Podocyte hypertrophic stress and detachment precedes hyperglycemia or albuminuria in a rat model of obesity and type2 diabetes-associated nephropathy

AbstractType2 diabetes-associated nephropathy is the commonest cause of renal failure. Mechanisms responsible are controversial. Leptin-deficient hyperphagic Zucker (fa/fa) rats were modeled to test the hypothesis that glomerular enlargement drives podocyte hypertrophic stress leading to accelerated podocyte detachment, podocyte depletion, albuminuria and progression. By 6weeks, prior to development of either hyperglycemia or albuminuria, fa/fa rats were hyperinsulinemic with high urinary IGF1/2 excretion, gaining weight rapidly, and had 1.6-fold greater glomerular volume than controls (P < 0.01). At this time the podocyte number per glomerulus was not yet reduced although podocytes were already hypertrophically stressed as shown by high podocyte phosphor-ribosomal S6 (a marker of mTORC1 activation), high urinary pellet podocin:nephrin mRNA ratio and accelerated podocyte detachment (high urinary pellet podocin:aquaporin2 mRNA ratio). Subsequently, fa/fa rats became both hyperglycemic and albuminuric. 24 hr urine albumin excretion correlated highly with decreasing podocyte density (R2 = 0.86), as a consequence of both increasing glomerular volume (R2 = 0.70) and decreasing podocyte number (R2 = 0.63). Glomerular podocyte loss rate was quantitatively related to podocyte detachment rate measured by urine pellet mRNAs. Glomerulosclerosis occurred when podocyte density reached <50/106um3. Reducing food intake by 40% to slow growth reduced podocyte hypertrophic stress and “froze” all elements of the progression process in place, but had small effect on hyperglycemia. Glomerular enlargement caused by high growth factor milieu starting in pre-diabetic kidneys appears to be a primary driver of albuminuria in fa/fa rats and thereby an under-recognized target for progression prevention. Progression risk could be identified prior to onset of hyperglycemia or albuminuria, and monitored non-invasively by urinary pellet podocyte mRNA markers.

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Urinary podocyte mRNAs precede microalbuminuria as a progression risk marker in human type 2 diabetic nephropathy

Scientific Reports ◽

10.1038/s41598-020-75320-1 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Akihiro Fukuda ◽

Akihiro Minakawa ◽

Masao Kikuchi ◽

Yuji Sato ◽

Masanao Nagatomo ◽

...

Keyword(s):

Diabetic Nephropathy ◽

Risk Marker ◽

Cross Sectional ◽

Type 2 Diabetics ◽

Mrna Ratio ◽

Podocyte Detachment ◽

Progression Risk ◽

Sectional Analysis ◽

Mrna Markers

Abstract Earlier detection of progression risk in diabetic nephropathy will allow earlier intervention to reduce progression. The hypothesis that urinary pellet podocyte mRNA is a more sensitive progression risk marker than microalbuminuria was tested. A cross sectional cohort of 165 type 2 diabetics and 41 age and sex-matched controls were enrolled. Podocyte stress (Urinary pellet podocin:nephrin mRNA ratio), podocyte detachment (Urinary pellet podocin mRNA:creatinine ratio: UPPod:CR) and a tubular marker (Urinary pellet aquaporin 2:creatinine ratio) were measured in macro-albuminuric, micro-albuminuric and norm-albuminuric groups. eGFR was reassessed after 4 years in 124 available diabetic subjects. Urinary pellet podocyte and tubular mRNA markers were increased in all diabetic groups in cross-sectional analysis. After 4 years of follow-up univariable and multivariate model analysis showed that the only urinary markers significantly related to eGFR slope were UPPod:CR (P < 0.01) and albuminuria (P < 0.01). AUC analysis using K-fold cross validation to predict eGFR loss of ≥ 3 ml/min/1.73m2/year showed that UPPod:CR and albuminuria each improved the AUC similarly such that combined with clinical variables they gave an AUC = 0.70. Podocyte markers and albuminuria had overlapping AUC contributions, as expected if podocyte depletion causes albuminuria. In the norm-albuminuria cohort (n = 75) baseline UPPod:CR was associated with development of albuminuria (P = 0.007) and, in the tertile with both normal kidney function (eGFR 84 ± 11.7 ml/min/1.73m2) and norm-albuminuria at baseline, UPPod:CR was associated with eGFR loss rate (P = 0.003). In type 2 diabetics with micro- or macro-albuminuria UPPod:CR and albuminuria were equally good at predicting eGFR loss. For norm-albuminuric type 2 diabetics UPPod:CR predicted both albuminuria and eGFR loss.

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Korelasi Jumlah Netrofil, Limfosit, dan Monosit dengan Kadar Albumin Urin pada Pasien DM Tipe 2 dengan Mikroalbuminuria

Biomedika ◽

10.23917/biomedika.v1i1.287 ◽

2009 ◽

Vol 1 (1) ◽

Author(s):

Edy Purwanto

Keyword(s):

Type 2 Diabetes ◽

Albumin Level ◽

Cost Of Care ◽

Monocyte Count ◽

Cross Sectional ◽

Urine Albumin ◽

Type2 Diabetes ◽

Coefficient Corrélation ◽

Analyzer Cell

The most common complication of diabetes is diabetic nephropathy which is a progressive disease and in the terminal stages, needs a very large cost of care. Nephropathy diabetic can be prevented if it is detected earlier. Microalbuminuria is a test to detect nepropathy diabetic early nowadays, but it is still considered expensive by the majority of the community and has not been widely done in laboratories. What ever it needs other alternatives, such as neutrophils, lymphocyte, and monocyte counts. The purpose of this study is to analyse the correlations between neutrophils, lymphocyte, monocyte counts and urine albumin levels in type2 diabetes with microalbuminuria. The research design is analytic observational with cross sectional approach. Twenty two patients met the inclusion criteria. Their urine albumin levels tested by Nycocard® U-ALBUMIN reagent. Neutrophils, lymphocyte, monocyte count was examined by hematology analyzer CELL-Dyn 3700. The correlations between neutrophils, lymphocyte, monocyte counts and urine albumin levels analyzed using coefficient correlation Spearman's. No correlation between neutrophil countsand urine albumin levels (r= -0,250;p=0,263). No correlation between monocyte counts and urine albumin levels (r= -0,191;p=0,395). No correlation between lymphocyte counts and urine albumin levels (r=0,130;p=0,565) in type 2 diabetes with microalbuminuria. No correlation between neutrophils, lymphocyte, monocyte counts and urine albumin level in type 2 diabetes patients with microalbuminuriaKeywords: type 2 diabetes, neutrophils, lymphocytes, monocytes, microalbuminuria.

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Accelerated podocyte detachment and progressive podocyte loss from glomeruli with age in Alport Syndrome

Kidney International ◽

10.1016/j.kint.2017.05.017 ◽

2017 ◽

Vol 92 (6) ◽

pp. 1515-1525 ◽

Cited By ~ 11

Author(s):

Fangrui Ding ◽

Larysa Wickman ◽

Su Q. Wang ◽

Yanqin Zhang ◽

Fang Wang ◽

...

Keyword(s):

Alport Syndrome ◽

Podocyte Detachment ◽

Podocyte Loss

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Effects of Perfusion Pressures on Podocyte Loss in the Isolated Perfused Mouse Kidney.

Cellular Physiology and Biochemistry ◽

10.33594/000000355 ◽

2021 ◽

Vol 55 (S4) ◽

pp. 1-12

Keyword(s):

Ex Vivo ◽

Early Time ◽

Filtration Flow ◽

Glomerular Diseases ◽

Aged Mice ◽

Foot Process Effacement ◽

Podocyte Detachment ◽

Podocyte Loss ◽

Foot Process ◽

Young Mice

BACKGROUND/AIMS: Podocytes are lost in most glomerular diseases, leading to glomerulosclerosis and progressive kidney disease. It is generally assumed, that podocytes are exposed to the filtration flow and thus to significant shear forces driving their detachment from the glomerular basement membrane (GBM). In this context, foot process effacement has been proposed as potential adaptive response to increase adhesion of podocytes to the GBM. METHODS: We have tested these hypotheses using optical clearing and high-resolution 3-dimensional morphometric analysis in the isolated perfused murine kidney. We investigated the dynamics of podocyte detachment at different perfusion pressures (50, 300 and more than 450 mmHg) in healthy young or old mice (20 vs. 71 weeks of age), or mice injected with anti-GBM serum to induce global foot process effacement. RESULTS: Results show that healthy podocytes in young mice are tightly attached onto the GBM and even supramaximal pressures did not cause significant detachment. Compared to young mice, in aged mice and mice with anti-GBM nephritis and foot process effacement, gradual progressive loss of podocytes had occurred already before perfusion. High perfusion pressures resulted in a relatively minor additional loss of podocytes in aged mice. In mice with anti-GBM nephritis significant additional podocyte loss occurred at this early time point when increasing perfusion pressures to 300 mmHg or higher. CONCLUSION: This work provides the first experimental evidence that podocytes are extraordinarily resistant to acutely increased perfusion pressures in an ex vivo isolated kidney perfusion model. Only in glomerular disease, significant numbers of injured podocytes detached following acute increases in perfusion pressure.

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Podocyte Foot Process Effacement Precedes Albuminuria and Glomerular Hypertrophy in CD2-Associated Protein Deficient Mice

Frontiers in Medicine ◽

10.3389/fmed.2021.745319 ◽

2021 ◽

Vol 8 ◽

Author(s):

John M. Basgen ◽

Jenny S. Wong ◽

Justina Ray ◽

Susanne B. Nicholas ◽

Kirk N. Campbell

Keyword(s):

Light And Electron Microscopy ◽

Glomerular Hypertrophy ◽

Mesangial Expansion ◽

Podocyte Injury ◽

Glomerular Volume ◽

Urine Albumin ◽

Foot Process Effacement ◽

Foot Process ◽

Grid Points ◽

Deficient Mice

Background: Podocyte foot process effacement is a key histologic finding in proteinuric kidney disease. We previously showed that 3-week old CD2AP-deficient mice have significant proteinuria, glomerular hypertrophy and mesangial expansion. The goal of this study is to use morphometry to establish the temporal sequence of podocyte foot process effacement, glomerular volume expansion and albuminuria in Cd2ap−/− mice by measuring these parameters at the 2-week time point.Methods: Wild-type mice age 14 ± 1 days with the Cd2ap gene (WT, N = 5) and mice deficient for Cd2ap (Cd2ap KO, N = 5) were generated. Kidneys were harvested and fixed in 2.5% glutaraldehyde and processed for examination by light and electron microscopy. An average of 415.2 (range 268–716) grid points were counted for all the glomeruli, and quantification of glomerular volume from each kidney. Urine was collected the day prior to sacrifice for urine albumin-to-creatinine ratio (ACR) measurements.Results: There was no difference in albuminuria [median (range) mg/g] between WT [212.2 (177.6–388.4) mg/g] vs. Cd2ap KO mice [203.3 (164.7–910.2) mg/g], P = 0.89; or glomerular volume 68,307[10,931] vs. 66,844[13,022] μm3, p = 0.92. The volume densities of glomerular components of the podocyte, capillary lumen and mesangium were not different for the two groups, P = 0.14, 0.14 and 0.17 respectively. However, foot process width was increased in Cd2ap KO 1128[286] vs. WT [374 ± 42] nm, P = 0.02.Conclusion: Here we show that while 2-week old WT and Cd2ap KO mice have similar levels of albuminuria, glomerular and mesangial volume, Cd2ap KO mice have more extensive podocyte foot process effacement. The data suggests that podocyte injury is the initiating event leading to mesangial expansion and albuminuria in this model.

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Controversies in Podocyte Loss: Death or Detachment?

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.771931 ◽

2021 ◽

Vol 9 ◽

Author(s):

Lijun Yin ◽

Lu Yu ◽

John Cijiang He ◽

Anqun Chen

Keyword(s):

Cell Death ◽

Apoptotic Cell ◽

Large Body ◽

Mitotic Catastrophe ◽

Common Mechanism ◽

Glomerular Diseases ◽

Related Cell ◽

Podocyte Detachment ◽

Podocyte Loss

Glomerular podocytes are characterized by terminally differentiated epithelial cells with limited proliferating ability; thus, podocyte loss could not be fully compensated by podocyte regeneration. A large body of clinical studies collectively demonstrated that podocyte loss correlated with glomerular diseases progression. Both podocyte death and podocyte detachment lead to podocyte loss; however, which one is the main cause remains controversial. Up to date, multiple mechanisms are involved in podocyte death, including programmed apoptotic cell death (apoptosis and anoikis), programmed nonapoptotic cell death (autophagy, entosis, and podoptosis), immune-related cell death (pyroptosis), and other types of cell death (necroptosis and mitotic catastrophe-related cell death). Apoptosis is considered a common mechanism of podocyte loss; however, most of the data were generated in vitro and the evidence of in vivo podocyte apoptosis is limited. The isolation of podocytes in the urine and subsequent culture of urinary podocytes in vitro suggest that detachment of viable podocytes could be another important mechanism for podocyte loss. In this review, we summarize recent advances that address this controversial topic on the specific circumstances of podocyte loss.

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