Limits...
Integrin α1/Akita double-knockout mice on a Balb/c background develop advanced features of human diabetic nephropathy.

Yu L, Su Y, Paueksakon P, Cheng H, Chen X, Wang H, Harris RC, Zent R, Pozzi A - Kidney Int. (2012)

Bottom Line: Animal models that mimic human diabetic nephropathy are useful to identify key factors in pathogenesis of this disease, as well as the development of new therapies.Interestingly, crossing these AkitaKO mice with integrin α1KO mice, a model of exacerbated glomerulosclerosis after injury and also on the Balb/c background, resulted in a 16-fold increase in albuminuria, significant mesangial matrix expansion, nodular and diffuse glomerulosclerosis, and a 2-fold increase in glomerular basement membrane thickening when compared with nondiabetic mice.Moreover, a significant decline in glomerular filtration was evident in the α1KOAkitaKO mice at 6 months of age.

View Article: PubMed Central - PubMed

Affiliation: Division of Nephrology, Department of Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA.

ABSTRACT
Animal models that mimic human diabetic nephropathy are useful to identify key factors in pathogenesis of this disease, as well as the development of new therapies. Several mouse models of diabetes have features of human diabetic nephropathy, yet none of these completely fulfill the Animal Models of Diabetes Complications Consortium criteria and completely reproduce pathological and functional features of the human disease. The Akita mouse carries a mutation in the insulin-2 gene and, to date, only survives as heterozygotes that develop spontaneous type 1 diabetes. Here we show that Akita mice with mutation of both insulin-2 alleles (Akita knockout (KO)) survive if crossed onto the Balb/c background. These mice develop hyperglycemia, more severe albuminuria, and mesangial sclerosis compared with heterozygous mice on the same genetic background. Interestingly, crossing these AkitaKO mice with integrin α1KO mice, a model of exacerbated glomerulosclerosis after injury and also on the Balb/c background, resulted in a 16-fold increase in albuminuria, significant mesangial matrix expansion, nodular and diffuse glomerulosclerosis, and a 2-fold increase in glomerular basement membrane thickening when compared with nondiabetic mice. Moreover, a significant decline in glomerular filtration was evident in the α1KOAkitaKO mice at 6 months of age. Thus, the integrin α1KOAkitaKO Balb/c mouse represents a promising model presenting with most features of human diabetic nephropathy.

Show MeSH

Related in: MedlinePlus

No significant evidence of tubulointerstitial fibrosis in α1KOAkitaKO Balb/c mice(A) Electron microscopy pictures of tubules of 6 month old WT, AkitaKO and α1KOAkitaKO mice. Scale bar, 2 μm. The values (in nm) represent the mean +/− SD of tubular basement membrane thickness of 30 measurements. (B) Paraffin kidney sections were co-stained with Dolichos biflorus agglutinin (DBA) and anti-collagen I (upper panel) or anti-α-smooth muscle action (α-SMA, lower panel). Merged images are shown. V = vessel (C) Paraffin kidney sections were co-stained with anti-mouse E-cadherin antibodies or DAPI. Merged images at both low and high magnification are shown.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3345314&req=5

Figure 9: No significant evidence of tubulointerstitial fibrosis in α1KOAkitaKO Balb/c mice(A) Electron microscopy pictures of tubules of 6 month old WT, AkitaKO and α1KOAkitaKO mice. Scale bar, 2 μm. The values (in nm) represent the mean +/− SD of tubular basement membrane thickness of 30 measurements. (B) Paraffin kidney sections were co-stained with Dolichos biflorus agglutinin (DBA) and anti-collagen I (upper panel) or anti-α-smooth muscle action (α-SMA, lower panel). Merged images are shown. V = vessel (C) Paraffin kidney sections were co-stained with anti-mouse E-cadherin antibodies or DAPI. Merged images at both low and high magnification are shown.

Mentions: One of the hallmarks of late stages of DN is the development of tubulointerstitial fibrosis. On examination by light microscopy of the kidneys, no evidence of severe tubulointerstitial fibrosis was seen (Figs. 2 and 4). However, we wanted to define subtle changes that might be present in the tubulointerstitium of the AkitaKO and α1KOAkitaKO mice. We therefore examined the tubulointerstitium by electron microscopy to define tubular morphology and tubular basement membrane thickness in the kidneys of 6 month old wild type, AkitaKO and α1KOAkitaKO mice (Fig 9A). No differences in any of the parameters analyzed were seen between the three genotypes. We next co-stained kidney paraffin sections for collagen I and Dolichos biflorus agglutinin [a glycoprotein that binds the apical aspect of CD cells, 20] to define whether there was increased collagen I in the tubulointerstitial compartment (Fig 9B). A small, but equal increase in collagen I staining was seen in both AkitaKO and α1KOAkitaKO mice when compared to non-diabetic wild type animals. When we immunostained with anti-α-smooth muscle actin antibodies to define whether there were increased interstitial fibroblasts or if tubular cells had acquired a more mesenchymal morphology, no differences were seen between the genotypes (Fig 9C). Finally, no differences in tubular integrity were seen in the different genotypes when kidneys were immunostained with anti-E-cadherin antibodies. Thus, other than a minimal increase in collagen I expression, there was negligible tubulointerstitial disease in the AkitaKO and α1KOAkitaKO mice at 6 months of age.


Integrin α1/Akita double-knockout mice on a Balb/c background develop advanced features of human diabetic nephropathy.

Yu L, Su Y, Paueksakon P, Cheng H, Chen X, Wang H, Harris RC, Zent R, Pozzi A - Kidney Int. (2012)

No significant evidence of tubulointerstitial fibrosis in α1KOAkitaKO Balb/c mice(A) Electron microscopy pictures of tubules of 6 month old WT, AkitaKO and α1KOAkitaKO mice. Scale bar, 2 μm. The values (in nm) represent the mean +/− SD of tubular basement membrane thickness of 30 measurements. (B) Paraffin kidney sections were co-stained with Dolichos biflorus agglutinin (DBA) and anti-collagen I (upper panel) or anti-α-smooth muscle action (α-SMA, lower panel). Merged images are shown. V = vessel (C) Paraffin kidney sections were co-stained with anti-mouse E-cadherin antibodies or DAPI. Merged images at both low and high magnification are shown.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3345314&req=5

Figure 9: No significant evidence of tubulointerstitial fibrosis in α1KOAkitaKO Balb/c mice(A) Electron microscopy pictures of tubules of 6 month old WT, AkitaKO and α1KOAkitaKO mice. Scale bar, 2 μm. The values (in nm) represent the mean +/− SD of tubular basement membrane thickness of 30 measurements. (B) Paraffin kidney sections were co-stained with Dolichos biflorus agglutinin (DBA) and anti-collagen I (upper panel) or anti-α-smooth muscle action (α-SMA, lower panel). Merged images are shown. V = vessel (C) Paraffin kidney sections were co-stained with anti-mouse E-cadherin antibodies or DAPI. Merged images at both low and high magnification are shown.
Mentions: One of the hallmarks of late stages of DN is the development of tubulointerstitial fibrosis. On examination by light microscopy of the kidneys, no evidence of severe tubulointerstitial fibrosis was seen (Figs. 2 and 4). However, we wanted to define subtle changes that might be present in the tubulointerstitium of the AkitaKO and α1KOAkitaKO mice. We therefore examined the tubulointerstitium by electron microscopy to define tubular morphology and tubular basement membrane thickness in the kidneys of 6 month old wild type, AkitaKO and α1KOAkitaKO mice (Fig 9A). No differences in any of the parameters analyzed were seen between the three genotypes. We next co-stained kidney paraffin sections for collagen I and Dolichos biflorus agglutinin [a glycoprotein that binds the apical aspect of CD cells, 20] to define whether there was increased collagen I in the tubulointerstitial compartment (Fig 9B). A small, but equal increase in collagen I staining was seen in both AkitaKO and α1KOAkitaKO mice when compared to non-diabetic wild type animals. When we immunostained with anti-α-smooth muscle actin antibodies to define whether there were increased interstitial fibroblasts or if tubular cells had acquired a more mesenchymal morphology, no differences were seen between the genotypes (Fig 9C). Finally, no differences in tubular integrity were seen in the different genotypes when kidneys were immunostained with anti-E-cadherin antibodies. Thus, other than a minimal increase in collagen I expression, there was negligible tubulointerstitial disease in the AkitaKO and α1KOAkitaKO mice at 6 months of age.

Bottom Line: Animal models that mimic human diabetic nephropathy are useful to identify key factors in pathogenesis of this disease, as well as the development of new therapies.Interestingly, crossing these AkitaKO mice with integrin α1KO mice, a model of exacerbated glomerulosclerosis after injury and also on the Balb/c background, resulted in a 16-fold increase in albuminuria, significant mesangial matrix expansion, nodular and diffuse glomerulosclerosis, and a 2-fold increase in glomerular basement membrane thickening when compared with nondiabetic mice.Moreover, a significant decline in glomerular filtration was evident in the α1KOAkitaKO mice at 6 months of age.

View Article: PubMed Central - PubMed

Affiliation: Division of Nephrology, Department of Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA.

ABSTRACT
Animal models that mimic human diabetic nephropathy are useful to identify key factors in pathogenesis of this disease, as well as the development of new therapies. Several mouse models of diabetes have features of human diabetic nephropathy, yet none of these completely fulfill the Animal Models of Diabetes Complications Consortium criteria and completely reproduce pathological and functional features of the human disease. The Akita mouse carries a mutation in the insulin-2 gene and, to date, only survives as heterozygotes that develop spontaneous type 1 diabetes. Here we show that Akita mice with mutation of both insulin-2 alleles (Akita knockout (KO)) survive if crossed onto the Balb/c background. These mice develop hyperglycemia, more severe albuminuria, and mesangial sclerosis compared with heterozygous mice on the same genetic background. Interestingly, crossing these AkitaKO mice with integrin α1KO mice, a model of exacerbated glomerulosclerosis after injury and also on the Balb/c background, resulted in a 16-fold increase in albuminuria, significant mesangial matrix expansion, nodular and diffuse glomerulosclerosis, and a 2-fold increase in glomerular basement membrane thickening when compared with nondiabetic mice. Moreover, a significant decline in glomerular filtration was evident in the α1KOAkitaKO mice at 6 months of age. Thus, the integrin α1KOAkitaKO Balb/c mouse represents a promising model presenting with most features of human diabetic nephropathy.

Show MeSH
Related in: MedlinePlus