Stains
Renin

Author: Rebecca Obeng, M.D. (see Authors page)

Revised: 15 July 2016, last major update July 2016

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Renin [title] stains

Cite this page: Renin. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/stainsrenin.html. Accessed October 20th, 2017.
Definition / general
  • Endopeptidase encoded by the REN gene on chromosome 1
  • A component of the renin-angiotensin-aldosterone system
  • Secreted by juxtaglomerular cells in the afferent arterioles in the kidney
Essential features
  • Cleaves angiotensinogen to angiotensin I
  • Regulates extracellular volume, blood pressure and sodium levels
  • Activation of the renin-angiotensin-aldosterone system results in vasoconstriction, increased secretion of ADH and aldosterone, and stimulation of the hypothalamus to activate the thirst reflex
  • Mutations in renin lead to kidney disease
Terminology
  • Renin, angiotensinogenase, angiotensin-forming enzyme, renin precursor, HNFJ2
Epidemiology
  • Renin mutations are rare and account for <1% of people with kidney disease
  • Reninoma: rare tumor with female predominance; presents in adolescence or early adulthood
  • Autosomal dominant tubulointerstitial kidney disease (ADTKD): rare, approximately 400 families affected in the United States
Sites
  • Kidney - juxtaglomerular cells
  • Overexpression of renin is evident in tumors such as reninoma, Wilm tumor and renal cells carcinoma (Int J Surg Pathol 2011;19:93)
Pathophysiology
Etiology
  • Unknown
Clinical features
  • Reninoma: headaches and hypertension, polydipsia, polyuria
  • ADTKD: hypotension, childhood anemia
Diagnosis
  • Reninoma: hypokalemia and metabolic alkalosis are important diagnostic clues
  • Plasma renin activity and aldosterone levels
Laboratory
  • Reninoma: elevated plasma renin activity and aldosterone
  • ADTKD: hyperuricemia, hyperkalemia, low urinary excretion of uromodulin
Radiology description
  • Reninoma: Usually small solitary mass on imaging
    • Ultrasound: homogenously hyperechogenic
    • CT: hypo or isodense and hypovascular in arterial phase
    • MRI: T1 and T2 hypodense lesion
Prognostic factors
  • Reninoma: surgical resection is curative
Treatment
  • Reninoma: nephron sparing surgical resection
  • ADTKD: same guidelines as chronic kidney disease
Microscopic (histologic) description
  • Granular cytoplasmic expression
Microscopic (histologic) images

Images hosted on other servers:

Renin expression in normal kidney

Figure 3a: Adrenocortical carcinoma

Positive stains
  • Juxtaglomerular cells in the afferent arterioles of the kidney
  • Cytoplasmic and perinuclear staining seen in oncocytoma (61%), chromophobe carcinoma (33%) and conventional renal cell carcinoma (12.5%) (Path Res Pract 2010;206:731)
  • Immunohistochemical stain used in combination with smooth muscle actin to highlight blood vessels
Negative stains
Electron microscopy description
  • Granules in juxtaglomerular cells secreted by exocytosis and diacrine secretion
Electron microscopy images

Images hosted on other servers:

Figure 4D: Tumor cells characterized by uniform non-enlarged nuclei

Molecular / cytogenetics description
  • Deletions, missense mutation, exon 1 mutations (autosomal dominant)
Differential diagnosis
  • Reninoma:
    • Renal artery stenosis
    • Pheochromocytoma