ADIPOSE TISSUE BIOLOGY Flashcards
WHICH FACTOR IN OBESE INDIVIDUALS IS CRITICAL FOR DETERMINING HOW SUSCEPTIBLE THEY ARE OR WILL BE TO DEVELOPING COMORBIDITIES LIKE TD2 AND CVD?
FAT DISTRIBUTION
ROLES OF ADIPOSE TISSUE:
- ACCUMULATES TRIGLYCERIDES (LIPOGENESIS)
- RELEASES FATTY ACIDS AND GLYCEROL WHEN NEEDED (LIPOLYSIS)
- INSULATION AND PROTECTION (CUSHIONING FOR ORGANS)
- SECRETORY FUNCTION (E.G. ENZYME ADIPSIN)
- ENDOCRINE FUNCTION (E.G. LEPTIN)
APART ON HYPOTHALAMUS, LEPTIN HAS EFFECTS ON WHICH OTHER BRAIN AREA?
HIPPOCAMPUS; INVOLVED IN MEMORY REGULATION AND COGNITIVE FUNCTIONS
HOW MANY ADIPOKINES ARE THERE?
MORE THAN 600
WHAT IS THE LARGEST ENDOCRINE TISSUE OF THE BODY?
ADIPOSE TISSUE
FIRST ADIPOKINE DESCRIBED?
ADIPSIN
OTHER NAMES FOR ADIPSIN + ROLE?
AKA COMPLEMENT FACTOR D
IT IS A SERINE PROTEASE; SPLITS PEPTIDE BONDS IN PROTEINS
+ HAS PROTECTIVE PROPERTIES FOR BETA CELLS
WHAT ARE SERINE PROTEASES?
ENZYMES THAT BREAK PEPTIDE BONDS IN PROTEINS
ADIPOKINES EXAMPLES:
ADIPSIN, ADIPONECTIN, RESISTIN, VISFATIN, FGF21, LEPTIN, RBP4..
APART FROM BEING RELEASED BY THE ADIPOSE TISSUE, FGF21 AND RBP4 ARE ALSO RELEASED BY WHICH ORGAN?
LIVER
ADIPONECTIN?
AN ADIPOKINE THAT HAS AN IMPORTANT ROLE IN BODY’S RESPONSE TO INSULIN, HIGH LEVELS PROTECT AGAINST CVD
FGF21 ADIPOKINE HAS A ROLE IN BODY’S ABILITY TO ADAPT TO CONDITIONS LIKE:
COLD AND STARVATION
ROLE OF ADIPOKINE RBP4?
- BINDS AND TRANSPORTS VIT A IN THE LIVER
- INCREASES LIPOLYSIS
DOES THE ADIPOKINE VISFATIN HAVE HYPOGLYCEMIC OR HYPERGLYCEMIC EFFECTS?
HYPOG.
WHICH OTHER GROUP OF MOLECULES DOES ADIPOSE TISSUE RELEASE APART FROM ADIPOKINES AND WHAT IS THEIR ROLE?
EXOSOMES; SMALL VESICLES THOUGH TO MEDIATE CELL-CELL COMMUNICATION BY TRANSFERRING ACTIVE PROTEINS AND miRNA (DIRECTLY REGULATES GENE EXPRESSION) STABLY
ADIPOSE TISSUE IS INVOLVED IN REGULATION OF GENE EXPRESSION THROUGH RELEASE OF WHICH MOLECULES?
EXOSOMES
% OF KCAL COMING FROM FAT IN A ‘HIGH FAT DIET’?
60%
WHAT IS LIPODYSTROPHY?
- LACK OF ADIPOSE TISSUE, NOT AS A RESULT OF STARVATION BUT LACK OF ADIPOCYTES THEMSELVES (ABSENCE OF TISSUE)
- IN HUMANS COMPLETE LACK OF ADIPOSE TISSUE IS RARE, PARTIAL LACK POSSIBLE
COMMON FEATURES OF LIPODYSTROPHIES?
- LOSS OR LACK OF FAT IN SOME PARTS OF THE BODY
- REDISTRIBUTION OF FAT IN OTHER LOCATIONS (OFTEN UPPER BODY AND BELLY AREA)
- INCREASED VISCERAL FAT
- INSULIN RESISTANCE
- FATTY LIVER
WHAT IS A SIGN OF LIPID ACCUMULATION IN THE LIVER?
WHITISH COLOUR INSTEAD OF BRIGHT RED
PATIENTS UNDERGOING TREATMENT FOR WHICH CONDITION OFTEN SUFFER LIPODYSTROPHY, ESP VISIBLE ON THE FACE?
HIV-POSITIVE PATIENTS ON RETRO-VIRAL THERAPIES
IMPORTANCE OF A/ZIP MOUSE?
- HAD A MUTATION IN C/EBPalpha PROTEIN WHICH IS IMPORTANT FOR ADIPOSE TISSUE DEVELOPMENT
- HAD NO FAT AND A HUGE FATTY LIVER
- SPARKED INTEREST AROUND DANGEROUS OF LACK OF ADIPOSE TISSUE
- SYMPTOMS IMPROVED WITH INJECTIONS OF ADIPOSE TISSUE
FAT REMOVAL OR RELOCATION (E.G. LIPOSUCTION, IN OBESITY) AND INSULIN RESISTANCE LINK?
- RESEARCH NOT CONCLUSIVE
- SLIGHT INCREASE IN INSULIN RESISTANCE POST LIPOSUCTION BUT CAN BE PREVENTED BY EXERCISE
- REMOVING FAT FROM MORBIDLY OBESE IN GENERAL DOES HELP
WHEN TALKING ABOUT FAT MASS, WE ARE MAINLY REFERRING TO WHICH TYPE OF ADIPOSE TISSUE?
WHITE
CATEGORIES OF ADIPOSE TISSUE?
BY COLOUR; WHITE, BROWN, BEIGE, PINK
WHICH ADIPOSE TISSUE TYPE IS LARGEST IN VOLUME?
WHITE ADIPOSE TISSUE
WHERE DOES THE BROWN ADIPOSE TISSUE GET ITS COLOUR FROM?
A HUGE NUMBER OF MITOCHONDRIA
BEIGE ADIPOSE TISSUE LOCATION AND CHARACTERISTICS?
MOSTLY DEVELOPS WITHIN WHITE ADIPOSE TISSUE AND SHARES CHARACTERISTICS OF BOTH WHITE AND BROWN ADIPOSE TISSUE
PINK ADIPOSE TISSUE?
- ARISES FROM WHITE ADIPOSE TISSUE IN FEMALE MICE DURING PREGNANCY AND LACTATION
- ADAPTED INTO A SORT OF EPITHELIAL CELL, VERY SPECIALISED
- INVOLVED IN MILK PRODUCTION
ADIPOCYTE STRUCTURE IN WHITE ADIPOSE TISSUE?
- BIG CELLS, HAVE AN ENORMOUS LIPID DROPLET THAT TAKES MOST OF THE SPACE AND SHOVES THE NUCLEUS TO THE SIDE OF THE CELL
MAIN FUNCTIONS OF WHITE ADIPOSE TISSUE?
STORAGE, SECRETION AND PRODUCTION OF ADIPOKINES WHICH SUPPORT THE ROLE OF THE WHITE ADIPOSE TISSUE AS AN ENDOCRINE ORGAN
STRUCTURE OF BROWN ADIPOSE TISSUE?
- CONTAINS FAT DROPLETS, BUT MUCH SMALLER THAN WHITE AT
- INNERVATED BY THE SYMPATHETIC NERVOUS SYSTEM
- HAS A LOT OF MITOCHONDRIA
WHICH CHARACTERISTICS OF BROWN ADIPOSE TISSUE SUGGEST THAT IT BURNS FAT MORE THAN IT STORES IT?
- LARGE AMOUNT OF MITOCHRONDRIA
- EXPRESSES A PROTEIN UCP1 (UNCOUPLING PROTEIN 1)
- SPECIALISES IN NON SHIVERING THERMOGENESIS
ROLE OF UCP1 (UNCOUPLING PROTEIN 1) IN BROWN ADIPOSE TISSUE?
- USES A LARGE AMOUNT OF PROTON GRADIENT PRODUCED BY NADH OXIDATION
- UNCOUPLES THE USE OF GRADIENT FROM THE ATP PRODUCTION SO IT CAN BE USED TO GENERATE HEAT WITHOUT MUSCLE CONTRACTION
WHICH ORGANISMS HAVE BROWN ADIPOSE TISSUE?
ALL MAMMALS
HOW IS NON SHIVERING THERMOGENESIS ACTIVATED IN BROWN ADIPOSE TISSUE?
BY STRESS SIGNALS (COLD, LOW TEMPS) VIA SYMPATHETIC SYSTEM (E.G. NORADRENALINE)
% OF BABY’S BODY WEIGHT THAT IS BROWN ADIPOSE TISSUE?
5%
WHERE IS BROWN ADIPOSE TISSUE LOCATED IN BABIES?
IN THE UPPER BODY (BACK AND SHOULDERS)
ROLE OF BROWN ADIPOSE TISSUE IN BABIES?
- THEY DO NOT REGULATE HEAT WELL BECAUSE THEY HAVE IMMATURE ENDOCRINE SYSTEM AND A LARGE HEAD THAT LOSES THEM A LOT OF HEAT
- THEY DO NOT HAVE ENOUGH MUSCLE TO SHIVER EFFECTIVELY
- NEED BAT TO KEEP WARM
WHEN BAT (BROWN ADIPOSE TISSUE) IS STIMULATED BY COLDER TEMP (E.G. 16 DEGREES) IN ADULTS, IT WILL HELP BURN ADDITIONAL HOW MANY CALORIES IN A DAY?
15-25kcal
HOW MANY GRAMS OF BROWN ADIPOSE TISSUE IS THERE IN ADULT HUMAN MALES?
50-60 g (0.08% BODY WEIGHT)
BEIGE ADIPOSE TISSUE IS ALSO CALLED:
BRITE ADIPOSE TISSUE
DOES BEIGE ADIPOSE TISSUE HAVE UCP1?
YES
WHITE ADIPOSE TISSUE CHANGES ITS PROPERTIES AND BECOMES BEIGE IN RESPONSE TO EXTERNAL CUES IN A PROCESS CALLED:
‘BROWNING OF THE WHITE ADIPOSE TISSUE’
BROWN ADIPOSE TISSUE IN ADULTS WAS DISCOVERED THROUGH WHICH TECHNIQUE?
positron emission tomography–computed tomography (PET-CT) scans