ADIPOSE CELLS

Kibbe Sandin

11/21/05

Overview:

-Types of tissue

- Storage of Fat

- Components of Adipose tissue and how they bond

- Location

- Purpose

-Types

-Relation to cancer

-Relation to Insulin

• There are four main tissue types– epithelial tissue

– connective tissue

– nervous tissue

– muscle tissue

Adipose tissue is another loose form of connective tissue

- stores fat in adipose cells that is distributed throughout the matrix.

How does this store fat? …..

• Adipose cells store fat

• Swell when fat is stored and shrink when the fat is used as fuel.

• Key in storing fuel molecules and insulating and padding the body

• fat stored in these cells –– fats eaten – manufactured within the body from fats,

carbohydrates and protein in the food

• Key components of adipose cells

• neutral glycerol esters – part of a group of Carboxylic acids

• Stearic acid CH3(CH2)16COOH

• Oleic acid CH3(CH2)7CH=CH(CH2)7COOH

• Palmitic acids CH3(CH2)14COOH

• Bonding of carboxylic acids

• Carboxylic acids are the most acidic class of compounds that contain only carbon, hydrogen, and oxygen

• Hydrophilic

• Lipophilic

• Amphiphilic

• Found?• Mainly beneath the skin - panniculus adiposus

• deposits between the muscles

• among the intestines and in their mesentery

• around the heart

• Purpose – Uses…

• fuel reserve

• Conservation of heat of the body

• forms soft and elastic pads between the various organs.

• Types

• White – single large lipid

vacuole directly

below skin

• Brown – multiple lipid vacuole • interscapular region and the axillae

• When adipocytes (adipose cells) fill with lipid and get to a critical size, it results in an increase in their numbers

• This critical size does not occur with moderate overfeeding, but rather long term

• Once new adipocytes are formed, they remain throughout life and only a reduction in size of the cell is possible

• This increased number of adipocytes has consequences for the treatment and prevention of obesity

• Lipogenesis is the deposition of fat.

• Lipolysis is the chemical decomposition and release of fat from adipose tissue.

• Adipose cells related to cancer?

• Relationship between adipocytokines (adipose tissue hormone) and cell regulation - Leptin : main effect is regulation of homeostasis

Glucose and lipid metabolism, angiogenesis, blood pressure reglation, bone formation

- Adioponecctin: protein exclusive in white adipose cells

anti-atherogenic, anti-inflammatory, insulin-sensitizing

- Well documented that obesity increases risk of prostate, breast and colon cancer

- Leptin – shown to stimulate growth migration and invasion of cancer cells in vitro,promoting malignant biological behavior

• Insulin and Adipose cells?

• Insulin well known to play a key

role in adipose differentiation

• Insulin signals for Lipogenesis and Adipogenesis– Insulin is a major hormone controlling energy function

due to insulin binding to receptors

• Large lipid droplets observed

• Glycerol released form cells increased

• Glucose uptake increased

Mouse study:–Stromal cell line used – differentiation by

treating cells with alpha –MEM

(a mimal essential medium for in vitro experimentation)

–Preadipocyte cell line – cultured in DMEM and Dex ( dexamethasone)

–Differentiation initiated by addition

of insulin

The Stromal line was found to be able to convert to mature adipose cells and accumulate tryglicerides and glycerol

Showing stimulation between intracellular signaling = easy reaction and binding = easy growth and multiplication

• References• Adipose Tissue, Encyclopedia Britannica, 2005

• Ann L. Albright, Judith S. Stern, Adipose Tissue, Encyclopedia of Sports Medicine and Science, May 1998

 • Christopher F. Lurat, Klaus Natter, Julia Petshnig, Heino Wolinski, Kim Scheuringer, Harald Scholz,

Robert Zimmerman, Regina Leber, Rudolf Zechner, Sepp D. Kohlein, Obese yeast: Triglycerides Lipolysis is Funtionally conserved from Mammals to Yeast, JBC Papers in Press. Nov. 2, 2005

• D. Housa, J. Housova, Z. Vernerova, M. Haluzik, Adipocytes and Cancer, Psychological Research Pre-Press Article, 1-22

 • Leonard Napolitano Ph.D., The Differentiation of White Adipose Cells: An Electron Microscope

Study, The Journal of Cell Biology, Vol. 18, 663-679, 1963 • Satoshi Morito, Kuniko Yaguchi, Mikki Imada, Chihiro Tachikawa, Masaaki Nomuro, Shuzo

Moritani, Manabu Igarashi, Kiochi Yokogawa, Ken-ichi Miyamoto, Insulin Signaling in Adipocytes Differentiated form Mouse Stromal MC3T3-G2/PA6 Cells, Biology Pharmacy Bullitin, Vol. 28, No. 11, 2040-2045, July 2005

• Varastehpour Ali, Radaelli Tatjana, Minium Judi, Ortega Henar, Herrera Emilio, Castalano Patrick, Hauguel-de Mouzon Sylvie, Activation of Phospholipase A2 is associated with Generation of Placental Lipid Signals and Fetal Obesity, Journal of Clinical Endocrinology & Metabolism. October 25, 2005