Fetal partial urethral obstruction causes renal fibrosis and is associated with proteolytic imbalance

Rita Gobet, Jeffrey Bleakley, Lars Cisek, Martin Kaefer, Marsha A. Moses, Cecilia A. Fernandez, Craig A. Peters

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Purpose: We determine whether fetal bladder outlet obstruction induces renal fibrosis, and is associated with an alteration in the regulation of connective tissue degradation and the presence of fibrogenic interstitial cells. Materials and Methods: Partial bladder outlet obstruction was surgically induced in 33 fetal sheep at 95 days of gestation. These animals and 24 normal age matched controls were sacrificed at 109, 116 and 135 (term) days of gestation, and the kidneys were rapidly retrieved, drained and weighed. Representative whole kidney samples were snap frozen for assessment of deoxyribonucleic acid, protein and collagen content. Morphometric analysis and α-smooth muscle actin immunohistochemistry were performed on histological specimens from formalin fixed kidneys. Tissue extract from fresh kidney specimens were analyzed for metalloproteinase and tissue inhibitor of metalloproteinase activity. Urine samples obtained at the time of sacrifice were analyzed for electrolyte, creatinine and N-acetyl glucosaminidase excretion. Results: All obstructed kidneys were hydronephrotic and larger than age matched controls. Obstructed kidneys at term showed interstitial fibrosis, as measured by increased extracellular matrix volume fraction (45% in male obstructed kidneys versus 2.5% in normal male kidneys, p = 0.0004), increased total collagen content (120 mg./kidney in male obstructed versus 20 mg. in normal male animals, p = 0.016) and collagen/deoxyribonucleic acid content per kidney (2.78 versus 0.53 mg./mg., p = 0.016). Metalloproteinase-1 activity was significantly lower in obstructed kidneys (210 versus 380 U./mg. protein in normal kidneys). Tissue inhibitor of metalloproteinase activity was undetectable in both groups. The presence of an increased population of myofibroblasts often associated with fibrotic processes was seen by α-smooth muscle actin staining which was localized to interstitial cells throughout the cortex in obstructed kidneys. Conclusions: Fetal partial bladder outlet obstruction induces renal interstitial fibrosis as early as 2 weeks after obstruction. A possible mechanism for this process is a shift in proteolytic activity to reduce matrix degradation in obstructed kidneys. These changes might be mediated by the increased number of fibrogenic interstitial cells. The observations suggest several potential approaches to developing an understanding of congenital obstructive uropathy.

Original languageEnglish
Pages (from-to)854-860
Number of pages7
JournalJournal of Urology
Volume162
Issue number3 I
DOIs
StatePublished - Sep 1999
Externally publishedYes

Fingerprint

Urethral Obstruction
Fibrosis
Kidney
Urinary Bladder Neck Obstruction
Tissue Inhibitor of Metalloproteinases
Collagen
Metalloproteases
Smooth Muscle
Actins
Hexosaminidases
Pregnancy
Tissue Extracts

Keywords

  • Fibrosis
  • Kidney
  • Metalloproteinases
  • Urethral obstruction

ASJC Scopus subject areas

  • Urology

Cite this

Fetal partial urethral obstruction causes renal fibrosis and is associated with proteolytic imbalance. / Gobet, Rita; Bleakley, Jeffrey; Cisek, Lars; Kaefer, Martin; Moses, Marsha A.; Fernandez, Cecilia A.; Peters, Craig A.

In: Journal of Urology, Vol. 162, No. 3 I, 09.1999, p. 854-860.

Research output: Contribution to journalArticle

Gobet, Rita ; Bleakley, Jeffrey ; Cisek, Lars ; Kaefer, Martin ; Moses, Marsha A. ; Fernandez, Cecilia A. ; Peters, Craig A. / Fetal partial urethral obstruction causes renal fibrosis and is associated with proteolytic imbalance. In: Journal of Urology. 1999 ; Vol. 162, No. 3 I. pp. 854-860.
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abstract = "Purpose: We determine whether fetal bladder outlet obstruction induces renal fibrosis, and is associated with an alteration in the regulation of connective tissue degradation and the presence of fibrogenic interstitial cells. Materials and Methods: Partial bladder outlet obstruction was surgically induced in 33 fetal sheep at 95 days of gestation. These animals and 24 normal age matched controls were sacrificed at 109, 116 and 135 (term) days of gestation, and the kidneys were rapidly retrieved, drained and weighed. Representative whole kidney samples were snap frozen for assessment of deoxyribonucleic acid, protein and collagen content. Morphometric analysis and α-smooth muscle actin immunohistochemistry were performed on histological specimens from formalin fixed kidneys. Tissue extract from fresh kidney specimens were analyzed for metalloproteinase and tissue inhibitor of metalloproteinase activity. Urine samples obtained at the time of sacrifice were analyzed for electrolyte, creatinine and N-acetyl glucosaminidase excretion. Results: All obstructed kidneys were hydronephrotic and larger than age matched controls. Obstructed kidneys at term showed interstitial fibrosis, as measured by increased extracellular matrix volume fraction (45{\%} in male obstructed kidneys versus 2.5{\%} in normal male kidneys, p = 0.0004), increased total collagen content (120 mg./kidney in male obstructed versus 20 mg. in normal male animals, p = 0.016) and collagen/deoxyribonucleic acid content per kidney (2.78 versus 0.53 mg./mg., p = 0.016). Metalloproteinase-1 activity was significantly lower in obstructed kidneys (210 versus 380 U./mg. protein in normal kidneys). Tissue inhibitor of metalloproteinase activity was undetectable in both groups. The presence of an increased population of myofibroblasts often associated with fibrotic processes was seen by α-smooth muscle actin staining which was localized to interstitial cells throughout the cortex in obstructed kidneys. Conclusions: Fetal partial bladder outlet obstruction induces renal interstitial fibrosis as early as 2 weeks after obstruction. A possible mechanism for this process is a shift in proteolytic activity to reduce matrix degradation in obstructed kidneys. These changes might be mediated by the increased number of fibrogenic interstitial cells. The observations suggest several potential approaches to developing an understanding of congenital obstructive uropathy.",
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T1 - Fetal partial urethral obstruction causes renal fibrosis and is associated with proteolytic imbalance

AU - Gobet, Rita

AU - Bleakley, Jeffrey

AU - Cisek, Lars

AU - Kaefer, Martin

AU - Moses, Marsha A.

AU - Fernandez, Cecilia A.

AU - Peters, Craig A.

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N2 - Purpose: We determine whether fetal bladder outlet obstruction induces renal fibrosis, and is associated with an alteration in the regulation of connective tissue degradation and the presence of fibrogenic interstitial cells. Materials and Methods: Partial bladder outlet obstruction was surgically induced in 33 fetal sheep at 95 days of gestation. These animals and 24 normal age matched controls were sacrificed at 109, 116 and 135 (term) days of gestation, and the kidneys were rapidly retrieved, drained and weighed. Representative whole kidney samples were snap frozen for assessment of deoxyribonucleic acid, protein and collagen content. Morphometric analysis and α-smooth muscle actin immunohistochemistry were performed on histological specimens from formalin fixed kidneys. Tissue extract from fresh kidney specimens were analyzed for metalloproteinase and tissue inhibitor of metalloproteinase activity. Urine samples obtained at the time of sacrifice were analyzed for electrolyte, creatinine and N-acetyl glucosaminidase excretion. Results: All obstructed kidneys were hydronephrotic and larger than age matched controls. Obstructed kidneys at term showed interstitial fibrosis, as measured by increased extracellular matrix volume fraction (45% in male obstructed kidneys versus 2.5% in normal male kidneys, p = 0.0004), increased total collagen content (120 mg./kidney in male obstructed versus 20 mg. in normal male animals, p = 0.016) and collagen/deoxyribonucleic acid content per kidney (2.78 versus 0.53 mg./mg., p = 0.016). Metalloproteinase-1 activity was significantly lower in obstructed kidneys (210 versus 380 U./mg. protein in normal kidneys). Tissue inhibitor of metalloproteinase activity was undetectable in both groups. The presence of an increased population of myofibroblasts often associated with fibrotic processes was seen by α-smooth muscle actin staining which was localized to interstitial cells throughout the cortex in obstructed kidneys. Conclusions: Fetal partial bladder outlet obstruction induces renal interstitial fibrosis as early as 2 weeks after obstruction. A possible mechanism for this process is a shift in proteolytic activity to reduce matrix degradation in obstructed kidneys. These changes might be mediated by the increased number of fibrogenic interstitial cells. The observations suggest several potential approaches to developing an understanding of congenital obstructive uropathy.

AB - Purpose: We determine whether fetal bladder outlet obstruction induces renal fibrosis, and is associated with an alteration in the regulation of connective tissue degradation and the presence of fibrogenic interstitial cells. Materials and Methods: Partial bladder outlet obstruction was surgically induced in 33 fetal sheep at 95 days of gestation. These animals and 24 normal age matched controls were sacrificed at 109, 116 and 135 (term) days of gestation, and the kidneys were rapidly retrieved, drained and weighed. Representative whole kidney samples were snap frozen for assessment of deoxyribonucleic acid, protein and collagen content. Morphometric analysis and α-smooth muscle actin immunohistochemistry were performed on histological specimens from formalin fixed kidneys. Tissue extract from fresh kidney specimens were analyzed for metalloproteinase and tissue inhibitor of metalloproteinase activity. Urine samples obtained at the time of sacrifice were analyzed for electrolyte, creatinine and N-acetyl glucosaminidase excretion. Results: All obstructed kidneys were hydronephrotic and larger than age matched controls. Obstructed kidneys at term showed interstitial fibrosis, as measured by increased extracellular matrix volume fraction (45% in male obstructed kidneys versus 2.5% in normal male kidneys, p = 0.0004), increased total collagen content (120 mg./kidney in male obstructed versus 20 mg. in normal male animals, p = 0.016) and collagen/deoxyribonucleic acid content per kidney (2.78 versus 0.53 mg./mg., p = 0.016). Metalloproteinase-1 activity was significantly lower in obstructed kidneys (210 versus 380 U./mg. protein in normal kidneys). Tissue inhibitor of metalloproteinase activity was undetectable in both groups. The presence of an increased population of myofibroblasts often associated with fibrotic processes was seen by α-smooth muscle actin staining which was localized to interstitial cells throughout the cortex in obstructed kidneys. Conclusions: Fetal partial bladder outlet obstruction induces renal interstitial fibrosis as early as 2 weeks after obstruction. A possible mechanism for this process is a shift in proteolytic activity to reduce matrix degradation in obstructed kidneys. These changes might be mediated by the increased number of fibrogenic interstitial cells. The observations suggest several potential approaches to developing an understanding of congenital obstructive uropathy.

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KW - Kidney

KW - Metalloproteinases

KW - Urethral obstruction

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