吴茱萸次碱治疗重症急性胰腺炎的实验研究

目的：探讨吴茱萸次碱对大鼠重症急性胰腺炎（SAP）的疗效及其机制。 方法：50只SD大鼠随机均分为假手术组和4个实验组,实验组大鼠以5%牛磺胆酸钠胰胆管逆行注射制作SAP模型后,分别给予生理盐水、乌司他丁、吴茱萸次碱、乌司他丁+吴茱萸次碱处理。术后24 h,行病理学检查,并检测各组血清淀粉酶活性及血浆与胰腺组织和内皮素1（EF-1）、降钙素基因相关肽（CGRP）水平。 结果：除假手术组外,各实验组大鼠均胰腺组织均出现不同程度的胰腺炎病理改变;与假手术组比较,各实验组均出现不同程度的血清淀粉酶活性升高,血浆与胰腺组织ET-1浓度增加,而血浆与胰腺组织CGRP含量在吴茱萸次碱处理组与联合用药组均明显升高（均P<0.05）,其余实验组无明显改变（均P>0.05）;实验组中,各药物处理组胰腺病变程度、血清淀粉酶活性、血浆与胰腺组织ET-1浓度均较生理盐水处理的模型组明显降低,且均以联合用药组最为明显（均P<0.05）。 结论：吴茱萸次碱对大鼠SAP具有治疗作用,其作用可能与增加CGRP水平从而改善胰腺组织微循环有关。     

Identification of a peptide targeting CD56

Neural cell adhesion molecule 1 (NCAM1/CD56) is expressed on immune cells, myoblasts, and malignant cells, and there is a growing demand for the genetic detection of CD56 and CD56-targeted therapy. In the present study, we developed a novel peptide ligand (designated Natein) that binds to human CD56 by using T7 phage display technology. Natein recognized the extracellular region of CD56 and could bind to natural killer (NK) cells and CD56-positive (CD56⁺) cancer cells. CD56⁺ cells enriched from human peripheral blood mononuclear cells (PBMCs) using biotinylated Natein-conjugated microbeads, similarly to CD56 antibody-isolated cells, demonstrated functional cytotoxicity against K562 cells. In addition, Natein could be used to stain CD56⁺ lymphoma cells in nasal-type extranodal NK/T-cell lymphoma tissues similarly to a CD56 antibody. These findings suggest that Natein has the potential to be alternative to CD56 antibody that could be used for peptide-based cell isolation and diagnosis.     

A bioengineered peripheral nerve construct using aligned peptide amphiphile nanofibers

Peripheral nerve injuries can result in lifelong disability. Primary coaptation is the treatment of choice when the gap between transected nerve ends is short. Long nerve gaps seen in more complex injuries often require autologous nerve grafts or nerve conduits implemented into the repair. Nerve grafts, however, cause morbidity and functional loss at donor sites, which are limited in number. Nerve conduits, in turn, lack an internal scaffold to support and guide axonal regeneration, resulting in decreased efficacy over longer nerve gap lengths. By comparison, peptide amphiphiles (PAs) are molecules that can self-assemble into nanofibers, which can be aligned to mimic the native architecture of peripheral nerve. As such, they represent a potential substrate for use in a bioengineered nerve graft substitute. To examine this, we cultured Schwann cells with bioactive PAs (RGDS-PA, IKVAV-PA) to determine their ability to attach to and proliferate within the biomaterial. Next, we devised a PA construct for use in a peripheral nerve critical sized defect model. Rat sciatic nerve defects were created and reconstructed with autologous nerve, PLGA conduits filled with various forms of aligned PAs, or left unrepaired. Motor and sensory recovery were determined and compared among groups. Our results demonstrate that Schwann cells are able to adhere to and proliferate in aligned PA gels, with greater efficacy in bioactive PAs compared to the backbone-PA alone. In vivo testing revealed recovery of motor and sensory function in animals treated with conduit/PA constructs comparable to animals treated with autologous nerve grafts. Functional recovery in conduit/PA and autologous graft groups was significantly faster than in animals treated with empty PLGA conduits. Histological examinations also demonstrated increased axonal and Schwann cell regeneration within the reconstructed nerve gap in animals treated with conduit/PA constructs. These results indicate that PA nanofibers may represent a promising biomaterial for use in bioengineered peripheral nerve repair.     

Peptide encapsulation regulated by the geometry of carbon nanotubes

In this work the encapsulation of an α-helical peptide in single carbon nanotubes (CNTs) with similar diameter and length but different geometry (armchair and zigzag) was investigated through molecular dynamics simulations and free energy calculations. Our simulation results showed that in vacuo it makes no evident difference whether the investigated peptide is encapsulated in armchair or zigzag CNTs; however, in aqueous solution the armchair CNT encapsulates the peptide remarkably easier than the zigzag CNT does. A detailed analysis revealed that the equilibrium conformation of the water molecules inside the CNTs with varying geometry mediates the peptide encapsulation. It suggests that the water molecules play an important role in regulating behaviors of biomolecules in bio-systems. Then the impact of the CNT geometry on the conformational changes of the confined peptide was studied. Analyses of secondary structures showed the α-helix of the peptide could be better maintained in the zigzag CNT.     

Uncoupling angiogenesis and inflammation in peripheral artery disease with therapeutic peptide-loaded microgels

Peripheral artery disease (PAD) is characterized by vessel occlusion and ischemia in the limbs. Treatment for PAD with surgical interventions has been showing limited success. Moreover, recent clinical trials with treatment of angiogenic growth factors proved ineffective as increased angiogenesis triggered severe inflammation in a proportionally coupled fashion. Hence, the overarching goal of this research was to address this issue by developing a biomaterial system that enables controlled, dual delivery of pro-angiogenic C16 and anti-inflammatory Ac-SDKP peptides in a minimally-invasive way. To achieve the goal, a peptide-loaded injectable microgel system was developed and tested in a mouse model of PAD. When delivered through multiple, low volume injections, the combination of C16 and Ac-SDKP peptides promoted angiogenesis, muscle regeneration, and perfusion recovery, while minimizing detrimental inflammation. Additionally, this peptide combination regulated inflammatory TNF-α pathways independently of MMP-9 mediated pathways of angiogenesis in vitro, suggesting a potential mechanism by which angiogenic and inflammatory responses can be uncoupled in the context of PAD. This study demonstrates a translatable potential of the dual peptide-loaded injectable microgel system for PAD treatment.     

Vitamin D receptor gene polymorphism as possible risk factor in rheumatoid arthritis and rheumatoid related osteoporosis

Objective

To study the role of VDR polymorphisms as risk factor for RA and osteoporosis, and whether osteoporosis complicating RA is due to RA or VDR polymorphisms.

Methods

VDR gene polymorphisms ApaI, TaqI, BsmI and FokI were typed by RFLP for 128 RA patients, 30 postmenopausal osteoporotic females and 150 healthy controls.

Results

Significant differences were found between patients and healthy controls in the frequency of BsmI and TaqI (Pc < 0.05) but no significant associations were found for FokI and ApaI polymorphisms except for aa genotype (Pc < 0.001). Titers of RF were higher with aa and bb genotypes. Anti-CCP and CRP levels were higher with aa genotype and more bone loss was associated with Bb genotype. Ff genotype frequency was higher in RA patients with osteoporosis than those without osteoporosis.

Conclusions

The ApaI, BsmI and TaqI polymorphisms may be a susceptibility risk factors for RA and the Ff genotype may be responsible for development of osteoporosis in RA Egyptian patients. However, the present study needs to be replicated in a large number of patients from allover the Egypt and also in multi-ethnic populations.     

Effect of peptide secondary structure on adsorption and adsorbed film properties on end-grafted polyethylene oxide layers

Poly-l-lysine (PLL), in α-helix or β-sheet configuration, was used as a model peptide for investigating the effect of secondary structures on adsorption events to poly(ethylene oxide) (PEO) modified surfaces formed using θ solvents. Circular dichroism results showed that the secondary structure of PLL persisted upon adsorption to Au and PEO modified Au surfaces. Quartz crystal microbalance with dissipation (QCM-D) was used to characterize the chemisorbed PEO layer in different solvents (θ and good solvents), as well as the sequential adsorption of PLL in different secondary structures (α-helix or β-sheet). QCM-D results suggest that chemisorption of PEO 750 and 2000 from θ solutions led to brushes 3.8 ± 0.1 and 4.5 ± 0.1 nm thick with layer viscosities of 9.2 ± 0.8 and 4.8 ± 0.5 cP, respectively. The average number of H₂O per ethylene oxides, while in θ solvent, was determined as ∼0.9 and ∼1.2 for the PEO 750 and 2000 layers, respectively. Upon immersion in good solvent (as used for PLL adsorption experiments), the number of H₂O per ethylene oxides increased to ∼1.5 and ∼2.0 for PEO 750 and 2000 films, respectively. PLL adsorbed masses for α-helix and β-sheet on Au sensors was 231 ± 5 and 1087 ± 14 ng cm⁻², with layer viscosities of 2.3 ± 0.1 and 1.2 ± 0.1 cP, respectively; suggesting that the α-helix layer was more rigid, despite a smaller adsorbed mass, than that of β-sheet layers. The PEO 750 layer reduced PLL adsorbed amounts to ∼10 and 12% of that on Au for α-helices and β-sheets respectively. The PLL adsorbed mass to PEO 2000 layers dropped to ∼12% and 4% of that on Au, for α-helix and β-sheet respectively. No significant differences existed for the viscosities of adsorbed α-helix and β-sheet PLL on PEO surfaces. These results provide new insights into the fundamental understanding of the effects of secondary structures of peptides and proteins on their surface adsorption.     

降钙素原、BNP、心肌肌钙蛋白I及D-二聚体评估慢性心力衰竭患者预后的价值

【目的】探讨降钙素原(PCT)、B型利钠肽(BNP)、心肌肌钙蛋白I(cTnI)及D-二聚体(D-D)评估慢性心力衰竭(CHF)患者预后的价值。【方法】本院就诊的70例CHF患者作为CHF组,根据美国纽约心脏病协会颁布的心功能分级标准(NYHA)分级法分为心功能Ⅱ级组、心功能Ⅲ级组、心功能Ⅳ级组,分别为33例、26例、11例。同时选取同一时期本院70例体检正常者分为对照组。采集所有研究对象入院时及1个月后的血液标本,对所有研究对象血清PCT、BNP、cTnI及D-D进行检测,并进行统计分析。【结果】CHF组血清PCT、BNP、cTnI及D-D水平均较对照组高,其差异具有显著性(P均<0.05)。CHF组中心功能Ⅱ级组、心功能Ⅲ级组、心功能Ⅳ级组血清PCT、BNP、cTnI及D-D水平随着心衰程度加重而逐渐升高,三组间两两比较差异均具有显著性(P均<0.05)。CHF患者经治疗1月后,血清PCT、BNP、cTnI、D-D水平明显较治疗前降低,其差异具有显著性(P<0.01);CHF患者经治疗1月后左室射血分数(LVEF)较治疗前升高,且差异具有显著性(P<0.01);CHF患者经治疗1月后NYHA心功能级别较治疗前明显降低,且差异具有显著性(P<0.01)。血清PCT、BNP、cTnI、D-D水平与NYHA心功能级别均呈正相关(P均<0.05),与LVEF均呈负相关(P均<0.05)。【结论】血清中PCT、BNP、CTnI、D-D水平均可对CHF患者病情变化进行反映,对于CHF患者疗效监测具有重要预测价值。     

Small Nogo-66-binding peptide promotes neurite outgrowth through RhoA inhibition after spinal cord injury

Abortive regeneration in the adult mammalian central nervous system (CNS) is partially mediated through CNS myelin proteins, among which Nogo-A plays an important role. Nogo-66, which is located at the C-terminus of Nogo-A, inhibits axonal regrowth through the Nogo-66/NgR signalling pathway. In this study, two small peptides were tested in a neurite outgrowth assay and spinal cord injury (SCI) model to examine the effects of these molecules on the inhibition of Nogo-66/NgR signalling. PepIV was selected from a phage display peptide library as a Nogo-66 binding molecule. And PepII was synthesized as a potential NgR antagonist. The results indicated that PepIV and PepII decrease the mRNA levels of the small GTPase RhoA and partially neutralize CNS myelin inhibition to cultured cerebellar granule cells (CGCs). Moreover, treatment with both peptides was propitious to maintaining residual axons after SCI, thereby promoting regeneration and locomotion recovery. Because RhoA plays a role in stabilizing the cytoskeleton in growth cones and axons, enhanced neurite outgrowth might reflect a decrease in RhoA expression through PepIV and PepII treatment. Moreover, PepIV induced lower RhoA mRNA expression compared with PepII. Therefore, PepIV could block Nogo-66/NgR signalling and reduce RhoA mRNA level, and then contribute to neuronal survival and axonal regrowth after SCI, showing its ability to reverse CNS myelin inhibition to regeneration. Furthermore, selected small peptide might cover some unknown active sites on CNS myelin proteins, which could be potential targets for improving neurite outgrowth after injury.     

Experimental immunotherapeutic approaches for atherosclerosis

Therapeutic options in atherosclerosis have largely been limited to the control of risk factors, such as hypercholesterolemia, hypertension, or diabetes. However, atherosclerosis is a chronic inflammatory disease in which dyslipidemia and inflammation are equally involved in disease pathogenesis. Moreover, abundant epidemiological and experimental evidence point to an important modulatory role of innate and adaptive immunity in atherogenesis, providing novel therapeutic targets for this disease. Indeed, there is now accumulating data in animal models demonstrating the potential for immunotherapeutic approaches to treat atherosclerosis. These include both general and antigen-specific ways of modulating immune functions, and they show great promise for the development of alternative and/or adjuvant therapies for atherosclerosis.