Adipose tissue

characterization

FACS markers that should be positive for adipose stromal cells

CD 73

CD 90

CD 105

tissue organization

cells

cell populations

pre-adipocytes

fibroblasts

endothelial cells

immune cells

adipocytes

production of endocrine proteins

adipokines

adiponectin

leptin

proinflammatory regulators

IL-6

monocyte chemoattractant protein 1=MPC-1

tumor necrosis factor a=TNF-a

macrophages

types

lean

obese

cell ratio

cell ratio

immune cells

other cells

5%

95%

other cells

immune cells

50%

characteristics

morphology

50%

crown-like structures

endocrinology

MPC-1 ⬆

adiponectin ⬇

resulting in increased peripheral monocyte infiltration to the site

monocyte differentiation into macrophages

affecting factors

Paracrine factors

leptin

IGF-I

stimulating angiogenesis

triggers proliferation

IGFBP

regulation of preadipocyte proliferation and differentiation

TNF-alfa

🚩elevated levels in obese individuals 🚩

decreases preadipocyte number

inhibiting differentiation of adipocytes

angiotensin II

🚩elevated levels in obese individuals 🚩

TGF-beta

local mitogen

antagonizes adipose cell differentiation

larger cells secreting more TNF-alfa

neural control

denervation

increases fat cell proliferation

inhibits lipolysis

thyroxin

glucocorticoids

dexamethasone

remove dead cells

lipid storage

blood vessels

lymph nodes

nerves

variable size

🚩in obesity, cell size heterogeneity ⬇

adipose tissue influenced by secretions

TNF receptors present in proximal area, decreases in distal parts of AT

phagocytic activity toward micro-organisms

function disappears when differentiated ointo adipocytes

sympathetic nervous system

sensory

not known why

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mass growth

hypertrophy

cell size ⬆

hyperplasia

cell number⬆

lack of capillaries

overgrowth of adipocytes

hypoxia

adipocyte necrosis

upreg. inflammatory cytokines

inflitration of macrophages

adiponectin ⬇

macrophage differentiation to M1