Adipose Tissue Development

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Introduction

Brown adipose tissue

Adipose tissue is a form of loose connective tissue composed of adipocytes, fibroblasts, vascular endothelial cells, and some immune cells. Connective tissues in the body have a mesoderm origin, while in the head neural crest also contributes to these tissues.

There are two main forms of adipose tissue, White Adipose Tissue (WAT) and Brown Adipose Tissue (BAT). White adipose tissue, is the main depot for lipid storage, while brown adipose tissue is involved in thermogenesis. We now know that adipose tissue also has important endocrine hormones secreting leptin, adiponectin, and resistin. (More? Endocrine Adipose Tissue | Endocrine other tissues)


Postnatally, a third form of "beige adipose tissue" has been identified in the mouse model.[1] This form of adipose can be induced in subcutaneous white adipose tissue as a response to cold and other thermogenic activators.[2]


In the adult tissues, White Adipose Tissue is found extensively within the hypodermis layer of the skin (integumentary).


Connective Tissue: adipose | tendon | integumentary

Some Recent Findings

  • A mesodermal fate map for adipose tissue[3] "The embryonic origin of distinct fat depots and the role for ontogeny in specifying the functional differences among adipocyte lineages between and within depots is unclear. Using a Cre/Lox-based strategy to track the fate of major mesodermal subcompartments in mice we present evidence that fewer than 50% of interscapular brown adipocytes are derived from progenitors of the central dermomyotome. Furthermore, we demonstrate that depot-specific adipocyte lineages spatially diverge as early as gastrulation and that perigonadal adipocytes arise from separate mesodermal subcompartments in males and females. Last, we show adipocyte precursors (APs) of distinct lineages within the same depot exhibit indistinguishable responses to a high fat diet, indicating ontogenetic differences between APs do not necessarily correspond to functional differences in this context. Altogether, these findings shed light on adipose tissue patterning and suggest the behavior of adipocyte lineage cells is not strictly determined by developmental history."
  • The fat controller: adipocyte development[4] "Obesity is a condition characterized by excess adipose tissue that results from positive energy balance and is the most common metabolic disorder in the industrialized world. ... Adipocytes are not created from other adipocytes, but they arise from precursor cells. In the last two decades, scientists have discovered the function of many proteins that influence the ability of precursor cells to become adipocytes. If the expansion of the adipose tissue is the problem, it seems logical that adipocyte development inhibitors could be a viable anti-obesity therapeutic. However, factors that block adipocyte development and limit adipocyte expansion also impair metabolic health. This notion may be counterintuitive, but several lines of evidence support the idea that blocking adipocyte development is unhealthy. For this reason it is clear that we need a better understanding of adipocyte development."
  • Brown adipose tissue: function and physiological significance[5] "The function of brown adipose tissue is to transfer energy from food into heat; physiologically, both the heat produced and the resulting decrease in metabolic efficiency can be of significance. ... The development of brown adipose tissue with its characteristic protein, uncoupling protein-1 (UCP1), was probably determinative for the evolutionary success of mammals, as its thermogenesis enhances neonatal survival and allows for active life even in cold surroundings."
More recent papers  
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Search term: Adipose Embryology | Adipose Development | Brown Adipose | White Adipose | Beige Adipose

Development Overview

Adipose Tissue Timeline
Anatomical Region Specific Location Start
(weeks)
CRL (mm) Complete
(weeks)
CRL (mm)
Head Buccal pad 14 100 17 153
Cheek 14.5 103 17 150
Chin 14.5 103 17 150
Ocular pad 15 113 19.5 170
Neck Neck 15 113 19.5 170
Thorax Anterior wall 16 135 19.5 170
Posterior wall 15 113 20.5 190
Mammary 14.5 106 17.5 156
Abdomen Abdominal wall 14.5 106 20.5 190
Perirenal 15 113 20.5 190
Upper limb Shoulder 15 113 23.5 216
Forearm 16 131 20.5 190
Arm 16 131 20.5 190
Hand 16 131 l9.5 172
Lower limb Gluteal 16 131 20.5 190
Thigh 16.5 141 22.5 212
Leg 16 131 22.5 212
Foot 16 131 19.5 170
Table Notes - weeks are fertilization age (FA), not GA, both male and female data are combined.

Table Data source[6]   Links: adipose | Second Trimester


  • hand - begins in the subcutis of the palm and then progresses proximally to the wrist and distally into the fingers.
  • week 23 - thickened layer of subcutaneous fat covers the extremities of the limbs, as for newborn.

Mesoderm Development

Mesoderm cartoon 01.jpg Cells migrate through the primitive streak to form mesodermal layer. Extraembryonic mesoderm lies adjacent to the trilaminar embryo totally enclosing the amnion, yolk sac and forming the connecting stalk.
Mesoderm cartoon 02.jpg Paraxial mesoderm accumulates under the neural plate with thinner mesoderm laterally. This forms 2 thickened streaks running the length of the embryonic disc along the rostrocaudal axis. In humans, during the 3rd week, this mesoderm begins to segment. The neural plate folds to form a neural groove and folds.
Mesoderm cartoon 03.jpg Segmentation of the paraxial mesoderm into somites continues caudally at 1 somite/90minutes and a cavity (intraembryonic coelom) forms in the lateral plate mesoderm separating somatic and splanchnic mesoderm.

Note intraembryonic coelomic cavity communicates with extraembryonic coelom through portals (holes) initially on lateral margin of embryonic disc.

Mesoderm cartoon 04.jpg Somites continue to form. The neural groove fuses dorsally to form a tube at the level of the 4th somite and "zips up cranially and caudally and the neural crest migrates into the mesoderm.


Molecular Development

Adipocyte differentiation regulation 01.jpg

Adipocyte differentiation regulation.[4]


Notch1 signaling in adipocyte progenitor cells regulates the adipogenesis process including proliferation and differentiation of the adipocyte progenitor cells.[7]


Links: NOTCH

White Adipose

White adipose 01.jpg White adipose 02.jpg

Brown Adipose

Brown adipose tissue
  • Brown Adipose Tissue (BAT) arises from progenitor cells that also give rise to skeletal muscle,
  • Brown adipocytes have numerous small lipid droplets rather than a single large one as in white adipocytes
  • Elevated numbers of mitochondria
    • mitochondrial expression of the nuclear gene UCP1, the uncoupler of oxidative phosphorylation responsible for non-shivering thermogenesis.

BAT distribution in the newborn infant:[8]

  1. Interscapular - mass lies in a thin diamond-shaped sheet between the shoulder blades, separated from the subcutaneous WAT by a discontinuous fibrous layer. When replete with fat it has a yellowish-brown colour; depleted it is much darker. It has a fine lobular structure.
  2. Neck muscles and blood vessels - many smaller masses with the main mass following the course of the internal jugular vein and common carotid artery.
  3. Axilla - large deposits as extensions from the neck tissue that pass under the clavicles.
  4. Great vessels - entering the thoracic inlet extending as fine fingers that spread out from the midline with each intercostal artery. Similar deposits lie among the internal mammary vessels. Many discrete, moderately large masses lie in the mediastinum between the oesophagus and the trachea.
  5. Abdomen - discrete masses accompany the aorta and lie in relation to many structures on the posterior abdominal wall such as the pancreas, autonomic ganglia and chromaffin tissue. The largest abdominal mass envelops the [[renal}} and adrenals.

Beige Adipose

A third form of "beige adipose tissue" has been identified in the mouse model.[1] This form of adipose can be induced in subcutaneous white adipose tissue as a response to cold and other thermogenic activators.[2] This conversion process has also been described as "browning".

Periaortic Arch Adipose Tissue

Periaortic arch adipose tissue (PAAT) surrounds the aortic arch, its major branches, and surrounds the pulmonary artery, the ascending aorta, and the beginning of descending aorta. PAAT originate from different lineages including neural crest[9] and functionally have roles in regulating vascular homeostasis.

In the mouse, thoracic periaortic adipose tissue is mainly BAT, while abdominal periaortic adipose tissue is both BAT and WAT.


Somite - Dermatome

The dermis and hypodermis layers of the skin.

Integumentary Hypodermis

Adult skin histology 02.jpg Histological section of skin showing the 3 main layers: epidermis, dermis and hypodermis layers. ((Stain - Haematoxylin Eosin))
  • epidermis - outer layer, stratified squamous epithelium.

Highlighted ringed regions show:

  • dermis - middle layer, dense irregular connective tissue.
  • hypodermis - inner layer, adipose tissue.

Note the junctional region between dermis and hypodermis contains macroscopically visible glands and blood vessels.

Somatic Mesoderm

The body wall connective tissue.

Splanchnic Mesoderm

The lamina propria and submucosa layers of the gastrointestinal tract wall.

References

  1. 1.0 1.1 Chan M, Lim YC, Yang J, Namwanje M, Liu L & Qiang L. (2019). Identification of a natural beige adipose depot in mice. J. Biol. Chem. , , . PMID: 30824545 DOI.
  2. 2.0 2.1 Tanimura K, Suzuki T, Vargas D, Shibata H & Inagaki T. (2019). Epigenetic regulation of beige adipocyte fate by histone methylation. Endocr. J. , 66, 115-125. PMID: 30606913 DOI.
  3. Sebo ZL, Jeffery E, Holtrup B & Rodeheffer MS. (2018). A mesodermal fate map for adipose tissue. Development , , . PMID: 30045918 DOI.
  4. 4.0 4.1 Stephens JM. (2012). The fat controller: adipocyte development. PLoS Biol. , 10, e1001436. PMID: 23209380 DOI.
  5. Cannon B & Nedergaard J. (2004). Brown adipose tissue: function and physiological significance. Physiol. Rev. , 84, 277-359. PMID: 14715917 DOI.
  6. Poissonnet CM, LaVelle M & Burdi AR. (1988). Growth and development of adipose tissue. J. Pediatr. , 113, 1-9. PMID: 3290412
  7. Shan T, Liu J, Wu W, Xu Z & Wang Y. (2017). Roles of Notch Signaling in Adipocyte Progenitor Cells and Mature Adipocytes. J. Cell. Physiol. , 232, 1258-1261. PMID: 27869309 DOI.
  8. Aherne W & Hull D. (1966). Brown adipose tissue and heat production in the newborn infant. J Pathol Bacteriol , 91, 223-34. PMID: 5941392 DOI.
  9. Fu M, Xu L, Chen X, Han W, Ruan C, Li J, Cai C, Ye M & Gao P. (2019). Neural Crest Cells Differentiate Into Brown Adipocytes and Contribute to Periaortic Arch Adipose Tissue Formation. Arterioscler. Thromb. Vasc. Biol. , 39, 1629-1644. PMID: 31189430 DOI.


Reviews

Tews D & Wabitsch M. (2011). Renaissance of brown adipose tissue. Horm Res Paediatr , 75, 231-9. PMID: 21372557 DOI.

Schulz TJ & Tseng YH. (2009). Emerging role of bone morphogenetic proteins in adipogenesis and energy metabolism. Cytokine Growth Factor Rev. , 20, 523-31. PMID: 19896888 DOI.

Forhead AJ & Fowden AL. (2009). The hungry fetus? Role of leptin as a nutritional signal before birth. J. Physiol. (Lond.) , 587, 1145-52. PMID: 19188249 DOI.

Billon N, Monteiro MC & Dani C. (2008). Developmental origin of adipocytes: new insights into a pending question. Biol. Cell , 100, 563-75. PMID: 18793119 DOI.

Cannon B & Nedergaard J. (2004). Brown adipose tissue: function and physiological significance. Physiol. Rev. , 84, 277-359. PMID: 14715917 DOI.

Articles

Billon N, Kolde R, Reimand J, Monteiro MC, Kull M, Peterson H, Tretyakov K, Adler P, Wdziekonski B, Vilo J & Dani C. (2010). Comprehensive transcriptome analysis of mouse embryonic stem cell adipogenesis unravels new processes of adipocyte development. Genome Biol. , 11, R80. PMID: 20678241 DOI.

Billon N, Iannarelli P, Monteiro MC, Glavieux-Pardanaud C, Richardson WD, Kessaris N, Dani C & Dupin E. (2007). The generation of adipocytes by the neural crest. Development , 134, 2283-92. PMID: 17507398 DOI.

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Cite this page: Hill, M.A. (2024, March 28) Embryology Adipose Tissue Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Adipose_Tissue_Development

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