Bladder
Acquired non-neoplastic anomalies
Tamm-Horsfall protein

Author: Monika Roychowdhury, M.D. (see Authors page)

Revised: 16 March 2016, last major update March 2015

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: Bladder Tamm-Horsfall protein
Cite this page: Tamm-Horsfall protein. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/bladdertamm.html. Accessed December 7th, 2016.
Definition / General
  • Tamm-Horsfall protein (THP) is a high molecular weight glycoprotein discovered by Tamm and Horsfall (J Exp Med 1952;95:71)
  • Normally synthesized by thick ascending limb of loop of Henle, possibly distal convoluted tubules
  • Most abundant protein in urine of healthy individuals
  • May accumulate in renal parenchyma, perirenal soft tissue, renal hilar lymph nodes or bladder with pathologic conditions
Terminology
  • Also known as uromodulin, from UMOD gene on #16 (Wikipedia)
Pathophysiology
  • Inserted into luminal cell surface of renal tubules by glycosyl-phosphatidylinositol (GPI)-anchor, then excreted in urine at a rate of 50 - 100 mg/day
  • Stones may form due to defective urinary Tamm Horsfall protein, due to lack of sialic acid (Int J Biol Sci 2008;4:215)
  • Has a strong tendency to form macroaggregates of several million Daltons, particularly in highly tonic solutions
  • Forms the matrix of urinary casts and stones
Epidemiology
  • THP deposits are present in 60% of cystectomy specimens, 4% of bladder biopsies
  • In bladder specimens with THP deposits, mean age is 61 years, range 45-78 years, 85% are men (Am J Surg Pathol 1994;18:615)
Etiology
  • Deposited in areas of necrosis, inflammation, fibrinous exudates, ulcer, crystalline material
  • May be host defense factor against Proteus mirabilis urinary tract infections (J Urol 2009;181:2332)
  • May have role in pathophysiology of interstitial cystitis (BJU Int 2009;103:1085)
  • Comprises matrix of urinary casts formed during acute kidney injury (Webpath tutorial) and matrix of urinary stones
  • Also present in deposits associated with interstitial kidney disease
  • Also associated with urothelial carcinoma, nephrogenic adenoma
Gross Description
  • Large, waxy, pale or weakly eosinophilic mass
Micro Description
  • Glassy, PAS+ acellular material
  • May also appear as strands of eosinophilic material obscured by fibrinous exudates or necrotic tissue
Micro Images

Images hosted on other servers:

Diagram of Tamm-Horsfall protein secretion (green dots), forming a hyaline cast in the collecting duct



Images hosted on Nature.com:

Pelvic granulomatous inflammation is focally associated with Tamm–Horsfall protein (asterisks) in the pelvic lumen



No thumbnails: Nephronophthisis: end-stage renal disease; lymphatics; pyelonephritis #1-protein cylinder; #2-protein cylinder; #3-immunostain
Positive Stains
  • PAS, trichrome (pale blue)
  • Anti Tamm-Horsfall protein antibody
Electron Microscopy Description
  • Nonbranching 4 nm wide parallel fibrils
Electron Microscopy Images