Patofyziologie a zajímavosti kolem

Connective tissue disorder

• Loss of elastic recoil in adipose tissue
• Fluid to collect rather than exit into lymphatics
• Loss of recoil is seen when dye is injected into lipedema tissue
• Instead of forming a small rounded spot before entering lymphatics
• Dye seeps into the tissue forming flame-like structures [7]

Histological exam

• Cellulite with dilation of subdermal blood capillaries, perivascular cells,
• Fibrosis of arterioles,
• Fibrosis and dilation of venules,
• Hypertrophy and hyperplasia of adipocytes
• Histology of lipedema SAT can also appear as norma

Histochemical studies

• Adipocytes death
• Stem cell regeneration
• Increased numbers of blood vessels especially capillaries and prominent venules
• Large clusters of macrophages are found around multiple fat cells
• Not isolated crown-like structures
• Surrounding blood vessels
• Forming oil cysts in lipedema SAT
• Macrophages may also be a prominent component of cellulite
• www.ncbi.nlm.nih.gov/pmc/articles/PMC4010336/

Elasticity of the skin and fascia

• Decreased in lipedema
• In Stage III may progress to abnormally clumped elastic fibers or pseudoxanthoma
• The skin loses its role as an abutment for the skeletal muscle venous pump
• Increased compliance of the SAT results in an increase in capillary compliance

• The permeable capillaries release excess protein-rich fluid into the interstitium along with blood
• Veno-arteriolar reflex in lipedema
• Absent so that under orthostatic conditions (standing)
• Limited vasoconstriction
• Increased net filtration driving edema
• Early on, lymphatic transport increases to accommodate the increased fluid flux from the capillaries
• As lipedema progresses, microaneurysms appear in the lymphatics in the skin
• Eventually leak
• Hypertrophy and hyperplasia of fat cells accelerates
• Further altering the microlymphatic architecture
• Increasing venous congestion
• Edema increases hydrostatic pressure in the tissue and pain

Leptin

• Believed that the hormone leptin could be the key hormone in the dysregulation of fat deposition and distribution [1]

Obesity - lymphedema and aggravati of lipoedema

• Itself a risk factor for lymphedema
• Can exacerbate lipedema
• Lymphedema is the retention of fluid in tissues causing swelling due to congenital or acquired damage to the lymphatic system
• “lipedema” is defined as “fluid in fat”
• Excess tissue fluid from lymphedema
• Adds to the fluid already present in lipedema fat
• Induces additional fat growth
• Adding to the burden of fat in lipedema [7]

Tissue Sodium Content Elevated in the Skin and Subcutaneous Adipose Tissue in Women with Lipedema.

• Participants with lipedema (n?=?10) and control (n?=?11) volunteers matched for biological sex, age, BMI, and calf circumference were scanned with 3.0-T sodium and conventional proton magnetic resonance imaging (MRI)
• Skin (P?=?0.01) and SAT (P?=?0.04) sodium content
• Elevated in lipedema
• Skin: 14.9?±?2.9 mmol/L
• SAT: 11.9?±?3.1 mmol/L
• Control participants
• Skin: 11.9?±?2.0 mmol/L
• SAT: 9.4?±?1.6 mmol/L
• Relative fat-to-water volume in the calf
• Was elevated in lipedema (1.2?±?0.48 ratio)
• Relative to control participants (0.63?±?0.26 ratio; P?
• Skin sodium content
• Was directly correlated with fat-to-water volume (Spearman's rho?=?0.54; P?=?0.01)
• Providing objective imaging-based biomarkers for differentially diagnosing the under-recognized condition of lipedema from obesity