and 61.8%, respectively. Median overall survival was not reached, with 1- and 2-year overall survival rates of 92.2% and 87.3%, respectively. Multivariate Cox regression analysis revealed that pathological complete response (pCR) and intraoperative blood transfusion served as independent prognostic determinants for postoperative RFS. CONCLUSIONS: Our study provides preliminary evidence suggesting that salvage liver resection may be an effective and feasible treatment option for patients with unresectable HCC who achieve resectability after conversion therapy with TACE, TKIs, and α-PD-1. The perioperative safety of salvage liver resection for these patients was manageable and acceptable. However, further research, particularly prospective comparative studies, is needed to better evaluate the potential benefits of salvage liver resection in this patient population.

Association of primary tumor location with long-term oncological prognosis following hepatectomy for hepatocellular carcinoma:A multicenter propensity score matching analysis.

PURPOSE: There is a striking laterality in the site of hepatocellular carcinoma (HCC), with a strong predominance for the right side; however, the impact of primary tumor location on long-term prognosis after hepatectomy of HCC remains unclear. This study aimed to investigate the effect of primary tumor location on long-term oncological prognosis after hepatectomy for HCC. PATIENTS AND METHODS: Data of consecutive patients undergoing curative hepatectomy for HCC between 2008 and 2017 were analyzed. Overall survival (OS) and recurrence-free survival (RFS) of left-sided HCC (LS group) and right-sided HCC (RS group) were compared by using propensity score matching (PSM) analysis. COX regression analysis was performed to assess the adjusted effect of tumor location on long-term oncological prognosis. RESULTS: Of the 2799 included patients, 707 (25.3%) and 2092 (74.7%) were in the LS and RS groups, respectively. Using PSM analysis, 650 matched pairs of patients were created. In the PSM cohort, median OS (66.0 vs. 72.0 months, P = 0.001) and RFS (28.0 vs. 51.0 months, P < 0.001) were worse among patients in the LS group compared to individuals in the RS group. After further adjustment for other confounders using multivariable COX regression analyses, HCC located on the left side remained independently associated with worse OS and RFS. CONCLUSION: Tumors located on the left side are associated with poorer OS and RFS after hepatectomy for HCC. Careful surgical options selection and frequent follow-up to improve long-term survival may be justified for HCC patients with left-sided primary tumors.

DEPTOR exacerbates bone-fat imbalance in osteoporosis by transcriptionally modulating BMSC differentiation.

Bone marrow-derived mesenchymal stem cells (BMSCs) tend to differentiate into adipocytes rather than osteoblasts in osteoporosis and other pathological conditions. Understanding the mechanisms underlying the adipo-osteogenic imbalance greatly contributes to the ability to induce specific MSC differentiation for clinical applications. This study aimed to explore whether DEP-domain containing mTOR-interacting protein (DEPTOR) regulated MSC fate and bone-fat switch, which was indicated to be a key player in bone homeostasis. We found that DEPTOR expression decreased during the osteogenesis of BMSCs but increased during adipogenesis and the shift of cell lineage commitment of BMSCs to adipocytes in mice with osteoporosis. DEPTOR facilitated adipogenic differentiation while preventing the osteogenic differentiation of BMSCs. Deptor ablation in BMSCs alleviated bone loss and reduced marrow fat accumulation in mice with osteoporosis. Mechanistically, DEPTOR binds transcriptional coactivator with a PDZ-binding motif (TAZ) and inhibits its transactivation properties, thereby repressing the transcriptional activity of RUNX2 and elevating gene transcription by peroxisome-proliferator-activated receptor-gamma. TAZ knockdown in BMSCs abolished the beneficial role of Deptor ablation in bone-fat balance in mice. Together, our data indicate that DEPTOR is a molecular rheostat that modulates BMSC differentiation and bone-fat balance, and may represent a potential therapeutic target for age-related bone loss.

mTORC1 induces plasma membrane depolarization and promotes preosteoblast senescence by regulating the sodium channel Scn1a.

Senescence impairs preosteoblast expansion and differentiation into functional osteoblasts, blunts their responses to bone formation-stimulating factors and stimulates their secretion of osteoclast-activating factors. Due to these adverse effects, preosteoblast senescence is a crucial target for the treatment of age-related bone loss; however, the underlying mechanism remains unclear. We found that mTORC1 accelerated preosteoblast senescence in vitro and in a mouse model. Mechanistically, mTORC1 induced a change in the membrane potential from polarization to depolarization, thus promoting cell senescence by increasing Ca2+ influx and activating downstream NFAT/ATF3/p53 signaling. We further identified the sodium channel Scn1a as a mediator of membrane depolarization in senescent preosteoblasts. Scn1a expression was found to be positively regulated by mTORC1 upstream of C/EBPα, whereas its permeability to Na+ was found to be gated by protein kinase A (PKA)-induced phosphorylation. Prosenescent stresses increased the permeability of Scn1a to Na+ by suppressing PKA activity and induced depolarization in preosteoblasts. Together, our findings identify a novel pathway involving mTORC1, Scn1a expression and gating, plasma membrane depolarization, increased Ca2+ influx and NFAT/ATF3/p53 signaling in the regulation of preosteoblast senescence. Pharmaceutical studies of the related pathways and agents might lead to novel potential treatments for age-related bone loss.

Postoperative Adjuvant Transarterial Chemoembolization Plus Tyrosine Kinase Inhibitor for Hepatocellular Carcinoma: a Multicentre Retrospective Study.

Purpose: This study aimed to assess the efficacy and safety of adjuvant transarterial chemoembolization (TACE) plus tyrosine kinase inhibitor (TKI) treatment in patients with hepatocellular carcinoma (HCC) with a high risk of early recurrence after curative resection. Patients and Methods: Patients from multiple centres were divided into postoperative adjuvant TACE with (n=57) or without (n=142) TKI administration groups. The disease-free survival (DFS) curve was depicted by the Kaplan-Meier method, and the difference between the two groups was tested using the log rank test. Univariate and multivariate Cox analyses were performed to identify independent risk factors for DFS. Additionally, three propensity score analyses were performed to minimise the potential confounding factors to facilitate a more reliable conclusion. Adverse events (AEs) were assessed according to the Common Terminology Criteria for Adverse Events, version 4.0. Results: The 1-and 2-year DFS rates of the TACE plus TKI treatment group were 45.5% and 34.9%, respectively, which were significantly better than those of the TACE alone group (26.8% and 18.3%, respectively). Multivariate analysis identified adjuvant TACE plus TKI treatment as an independent prognostic factor for DFS (hazard ratio: 0.611, 95% confidence interval: 0.408-0.915, P=0.017). Further analysis based on the various propensity score methods yielded similar results. Subgroup analysis showed that patients with tumour diameter ≥5 cm, tumour number <3, absence of hepatic vein tumour thrombus and bile duct tumour thrombus, ruptured tumours, and stage IIIB could benefit more from TACE plus TKI treatment (all P<0.05). Some patients (33.33%) experienced grade ≥3 AEs in the TACE plus TKI group. Conclusion: TACE plus TKI treatment can reduce the incidence of early recurrence with tolerable adverse events in HCC patients at high risk of recurrence after hepatectomy and may be an appropriate option in postoperative anti-recurrence treatment.

Skin chronological aging drives age-related bone loss via secretion of cystatin-A.

Although clinical evidence has indicated an association between skin atrophy and bone loss during aging, their causal relationship and the underlying mechanisms are unknown. Here we show that premature skin aging drives bone loss in mice. We further identify that cystatin-A (Csta), a keratinocyte-enriched secreted factor, mediates the effect of skin on bone. Keratinocyte-derived Csta binds the receptor for activated C-kinase 1 in osteoblast and osteoclast progenitors, thus promoting their proliferation but inhibiting osteoclast differentiation. Csta secretion decreases with skin aging in both mice and humans, thereby causing senile osteoporosis by differentially decreasing the numbers of osteoblasts and osteoclasts. In contrast, topical application of calcipotriol stimulates Csta production in the epidermis and alleviates osteoporosis. These results reveal a mode of endocrine regulation of bone metabolism in the skin, and identify Csta as an epidermally derived hormone linking skin aging to age-related bone loss. Enhancers of skin Csta levels could serve as a potential topical drug for treatment of senile osteoporosis.

Increased Osteoblastic Cxcl9 Contributes to the Uncoupled Bone Formation and Resorption in Postmenopausal Osteoporosis.

INTRODUCTION: Estrogen deficiency leads to bone loss in postmenopausal osteoporosis, because bone formation, albeit enhanced, fails to keep pace with the stimulated osteoclastic bone resorption. The mechanism driving this uncoupling is central to the pathogenesis of postmenopausal osteoporosis, which, however, remains poorly understood. We previously found that Cxcl9 secreted by osteoblasts inhibited osteogenesis in bone, while the roles of Cxcl9 on osteoclastic bone resorption and osteoporosis are unclear. MATERIALS AND METHODS: Postmenopausal osteoporosis mouse model was established by bilateral surgical ovariectomy (OVX). In situ hybridization was performed to detect Cxcl9 mRNA expression in bone. ELISA assay was conducted to assess Cxcl9 concentrations in bone and serum. Cxcl9 activity was blocked by its neutralizing antibody. Micro-CT was performed to determine the effects of Cxcl9 neutralization on bone structure. Cell Migration and adhesion assay were conducted to evaluate the effects of Cxcl9 on osteoclast activity. TRAP staining and Western blot were performed to assess osteoclast differentiation. CXCR3 antagonist NBI-74,330 or ERK antagonist SCH772984 was administered to osteoclast to study the effects of Cxcl9 on CXCR3/ERK signaling. RESULTS: Cxcl9 was expressed and secreted increasingly in OVX mice bone. Neutralizing Cxcl9 in bone marrow prevented bone loss in the mice by facilitating bone formation as well as inhibiting bone resorption. In vitro, Cxcl9 secreted from osteoblasts facilitated osteoclast precursors adhesion, migration and their differentiation into mature osteoclasts. The positive role of osteoblastic Cxcl9 on osteoclasts was eliminated by blocking CXCR3/ERK signaling in osteoclasts. Estrogen negatively regulated Cxcl9 expression and secretion in osteoblasts, explaining the increased Cxcl9 concentration in OVX mice bone. CONCLUSION: Our study illustrates the roles of Cxcl9 in inhibiting bone formation and stimulating bone resorption in osteoporotic bone, therefore providing a possible therapeutic target to the treatment of postmenopausal osteoporosis.