A matrix metalloproteinase-responsive hydrogel system controls angiogenic peptide release for repair of cerebral ischemia/reperfusion injury

Vascular endothelial growth factor and its mimic peptide KLTWQELYQLKYKGI(QK)are widely used as the most potent angiogenic factors for the treatment of multiple ischemic diseases.However,conventional topical drug delivery often results in a burst release of the drug,leading to transient retention(inefficacy)and undesirable diffusion(toxicity)in vivo.Therefore,a drug delivery system that responds to changes in the microenvironment of tissue regeneration and controls vascular endothelial growth factor release is crucial to improve the treatment of ischemic stroke.Matrix metalloproteinase-2(MMP-2)is gradually upregulated after cerebral ischemia.Herein,vascular endothelial growth factor mimic peptide QK was self-assembled with MMP-2-cleaved peptide PLGLAG(TIMP)and customizable peptide amphiphilic(PA)molecules to construct nanofiber hydrogel PA-TIMP-QK.PA-TIMP-QK was found to control the delivery of QK by MMP-2 upregulation after cerebral ischemia/reperfusion and had a similar biological activity with vascular endothelial growth factor in vitro.The results indicated that PA-TIMP-QK promoted neuronal survival,restored local blood circulation,reduced blood-brain barrier permeability,and restored motor function.These findings suggest that the self-assembling nanofiber hydrogel PA-TIMP-QK may provide an intelligent drug delivery system that responds to the microenvironment and promotes regeneration and repair after cerebral ischemia/reperfusion injury.

Gastric motor effects of ghrelin and growth hormone releasing peptide 6 in diabetic mice with gastroparesis

AIM:To investigate the potential therapeutic significance of ghrelin and growth hormone releasing peptide 6 (GHRP-6) in diabetic mice with gastric motility disorders. METHODS: A diabetic mouse model was established by intraperitoneal (ip) injection of alloxan. Diabetic mice were injected ip with ghrelin or GHRP-6 (20-200 μg/kg), and the effects on gastric emptying were measured after intragastric application of phenol red. The effect of atropine, NG-nitro-L-arginine methyl ester hydrochloride (L-NAME) or D-Lys3-GHRP-6 (a growth hormone secretagogue receptor (GHS-R) antagonist) on the gastroprokinetic effect of ghrelin or GHRP-6 (100 μg/kg) was also investigated. The effects of ghrelin or GHRP-6 (0.01-10 μmol/L) on spontaneous or carbachol-induced contractile amplitude were also investigated in vitro, in gastric fundic circular strips taken from diabetic mice. The presence of growth hormone secretagogue receptor 1a transcripts in the fundic strips of diabetic mice was detected by reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: We established a diabetic mouse model with delayed gastric emptying. Ghrelin and GHRP-6 accelerated gastric emptying in diabetic mice with gastroparesis. In the presence of atropine or L-NAME, which delayed gastric emptying, ghrelin and GHRP-6 (100 μg/kg) failed to accelerate gastric emptying. D-Lys3-GHRP-6 also delayed gastric emptying induced by the GHS-R agonist. Ghrelin and GHRP-6 increased the carbachol-induced contractile amplitude in gastric fundicstrips taken from diabetic mice. RT-PCR confirmed the presence of GHS-R mRNA in the strip preparations. CONCLUSION: Ghrelin and GHRP-6 increase gastric emptying in diabetic mice with gastroparesis, perhaps by activating peripheral cholinergic pathways in the enteric nervous system.

Progastrin-releasing peptide and gastrin-releasing peptide receptor mRNA expression in non-tumor tissues of the human gastrointestinal tract

AIM： To investigate the expression of gastrin-releasing peptide （GRP） and GRP-receptor mRNA in non-tumor tissues of the human esophagus, gastrointestinal tract, pancreas and gallbladder using molecular biology techniques. METHODS： Poly A^＋ mRNA was isolated from total RNA extracts using an automated nucleic acid extractor and, subsequently, converted into single-stranded cDNA （sscDNA）. PCR amplifications were carried out using genespecific GRP and GRP-receptor primers. The specificity of the PCR amplicons was further confirmed by Southern blot analyses using gene-specific GRP and GRP-receptor hybridization probes. RESULTS： Expression of GRP and GRP-receptor mRNA was detected at various levels in nearly all segments of the non-tumor specimens analysed, except the gallbladder. In most of the biopsy specimens, coexpression of both GRP and GRP-receptor mRNA appeared to take place. However, expression of GRP mRNA was more prominent than was GRP-receptor mRNA. CONCLUSION： GRP and GRP-receptor mRNAs are expressed throughout the gastrointestinal tract and provides information for the future mapping and determination of its physiological importance in normal and tumor cells.

In vitro antihistamine-releasing activity of a peptide derived from wasp venom of Vespa orientalis

Objective: To investigate the antihistamine-releasing effect of a peptide isolated from wasp venom of Vespa orientalis.Methods: This peptide was separated from crude venom by chromatography methods and mass spectrometry. Then various concentrations(2, 4, 8, 16, 32, 64, 128 and256 mmol/L) of the peptide were incubated with mast cells and lactate dehydrogenase assay was performed.Results: No significant effect was observed in lactate dehydrogenase absorbance under128 mmol/L concentration. This implied that the peptide did not cause cell death in mast cells and consequently, histamine release did not happen. Moreover, the results showed the IC50 of mast cells degranulation at 126 mmol/L, which was approximately high implying that this peptide had high selectivity for normal cells and did not cause histamine release from these cells.Conclusions: This would be a great aim in new drug development, in which an agent acts potentially on its target tissue without activating the immune system.

Effect of growth hormone-releasing peptide on cardiac cholinergic nerve fiber density distribution in a rat model of heart failure

BACKGROUND： Changes in the cardiac autonomic nerve are considered to be important factors in the mechanisms of heart failure. It is possible to reduce or slow down nerve degeneration and necrosis, provided that patients take effective neuroprotectants during the early stages of heart failure. Moreover, it is possible to relieve the pathological process and reduce the risk of death. OBJECTIVE： To study the effect of growth hormone releasing peptide （GHRP） on cardiac cholinergic nerve fiber density distribution in a rat model of heart failure, and verify whether GHRP can ameliorate denervation. DESIGN, TIME AND SETTING： A randomized controlled study was performed at the Key Laboratory of Anatomy, Harbin Medical University, between June and October 2009. MATERIALS： Fifty adult, healthy, female, Wistar rats, weighing （200± 20） g, were randomly divided into GHRP （n = 30）, model （n = 10）, and sham operation （n = 10） groups. GHRP-2 was made in Shanghai, China （batch No. z071212-03）. METHODS： Acute myocardial infarction was established by ligating the left anterior descending coronary artery in the GHRP and model groups. Five weeks later, myocardial function was detected using color ultrasound electrocardiograph a successful marker of chronic heart failure models Ejection fraction 〈 60% was considered to be However, the left anterior descending coronary artery was not ligated in the sham operation group. The GHRP group was injected with 100 μ g/kg GHRP-2, and the other two groups were injected with the same volume of physiological saline, once per day. MAIN OUTCOME MEASURES： After 4 weeks, pathological changes in cardiac cholinergic nerve fibers were detected under optic microscopy following hematoxylin/eosin staining. In addition, density distribution was measured using a multi-function color pathological image system. RESULTS： In the sham operation group, myocardial cells were regular, uniformly stained, and no inflammatory cells were present. In the model group, myocardial cells were unevenly stained, exhibited nuclear atrophy, degeneration, dissolution, or disappearance. In the GHRP group, myocardial damage was less than in the model group; cardiac muscle fibers exhibited slight degeneration. The myocardium in the sham operation group was serried, spreading the cholinergic innervations along the cardiac fiber. In the model group, there was a decreased number of cholinergic nerve fibers decreased, which also became shorter and smaller, compared with the sham operation group （P 〈 0.01）. In the GHRP group, cholinergic positive nerve fibers were significantly increased compared with the model group （P 〈 0.01）, but still less than the sham surgery group （P 〈 0.05）. CONCLUSION： GHRP delayed denervation and reduced nerve reconstitution following heart failure in rats.

Expression and Characterization of a Thermostable Acyl-peptide Releasing Enzyme ST0779 from Sulfolobus tokodaii

Acyl-peptide releasing enzyme（AARE） belongs to a serine peptidase family and catalyzes the NH2-terminal hydrolysis of Nα-acylpeptides to release Nα-acylated amino acids. ORF0779（ORF=open reading frame） from thermophilic archaea Sulfolobus tokodaii（ST0779） was cloned and expressed in E. coli BL21 and the expressed protein was identified as a thermostable AARE. The target protein could be optimally overexpressed in E. coli at 30 °C for 8 h with 0.1 mmol/L isopropyl β-dthiogalactoside（IPTG）. The crude enzyme was heated at 70 °C for 30 min, and then the target protein could account for above 40% of the total protein. The purification fold was 27 and the enzyme showed both esterase activity and peptidase activity. The optimal temperature and pH for ST0779 were 70 °C and 8.0 when Ac-Ala3 was used as substrate. The half-life of the enzyme（0.2 mg/mL） at 90 °C was about 16 h, indicating that the enzyme exhibits a favorable thermostability. The activity of ST0779 could still remain over 85% after being treated at 25 °C in different buffers with pH range from 6.0 to10.0 for 24 h, which indicates ST0779 is stable in neutral or slight alkali environment. Under neutral or slightly alkali conditions, the enzyme exhibits really high catalytic efficiency against acyl-peptide, and the optimal substrate is Ac-Ala3. Most metal ions have no inhibition effect on the activity of ST0779, while 4% activity of ST0779 is inhibited in the presence of K＋. This enzyme was supposed to be applied in the analysis of protein sequencing and the synthesis of small peptides.

PEGylated PLGA Nanoparticles as Tumor Ecrosis Factor-α Receptor Blocking Peptide Carriers:Preparation,Characterization and Release in vitro

To assess the merits of PEGylated poly （lactic-co-glycolic acid） （PEG-PLGA） nanoparticles as drug carriers for tumor necrosis factor-α receptor blocking peptide （TNFR-BP）, PEG-PLGA copolymer, which could be used to prepare the stealth nanoparticles, was synthesized with methoxypolyethyleneglycol, DL-lactide and glycolide. The structure of PEG-PLGA was confirmed with ^1H-NMR and FT-IR spectroscopy, and the molecular weight （MW） was determined by gel permeation chromatography. Fluorescent FITC-TNFR- BP was chosen as model protein and encapsulated within PEG-PLGA nanoparticles using the double emulsion method. Atomic force microscopy and photon correlation spectroscopy were employed to characterize the stealth nanoparticles fabricated for morphology, size with polydispersity index and zeta potential. Encapsulation efficiency （EE） and the release of FITC-TNFR-BP in nanopartieles in vitro were measured by the fluorescence measurement. The stealth nanoparticles were found to have the mean diameter less than 270 nm and zeta potential less than -20 mV. In all nanoparticle formulations, more than 45% of EE were obtained. FITC-TNFR-BP release from the PEG-PLGA nanoparticles exhibited a biphasic pattern, initial burst release and consequently sustained release. The experimental results show that PEG-PLGA nanoparticles possess the potential to develop as drug carriers for controlled release applications of TNFR-BP.

A peptide chain release factor 2a gene regulates maize kernel development by modulating mitochondrial function

Mitochondrial protein translation that is essential for aerobic energy production includes four essential steps of the mitochondrial ribosome cycle,namely,initiation,elongation,termination of the polypeptide,and ribosome recycling.Translation termination initiates when a stop codon enters the A site of the mitochondrial ribosome where it is recognized by a dedicated peptide release factor(RF).However,RFs and mechanisms involved in translation in plant mitochondria,especially in monocotyledons,remain largely unknown.Here,we identified a crumpled kernel(crk5 allele)mutant,with significantly decreased kernel size,100-kernel weight,and an embryo-lethal phenotype.The Crk5 allele was isolated using map-based cloning and found to encode a mitochondrial localization RF2a.As it is an ortholog of Arabidopsis mitochondrial RF2a,we named the gene ZmmtRF2a.ZmmtRF2a is missing the 5th–7th exons in the crk5 resulting in deletion of domains containing motifs GGQ and SPF that are essential for release activity of RF,mitochondrial ribosome binding,and stop codon recognition.Western blot and qRT-PCR analyses indicate that the crk5 mutation results in abnormal mitochondrion structure and function.Intriguingly,we observed a feedback loop in the crk5 with up-regulated transcript levels detected for several mitochondrial ribosome and mitochondrial-related components,in particular mitochondrial complexes CI,CIV,and a ribosome assembly related PPR.Together,our data support a crucial role for ZmmtRF2a in regulation of mitochondrial structure and function in maize.

Electron-induced rapid crosslinking in supramolecular metal-peptide assembly and chemically responsive disaggregation for catalytic application

The applications of supramolecular metal-peptide assemblies as catalyst or catalyst precursor have recent attracted increasing attentions.In this work,a fragment of the amyloid β-peptide,NH_(2)-KLVFF-COOH,was assembled into nanofilms with encapsulated Pd,Pt and Au nanoparticles(NPs)via a one-step room temperature electron induction method.The effects of building block,intermolecular interaction,driving force and side-chain on the assembly were investigated.The assembly mechanism was thereby proposed.The crosslinking of peptide monomers results in mainly random and unordered structures.The obtained metal-peptide assemblies are extremely stable in water at neutral pH for long term.However,the metal NPs are able to be responsively released under basic and reductive conditions.The released NPs show a high activity to catalyze the reduction of 4-nitrophenol.The present studies on assembly mechanism and responsive release will be helpful for the design of organic skeletons and also for the future development of peptide stabilized metallic NPs with applications beyond catalysts.

Preclinical therapy of benign prostatic hyperplasia with neuropeptide hormone antagonists

Benign prostatic hyperplasia(BPH)is a pathologic condition of the prostate described as a substantial increase in its number of epithelial and stromal cells.BPH may significantly reduce the quality of life due to the initiation of bladder outlet obstruction and lower urinary tract syndromes.Current medical therapies mostly consist of inhibitors of 5α-reductase orα1-adrenergic blockers;their efficacy is often insufficient.Antagonistic analogs of neuropeptide hormones are novel candidates for the management of BPH.At first,antagonists of luteinizing hormone-releasing hormone(LHRH)have been introduced to the therapy aimed to reduce serum testosterone levels.However,they have also been found to produce an inhibitory activity on local LHRH receptors in the prostate as well as impotence and other related side effects.Since then,several preclinical and clinical studies reported the favorable effects of LHRH antagonists in BPH.In contrast,antagonists of growth hormone-releasing hormone(GHRH)and gastrin-releasing peptide(GRP)have been tested only in preclinical settings and produce significant reduction in prostate size in experimental models of BPH.They act at least in part,by blocking the action of respective ligands produced locally on prostates through their respective receptors in the prostate,and by inhibition of autocrine insulin-like growth factors-Ⅰ/Ⅱand epidermal growth factor production.GHRH and LHRH antagonists were also tested in combination resulting in a cumulative effect that was greater than that of each alone.This article will review the numerous studies that demonstrate the beneficial effects of antagonistic analogs of LHRH,GHRH and GRP in BPH,as well as suggesting a potential role for somatostatin analogs in experimental therapies.

Incorporating antioxidative peptides within nanofibrous delivery vehicles:Characterization and in vitro release kinetics

L-carnosine(Car),an antioxidative dipeptide,is a promising health-promoting bioactive agent,which can be isolated from animal waste.In the present study,Car loaded pullulan(Pul)-sodium alginate(NaAlg)based nanofibrous delivery vehicles were fabricated by uniaxial,coaxial and emulsion electrospinning.The CaCl_(2) crosslinking was applied after electrospinning process to evaluate the effect on release behavior of Car.Results showed that Car was successfully loaded in water-in-oil-in-water(W_(1)/O/W_(2))double emulsion to produce nanofibers by emulsion electrospinning.Encapsulation efficiencies were found to be 74.11%and 81.69%for the uniaxial(UENFs)and coaxial nanofibers(CENFs),respectively.Encapsulation efficiency was determined for different formulas of emulsions,whereas among the samples that could form nanofibers(NFs)and encapsulate Car,the highest value was obtained for nanofibers from emulsion-Ⅷ(EE-Ⅷ NFs)at 68.63%.DPPH and CUPRAC assays revealed that all electrospinning methods demonstrated protective effect on the antioxidant activity of Car and thus helped in enhancing its antioxidant potential significantly.According to in vitro digestion results,the release of Car from all electrospun NFs was predominantly controlled by Fickian diffusion mechanism.The CaCl_(2) crosslinking treatment improved water resistance of NFs and enhanced sustained release of Car in the gastrointestinal tract.The initial burst release of Car from EE-Ⅷ NFs was significantly lower than for UENFs and CENFs in the gastric phase,and the release from EE-Ⅷ NFs in the intestinal phase was followed by sustained release,with/without crosslinking treatment.It can therefore be said that the simultaneously encapsulation of Car in double emulsion and in Pul-NaAlg based electrospun NFs can provide sustained release.

Biodistribution and preparation of technetium-99m-labeled D-D3 monoclonal antibody against pro-gastrin-releasing peptide ~31-98） in mice

Background We previously reported that iodine-131（131^I）-Iabeled anti-pro-gastrin-releasing peptide （ProGRP（31-98）） monoclonal antibody D-D3 could selectively accumulate in the tumor sites of nude mice bearing small cell lung cancer （SCLC） xenografts. However, 1311-D-D3 was cleared slowly from the body, and the best radioimmunoimaging time for SCLC was 72-96 hours after injection. The aims of this study were to radiolabel anti-ProGRP（31-98） D-D3 monoclonal antibody with technetium-99m（99m^Tc） and to investigate the biodistribution of this antibody in healthy ICR mice. Methods D-D3was labeled with 99m^Tc via the 2-mercaptoethanol reduction method. 99m^Tc-D-g3 was purified by the gel column separation method. The labeling efficiency and radiochemical purity were measured by thin-layer chromatography. The immunological activity of 99m^Tc-D-O3 was determined with cell conjugation assays. 99m^Tc-D-D3 was injected into healthy ICR mice via a tail vein, and all the healthy ICR mice were sacrificed by cervical dislocation at a designated time. Then, the blood and major organs were removed and weighed, and counted in a gamma scintillation counter to determine the percentage of the injected dose per gram （%ID/g）. Results The labeling rate and the radiochemical purity of 99m^TC-D-D3 were （73.87±2.89）% and （94.13±4.49）%, respectively. The immunobinding rates of 99m^Tc-O-D3 to the human small cell lung cancer NCI-H446 cell line and lung adenocarcinoma A549 cell line were （81.2±2.37）% and （24.3±1.46）%, respectively. The distribution data of normal ICR mice demonstrated that 99m^TC-D-D3was mainly distributed in the liver, kidney and lung, and less in the brain tissue and muscle. Conclusions 99m^Tc-D-D3 antibody not only had high radiochemical purity, but also had good stability both in vitro and in vivo, and maintained good immunological activity. 99m^Tc-D-D3 was metabolized mainly in the kidney and liver, and the blood radioactivity decreased rapidly. Thus, 99m^Tc-O-D3 is conducive to the radioimmunoimaging of SCLC.

自组装短肽水凝胶治疗肿瘤的作用

背景:自组装短肽水凝胶具有良好的生物相容性、可控的物理化学性质和释放性能,在组织工程、药物输送和生物传感等领域具有广泛的应用潜力。目的:总结近年来自组装短肽水凝胶在肿瘤治疗中的研究进展。方法:以“自组装短肽,水凝胶,缓释载体,抗肿瘤,肿瘤治疗;Self-assembling peptide,hydrogel,sustained release,antitumor,tumor therapy”为检索词,检索中国知网、PubMed、Elsevier ScienceDirect数据库2000-2024年发表的相关文献,最终纳入81篇文献进行综述。结果与结论:自组装短肽水凝胶作为一种新型的生物活性材料,可以作为缓释药物载体负载多种抗肿瘤药物、免疫抑制剂等,靶向肿瘤部位、诱导肿瘤细胞死亡、降低药物使用剂量、提高肿瘤部位药物蓄积量,从而降低毒副作用和多药耐药性的产生概率。此外,具有天然活性的抗肿瘤水凝胶能够不依赖于药物直接杀伤肿瘤细胞,单独使用能够最大限度避免抗肿瘤药物的毒副作用。

Visible light cross-linking and bioactive peptides loaded integrated hydrogel with sequential release to accelerate wound healing complicated by bacterial infection

The effective management of bacterial infections that are resistant to multiple drugs remains a substantial clinical challenge.The eradication of drug-resistant bacteria and subsequent promotion of angiogenesis are imperative for the regeneration of the infected wounds.Here,a novel and facile peptide containing injectable hydrogel with sustained antibacterial and angiogenic capabilities is developed.The antibacterial peptide that consists of 11 residues(CM11,WKLFKKILKVL)is loaded onto acrylate-modified gelatin through charge interactions.A vascular endothelial growth factor mimetic peptide KLT(KLTWQELYQLKYKGI)with a GCG(Gly-Cys-Gly)modification at the N-terminal is covalently coupled through a visible light-induced thiol-ene reaction.In this reaction,the acrylate gelatin undergoes cross-linkage within seconds.Based on the physical/chemical double crosslinking strategy,the bioactive peptides achieve sustained and sequential release.The results show that the hydrogel significantly inhibits methicillin-resistant Staphylococcus aureus(MRSA)growth through the rapid release of CM11 peptides at early stage;it forms obvious growth inhibition zones against pathogenic bacterial strains.Moreover,cell counting kit-8 assay and scratch test confirm that the CM11/KLT-functionalized hydrogels promote cell proliferation and migration through the later release of KLT peptides.In a mouse skin wound infected with self-luminous MRSA,the CM11/KLT-functionalized hydrogels enhance wound healing,with rapidly bacterial infection reduction,lower expression of inflammatory factors,and neovascularization promotion.These results suggest that the rationally designed,sustained and sequential release CM11/KLT-functionalized hydrogels have huge potential in promoting the healing of multi-drug resistant bacterial infected wounds.

Therapeutic effects of ghrelin and growth hormone releasing peptide 6 on gastroparesis in streptozotocin-induced diabetic guinea pigs in vivo and in vitro

Background Diabetic gastroparesis is a disabling condition with no consistently effective treatment. In normal animals, both ghrelin and its synthetic peptide, growth hormone releasing peptide 6 （GHRP-6）, increase gastric emptying. Thus, we investigated the potential therapeutic significance of ghrelin and GHRP-6 in diabetic guinea pigs with gastric motility disorders. Methods A diabetic guinea pig model was produced by intraperitoneal （i.p.） injection of streptozotocin （STZ, 280 mg/kg）. Diabetic guinea pigs were injected i.p. with ghrelin or GHRP-6 （10-100 μg/kg）, and the effects on gastric emptying were measured after intragastric application of phenol red. The effect of atropine or a growth hormone secretagogue receptor （GHS-R） antagonist, D-Lys^3-GHRP-6, on the gastroprokinetic effects of ghrelin or GHRP-6 （100 μg/kg） was also investigated. Further, the in vitro effects of ghrelin or GHRP-6 （0.01-10 μmol/L） on spontaneous or carbachol-induced contractile amplitude in gastric fundic circular strips taken from diabetic guinea pigs were examined. Growth hormone secretagogue receptor transcripts in the fundic strips of diabetic guinea pigs were detected by reverse transcriptase polymerase chain reaction （RT-PCR）. Results We established a guinea pig model of delayed gastric emptying. Ghrelin （20, 50, or 100 μg/kg） and GHRP-6 （20, 50, or 100 μg/kg） accelerated gastric emptying in diabetic guinea pigs with gastroparesis （n=6, P 〈0.05）. In the presence of atropine, which delayed gastric emptying, ghrelin and GHRP-6 （100 μg/kg） failed to accelerate gastric emptying （n=6, P 〈0.05）. D-Lys^3-GHRP-6 also delayed gastric emptying induced by the GHS-R agonist （n=6, P 〈0.05）. Ghrelin and GHRP-6 increased the carbachol-induced contractile amplitude in gastric fundic strips taken from diabetic guinea pigs （n=6, P〈0.05）. RT-PCR confirmed the presence of GHS-R mRNA in the strip preparations. Conclusions Ghrelin and GHRP-6 increased gastric emptying in diabetic guinea pigs with gastroparesis, potentially, by activating the peripheral cholinergic pathways in the enteric nervous system.

Development of composite PLGA microspheres containing exenatide-encapsulated lecithin nanoparticles for sustained drug release

This study aimed to prepare poly(D, L-lactic-co-glycolic acid) microspheres(PLGA-Ms)by a modified solid-in-oil-in-water(S/O/W) multi-emulsion technique in order to achieve sustained release with reduced initial burst and maintain efficient drug concentration for a prolonged period of time. Composite PLGA microspheres containing exenatideencapsulated lecithin nanoparticles(Ex-NPs-PLGA-Ms) were obtained by initial fabrication of exenatide-loaded lecithin nanoparticles(Ex-NPs) via the alcohol injection method,followed by encapsulation of Ex-NPs into PLGA microspheres. Compared to Ms prepared by the conventional water-in-oil-in-water(W/O/W) technique(Ex-PLGA-Ms), Ex-NPs-PLGAMs showed a more uniform particle size distribution, reduced initial burst release, and sustained release for over 60 d in vitro. Cytotoxicity studies showed that Ms prepared by both techniques had superior biocompatibility without causing any detectable cytotoxicity.In pharmacokinetic studies, the effective drug concentration was maintained for over 30 d following a single subcutaneous injection of two types of Ms formulation in rats, potentially prolonging the therapeutic action of Ex. In addition, administration of Ex-NPs-PLGA-Ms resulted in a more smooth plasma concentration-time profile with a higher area under the curve(AUC) compared to that of Ex-PLGA-Ms. Overall, Ex-NPs-PLGA-Ms prepared by the novel S/O/W method could be a promising sustained drug release system with reduced initial burst release and prolonged therapeutic efficacy.

USE OF HOEC ACTIVE ESTERS IN SOLIDPHASE PEPTIDE SYNTHESIS——THE SYNTHESIS OF GROWTH HORMONE RELEASING PEPTIDE

N-hydroxysuccinimide (HOSU) active esters have gained wide application in peptide synthesis, especially in the synthesis of longer peptides by segment conden sation, for they can avoid racemization during coupling processes. However, the HOSU active ester method is prone to side reactions, forming undesirable by-products such as succinimide-oxycarbonyl-alanine N-hydroxysuccinimide ester (Ⅰ) in activating steps and compound (Ⅱ) in the coupling steps sterically hindered by amino acids (proline, valine, isoleucine, etc.).

新型胃泌素释放肽受体靶向PET分子探针应用于肿瘤显像的研究进展

胃泌素释放肽受体(GRPR)是一种属于铃蟾肽受体家族的G蛋白偶联受体,主要分布于整个胃肠道和中枢神经系统,通过与其配体胃泌素释放肽结合发挥生物学作用。近年研究发现,GRPR在许多恶性肿瘤中过度表达并参与恶性肿瘤的发生发展,如乳腺癌、前列腺癌、肺癌、胰腺癌和多形性胶质母细胞瘤等。正电子发射计算机断层扫描(PET)是一种通过检测放射性标记物质在人体内部的分布和浓度来提供图像的医学成像技术,能够提供更全面、准确的诊断信息。已有研究表明靶向GRPR的PET显像在多种恶性肿瘤的诊断、治疗监测和预后评估等方面发挥重大作用,因此,开发特异性强、亲和性高的GRPR探针对肿瘤的诊断与治疗意义重大。本文针对已报道的新型GRPR靶向PET分子探针的种类及肿瘤显像的应用展开综述,以期为GRPR靶向PET分子探针的研发及临床转化提供新思路和新方向。

血清MMP-9、ProGRP及内皮素的水平与非小细胞肺癌分期的相关性分析

目的探究非小细胞肺癌患者中血清基质金属蛋白酶-9(MMP-9)、血清胃泌素释放肽前体(ProGRP)与肿瘤分期的相关性。方法选取非小细胞肺癌患者70例作为观察组,以同期健康体检者70例作为对照组,比较两组患者血清中MMP-9、ProGRP及内皮素水平,并采用ROC曲线分析上述指标的临床诊断价值。结果观察组患者MMP-9、ProGRP以及内皮素表达水平均显著高于对照组(P<0.05),MMP-9、ProGRP以及内皮素阳性表达率男性患者和Ⅲ、Ⅳ期患者显著高于女性患者和Ⅰ、Ⅱ期者,差异有统计学意义(P<0.05),MMP-9、ProGRP以及内皮素与肿瘤分期均具有显著相关性(P<0.05)。结论MMP-9、ProGRP以及内皮素均可作为非小细胞肺癌的检测指标,且其表达水平与肿瘤分期存在相关性,为临床诊断提供依据。

胃泌素释放肽前体与神经元特异性烯醇化酶在小细胞肺癌诊疗过程中的价值

目的:研究在小细胞肺癌诊疗过程中胃泌素释放肽前体(gastrin releasing peptide precursor,Pro-GRP)与神经元特异性烯醇化酶(neuron specific enolase,NSE)的价值。方法:选取蚌埠医学院第一附属医院2020年4月-2021年3月期间在呼吸与危重症医学科住院、且首次确诊的小细胞肺癌(38例)、非小细胞肺癌(65例)及肺良性病变(51例)的患者,收集纳入患者的临床资料,并通过电化学发光法检测ProGRP及NSE的水平,评估临床诊疗价值。结果:小细胞肺癌组血清Pro-GRP和NSE的水平明显高于非小细胞肺癌组(P<0.05)、肺良性病变组(P<0.05)。广泛期小细胞肺癌组血清Pro-GRP和NSE的水平均高于局限期小细胞肺癌组(P<0.05)。小细胞肺癌患者血清ProGRP水平与性别、年龄、吸烟史无明显相关性(P>0.05);血清NSE水平与性别、年龄史无明显相关性(P>0.05),但与吸烟存在相关性(P<0.05)。采用ROC曲线分析明确了血清Pro-GRP和NSE诊断小细胞肺癌的界值分别为65.78 pg/mL、14.84 ng/mL;血清Pro-GRP诊断小细胞肺癌的敏感度、特异度、约登指数分别为84.21%、96.1%、0.803。NSE的敏感度、特异度、约登指数分别为68.4%、96.1%、0.645。2个周期规范方案化疗后,小细胞肺癌患者化疗后血清Pro-GRP和NSE的水平较化疗前明显降低(P<0.05)。结论:血清Pro-GRP和NSE可作为辅助小细胞肺癌诊断和疗效评价的肿瘤标志物。