A photoelectrochemical aptasensor for omethoate determination based on a photocatalysis of CeO2@MnO2 heterojunction for glucose oxidation.

In the present work, we developed a photoelectrochemical aptasensor to determine omethoate (OMT) based on the dual signal amplification of CeO2@MnO2 photocatalysis for glucose oxidation and exonuclease I-assisted cyclic catalytic hydrolysis. CeO2@MnO2 heterojunction material prepared by hydrothermal method was linked with captured DNA (cDNA) and then assembled on the ITO conductive glass to form ITO/CeO2@MnO2-cDNA, which exhibited significant photocurrent response and good photocatalytic performance for glucose oxidation under visible light irradiation, providing the feasibility for sensitive determining OMT. After binding with the aptamer of OMT (apt), the formation of rigid double stranded cDNA/apt kept CeO2@MnO2 away from ITO surface, which ensured a low photocurrent background for the constructed ITO/CeO2@MnO2-cDNA/apt aptasensor. In the presence of target OMT, the restoration of the cDNA hairpin structure and the exonuclease I-assisted cyclic catalytic hydrolysis led to the generation and amplification of measurement photocurrent signals, and allowed the aptasensor to have an ideal quantitative range of 0.01-10.0 nM and low detection limit of 0.0027 nM. Moreover, the aptasensor has been applied for selective determination of OMT in real samples with good precision of the relative standard deviation less than 6.2 % and good accuracy of the recoveries from 93 % to 108 %. What's more, the aptasensor can be used for other target determination only by replacing the captured DNA and corresponding aptamer.

A colorimetric aptasensor for CA125 determination based on dual catalytic performance of CeO2 nanozyme confined in macroporous silica foam.

A portable colorimetric aptasensor was constructed based on the dual catalytic performance of CeO2 nanozyme to determine carbohydrate antigen 125 (CA125). Firstly, CeO2 nanozyme was synthesized by calcination and ultrasonically dispersed in a macroporous silica foam (MSF) to form CeO2@MSF. Then the aptamer of CA125 (apt) and complementary DNA (c-DNA) were successively assembled on the CeO2@MSF to construct a CeO2@MSF/apt/c-DNA colorimetric aptasensor, which exhibited excellent oxidase-mimic performance and phosphatase-mimic activity simultaneously. In the presence of CA125, the apt specifically binds to target CA125, and the single-strand c-DNA leaves the CeO2@MSF/apt surface, which is catalytically hydrolyzed by exonuclease I. The produced phosphate ions inhibit the phosphatase-mimic activity of CeO2 nanozyme. Thus, the absorbance at 652 nm of 3,3',5,5'-tetramethylbenzidine solution containing ascorbic acid-2-phosphate increases with the concentration of CA125. The response is linearly related to the logarithm of CA125 concentration from 1.0 to 10.0 U/mL under optimal experimental conditions. Based on this, the constructed colorimetric aptasensor has a high sensitivity, good selectivity, and high accuracy for CA125 determination in real human serum sample.

[Research Advances on Strategies to Promote Homing and Engraftment of Hematopoietic Stem Cells--Review].

The homing and engraftment of hematopoietic stem cells (HSC) into bone marrow is the first critical step for successful clinical hematopoietic stem cell transplantation (HSCT). SDF-1 / CXCR4 is considered to be a very promising target to promote HSC homing. In recent years, with the in-depth research on the HSC homing, a variety of new strategies for promoting HSC homing and engraftment have been explored, such as nuclear hormone receptor, histone deacetylase inhibitor, prostaglandin and metabolic regulation, so as to increase the success rate of HSCT and improve the survival of patients. In this review, the recent research advances in the mechanism of HSC homing and strategies to promote HSC homing and engraftment were summarized and discussed.

[Advances in the Treatment of Glucocorticoid Resistance and Relapsed Immune Thrombocytopenia --Review].

Immune thrombocytopenia (ITP) is an immune-mediated acquired hemorrhagic autoimmune disease. At present, the first-line therapeutic drugs for ITP include glucocorticoids and intravenous immunoglobulins. However, about 1/3 of the patients had no response to the first-line treatment, or relapsed after dose reduction or withdrawal of glucocorticoids. In recent years, with the gradual deepening of the understanding on the pathogenesis of ITP, the drugs targeting different pathogenesis continually emerge, including immunomodulators, demethylating agents, spleen tyrosine kinase (SYK) inhibitors and neonatal Fc receptor (FcRn) antagonist. However, most of these drugs are in clinical trials. This review summarized briefly the recent advances in the treatment of glucocorticoids resistance and relapsed ITP, so as to provide reference for the clinical treatments.

The RNA m6A Reader YTHDF1 Is Required for Acute Myeloid Leukemia Progression.

N6-methyladenosine (m6A), the most abundant modification in mRNAs, has been defined as a crucial modulator in the progression of acute myelogenous leukemia (AML). Identification of the key regulators of m6A modifications in AML could provide further insights into AML biology and uncover more effective therapeutic strategies for patients with AML. Here, we report overexpression of YTHDF1, an m6A reader protein, in human AML samples at the protein level with enrichment in leukemia stem cells (LSC). Whereas YTHDF1 was dispensable for normal hematopoiesis in mice, depletion of YTHDF1 attenuated self-renewal, proliferation, and leukemic capacity of primary human and mouse AML cells in vitro and in vivo. Mechanistically, YTHDF1 promoted the translation of cyclin E2 in an m6A-dependent manner. Structure-based virtual screening of FDA-approved drugs identified tegaserod as a potential YTHDF1 inhibitor. Tegaserod blocked the direct binding of YTHDF1 with m6A-modified mRNAs and inhibited YTHDF1-regulated cyclin E2 translation. Moreover, tegaserod reduced the viability of patient-derived AML cells in vitro and prolonged survival in patient-derived xenograft models. Together, our study defines YTHDF1 as an integral regulator of AML progression by regulating the expression of m6A-modified mRNAs, which might serve as a potential therapeutic target for AML. SIGNIFICANCE: The m6A reader YTHDF1 is required for progression of acute myelogenous leukemia and can be targeted with the FDA-approved drug tegaserod to suppress leukemia growth.

Confined catalysis of MOF-818 nanozyme and colorimetric aptasensing for cardiac troponin I.

Understanding the catalytic performance of nanozymes assembled in confined environment is an interesting topic. Herein, a three-dimensional nanozyme-catalytic nanoreactor was constructed by confining MOF-818 nanozyme in the pore of macroporous tungsten trioxide (p-WO3). The catalytic activity of MOF-818 assembled in-situ for the oxidation of 3,5-Di-tert-butylcatechol (3,5-DTBC) could be regulated by changing the pore size of p-WO3. Only when being confined in the pores of p-WO3 with an appropriate pore size, MOF-818 could exhibit high affinity towards 3,5-DTBC, and excellent catalytic activity for 3,5-DTBC oxidation, the catalytic rate constant kcat and Michaelis constant Km were determined to be 31.47 s-1 and 1.42 mM, respectively, and the maximum yield of 3,5-DTBC oxidation reached 95.2%. Furthermore, the as-constructed nanozyme-catalytic nanoreactor could be designed to construct a colorimetric aptasensor for selective determining cardiac troponin I based on the enzymatic inhibition effect and the exonuclease I-assisted target recycling signal amplification, which exhibited a good linear range of 50 fg mL-1 - 100 ng mL-1, low detection limit of 18 fg mL-1, and was applied for human serum analysis with RSD less than 5.2% and the recoveries ranged from 95% to 107%.

Identification and validation of a prognostic risk-scoring model for AML based on m7G-associated gene clustering.

Background: Acute myeloid leukemia (AML) patients still suffer from poor 5-year survival and relapse after remission. A better prognostic assessment tool is urgently needed. New evidence demonstrates that 7-methylguanosine (m7G) methylation modifications play an important role in AML, however, the exact role of m7G-related genes in the prognosis of AML remains unclear. Methods: The study obtained AML expression profiles and clinical information from TCGA, GEO, and TARGET databases. Using the patient data from the TCGA cohort as the training set. Consensus clustering was performed based on 29 m7G-related genes. Survival analysis was performed by KM curves. The subgroup characteristic gene sets were screened using WGCNA. And tumor immune infiltration correlation analysis was performed by ssGSEA. Results: The patients were classified into 3 groups based on m7G-related genebased cluster analysis, and the differential genes were screened by differential analysis and WGCNA. After LASSO regression analysis, 6 characteristic genes (including CBR1, CCDC102A, LGALS1, RD3L, SLC29A2, and TWIST1) were screened, and a prognostic risk-score model was constructed. The survival rate of low-risk patients was significantly higher than that of high-risk patients (p < 0.0001). The area under the curve values at 1, 3, and 5 years in the training set were 0.871, 0.874, and 0.951, respectively, indicating that this predictive model has an excellent predictive effect. In addition, after univariate and multivariate Cox regression screening, histograms were constructed with clinical characteristics and prognostic risk score models to better predict individual survival. Further analysis showed that the prognostic risk score model was associated with immune cell infiltration. Conclusion: These findings suggest that the scoring model and essential risk genes could provide potential prognostic biomarkers for patients with acute myeloid leukemia.

Abnormal immune function of MDSC and NK cells from chronic phase CML patients restores with tyrosine kinase inhibitors.

BACKGROUND: Myeloid-derived suppressor cell (MDSC) -mediated immune suppression, and natural killer (NK) and/or T cell-mediated immune responses play important roles in Chronic myeloid leukemia (CML). However, detailed regulation mechanisms of these immune cells in CML have not been fully elucidated. METHODS: The proportion of MDSCs and effector NK cells in newly diagnosed CML patients, patients during TKI treatment, and healthy donors (HD) were detected using flow cytometry. Serum levels and mRNA expression of Arg1 and iNOS in newly diagnosed CML patients, patients during TKI treatment, and HD were measured by ELISA and qPCR, respectively. Effect of CML serum or peripheral blood mononuclear cells (PBMCs) on HD derived CD3+ T cell proliferation was evaluated by CFSE-labeled HD CD3+ T cells co-cultured with PBMCs and serum from CML patients. Effect of CML serum on NK cells killing activity was evaluated via detecting apoptosis of K562 cells. RESULTS: Proportion of Gr-MDSCs and the serum levels of Arg1 and iNOS were significantly increased in patients at diagnosis, and reduced following TKI treatment. However, the proportion of effector NK cells were decreased in patients at diagnosis, and increased following TKI treatment. Serum and PBMC from CML patients suppressed HD derived T cell proliferation in vitro. Additionally, serum from CML patients enhanced HD derived NK cell killing activity in vitro, while the addition of Arg1 inhibitor to CML serum suppressed this phenomenon. CONCLUSIONS: Gr-MDSCs and effector NK cells play an important role in the pathogenesis of CML, inhibiting the function of MDSC and restoring the function of NK cells is expected to be a therapeutic strategy for CML.

Genome editing using CRISPR/Cas9 to treat hereditary hematological disorders.

The clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) system is a versatile and convenient genome-editing tool with prospects in gene therapy. This technique is based on customized site-specific nucleases with programmable guiding RNAs that cleave and introduce double-strand breaks (DSBs) at the target locus and achieve precise genome modification by triggering DNA repair mechanisms. Human hematopoietic stem/progenitor cells (HSPCs) are conventional cell targets for gene therapy in hematological diseases and have been widely used in most studies. Induced pluripotent stem cells (iPSCs) can be generated from a variety of somatic cells and hold great promise for personalized cell-based therapies. CRISPR/Cas9-mediated genome editing in autologous HSPCs and iPSCs is an ideal therapeutic solution for treating hereditary hematological disorders. Here, we review and summarize the latest studies about CRISPR/Cas9-mediated genome editing in patient-derived HSPCs and iPSCs to treat hereditary hematological disorders. Current challenges and prospects are also discussed.

The Protective Effect of Dexmedetomidine Against Ischemia-Reperfusion Injury after Hepatectomy: A Meta-Analysis of Randomized Controlled Trials.

Background: Hepatic inflow occlusion proceeded to reduce blood loss during hepatectomy induces ischemia-reperfusion (IR) injury in the remnant liver. Dexmedetomidine, a selective α2-adrenoceptor agonist used as an anesthetic adjuvant, has been shown to attenuate IR injury in preclinical and clinical studies. However, a meta-analysis is needed to systematically evaluate the protective effect of perioperative dexmedetomidine use on IR injury induced by hepatectomy. Methods: A prospectively registered meta-analysis following Cochrane and PRISMA guidelines concerning perioperative dexmedetomidine use on IR injury after hepatectomy was performed via searching Cochrane Library, PubMed, EMBASE, ClinicalTrials.gov, Web of Science, CNKI, WanFang, and Sinomed for eligible randomized controlled trials up to 2021.3.31. The main outcome is postoperative liver function. Risk of bias was assessed by the Cochrane Risk of Bias tool. Review Manager 5.3 and Stata12.0 were applied to perform data analyses. Results: Eight RCTs enrolling 468 participants were included. Compared with 0.9% sodium chloride, dexmedetomidine decreased serum concentration of ALT (WMD = -66.54, 95% CI: -92.10--40.98), AST (WMD= -82.96, 95% CI: -106.74--59.17), TBIL (WMD = -4.51, 95% CI: -7.32--1.71), MDA (WMD = -3.09, 95% CI: -5.17--1.01), TNF-α (WMD = -36.54, 95% CI: -61.33--11.95) and IL-6 (WMD = -165.05, 95% CI: -225.76--104.34), increased SOD activity (WMD = 24.70, 95% CI: 18.09-31.30) within postoperative one day. There was no significant difference in intraoperative or postoperative recovery parameters between groups. Conclusions: Perioperative administration of dexmedetomidine can exert a protective effect on liver IR injury after hepatectomy. Additional studies are needed to further evaluate postoperative recovery outcomes of dexmedetomidine with different dosing regimens.

[Research Advances on Ex Vivo Expansion Strategy of Hematopoietic Stem Cells--Review].

Abstract　　Hematopoietic stem cells (HSCs), as a kind of adult stem cell, is first used in clinical practice. It has been widely used in hematopoietic stem cell transplantation and has broad application prospects in the field of gene therapy. However, the shortage of HSC is still the main bottleneck restricting the clinical application of HSC transplantation, especially cord blood HSC transplantation. With the continuous improvement of the concept of HSC and the in-depth study of the molecular mechanism regulating HSC self-renewal and differentiation, it have been explored that a variety of strategies for ex vivo expansion of HSC, such as adding small molecule compounds in vitro culture system, simulating bone marrow microenvironment, regulating HSC metabolism and biomaterial-based amplification methods. In this review, recent advances in research of ex vivo expansion strategy of HSC are summarized and discussed.

UM171 promotes expansion of autologous peripheral blood hematopoietic stem cells from poorly mobilizing lymphoma patients.

BACKGROUND: Autologous hematopoietic stem cell transplantation is an effective therapeutic strategy for lymphoma patients. However, some patients have to give up receiving transplantation because of failing to obtain sufficient CD34+ cells yields. Therefore, we ex vivo expanded HSCs of lymphoma patients using UM171 to solve the problem of HSCs deficiency. METHODS: Mobilized peripheral blood-derived CD34+ cells from lymphoma patients were cultured for 10 days with or without UM171. The fold of cell expansion and the immunophenotype of expanded cells were assessed by flow cytometry. RNA-seq experiment was performed to identify the mechanism by which UM171 promoted HSCs expansion. RESULTS: UM171 treatment increased the proportion of CD34+ (68.97 ± 6.91%), CD34+ CD38- cells (44.10 ± 9.20%) and CD34+CD38-CD45RA-CD90+ LT-HSCs (3.05 ± 2.08%) compared to vehicle treatment (36.08 ± 11.14%, 18.30 ± 9.49% and 0.56 ± 0.45%, respectively). UM171 treatment led to an 85.08-fold increase in LT-HSC numbers relative to initial cells. Importantly, UM171 promoted expansion of LT-HSCs achieved 138.57-fold in patients with poor mobilization. RNA-seq data showed that UM171 upregulated expression of HSC-, mast cell-specific genes and non-canonical Wnt signaling related genes, and inhibited genes expression of erythroid, megakaryocyte and inflammatory mediated chemokine. CONCLUSIONS: Our study shows that UM171 can efficiently promote ex vivo expansion of HSCs from lymphoma patients, especially for poorly mobilizing patients. In terms of mechanism, UM171 upregulate HSC-specific genes expression and suppress erythroid and megakaryocytic differentiation, as well as activate non-classical Wnt signaling.

Cellular immune dysregulation in the pathogenesis of immune thrombocytopenia.

: Immune thrombocytopenia (ITP) is an acquired autoimmune hemorrhagic disease characterized by immune-mediated increased platelet destruction and decreased platelet production, resulting from immune intolerance to autoantigen. The pathogenesis of ITP remains unclear, although dysfunction of T and B lymphocytes has been shown to be involved in the pathogenesis of ITP. More recently, it is found that dendritic cells, natural killer, and myeloid-derived suppressor cells also play an important role in ITP. Elucidating its pathogenesis is expected to provide novel channels for the targeted therapy of ITP. This article will review the role of different immune cells in ITP.

An ion release controlled Cr(VI) treatment agent: Nano zero-valent iron/carbon/alginate composite gel.

A simple iron/carbon composite was prepared by ion exchange and carbothermal reduction, and the characterization results showed that this material contained a large amount of nanoscale zero-valent iron. Then above material was coated with alginate to form a stable gel, which combined adsorption and reduction to remove Cr(VI) efficiently and controllably. The experiment showed that the optimal conditions for Cr(VI) removal were pH value, dosage and Cr(VI) concentration of 2, 2 g L-1 and 20 mg L-1, respectively. For 150 mL of 20 mg L-1 Cr(VI) solution, the removal efficiency could reach 100% in 6 h (dosage: 2 g L-1). Compared with activated carbon-alginate complex and pure alginate, the introduction of nanoscale zero-valent iron greatly accelerated the rate of Cr(VI) removal. In addition, adsorption isotherm and kinetics conformed to Freundlich and Elovich model, respectively. Under pH 2, the release of iron ion increased linearly with time and reached 51.87 mg L-1 in 8 h. The mechanism of Cr(VI) removal of iron/carbon composite coated with alginate might be controlled by two steps: the initial adsorption and fixation, and subsequent reduction. In general, the material is efficient, recyclable and controllable, which provides a new idea for the treatment of chromium-containing wastewater.

Efficient removal of aqueous hexavalent chromium by activated carbon derived from Bermuda grass.

In this study, a novel raw material, Bermuda grass had been devised for the synthesis of activated carbon (BGAC) and enhanced the pore volume by potassium hydroxide. The effects of different factors on activated carbon products by orthogonal experiment was optimized. The synthesized BGAC was characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis, energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS) and then, Cr(VI) removal batch experiments were conducted to investigate the Cr(VI) removal performance. Kinetic model and Weber-Morris diffusion model were fitted to the Cr(VI) removal process indicated that the chemisorption was the predominant removal mechanism and intraparticle diffusion was the sole rate-controlling mechanism. Langmuir isotherms could fit the experimental date well, which revealed that the adsorption of Cr(VI) ions was monolayer adsorption and the maximum adsorption capacity could be reached at 403.23 mg g-1. The results also promulgated that BGAC had an excellent potential on Cr(VI) removal. The removal processes were considered to comprise adsorption, reduction, precipitation and other ways through the study of the removal mechanism.

Thalidomide induce response in patients with corticosteroid-resistant or relapsed ITP by upregulating Neuropilin-1 expression.

BACKGROUND: Immune thrombocytopenia (ITP) is an immune-mediated acquired autoimmune hemorrhagic disease. About one-third of patients are unresponsive to first-line therapies. Thalidomide (THD) as an immunomodulatory agent is now used to treat several autoimmune disorders. Therefore, we assessed the safety and efficacy of THD in corticosteroid-resistant or relapsed ITP patients, and preliminarily explore its mechanism. METHODS: 50 newly-diagnosed ITP patients and 47 healthy volunteers were enrolled in this study. Additionally, 17 corticosteroid-resistant or relapsed ITP patients were recruited, with 7 cases in the rhTPO + THD group and 10 cases in the THD monotherapy group. Overall response rate at 6, 12, and 24 months were assessed. Levels of Neuropilin-1(NRP-1), regulatory T cells (Tregs) and regulatory B cells (Bregs) were detected. RESULTS: Expression of NRP-1, Tregs and Bregs were reduced in newly-diagnosed ITP patients. In vitro, THD treatment upregulated expression of NRP-1and Tregs only in ITP patients. As for corticosteroid-resistant or relapsed ITP patients, overall response rate at 6, 12, and 24 months was 85.7%, 57.1% and 100% in the rhTPO + THD group and 60%, 75% and 83.3% in the THD group, respectively. Additionally, rhTPO plus THD or THD therapy significantly increased the levels of NRP-1, Tregs and Bregs in responders. CONCLUSIONS: Our study shows for the first time that NRP-1 is involved in the pathogenesis of ITP, THD could induce response in ITP patients by upregulating NRP-1 expression and restoring the proportion of Tregs and Bregs. THD might be served as a novel therapeutic agent in corticosteroid-resistant or relapsed ITP patients.

Recipient-Derived Allo-iTregs Induced by Donor DCs Effectively Inhibit the Proliferation of Donor T Cells and Reduce GVHD.

To compare the potency of recipient-derived, antigen-specific regulatory T cells induced by different dendritic cells (DCs; iTregs) and freshly isolated natural regulatory T cells (nTregs) in preventing mouse graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation (BMT). CD4+ T cells from recipient BALB/c mice were stimulated with DCs from recipient BALB/c (syn-DCs), donor B6 (allo-DCs), and third-party C3H (third-party-DCs) mice to induce different iTregs. In parallel, nTregs were isolated from spleen cells of recipient BALB/c (syn-nTregs) and donor B6 (allo-nTregs) mice using magnetic-activated cell sorting. Mixed lymphocyte reaction (MLR) assays were performed to evaluate the suppressive ability of these various regulatory T cells (Tregs). Both the iTregs and nTregs were transfused to GVHD mice on Days 0, 1, 3, and 5. Body weight, GVHD score, and survival time were monitored. Peripheral Tregs were subsequently examined on Days 7, 14, 21, and 28 after BMT, while chimerism was evaluated on Days 14 and 60. Histopathology of colon, liver, and spleen were also performed. DCs markedly induced CD25+ and Foxp3+ expression on CD4+ T cells. The allo-DC-induced Tregs (allo-iTregs) suppressed the proliferation of alloreactive T cells better than the other iTregs/nTregs in MLR assays (P < 0.05). Meanwhile, transfusion of the allo-iTregs reduced the severity of GVHD (P < 0.05), increased survival time compared with the GVHD group (P < 0.05), and enhanced the chimerism proportion. On Day 28 after BMT, the allo-iTregs group had the highest frequency of peripheral Tregs (P < 0.05). Recipient-derived allo-iTregs induced by donor DCs included predominant clones that specifically recognized donor antigens. These allo-iTregs not only prevented GVHD by suppressing the proliferation of donor-alloreactive T cells, but also promoted engraftment, and prolonged the survival of GVHD mice. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc. Anat Rec, 302:825-836, 2019. © 2018 Wiley Periodicals, Inc.

The Neuropilin-1 Ligand, Sema3A, Acts as a Tumor Suppressor in the Pathogenesis of Acute Leukemia.

Semaphorin-3A (Sema3A) and vascular endothelial growth factor (VEGF165) are ligands of neuropilin-1 (NRP-1 or CD304) and are related to immunoregulation and tumor angiogenesis, respectively. However, possible interactions between NRP-1 and Sema3A and VEGF165 in acute leukemia remain unclear, especially whether Sema3A plays a role in acute leukemia. In this study, both of the proportion of regulatory T cells (Tregs) and their expression of NRP-1 were found to increase in acute leukemia patients compared with healthy controls. In contrast, lower mRNA and plasma levels of Sema3A were detected in the acute leukemia patients. In vitro, the addition of exogenous Sema3A inhibited the expression of NRP-1 on Tregs and it promoted apoptosis of leukemia cells. However, in the presence of anti-Sema3A antibody, the effect of rhSema3A on NRP-1 expression was reversed. These results suggest that Sema3A promotes apoptosis in leukemia cells by inhibiting expression of NRP-1, and thus, represents a tumor suppressor protein with a role in the pathogenesis of acute leukemia. Consequently, NRP-1/Sema3A signaling may represent a novel target for the treatment of acute leukemia and should be further studied. Anat Rec, 302:1127-1135, 2019. © 2018 Wiley Periodicals, Inc.

Preparation and in vivo pharmacokinetics of rhGH-loaded PLGA microspheres.

Recombinant human growth hormone (rhGH) therapy must be administered as a daily injection due to its short half-life. To achieve sustained release of rhGH, the preparation of rhGH-loaded PLGA microspheres was investigated, and the influence of various factors on encapsulation efficiency was tested, including rhGH concentration, the ratio of internal phase to organic phase, stirring speed, PVA concentration, surrounding pH value, and the type of emulsifier and organic solvent. A pharmacokinetic study was performed by subcutaneous administration to explore the sustained release effect. It was found that rhGH-loaded PLGA microspheres were prepared with a narrow size distribution, and optimization of the formulation could enhance encapsulation efficiency. FTIR analysis indicated that the activity of rhGH was maintained after encapsulation. The pharmacokinetic behavior of rhGH solutions was consistent with a two-compartment model, which showed fast absorption and distribution. RhGH-loaded PLGA microspheres achieved a higher bioavailability and a long-term effective concentration by controlling the release, and PLGA 50/50 demonstrated favorable AUC compared with PLGA 75/25. Nevertheless, the higher bioavailability of rhGH-loaded PLGA microspheres lacking Span 80 did not predicate better sustained release behavior, indicating that further investigation is needed to explore the use of bioavailability as the standard in evaluating the sustained release characteristics and in vivo behavior of microspheres.