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【20230720期】蛋白尿形成的原因及機制
2023-07-24
01
腎小球性蛋白尿(glomerular proteinuria)

腎(shen)(shen)(shen)(shen)小(xiao)(xiao)球(qiu)(qiu)(qiu)(qiu)因受到(dao)炎癥(zheng)、毒素等的損害,引起腎(shen)(shen)(shen)(shen)小(xiao)(xiao)球(qiu)(qiu)(qiu)(qiu)毛(mao)細血管(guan)壁通(tong)透性(xing)(xing)(xing)(xing)增加。濾(lv)出較多的血漿蛋(dan)(dan)白(bai)(bai)(bai),超(chao)過(guo)了(le)腎(shen)(shen)(shen)(shen)小(xiao)(xiao)管(guan)重吸收(shou)能(neng)力所(suo)形成的蛋(dan)(dan)白(bai)(bai)(bai)尿,稱為(wei)腎(shen)(shen)(shen)(shen)小(xiao)(xiao)球(qiu)(qiu)(qiu)(qiu)性(xing)(xing)(xing)(xing)蛋(dan)(dan)白(bai)(bai)(bai)尿。形成蛋(dan)(dan)白(bai)(bai)(bai)尿的機制(zhi)除腎(shen)(shen)(shen)(shen)小(xiao)(xiao)球(qiu)(qiu)(qiu)(qiu)濾(lv)過(guo)膜的物理(li)性(xing)(xing)(xing)(xing)空間(jian)構型(xing)改變(bian)(bian)導致“孔(kong)徑”增大外(wai),還與腎(shen)(shen)(shen)(shen)小(xiao)(xiao)球(qiu)(qiu)(qiu)(qiu)濾(lv)過(guo)膜的各層特別是足突細胞層的唾液(ye)酸(suan)減少或消失,以致靜電屏障作用減弱有關。蛋(dan)(dan)白(bai)(bai)(bai)電泳檢查漏出的蛋(dan)(dan)白(bai)(bai)(bai)質中(zhong)白(bai)(bai)(bai)蛋(dan)(dan)白(bai)(bai)(bai)約占70-80%,β2微球(qiu)(qiu)(qiu)(qiu)蛋(dan)(dan)白(bai)(bai)(bai)可輕度增多。此(ci)型(xing)蛋(dan)(dan)白(bai)(bai)(bai)尿中(zhong)尿蛋(dan)(dan)白(bai)(bai)(bai)含量常大于(yu)2g/24h,主要(yao)見(jian)于(yu)腎(shen)(shen)(shen)(shen)小(xiao)(xiao)球(qiu)(qiu)(qiu)(qiu)疾(ji)病(bing)如(ru)急性(xing)(xing)(xing)(xing)腎(shen)(shen)(shen)(shen)小(xiao)(xiao)球(qiu)(qiu)(qiu)(qiu)腎(shen)(shen)(shen)(shen)炎,某些繼(ji)發(fa)性(xing)(xing)(xing)(xing)腎(shen)(shen)(shen)(shen)臟病(bing)變(bian)(bian)如(ru)糖尿病(bing)性(xing)(xing)(xing)(xing)腎(shen)(shen)(shen)(shen)病(bing),免疫(yi)復合物病(bing)如(ru)斑狼(lang)瘡性(xing)(xing)(xing)(xing)腎(shen)(shen)(shen)(shen)病(bing)等。此(ci)外(wai),功(gong)能(neng)性(xing)(xing)(xing)(xing)蛋(dan)(dan)白(bai)(bai)(bai)尿體位性(xing)(xing)(xing)(xing)蛋(dan)(dan)白(bai)(bai)(bai)尿產生的機制(zhi)也與此(ci)相(xiang)關。

02
腎小管性蛋白尿(tubular proteinuria)

由(you)于(yu)(yu)炎癥或(huo)中(zhong)毒(du)引起的近(jin)曲小(xiao)(xiao)管(guan)對低(di)分子量(liang)蛋(dan)白(bai)(bai)質(zhi)的重吸收功能減退而出現以(yi)低(di)分子量(liang)蛋(dan)白(bai)(bai)質(zhi)為主(zhu)的蛋(dan)白(bai)(bai)尿(niao)(niao)(niao)(niao),稱為腎(shen)小(xiao)(xiao)性(xing)(xing)蛋(dan)白(bai)(bai)尿(niao)(niao)(niao)(niao),通過尿(niao)(niao)(niao)(niao)蛋(dan)白(bai)(bai)電泳及(ji)(ji)免疫化學(xue)方法檢查,發(fa)現尿(niao)(niao)(niao)(niao)中(zhong)以(yi)β2微(wei)球(qiu)蛋(dan)白(bai)(bai)、溶菌(jun)酶(mei)等增(zeng)(zeng)多為主(zhu),白(bai)(bai)蛋(dan)白(bai)(bai)正常或(huo)輕(qing)度增(zeng)(zeng)多,單純性(xing)(xing)腎(shen)小(xiao)(xiao)管(guan)性(xing)(xing)蛋(dan)白(bai)(bai)尿(niao)(niao)(niao)(niao),尿(niao)(niao)(niao)(niao)蛋(dan)白(bai)(bai)含量(liang)較低(di),一般低(di)于(yu)(yu)1g/24h。此(ci)型蛋(dan)白(bai)(bai)尿(niao)(niao)(niao)(niao)常見于(yu)(yu)腎(shen)盂腎(shen)炎、間質(zhi)性(xing)(xing)腎(shen)炎、腎(shen)小(xiao)(xiao)管(guan)性(xing)(xing)酸(suan)中(zhong)毒(du)、重金屬中(zhong)毒(du),應用慶(qing)林毒(du)素(su)、多粘菌(jun)素(su)B及(ji)(ji)腎(shen)移植(zhi)術后(hou)等。尿(niao)(niao)(niao)(niao)中(zhong)β2微(wei)球(qiu)蛋(dan)白(bai)(bai)與(yu)(yu)白(bai)(bai)蛋(dan)白(bai)(bai)的比(bi)值,有助于(yu)(yu)區(qu)別(bie)腎(shen)小(xiao)(xiao)球(qiu)與(yu)(yu)腎(shen)小(xiao)(xiao)管(guan)性(xing)(xing)蛋(dan)白(bai)(bai)尿(niao)(niao)(niao)(niao)。

03
混全性蛋白尿(mixed proteinuria)
腎(shen)臟病變(bian)如何同(tong)時累及腎(shen)小(xiao)球(qiu)及腎(shen)小(xiao)管,產生(sheng)的(de)蛋(dan)白(bai)尿稱混(hun)合性蛋(dan)白(bai)尿。在尿蛋(dan)白(bai)電泳的(de)圖譜中(zhong)顯示低(di)分子(zi)量的(de)β2M及中(zhong)分子(zi)量的(de)白(bai)蛋(dan)白(bai)同(tong)時拉多(duo),而大(da)分子(zi)量的(de)蛋(dan)白(bai)質較少。

04
溢出性蛋白尿(overfiow proteinuria)

主要(yao)指血循環中出(chu)(chu)現大量低子量(分(fen)子量小于(yu)4.5萬)的蛋(dan)白質如(ru)本(ben)周(zhou)蛋(dan)白。血漿肌(ji)紅(hong)肌(ji)紅(hong)蛋(dan)白(分(fen)子量為(wei)(wei)1.4萬)增多(duo)超過腎小管回吸收的極限于(yu)尿中大量出(chu)(chu)現時稱為(wei)(wei)肌(ji)紅(hong)蛋(dan)白尿,也屬(shu)于(yu)溢出(chu)(chu)性蛋(dan)白尿,可見于(yu)骨骼(ge)肌(ji)嚴重創傷及大面積心肌(ji)梗死等時。

05
偶然性蛋白尿(accidental priteinutia)

當尿(niao)中混(hun)有(you)多量血(xue)、膿、粘液等(deng)(deng)成分(fen)而導致蛋(dan)白定性試(shi)驗陽性時稱為偶然性蛋(dan)白尿(niao)。主要見(jian)于(yu)泌尿(niao)道炎癥(zheng)、出血(xue)及(ji)在尿(niao)中混(hun)入陰道分(fen)泌物、男性精液等(deng)(deng),一般并(bing)不伴有(you)腎本身的(de)損害。

06
生理性蛋白尿或無癥狀性蛋白尿

指由于各種體(ti)內外交(jiao)困環境因素結機(ji)體(ti)的影響而導(dao)致的尿(niao)蛋白(bai)含量增多,又可(ke)分為功能(neng)性蛋白(bai)尿(niao)及體(ti)位性(直立性)蛋白(bai)尿(niao)。



功能性(xing)(xing)蛋白(bai)(bai)(bai)尿(niao)(tunctionalproteinuria)指機體在(zai)劇烈運動、發(fa)熱、低溫刺激、精神緊(jin)張、交感神經興奮等所致(zhi)的暫時(shi)性(xing)(xing)、輕度性(xing)(xing)的蛋白(bai)(bai)(bai)尿(niao)。其形成(cheng)強制可(ke)能與上述原因造成(cheng)腎血(xue)痙攣或充血(xue)而使腎小球毛(mao)細積壓管壁的通透性(xing)(xing)增(zeng)加所致(zhi)當誘發(fa)因素消失時(shi),尿(niao)蛋白(bai)(bai)(bai)也迅速(su)消失。生理性(xing)(xing)蛋白(bai)(bai)(bai)尿(niao)定(ding)性(xing)(xing)一般不超過(+)定(ding)量小于0.5g/24h,多見于青(qing)少年期。



體位性蛋白尿(niao)(niao)(posturalproteinuria)又稱(cheng)直(zhi)立性蛋白尿(niao)(niao)(orthostatic proteinuria),指由于直(zhi)立體位或(huo)腰部前(qian)突(tu)時(shi)引起的(de)蛋白尿(niao)(niao)。其(qi)特點為臥床(chuang)時(shi)尿(niao)(niao)蛋白定性為陰(yin)性,起床(chuang)活動(dong)若干時(shi)間后即(ji)可出(chu)現(xian)蛋白尿(niao)(niao),尿(niao)(niao)蛋白定性可達(2+)甚(shen)至(zhi)(3+),而平(ping)臥后又轉(zhuan)成(cheng)陰(yin)性,常見(jian)于青(qing)少年,可隨年齡增長而消失。此種(zhong)蛋白尿(niao)(niao)了生機制(zhi)可能與直(zhi)立時(shi)前(qian)突(tu)的(de)脊柱壓(ya)迫腎(shen)(shen)靜脈(mo)(mo),或(huo)直(zhi)立位時(shi)腎(shen)(shen)的(de)位置向下移動(dong),使(shi)腎(shen)(shen)靜脈(mo)(mo)扭曲而致(zhi)腎(shen)(shen)臟(zang)處于瘀(yu)血(xue)狀態,淋巴(ba)、血(xue)流受(shou)阻有(you)關。


有關各種蛋白尿的分類及機制見下圖




蛋(dan)白(bai)尿分類及發生(sheng)機制(zhi)
參考文獻:叢玉隆,馬俊龍,張時民(min).北京:現代尿液分析技術(shu)與臨(lin)床(chuang).人(ren)民(min)軍醫出版,2007.7