Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box AA53, 9713 GZ, Groningen, The Netherlands.
Department of Vascular Surgery, Maastricht University Medical Center+, Maastricht, The Netherlands.
J Nephrol. 2023 Sep;36(7):2111-2124. doi: 10.1007/s40620-023-01734-5. Epub 2023 Sep 28.
Peritubular capillary rarefaction plays an important role in the progression of chronic kidney disease. Little is known about the relation between peritubular capillary density, glomerular volume and filtration rate in the healthy kidney.
In this single-center study, we included 69 living kidney donors who donated between 2005 and 2008 and had representative renal biopsies available. In all donors, glomerular filtration rate was measured using I-Iothalamate before donation and at five years after donation. Before donation, the increase in glomerular filtration rate after dopamine stimulation was measured. Glomerular volume and peritubular capillary density were determined in biopsies taken at the time of transplantation. Pearson's correlation coefficient and linear regression were used to assess relations between parameters.
Mean donor age was 52 ± 11 years and mean measured glomerular filtration rate was 119 ± 22 mL/min before donation and 82 ± 15 mL/min at five years after donation. While peritubular capillary density (measured by either number of peritubular capillaries/50,000 μm or number of peritubular capillaries/tubule) was not associated with measured glomerular filtration rate before or after donation, number of peritubular capillaries/tubule was associated with the increase in measured glomerular filtration rate after dopamine stimulation (St.β = 0.33, p = 0.004), and correlated positively with glomerular volume (R = 0.24, p = 0.047). Glomerular volume was associated with unstimulated measured glomerular filtration rate before donation (St.β = 0.31, p = 0.01) and at five years (St.β = 0.30, p = 0.01) after donation, independent of age.
In summary, peritubular capillary density was not related to unstimulated kidney function before or after kidney donation, in contrast to glomerular volume. However, number of peritubular capillaries/tubule correlated with the increase in glomerular filtration rate after dopamine stimulation in healthy kidneys, and with glomerular volume. These findings suggest that peritubular capillary density and glomerular volume differentially affect kidney function in healthy living kidney donors.
肾小管周毛细血管稀疏在慢性肾脏病的进展中起着重要作用。在健康的肾脏中，肾小管周毛细血管密度、肾小球体积和滤过率之间的关系知之甚少。
在这项单中心研究中，我们纳入了 69 名在 2005 年至 2008 年间捐赠肾脏的活体供者，他们在捐赠时和捐赠后 5 年均有代表性的肾活检样本。在所有供者中，在捐赠前和捐赠后 5 年使用 I-碘酞酸盐测量肾小球滤过率。在捐赠前，测量多巴胺刺激后肾小球滤过率的增加量。在移植时采集的活检中确定肾小球体积和肾小管周毛细血管密度。使用 Pearson 相关系数和线性回归来评估参数之间的关系。
供者的平均年龄为 52 ± 11 岁，在捐赠前的平均测量肾小球滤过率为 119 ± 22 mL/min，在捐赠后 5 年的平均测量肾小球滤过率为 82 ± 15 mL/min。虽然肾小管周毛细血管密度（通过每 50,000 μm 的肾小管周毛细血管数或每管的肾小管周毛细血管数来测量）与捐赠前后的测量肾小球滤过率无关，但每管的肾小管周毛细血管数与多巴胺刺激后测量肾小球滤过率的增加量相关（St.β=0.33，p=0.004），并且与肾小球体积呈正相关（R=0.24，p=0.047）。肾小球体积与捐赠前未受刺激的测量肾小球滤过率（St.β=0.31，p=0.01）和捐赠后 5 年（St.β=0.30，p=0.01）相关，与年龄无关。
总之，与肾小球体积相比，肾小管周毛细血管密度与捐赠前后未受刺激的肾功能无关。然而，在健康的肾脏中，每管的肾小管周毛细血管数与多巴胺刺激后肾小球滤过率的增加量以及肾小球体积相关。这些发现表明，肾小管周毛细血管密度和肾小球体积对健康活体供者的肾功能有不同的影响。
