Lecture 2: Calcification Flashcards
__ is the abnormal Ca deposition in damaged tissues intracellularly or extracellularly which may cause the functional loss of tissue (i.e. elasticity)
dystrophic calcification
intracellular = mitochondrial extracellular = plasma membrane, elastic tissue, basement membrane
sequelae of dystrophic calcification: may be reorganized to form __
heterotopic bone
__ is acute necrosis of skeletal and cardiac m due to vitamin E and selenium deficiency
white muscle dz
__ is abnormal Ca deposition in tissue secondary to hypercalcemia
metastatic
Mechanisms that lead to hypercalcemia
hypervitaminosis D toxic plants primary hyperparathyroidism nutritional secondary hyperparathyroidism hypercalcemia of malignancy
What causes hypervitaminosis D (leads to hypercalcemia/dystrophic calcification)
dietary supplementation plant toxicity (cestrum diurnum and solanum malacoxylon)
Mechanism of hypervitaminosis D
stimulates intestinal Ca absorption and renal tubular Ca reabsorption
Metastatic calcification is located in the
BVs, elastic fibers, basement membranes (lung, kidney, stomach, oral cavity)
Common BV for metastatic calcification via hypervitaminosis D
aorta
sequelae of metastatic calcification
- renal tubular dysfunction (nephrocalcinosis)
- aortic rupture (rare)
- lung (hypoxemia, decreased capacity)
special stain for calcification that stains it black
von kossa stain
what causes primary hyperparathyroidism
primary parathyroid adenoma produces elevated PTH (stimulates osteoclast activity to increase bone resportion = increased Ca = hypercalcemia)
what happens with nutritional secondary hyperparathyroidism
inadequate Ca intake = decreased serum Ca = increased PTH = bone resoprtion = hypercalcemia
what happens with renal secondary hyperparathyroidism (very common!)
renal dz = decreased tubular phosphate excretion = increased phosphate in serum leads to CaP ppt. Also, Renal interference with Vit D metabolism (abnormal absorption) = HYPOcalcemia which stimulates PTH secretion = bone resorption = HYPERcalcemia. Widespread tissue calcification.
Many neoplasms produce ___ that induces bone resporption and hypercalcemia (anal apocrine gland adenocarcinoma, lymphoma)
PTH related protein (PTHrP)
__ pigment is a lipid-protein complex made from membrane lipids that is known as the “wear and tear” pigment
lipofuscin/ceroid
vitamin E deficiency, stress, increased lipid peroxidation product, age, etc will have__ pigment in tissues commonly seen the heart, liver, and brain
lipofuscin/ceroid
Lipofuscin/ceriod pigment is intralysosomal, it forms lysosomes by __
autophagocytosis
see an increased amount of lipofuscin pigment in neurons with genetic autosomal recessive dz called __ (abnormal metabolism of phospholipid)
neuronal ceroid lipofuscinosis
special stains/features for lipofuscin/ceroid (stains brown with H&E)
acid fast stain (blue) and autofluorescence
__ occurs in vitamin E deficient dogs and is also known as “brown gut dz”
Intestinal lipofuscinosis (lipofuscin/ceriod)
brown gut dz in dogs is due to increased membrane __ and accumulation of __ in intestinal smooth m.
lipid peroxidation, lipofuscin
Cats with vitamin E deficency do not get brown gut dz but have
fat necrosis in abdominal cavity
__ and __ pigments are derived from hemoglobin
hemosiderin and bilirubin
__ is derived from Hb when RBCs are phagocytosed and degraded intracellularly
hemosiderin
hemosiderin is normal in mononuclear phagocytes in the __, __, __
BM, spleen, liver
There is excess hemosiderin with __, __, __
hemorrhage/congestion, increased diet Fe, Hemolytic anemia
hemosiderin is usually not __ unless there is too much free ferrous iron (not bound) and the fenton rxn occurs making free radicals.
toxic
When Fe is freed from Hb the body binds it to __ protein so it is less reactive and less likely to make free radicals (fenton rxn)
apoferritin/ferritin
__ is a pathologic disorder of Fe metabolism
hemochromatosis
hemosiderosis is seen with __ due to increased hydrostatic pressure in the lungs and RBC leak into alveoli where macs phagocytize them (brown macs)
chronic left heart failure
special stain for hemosiderin that stains Fe dark blue
prussian blue (perls iron stain)
how is hemosiderin made by macrophages phagocytizing RBC
macrophage breaks down RBC and Fe is bound to apoferritin making granular pigment (hemosiderin) in mac
__ is a porphyrin (heme) ring of hemoglobin and other sources
bilirubin
bilirubin is conjugated in the __ and excreted in the __
liver, bile
clinical __ is seen when plasma bilirubin is >2-3mg/dl
icterus
__ is toxic, cannot be excreted in the urine (bound to Albumin)
unconjugated bilirubin
__ has low toxicity and can be excreted in the urine
conjugated bilirubin
RBC are broken down into __ and __
ferrous iron and unconjugated bilirubin
unconjugated bilirubin is taken up by the __ where it is conjugated and excreted to the bile duct for transportation to the __
hepatocyte, intestine (reabsorption and/or excretion via kidney)
5 things that can cause hyperbilirubinemia/icterus/jaundice
- increased heme breakdown (anemai, hemorrhage)
- decreased hepatic uptake (drugs, dz)
- impaired conjugation (neonate, dz)
- impaired intra-hepatic excretion (cirrhosis, drugs)
- bile duct obstruction (inflamm, parasites, neoplasm, fb)
Melanin pigment is formed by oxidation of __
Tyrosine
special stain for melanin that stains it black
fontana masson (argentaffin stain)
some animals have normally occurring __in their lungs, heart, aorta, brain (sheep, pigs, etc)
melanosis
melanosis is common/normal in __
black-faced sheep breeds
__ occurs when liver accumulates excess fat, turns yellow, and has a greasy consistency. When placed in water the liver will float and histologically hepatocytes will have “holes”
lipidosis, fatty change, steatosis
Cats develop __ frequently due to too much FA to liver which is converted into triglycerides. Difficult to manage medically.
sever lipidosis
Normally fat is processed by the liver via __ entering the cell and being converted into ___ by acetate and glycerophosphate. These TG must be bound to apoprotein to make __ that can leave the cell.
Free FA, triglycerides, lipoproteins
if a dz or toxin affects protein synthesis what happens to the fat in the hepatocyte?
Steatitis - lipid gets trapped, TG need to be protein bound to exit the cell.
lipidosis occurs normally during __
late pregnancy, lactation
5 pathologic causes of lipidosis
- increased synthesis of FA, TG
- increased lipolysis and uptake of free FA
- decreased FA oxidation
- decreased Apoprotein synthesis
- decreased lipoprotein excretion
___ is the accumulation of abnormal proteinaceous substance from several protein sources iwth eosinophilic staining that accumulates between cells and has beta pleated sheets
amyloidosis
4 characteristics defining amyloid
- Abnormal proteinaceous substance
- Deposited extracellularly
- Results in organ dysfunction
- Derived from different proteins
__ form crystals in the tissue (seen in renal granular amyloidosis) which can be stained with __
Amyloid Beta pleated sheets, congo red stain and polarized light (birefringence)
2 Special stains for amyloidosis
Microscopically: Congo red - stains amyloid red (and polarized light for birefringence - yellow refraction)
Grossly: Lugol’s iodine and dilute sulfuric acid treatment (black) - used to see amyloid grossly (i.e. Dots in kidney)
H&E stains eosinophilic
Amyloid more common in people/primates, occurs in vet med but it is less important
Primary Amyloid:AL - Ig light chains
Most common form of amylodosis in animals that causes clinical disease
Secondaryr amyolid: AA - chronic inflammation, SAA precursor
Amylodiosis that commonly is seen in cats caused by a partial degradation of protein in the pancreas leads to amyloid deposits in pancreatic islets (beta cell damage = diabetes)
Endocrine Amyloid
Islet amyloid polypeptide (IAPP) precursor secreted by beta cells with insulin, abormal synthesis/process/degradation = amylodosis.
Amyloidosis associated with alzheimer’s dz in people described in dogs (human models)
Beta amyloid: senile plaques (APP amyloid precursor protein)
Commonly seen in horses is amylodosis of apolipoprotein AI and AII
Aging associated amyloid
How does secondary amyloidosis arise
Chronic inflammation - macrophage activate - IL and TNF secreted - Hepatocytes make SAA protein (serum amyloid A) - LIMITED PROTEOLYSIS occurs = AA
How do you monitor secondary amylodosis
Via the acute phase reactant protein, SAA - serum amyloid A production
Animal that develop dz from secondary amyloidosis is due to
BOTH limited proteolysis AND abundant production of SAA via the liver
Primary amyloidosis is caused by
Ig light chains and limited proteolysis
Consequences of amyloidosis in the kidney
Protein losing nephropathy
Consequences of amyloidosis in the pancrease
Type 2 diabetes mellitus
Consequences of amyloidosis in the GI tract
Impaired absorption
Consequences of amyloidosis in the brain
Reduced cognitive performance/dementia (alzheimer’s in people)
What organs are consequences more commonly seen in people
Liver (atropy, failure)
Heart (arrhythmia, failure)
Brain (dementia)