Diabetes and lipid disorders Flashcards

1
Q

insulin receptors

A

acts on specific insulin receptors on the cell

triggers the addition of GLUT4 transporters, which transport glucose from the blood into the cell

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2
Q

effects of insulin

A

liver:
promotes glycogen synthesis and storage
synthesis of protein, triglycerides and VLDL
glycolysis
inhibits gluconeogenesis, glycogenolysis, ketogenesis, lipolysis

muscle:
protein synthesis - amino acid transport, ribosomal protein synthesis
glycogen synthesis
increased glucose entry into muscle cells (GLUT4)

adipose tissue:
triglyceride storage - increases lipoprotein lipase activity to hydrolyse triglycerides from lipoproteins
increased glucose entry
inhibits intracellular lipoprotein lipase

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3
Q

biguanides - metformin

A

inhibit hepatic gluconeogenesis

+
weight neutral/loss
low cost
provem track record

-
nausea
loose stool
flatuence
lactic acidosis in:
renal impairment
heart failure
liver disease
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4
Q

sulphonylureas - gliclazide, glimepiride

A

increase insulin secretion
bind to sulfonylurea receptor on beta cell, opening K+ channel causing K+ efflux and the cell membrane to depolarize. this opens a Ca2+ channel, and Ca2+ enters the cell, which increases insulin release

+
cheap
track record

-
hypo’s
weight gain

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5
Q

thiazolidinediones - pioglitazone

A

enhance lipogenesis
decrease lipolysis
decrease plasma FFAs

+
insulin sensitisers

- 
fluid retention
weight gain
increased peripheral fracture rate
? bladder Ca
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6
Q

SGLT2 inhibitors - empagliflozin

…flozin

A

prevent renal glucose reabsorption by inhibiting SGLT2 in the proximal tubule

\+
weight loss
? reno-protective effect
-
UTIs
uncertain long term effects
expensive

also reduces death rate for CVD
may help delay the onset of diabetic neuropathy

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7
Q

incretins

A

secreted by intestinal endocrine cells in response to nutrient intake
eg GLP-1 (glucagon like peptide)
GLP-1:
promotes satiety and reduces appetite
slows rate of gastric emptying
reduces hepatic glucose output
enhances glucose dependent insulin secretion
suppresses post-prandial glucagon secretion

hgalf life 1-2mins
DDP-IV breaks down GLP-1

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8
Q

DDP-IV inhibitors - sitagliptin

A

inhibit DDP-IV and prolong half life of GLP-1

\+
oral
no hypo's
well tolerated
some licensed in renal impairment

-
expensive
unknown long term effects

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9
Q

GLP-1 mimetics - exanetide

A

resistant to DDP-IV
enhanced incretin effects

+
no hypo
weight loss

-
sub cut injection
N&V
expensive

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10
Q

stepped approach

A
  1. lifestyle
  2. monotherapy - add metformin
  3. dual therapy - add sulfonylurea
  4. triple therapy - add on agent (GLP-1 enhancer/SGLT2 inhibitor)
  5. insulin, if not already used
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11
Q

statins

A

act directly by:
decreasing cholesterol biosynthesis
increasing uptake of cholesterol from the circulation into the liver

possibly indirectly by:
improving endothelial function
reducing inflammation
plaque stabilisation
inhibiting thrombus formation
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12
Q

statin side effects

A

hepatic: deranged LFTs, liver injury
myalgia and myositis - elevated CK levels

minor: rash, GI upset, sleep disturbance, aches and pains

v small increased risk of DM in non diabetic population
peripheral neuropathy

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13
Q

statin interaction

A

P450 metabolism (CYP3A4)
CYP3A4 inhibitors include:
ciclosporin, clarithromycin, erythromycin, grapefruit juice

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14
Q

Fibrates

A

peroxisome proliferator activated receptor alpha (PPARa) activators
reduces VLDL & LDL while increasing HDL

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15
Q

ezetimibe

A

NPC1L1 inhibition - reduces transport of cholesterol from intestinal lumen
as secondary prevention, reduces in CVD in combination with statins

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16
Q

PCSK9 inhibitors - alirocumab, evolocumab

A

monoclonal IgG antibodies to proprotein convertase subtilisin kexin type 9 (PCSK9)
PCSK9 binds to LDL receptor on hepatocyte surface and promotes intracellular degradation
inhibiting PCSK9 lowers LDL, IDK and VLDL levels

17
Q

fat metabolism

A

packaged into chylomicrons
these are circulated around the body and used as an energy source
the remnants of chylomicrons are converted by the liver into VLDLs

18
Q

diabetes insipidus

A

hyposecretion/insensitivity to effects of, ADH

ADH: synthesised in the hypothalamus, transported to and released from the post pituitary.

cranial DI: decreased secretion of ADH. reduces the ability to concentrate urine, causing polyuria and polydipsia
nephrogenic DI: decreased ability to concentrate the urine because of resistance to ADH in the kidney

19
Q

ADH

A

released in response to hypertonicity and allows the kidney to reabsorb solute-free water and return it into circulation. this also leads to more concentrated urine and reduced urine volume

kidney: increases water permeability of DCT and collecting ducts, allowing for more water reabsorption. occurs through increased expression of aquaporin-2 water channels in the apical membrane of DCT and CD epithelial cells

ADH: allows for the reabsorption of water in the kidney without Na. leads to high urine Na concentration