Renal Pharm Part 3

Question 1

Nephrotoxicity and infectious causes are the most common in veterinary
medicine that lead to ARF. List the conditions.

Answer 1

CCAAANE

• Ethylene glycol, lilies (cats), raisins and grapes (dogs)
• Aminoglycosides
• Amphotericin B
• Cisplatin
• Contrast agents
• NSAIDs
• ACE inhibitors

Question 2

ARF
Ischemic injury causes:

Answer 2

• Dehydration (persisting vomiting and diarrhea)
• Shock
• Hypotension
• cardiac output failure
• Thrombosis

Question 3

Causes of Renal ischemic reperfusion injury

Answer 3

See below

Question 4

Define ischemia?

Answer 4

Ischemia: interruption of blood supply to a tissue

Question 5

Define repurfusion

Answer 5

Reperfusion: re-establishment of the blood flow

Question 6

Answer 6

A microvascular clamp blocks the
blood perfusion to the right kidney
for 30 minutes

Question 7

DON’T HAVE TO KNOW
Differences in therapy

At 4 hrs we will see
• tubular ____________
• protein _____ in lumen
At 8 h
• tubular _______
• _________ necrosis
• ___________ of the epithelium
At 16 h
• _________ necrosis
• tubular ______
• _______ cells infiltration
At 24 h
• ________
• Tubular ______
• ______ cells infiltration
At 48 h
• Tubular _______
• __________ and _________ infiltration
• Enlarged cell ______
At 96 h
• High ______ activity
At 168 h
• Focal ________
• Areas of ________

Answer 7

At 4 hrs we will see
• tubular obstruction
• protein cast in lumen
At 8 h
• tubular dilation
• incipient necrosis
• attenuation of the epithelium
At 16 h
• cellular necrosis
• tubular cast
• PMN cells infiltration
At 24 h
• Necrosis
• Tubular dilation
• PMN cells infiltration
At 48 h
• Tubular dilation
• Lymphocytes and macrophages infiltration
• Enlarged cell nuclei
At 96 h
• High mitotic activity
At 168 h
• Focal fibrosis
• Areas of regeneration
ARF: stimulate production ASAP
CRF: issue with urine concentration, so don’t necessarily have to stimulate production.

This table show us changes over time when perfusion is affected.

Tubular obstruction due to cellular debris (protein casts, brush borders) block lumen, 8 hours later, you will see very clear necrosis –> tubular dilation, flattening of epithelium, polymorphonuclear cells arrive 16 hours later. Release cytokines, and other components of immune system. 168 hours: cells in proximal tubules regenerate into pluripotent stem cells, severe damage –> collagen fibers, interstitial fibrosis

reduced function in affected kidney

Question 8

Answer 8

Clamp removal leads to a
fast reperfusion of the
kidney

Question 9

Question 10

Question 11

What are the consequences of Renal failure?

Answer 11

1. Poor secretion of waste products.
   - Explains accumulation of nitrogen in the blood
   - Explains accumulation of creatinine in serum
2. Reduced GFR
3. Reduced renal blood flow

Question 12

What is happening in the image below

Answer 12

Over time, there is overexpression of adhesion molecules so inflammatory cells can adhere to the endothelial wall. E.g. Neutrophils in beginning will infiltrate damaged tissues and release inflammatory mediators. ROS are generated and then diffuse out of the cell. At the same time, the endothelial cells will produce ROS E.g. NO produced by NO synthase (inducible) which reacts with other ROS. ROS are highly reactive –> cellular injury –> cell swelling –> further reduction of blood flow in the kidney, esp in PCT cells.
PCT are polar cells which is maintained by the cytoskeleton of the cell. The ROS will destroy the cytoskeleton components, many of the ROS take e- from proteins composed of cytoskeleton and when this happens the brush borders are lost and then carriers will appear on the wrong side of the membrane. These cells are unable to produce urine or reabsorb the necessary solutes –> renal failure. This happens very quickly and is therefore called ARF. The cell enters apoptosis and is characterized by upregulation of caspases, MAP kinases, release of Ca intracellularly, increase Ca, etc. Some cells do not die.

Poor urine formation, poor secretion of waste products, nitrogen in the blood and creatinine in the serum, reduced GFR, reduced renal blood flow.

Question 13

Answer 13

Interplay vascular endothelium/immune system/oxidative stress/apoptosis

Over time after ischemic repurfusion, there is overexpression of ? molecules so inflammatory cells can adhere to endothelial wall ? surrounding priximal tubules.

Neutrophils in the beginnign will infiltrate damaged tissues, release inflammatory mediators, and at the same time the cells will generate ROS. ROS will diffuse out of cell and at the same time, the endothelial cells will produce ROS such as NO (produced by NO synthase which is inducible) NO reacts with another ROS. The ROS are highly reactive –> cellular injury –> cell swelling –> further blood flow reduction. Proximal tubule cells are damaged by ROS; an important function of PTC are polarized cells (apical, basolateral membrane they havbe NA, K AtP pump at baso membrane. This polarity is maintained by cytoskeleton of cells aka microtubules, microfilments. The ROS destroy cytoskeleton compoentns by taking proteins that make up the skeleton and tubules. When this happens, the brush borders get lost so you do not see a brush border anymore a d the carriers normally characteized on one side will appear at apical side where it has nothing to do. This cell si unable to work aka produce urine nad reabsorb the necessary solutes. –> renal failure. This happens fast so Acute renal failure.
Fate of this cell, if damage is severe –> apoptosis.
Characterized by upregulation of caspases, makinases?, release of intracellular Ca to activate nother proteins and heat shock proteins so the cell dies. Some cells may survive and undergo mitosis to replace lost cells.

Question 14

What are the Key events in renal IRI?

Answer 14

• Inflammatory cells infiltrate the injured tubular cells → release of cytokines
• Generation of ROS (NO, ONOO- .OH, O2-)
  * Mitochondrial complexes
  * Hypoxanthine
• Disruption of the cytoskeleton
• Translocation of carriers – loss of function
• Damaged cells activate apoptotic pathways (caspases, MAP kinases)
• Impaired renal function

Question 15

List the key events of ischemic reperfusion (ARF).

Answer 15

1. Inflammatory cells infiltrate the injured tubular cells → release of cytokines
2. Generation of ROS (NO, ONOO- .OH, O2-)
   * Mitochondrial complexes
   * Hypoxanthine
3. Disruption of the cytoskeleton
4. Translocation of carriers – loss of function
5. Damaged cells activate apoptotic pathways (caspases, MAP kinases)
6. Impaired renal function

Question 16

How are ROS and RNS generated?

Answer 16

Oxygen –>
1. superoxide anion produced by Lipoxygenase; (free radical, unpaired e-).
- SOD = convert SO into hydrogen peroxide which is less reactive, not a free radical).
- catalase takes H2O2 and produces water.
- catalase and SOD should prevent hydroxyl radical from forming. If iron is here, bad news.
2. Nitric Oxide produced by Nitric Oxide Synthase, comes from AA Argenine.

H2O2 produces the hydroxyl radical in the presence of iron or copper, this is called the phantom reaction. Oxidizes proteins, DNA, membrane lipids. PUFA reacts with hydroxyl radicals produces lipid radicals –> etc. BAD time.

Question 17

Why are there so many ROS produced after ischemic reperfusion?

Answer 17

During the Electron transport chain in the mitochondria, normally: priduces ATP and use ozygen to catch e- so tha they are not running around harming the cell, whihc priduces water.

In this case, the cell deprived of O2 for a long time –> a lot of O2 arrives suddenly aka reperfusion –> many e- that go away and cause harm and some O2 not completely reduced –> ROS produced –> the ones producing the damage observed in ARF.

Source of ROS: Mitochondrial complexes, 1 and 3, are the ones that direct e- towards O2 molecule and produce water. If they are not working prpopery or too muhc O2 arriving –> complexes release ROS.
Hypoxanthine does the same

Question 18

How are ROS generated?

Answer 18

1. Enzymes produce superoxide anion, the first ROS in this reaction chain.
   - dot next to superoxide means it is unpaired. Can catch an e- from another molecule in the cell –> oxidize the molecule.
   - some defense mechanisms such as superoxide dismutase –> convert superoxide anion into hydrogen peroxide which is less reactive and does not have a dot.
   - When iron or copper is available, hydrogen peroxide produces radical –> highly reactive –> a lot of harm in cell –> oxidize membrane lipids, DNA.
   - PUFA when reacts with ? –> PUFA radicals –> reactive with PUFA –> radicals –> vicious cycle that never stops as long as there are heavy metals such as iron and copper in cell and hydrogen peroxide is being produced.

When SOD upregulated, will produce hydrogne perozide and then there is another enzyme called catalase (not shown) whihc takes hydrogen peroxide and produces water.
Catalases and superoxide dismutae, won’t be a lot of peroxide iron.

Study red and blue circles

Question 19

What is the proposed mechanism for
Ischemia/reperfusion injury (IRI) formation of ROS?

Answer 19

During ischemia, ATP is hydrolyzed

Hypoxanthine converted into ROS by xanthine oxidase, produced during reperfusion or reoxygenation phase. Proteases are active during ischemic reperfusion and by presence of calcium

Allopurional is a xanthine oxidase inhibitor because xanthine oxidase produces urate that can lead to formation of urate stones.

Question 20

What are the therapeutic approaches to treating ARF?

Answer 20

1. Antioxidants: Selenium, Vitamin E, Vitamin C, Glutathione, ROS Scavengers

Systemic: other organs can be compromised
Orange - direct approaches

Question 21

ARF: Fluid therapy
- Rapid replacement of fluid deficit (__-__ h)
- What is the formula?
- Most popular fluids used are?

Check urine _____ (aim should be __-__ ml/kg/h), body _____, _________ (if kidney not working, RBC not formed properly), plasma protein (some proteins get ______ due to renal damage) and _______ concentration

Answer 21

• Rapid replacement of fluid deficit (4-6 h)
  % dehydration x BW (kg) = liters required

Most popular fluids used are: 0.9% NaCl
Low-sodium fluids (0.45% saline/2.5% dextrose; lactated Ringer‘s solution/2.5% dextrose in hypernatremia or cardiac insufficiency

Check urine output (aim should be 1-2 ml/kg/h), body weight, hematocrit (if kidney not working, RBC not formed properly), plasma protein (some proteins get filtered due to renal damage) and sodium concentration

Question 22

How is urine production enhanced in a case of ARF?

Answer 22

1. Furosemide (2-3 mg/kg IV q 6-8 h or 1 mg/kg/h constant rate infusion) (furosemide exacerbates gentamicin (nephrotoxic) toxicity!)
2. Dopamine (1-5 ug/kg/min IV in combination with furosemide), positive inotrope (makes heart work harder), vasodilator, ↑ RBF and GFR. Adverse effects: tachycardia, hypertension, vomiting
3. Mannitol 20-25% solution (osmotic diuretic), ↓ cellular edema, ROS scavenger
4. Dextrose 10-20% solution (osmotic diuresis), caloric support, ↑ insulin; dextrose is a carbon molecule which increases insulin.

Question 23

Hyperkalemia normally improves after _____ therapy and ______. It can be treated with?

Answer 23

Hyperkalemia normally improves after fluid therapy and diuresis. It can be treated with:
1. Calcium gluconate (10% solution; 0.5-1 ml/kg IV over 10-15 min), cardioprotective
2. Dextrose (0.1-0.5 g/kg) or insulin/dextrose (0.25-0.5 U/kg, 1-2 g), ↑ intracellular movement of K+

Question 24

Metabolic acidosis can be treated with _________ _______, which __________ the ECF. This is important because the kidneys eliminate _________, so if this function is impaired, the _____ accumulate –> metabolic acidosis —-> treat with ______ _______ –> _________ the ECF.

Answer 24

Sodium bicarbonate, alkalinzes, protons, protons, NaBicarb, alkalinze

Question 25

Nausea/vomiting associated with ARF can be treated with?

Answer 25

1. Famotidine, ranitidine (H2 antagonists)
2. Dolasetron (SR antagonist)
3. Metoclopramide (dopamine antagonist);
4. Misoprostol (PG analog)

All to protect stomach or reduce formation of gastric acid or to act at vomiting center (metoclopramide)

Question 26

~____% of cats >___ y will develop CKD. It is the __________ most common cause of death in cats >5 y.

Answer 26

~30% of cats >12 y will develop CKD. It is the second most common cause of death in cats >5 y.

Question 27

CKD is a Complex mixture of disorders that cause __________ loss of ________ –> (___ GFR)

Answer 27

CKD is a Complex mixture of disorders that cause irreversible loss of nephrons –> (↓ GFR)

Question 28

The histological hallmarks of CKD are ?

Answer 28

Tubulointerstitial nephritis and fibrosis

Question 29

CKD leads to the Generation and accumulation of

Answer 29

ROS (NO, ONOO- .OH, O2-)

Question 30

CKD leads to hypertension due to release of _____.

Answer 30

ANGII

Question 31

CKD results in increased __________ in the tubular epithelium, ______, tissue ______ (exacerbates formation of _____), _________

Answer 31

metabolism, anemia, hypoxia, ROS, inflammation

Question 32

How do you pharmacologically manage CKD?

Answer 32

There are 4 stages.

Question 33

What is the CKD damage cascade?

Answer 33

Many causes of CKD, but look at what produces ROS.

Question 34

When kidneys see reduced GFR, will release?

Answer 34

Release of renin –> actibates RAAS –> AGII –> peripheral vasocontrsiction and acts at efferent arterioles to produce vasoconstriction to increase GFR.

AGII induces release of inflammatory mediators —> ROS produced –> GFR can not be brougt back to normal –> cuase glomeualr hyperfiltration and hypertension –> proteinuria and protein filtration

Question 35

What is the role of ANGII in CKD?

ANGII induces NADPH oxidase which produces _______. At the same time, NO is being released and is important for BV _______. When ______ is released, combines with NO and produces ______. This damages BV in other parts of the body.

Answer 35

ANGII induces NADPH oxidase which produces superoxide anion (O2-). At the same time, NO is being released and is important for BV dilation. When superoxide anion is released, combines with NO and produces ONOO-. This damages BV in other parts of the body.

Question 36

What are the dietary strategies of CKD?

1. _____ protein (but high quality) and _____ phosphorus diets help reduce ________
   wastes, ____ formation, and ______ deposition
2. Moderate ________ restriction (especially in hypertensive patients)
3. Control lipid intake to reduce ____________, __________, and protect renal ________ function
4. ___________ binders: Aluminium hydroxide, 30-100 mg/kg/d PO; calcium
   acetate, 60-90 mg/kg/d PO; calcium carbonate , 90-150 mg/kg.d PO
5. __________ (↑ serum Ca++ –> ↓ PTH), 2.5-3.5 mg/kg/d PO. Calcitriol is produced in the kidney so this is why they need calcitriol

Answer 36

1. Low, protein (but high quality) and low phosphorus diets help reduce nitrogen
   wastes, acid formation, and mineral deposition
2. Moderate sodium restriction (especially in hypertensive patients)
3. Control lipid intake to reduce hypercholesterolemia, inflammation, and protect
   renal hemodynamic function
4. Phosphorus binders: Aluminium hydroxide, 30-100 mg/kg/d PO; calcium
   acetate, 60-90 mg/kg/d PO; calcium carbonate , 90-150 mg/kg.d PO
5. Calcitriol (↑ serum Ca++ –> ↓ PTH), 2.5-3.5 mg/kg/d PO. Calcitriol is produced in the kidney so this is why they need calcitriol

Question 37

For Metabolic acidosis: Alkalinization is a strategy
Some animals with already metabolic acidosis may require additional
alkalinization therapy
If serum total CO2 < 15-17 mmol/L → ____ alkalinization
If serum total CO2 < 10-12 mmol/L → _________ alkalinization

Blood gas analysis!
- Sodium bicarbonate, 8-12 mg/kg PO q 8-12 h (it adds Na+, check Na+ levels!)
- Potassium citrate, 35 mg/kg PO q 8 h (it adds K+ in addition to alkali)

Answer 37

For Metabolic acidosis: Alkalinization is a strategy
Some animals with already metabolic acidosis may require additional
alkalinization therapy
If serum total CO2 < 15-17 mmol/L → PO alkalinization
If serum total CO2 < 10-12 mmol/L → parenteral alkalinization
Blood gas analysis!
Sodium bicarbonate, 8-12 mg/kg PO q 8-12 h (it adds Na+, check Na+ levels!)
Potassium citrate, 35 mg/kg PO q 8 h (it adds K+ in addition to alkali)

Question 38

High levels of gastrin –> ____ production

Answer 38

HCl

Question 39

What are two very common side effects of CKD?

Answer 39

Anorexia and vomiting

Question 40

What are the GI effects in CKD patients?

Answer 40

Anorexia and vomiting
GI effects (uremia): mucosal irritation, impaired GI mucosal barriers, and
hypergastrinemia
Anorexia, vomiting, and diarrhea are common in CKD patients!

Question 41

What are the treatment options for GI effects in CKD patients?

Answer 41

FOR Christine’s Sake!

Treatment options:
Cimetidine (5 mg/kg PO, IM, or IV q 6-8 h)
Famotidine (0.5-1 mg/kg PO q 12-24 h) [PPI]
Ranitidine (0.5-2 mg/kg PO q 12 h)
Omeprazole (0.7-1.5 mg/kg PO q 12-24 h)
Sucralfate (mucosal protectant)

Question 42

What are the treatment options for Anorexia-vomiting-hypertension in CKD patients?

Answer 42

1. Metoclopramide (0.2-0.4 mg.kg SC, IM, PO q 8 h)
   - More effective are serotonin receptor antagonists dolasetron and ondansetron
2. Maropitant (for dogs, not approved for use in cats), neurokinin type 1 selective
   receptor antagonist (motion sickness)
3. Misoprostol (synthetic PG analog) inhibits gastric acid, pepsin secretion, and
   protects the gastric mucosa

Question 43

Hypertension (due to many factors, among other _____ and low production of ______) is treated with _____ inhibitors as a first choice (2?) and/or _________ (2?)

Vasocontrict _________ arterioles to increase GFR.

Answer 43

Hypertension (due to many factors, among other RAAS and low production of vasodilators) is treated with ACE inhibitors as a first choice (enalapril, benazepril) and/or diuretics (furosemide, spironolactone)

Vasocontrict efferent arterioles to increase GFR.

Question 44

CKD and Ca homeostasis.

Answer 44

Ca in plasma levels are maintined by PTH and calcitonin. Thye react very quickly when there are changes in teh calcium cncentration in the plasma. Range is very narrow- as soon as cal become lower than 0.8 mmol per liter, PTH increases.
Of CA increase higher than 1.2, calcitonin will increase,

Question 45

Answer 45

Question 46

Phosphate homeostasis
Both __________ and ______ are involved in phosphate homeostasis

Regulation of phosphate reabsorption in the kidney is mediated by ______

Answer 46

calcitriol, PTH, PTH

Question 47

PTH in bone stimuolates phosphate mobiliszation from the bone.
Intestine: effect mediated by calcitriol; vitamin D hormone synthesis stimulated by PTH. Vitamin D stimulates phosphate ? by epithelium
PTH goes to proximal tubule in kidneys and inhibits phosphate reabsortion by cottransporters whihc increases excretion of phosphate.

relisten to last part!

Question 48

How does secondary hyperparathyroidism occur in CKD patients?

Answer 48

Secondary hyperparathyroidism
Hypocalcemia – hyperphosphatemia – impaired vitamin D → secondary
hyperparathyroidism

↑↑ PTH → ↑↑ mobilization of Ca++ and phosphate from bone Soft tissue mineralization

Dietary restriction of phosphorus and Ca++ supplementation

Calcitriol supplementation

Question 49

Why is anemia a common conseuqnce of CKD?

Answer 49

Eryth. released with low O2 levels in body.
Oxygen sensor in kidney is called HIF-1. It is basically a transcription factor.
HIF triggers this release.
Eryth goes to blood –> bone marrow –> erythro receptors at surface of erthyroid precursor cells –> differentiate and mature in bone marrow –> released

Question 50

Reticulocyte and anemia

Answer 50

regenerative anemia

Question 51

Question 52

What type of anemia is present in CKD patients?

Answer 52

Non-regenerative anemia

Question 53

Describe the consequences of anemia in CKD patients.

Answer 53

Progressive, non-regenerative
Apathy, lethargy, poor appetite, and poor body condition
GI blood loss and lack of EPO
Treatment: recombinant human EPO 100 U/kg SC 3x week (check
hematocrit!)
Resistance to EPO. Antibody-mediated. So effectiveness of EPO will be reduced over time.