肥大细胞与慢性肾小球肾炎肾间质损害的关系

目的 探讨肥大细胞(Mast cell,MC)在肾组织中的浸润与肾间质损害、转化生长因子β1(TGF-β1)、α-平滑肌肌动蛋白(α-SMA)表达及肾功能的关系。方法 收集46例不同病理类型的肾小球肾炎患者的临床资料和肾活检标本,采用免疫组织化学技术检测MC在肾组织中的浸润及TGF-β1、α-SMA的表达,并分析它们之间及其与肾间质损害、肾功能的相关性。结果 正常肾组织中偶有或无MC的存在,而在患肾的间质中则发现大量MC浸润,主要分布在皮质,少数在髓质,其分布与间质中α-SMA阳性细胞的分布大体一致。MC的数量与肾间质损害程度、TGF-β1、α-SMA的表达、Scr浓度呈正相关(r分别为0.49、0.90、0.94、0.71,P均<0.001);与Ccr呈负相关(r=-0.60,P<0.0001)。MC数随肾间质损害程度的加重明显增加(P<0.01)。结论 MC数与肾间质损害程度呈正相关。MC可能是肾间质损害的重要参与者。     

干细胞因子和肥大细胞在慢性肾衰竭大鼠皮肤中的表达和浸润

目的 探讨干细胞因子(SCF)和肥大细胞(MC)与慢性肾衰竭大鼠皮肤损害发生发展的关系.方法 36只雄性Wistar大鼠按随机数字表法分为两组:模型组(n=18)用腺嘌呤灌胃诱发大鼠慢性肾衰竭,对照组(n=18)用等量生理盐水灌胃.分别于实验第4、8和12周各组随机处死6只大鼠,甲苯胺蓝染色观察皮肤组织中MC的浸润,免疫组织化学方法和实时荧光定量PCR检测皮肤组织中SCF蛋白和mRNA的表达量,并分析它们之间的相关性.结果 从第8周开始,模型组大鼠皮肤组织中MC密度和SCF的表达均显著高于对照组(P＜0.01),且2者均随着灌胃天数的延长逐渐增加.模型组MC密度与SCF蛋白及mRNA的表达量均呈正相关(r分别为0.81、0.65,均P＜0.01).结论 慢性肾衰竭时皮肤组织中MC的浸润和SCF的表达均显著增多,提示2者可能参与慢性肾衰竭皮肤损害的发生发展.     

Role of stem cells in the management of chronic wounds

Chronic wounds continue to be a major challenge for the medical profession, and plastic surgeons are frequently called in to help in the management of such wounds. Apart from the obvious morbidity to the patient, these problem wounds can be a major drain on the already scarce hospital resources. Sometimes, these chronic wounds can be more taxing than the underlying disease itself. Although many newer methods are available to handle such situations, the role of stem cells in the management of such wounds is an exciting area that needs to be explored further. A review of literature has been done regarding the role of stem cells in the management of chronic wounds. The abnormal pathology in such wounds is discussed and the possible role of stem cells for optimal healing in such cases would be detailed.KEY WORDS: Adult stem cells, chronic wound, stem cells     

Role of mast cells in the pathogenesis of hypersensitivity pneumonitis.

To examine the possibility that mast cells have a central role in the pathogenesis of hypersensitivity pneumonitis, 20 patients with this disease were studied with the aim of seeking evidence for mast cell degranulation. The number of mast cells recovered by bronchoalveolar lavage from patients with hypersensitivity pneumonitis was more than 1,000 times greater than those recovered from normal individuals. Furthermore, discontinuation of antigen exposure resulted in an increase in the number of mast cells observed, consistent with the possibility that antigen exposure had induced mast cell degranulation. Cessation of antigen exposure also resulted in a rapid decrease in the number of neutrophils and eosinophils recovered by lavage, followed by an increase in the number of T8+ T lymphocytes present. In each case the time course of the changes was consistent with the possibility that mast cell degranulation had been important in regulating the number of the immune and inflammatory cells present in the lung. Histamine was present in lavage fluid supernatant from patients with hypersensitivity pneumonitis. The amount of histamine present was, however, closely correlated with the number of mast cells present and not with the interval since last antigen exposure. Delay in separating cells from lavage fluid supernatant resulted in an increase in histamine content. These results suggest that the free histamine in lavage fluid resulted from the degranulation of mast cells induced by the lavage procedure as histamine released in vivo has a short half life. We suggest that hypersensitivity pneumonitis results from a "late phase reaction" initiated by antigen induced mast cell degranulation.     

Role of platelet-activating factor in leukocyte-independent plasma extravasation and mast cell activation during endotoxemia

BACKGROUND: Independently from leukocyte adherence, endothelial factors and mast cell activation seems to promote microvascular permeability. Platelet-activating factor (PAF) has been shown to play a significant role in endotoxin-induced leukocyte adherence. The aim of our study was to investigate if there is also a role for PAF in mediating leukocyte-independent microvascular permeability changes and activation of mast cells during endotoxemia. Therefore, during endotoxemia microvascular permeability and mast cell activation were determined after inhibition of L-selectin-mediated leukocyte adherence by fucoidin and after inhibition of PAF effects by the PAF receptor antagonist BN52021. MATERIALS AND METHODS: In male Wistar rats, red cell velocity (V(RBC)), venular wall shear rate, microvascular permeability, leukocyte adherence, and mast cell activation were determined in mesenteric postcapillary venules using intravital microscopy at baseline and 60 and 120 min after start of a continuous infusion of endotoxin (ETX; 2 mg/kg/h, Escherichia coli O26:B6) (ETX group). Animals in the FUCO/ETX group received fucoidin (25 mg/kg body wt) in addition to the procedure described above. Animals in the FUCO/ETX/PAF-ANT group received fucoidin and the PAF receptor antagonist BN52021 (5 mg/kg body wt) prior to the continuous endotoxin infusion. Control animals (control group) received only equivalent volumes of NaCl 0.9%. RESULTS: There were no microhemodynamic and macrohemodynamic differences between groups. In all endotoxin-challenged groups macromolecular leakage and mast cell activity increased significantly, starting at 60 min. Both macromolecular leakage and mast cell activity were significantly higher in the FUCO/ETX group than in the FUCO/ETX/PAF-ANT group and control group. Differences in macromolecular leakage between groups were significant at 120 min. Differences in mast cell activity between groups were significant at 60 and 120 min. CONCLUSIONS: The results of our study demonstrate a leukocyte-independent plasma extravasation that can be inhibited by the PAF receptor antagonist BN52021, indicating the involvement of PAF in the pathophysiology of leukocyte-independent microvascular damage during early endotoxemia. Mast cell activity seems to precede leukocyte-independent macromolecular leakage.     

Role of mast cell tryptase in renal interstitial fibrosis.

Renal interstitial fibrosis is characterized by increased proliferation of fibroblasts and excessive accumulation of extracellular matrix. Mast cell tryptase has been implicated in the development of tissue fibrosis in skin and lungs. However, the significance of mast cell tryptase in human renal diseases has not been investigated. The potential role of mast cell-derived tryptase in the development of renal fibrosis was studied using immunohistochemical techniques and cultured human renal fibroblast cell lines. Semiquantitative immunostaining analysis of samples from 70 patients with several renal diseases, including IgA glomerulonephritis (GN) (n = 30), non-IgA GN (n = 5), membranous GN (n = 5), focal segmental glomerulosclerosis (n = 4), minor glomerular abnormalities (n = 5), lupus nephritis (n = 3), and acute or chronic tubulointerstitial nephritis (n = 18), revealed that the degree of renal interstitial fibrosis was well correlated with the number of infiltrating tryptase-positive mast cells (P < 0.01). Mast cells could not be detected in damaged glomeruli in any form of renal disease. [(3)H]Thymidine uptake experiments demonstrated that DNA synthesis by cultured renal fibroblasts was increased with the concentration of tryptase (0.5 to 5 nM) coincubated with heparin and was suppressed by coincubation with the protease inhibitors leupeptin and benzamidine hydrochloride. Tryptase alone also increased DNA synthesis by fibroblasts but exhibited less effectiveness, compared with the combination of tryptase and heparin. Conversely, heparin alone suppressed DNA synthesis by fibroblasts. Metabolic [(35)S]methionine-labeling experiments with cultured renal fibroblasts indicated that tryptase increased the synthesis of fibronectin and collagen type I, in a dose-dependent manner. These findings suggest that mast cell tryptase plays a role in the proliferation and extracellular matrix protein production of renal interstitial fibroblasts and thus contributes to the development of renal interstitial fibrosis.     

Role of mast cells in the pathogenesis of postburn inflammatory response: reactive oxygen species as mast cell stimulators

Thermal trauma has a direct effect on mast cells, triggering the secretion of histamine. This secretion leads to an enhanced xanthine oxidase activity and an increased production of reactive oxygen species (ROS), the latter being produced after burns through differing mechanisms. As ROS have been shown to have deleterious effects on cellular membranes, a lesion of the mast cell membrane could close the circle of autoinjury due to the vasoactive actions of mast cell mediators. Our studies were designed to assess the potentiality of ROS as stimulators of mast cell degranulation after burns by comparing two groups of rats treated, respectively, with SOD and saline solution after a scald injury. Plasma levels of tryptase and histamine were analyzed as markers of mast cell activity. A comparison of the mean increases of tryptase between baseline and 3-h postburn levels in the two groups shows significant differences (p < 0.001) (control: 0.13+/-0.04, SOD: 0.03+/-0.01). When comparing the mean increases between the baseline and 3 h postburn levels of histamine in the two groups, significant differences were also found (p < 0.001) (control group: 2.70+/-0.57. SOD group: 1.22+/-0.32). The lower levels of histamine and tryptase induced by SOD provides indirect evidence that ROS are involved in the process, causing the release of such mediators by mast cells, which may in turn suggest that ROS can act as stimulators of mast cell degranulation in burns.     

Role of mast cells in progressive renal diseases

Advances in understanding mast cell biology reveal their diverse functional capacity well beyond already established roles in host defense against parasites and allergic disease. Mast cells can initiate, amplify, and direct innate and adaptive immune responses. They also modulate inflammation and regulate immunity. Mast cells potentially induce tissue repair and direct fibrosis; however, they also play other roles in tissue remodeling and repair. Various activation and differentiating signals result in a diverse range of functional phenotypes called "mast cell heterogeneity." Mast cells are significant participants in chronic progressive kidney disease, and their presence is associated with function loss and fibrosis. This suggests a potential role in the fibrotic process, which may involve mast cell activation of local renin-angiotensin systems. Experimental animal studies suggest, however, they do not directly cause renal fibrosis but rather spark inflammation. Evidence for both pro- and anti-inflammatory roles in nephritis is emerging.     

结直肠癌肿瘤干细胞研究进展

结直肠癌是消化道常见的恶性肿瘤,在我国其发病率和死亡率呈明显上升趋势。肿瘤干细胞是指肿瘤内具有自我更新能力和形成异质性肿瘤的细胞亚群．是肿瘤耐药、复发、转移的根源。肿瘤干细胞的研究对结直肠癌的诊断、预防及治疗具有重要意义。本文就结直肠癌干细胞的研究热点和最新进展简要综述肿瘤干细胞的定义和起源、肿瘤干细胞表面标志物、维持肿瘤干细胞通路研究进展和肿瘤干细胞的治疗策略以及当前研究面临问题的思考。     

碱性成纤维细胞生长因子在富集结直肠癌肿瘤干细胞中的作用

目的 研究不同浓度碱性成纤维细胞生长因子（bFGF）作用于结直肠癌细胞不同时间,富集肿 瘤干细胞的效果。方法? 结直肠癌DLD-1细胞分别在含5 ng/mL、10 ng/mL、20 ng/mL bFGF的无血清培 养基中悬浮培养,分为G1、G2、G3组,设置培养时间梯度为10 d、20 d、30 d,获得球细胞。采用流式 细胞术（FCM）检测细胞球中的CD44+、CD133+及CD44+CD133+双阳性的细胞表达比例,Real-time PCR 检测球细胞中的干细胞基因（KLF4、Nanog）;上皮间质转化基因（E-cadherin、Snail）;Wnt/β-catenine通路 基因（Wnt-3a）的 mRNA表达情况,成球实验检测细胞球的自我更新能力。结果 FCM检测结果：CD44+ 阳性表达的细胞表达以G2组20 d最高,CD133+及CD44+CD133+双阳性的细胞表达均以G2组20 d及G3 组10 d最高,差异有统计学意义（F=98.895、147.641、13.321,P<0.05）。 Real-time PCR检测结果：各组中 KLF4、Nanog、Snail以及Wnt-3a mRNA的表达均以G2组20 d表达最高（F=2.424、7.694、2.951、3.771, 均P<0.05）, E-cadherin基因G2组20 d mRNA表达最低（G2组30 d、G1组10 d除外）（F=10.620,P<0.05）。 成球实验结果：各组比较G1组20 d和G2组20 d成球数量明显多于其他组,差异具有统计学意义（F=14.279, P<0.01）;但 G1组20 d和G2组20 d比较,无统计学差异（t=0.605,P=0.578）。 结论 碱性成纤维细胞生长 因子无血清悬浮培养能够有效富集肿瘤干细胞,其中G2组培养20 d较其余组能更有效地富集结直肠癌肿 瘤干细胞。     

Role of anemia in progression of chronic kidney disease

Anemia is a well-known consequence of chronic kidney disease (CKD), and its prevalence progressively increases when the estimated glomerular filtration rate decreases to less than 60 mL/min/1.73 m2. However, analyses of the consequences of anemia and of the mechanisms of progression of CKD suggest that anemia also could contribute to the deterioration of kidney function. This hypothesis is based mostly on experimental data that imply that hypoxia of tubular cells plays an important role in tubulointerstitial damage associated with CKD and, thus, in the progression of renal failure. It also is supported by the fact that red blood cells represent a major antioxidant component of blood and that oxidative stress appears to contribute to glomerulosclerosis and tubulointerstitial damage. In humans, post hoc analysis of the Reduction of End points in non insulin-dependent diabetes mellitus (NIDDM) with the Angiotensin II Antagonist Losartan study and analyses of smaller prospective cohorts of CKD patients have shown that anemia is an independent risk factor for progression of CKD. In addition, 3 small randomized studies have suggested that anemia correction could slow the progression of CKD. Thus, the existence of a relationship between anemia and progression of CKD is not only plausible biologically, but also is supported by observational studies and by small intervention studies. However, only a large, randomized, prospective trial will be able to establish if anemia correction can slow the progression of CKD effectively.     

间充质干细胞联合输注促进造血干细胞移植后的造血重建

目的探讨间充质干细胞(MSCs)与造血干细胞(HSCs)共同移植对造血重建的影响。方法将扩增的Balb/c小鼠骨髓MSCs与骨髓共同经尾静脉输入经致死剂量照射的同系小鼠体内(联合输注组),并设单输骨髓细胞的HSCs组、单输间充质干细胞的MSCs组以及输培养基的对照组,每隔5d计数白细胞,计算动物死亡率。将乙酰乙酸碳氧荧光素标记的人间充质干细胞输入SCID小鼠尾静脉,24h后取肺、心、肝、脾、肾和小肠组织做冰冻切片;取骨髓、肝脏及脾脏,制成单细胞悬液,涂片,在荧光显微镜下观察计数;用逆转录聚合酶链反应测定鼠骨髓中人特异性β2-微球蛋白。结果细胞输注后,联合移植组的白细胞恢复快,12d左右恢复正常,死亡率(3/11)低于HSCs组(5/10)、MSCs组(4/4)、输培养基的对照组(11/11)。人MSCs输入SCID小鼠后24h,其在体内的分布依次为肺、肾、脾、肝,小肠及心脏组织中几乎无阳性细胞,骨髓中有极少MSCs。结论MSCs与造血干细胞共输能促进造血恢复。     

肥大细胞在重症急性胰腺炎发病机制中的作用

重症急性胰腺炎是外科是常见的急腹症，迄今尚无特异性治疗。肥大细胞是重要炎症效应细胞，在重症急性胰腺炎发病机制中发挥重要作用，引起胰腺、肺、肠道等器官损害。肥大细胞稳定剂通过抑制其炎症反应，对重症急性胰腺炎时上述器官有重要的保护作用。     

Treatments of hemodynamic maladjustment and oxidative stress prevent renal disease progression in chronically severe glomerulonephritides

Hemodynamic maladjustment is a unique observation in chronically severe glomerulonephritides. It is characterized by a markedly elevated efferent arteriolar resistance (RE), an elevated intraglomerular hydrostatic pressure (PG) and a markedly decreased renal plasma flow (RPF), and peritubular capillary flow (PTCF). A correction of such hemodynamic maladjustment can be accomplished by administering a combination of vasodilators (angiotensin receptor antagonist, angiotensin converting enzyme inhibitor, and calcium channel blocker) in 14 chronic glomerulonephritides with severe renal function impairment (mean serum creatinine 3.6 + 1.3 mg/dL). Doses titration aim for maximal renal perfusion effect (increased RPF, PTCF) or maximal renal function improvement (increased CCr, reduced FE Mg) usually higher than needed for maximal blood pressure reduction. Evidence of oxidative stress is also corrected with high doses of vitamins C and E. After a mean period of treatment for 13.5 months, improvements in CCr (pre R(x) 22 +/- 10 vs. post R(x) 32 +/- 13 mL/min/1.73 m2), and FE Mg (pre R(x) 11.9 +/- 4% vs. post R(x) 10 +/- 3%) were observed in conjunction with the improvement in intrarenal hemodynamics namely RPF (pre R(x) 201 +/- 71 vs. post R(x) 288 +/- 99 mL/min/1.73 m2), PTCF (pre R(x) 161 +/- 57 vs. post R(x) 242 +/- 90 mL/ min/1.73 m2), PG (pre R(x) 56.7 +/- 0.5 vs. post R(x) 51 +/- 0.1 mm Hg), and RE (pre R(x) 12085 +/- 6503 vs. post R(x) 6550 +/- 1872 dyne.s.cm(-5)).