insulae pancreaticae

膵島

WordNet

1. of or involving the pancreas; "pancreatic cancer"

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1. 膵臓の

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/12/16 21:07:06」(JST)

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Not to be confused with Langerhans cells, found in the epidermis.

Islets of Langerhans
Islet of Langerhans (mouse) in its typical proximity to a blood vessel; insulin in red, nuclei in blue.
Islets of Langerhans, the lighter tissue among the darker, acinar pancreatic tissue, hemalum-eosin stain.
Details
Latin	insulae pancreaticae
Identifiers
TA	A05.9.01.019
FMA	FMA:76489
Anatomical terminology

This photograph shows a mouse pancreatic islet, an often spherical group of hormone-producing cells. Insulin is labelled here in green, glucagon in red, and the nuclei in blue.

The diagram shows the structural differences between rat islets (top) and humans islets (bottom) as well as the ventral part (left) and the dorsal part (right) of the pancreas. Different cell types are colour-coded. Rodent islets, unlike the human ones, show the characteristic insulin core.

A porcine islet of Langerhans. The left image is a brightfield image created using hematoxylin stain; nuclei are dark circles and the acinar pancreatic tissue is darker than the islet tissue. The right image is the same section stained by immunofluorescence against insulin, indicating beta cells.

Illustration depicting pancreatic islet

The islets of Langerhans are the regions of the pancreas that contain its endocrine (i.e., hormone-producing) cells. Discovered in 1869 by German pathological anatomist Paul Langerhans, the islets of Langerhans constitute approximately 1% to 2% of the mass of the pancreas.

Structure

There are about one million islets distributed throughout the pancreas of a healthy adult human,^:914 each of which measures about 0.2 mm in diameter.^:914 Each is separated from the surrounding pancreatic tissue by a thin fibrous connective tissue capsule which is continuous with the fibrous connective tissue that is interwoven throughout the rest of the pancreas.^:914 The combined mass of the islets is 1 to 1.5 grams.

Histology

Hormones produced in the islets of Langerhans are secreted directly into the blood flow by (at least) five types of cells. In rat islets, endocrine cell subsets are distributed as follows:

• Alpha cells producing glucagon (15–20% of total islet cells)
• Beta cells producing insulin and amylin (65–80%)
• Delta cells producing somatostatin (3–10%)
• PP cells (gamma cells) producing pancreatic polypeptide (3–5%)
• Epsilon cells producing ghrelin (<1%)

It has been recognized that the cytoarchitecture of pancreatic islets differs between species. In particular, while rodent islets are characterized by a predominant proportion of insulin-producing beta cells in the core of the cluster and by scarce alpha, delta and PP cells in the periphery, human islets display alpha and beta cells in close relationship with each other throughout the cluster.

Islets can influence each other through paracrine and autocrine communication, and beta cells are coupled electrically to other beta cells (but not to other cell types).

Function

The paracrine feedback system of the islets of Langerhans has the following structure:

• Glucose/Insulin: activates beta cells and inhibits alpha cells
• Glycogen/Glucagon: activates alpha cells which activates beta cells and delta cells
• Somatostatin: inhibits alpha cells and beta cells

A large number of G protein-coupled receptors (GPCRs) regulates the secretion of insulin, glucagon and somatostatin from pancreatic islets, and some of these GPCRs are the targets of drugs used to treat type-2 diabetes (ref GLP-1 receptor agonists, DPPIV inhibitors).

Electrical activity

Electrical activity of pancreatic islets has been studied using patch clamp techniques. It has turned out that the behavior of cells in intact islets differs significantly from the behavior of dispersed cells.

Clinical significance

Diabetes

The islets of Langerhans contain beta cells, which secrete insulin, and play a significant role in diabetes.

Transplantation

Restoration of metabolic control via the transplantation of islets of Langerhans is an appealing approach. This can be achieved by transplantation of the pancreas as vascularized organ or of isolated pancreatic islets (islet cell clusters). Islet transplantation has emerged as a viable option for the treatment of insulin requiring diabetes in the early 1970s with steady progress over the last three decades.

Islet transplantation has the possibility of restoring beta cell function from diabetes, offering an alternative to a complete pancreas transplantation or an artificial pancreas.

Because the beta cells in the islets of Langerhans are selectively destroyed by an autoimmune process in type 1 diabetes, clinicians and researchers are actively pursuing islet transplantation as a means of restoring physiological beta cell function in patients with type 1 diabetes.

Recent clinical trials have shown that insulin independence and improved metabolic control can be reproducibly obtained after transplantation of cadaveric donor islets into patients with unstable type 1 diabetes.

Islet transplantation for type 1 diabetes currently requires potent immunosuppression to prevent host rejection of donor islets.

An alternative source of beta cells, such insulin-producing cells derived from adult stem cells or progenitor cells would contribute to overcoming the shortage of donor organs for transplantation. The field of regenerative medicine is rapidly evolving and offers great hope for the nearest future. However, type 1 diabetes is the result of the autoimmune destruction of beta cells in the pancreas. Therefore, an effective cure will require a sequential, integrated approach that combines adequate and safe immune interventions with beta cell regenerative approaches.

Another potential source of beta cells may be xenotransplantation. The most likely source for xenogeneic islets for transplantation into human under evaluation is the pig pancreas. Interestingly, human and porcine insulin differ only for one amino acid, and insulin extracted from porcine pancreata has been used for the treatment of patients with diabetes before the development of recombinant human insulin technology. Several studies in small and large animals models have shown that transplantation of islet cells across species is possible. However, several problems need to be overcome for porcine islet transplantation to become a viable clinical option. The immunogenicity of xenogeneic tissues may be different from and even stronger than allogeneic tissues. For instance, Galalpha1-3Galbeta1-4GlcNAc (alpha galactosidase, alpha-Gal) expressed on porcine cells represents a major barrier to xenotransplantation being the target of preformed antibodies present in human blood.

Remarkable progress has been recorded in the development of genetically modified pigs lacking or overexpressing molecules that may improve acceptance of transplanted tissues across into humans. Pigs lacking alpha-Gal or overexpressing human decay accelerating factor (hDAF), amongst others, have been generated to study the impact on transplanted outcome in nonhuman primate models. Another possible antigenic target is the Hanganutziu-Deichter antigen, a sialic acid found in pigs and not humans, which may contribute to immunogenicity of porcine islets. Another limitation is the risk for transmission of zoonotic infections from pigs to humans, particularly from porcine endogenous retro-viruses (PERV). Amongst the approaches proposed to overcome islet xenorejection is immunoisolation of the clusters using encapsulation techniques that may shield them from immune attack. Studies in rodents and large animals have shown great promise that justify cautious optimism for the near future. Nonrandomized, uncontrolled pilot clinical trials are ongoing in subject with insulin-requiring diabetes to test the efficacy of encapsulation techniques to protect xenogeneic islets in the absence of chronic anti-rejection drugs.

Gallery

• Hormones/islet architecture
• Mouse islet immunostained for pancreatic polypeptide

• Mouse islet immunostained for insulin

• Mouse islet immunostained for glucagon

• Illustration of dog pancreas. 250x.

See also

• Betatrophin
• Human anatomy
• Pancreatic hormone
• Neuroendocrine tumor

References

External links

• "The Islets of Langerhans", Karolinska Institutet, Sweden
• "Islets"
• Islet Society
• MeSH A03.734.414
• "Pancreas, human – H&E", Blue Histology – Accessory Digestive Glands, School of Anatomy and Human Biology,

English Journal

• A pumpless microfluidic device driven by surface tension for pancreatic islet analysis.

• Xing Y1,2, Nourmohammadzadeh M1,2, Elias JE1,2, Chan M1,2, Chen Z1, McGarrigle JJ1, Oberholzer J3,4, Wang Y5,6.
• Biomedical microdevices.Biomed Microdevices.2016 Oct;18(5):80. doi: 10.1007/s10544-016-0109-4.
• We present a novel pumpless microfluidic array driven by surface tension for studying the physiology of pancreatic islets of Langerhans. Efficient fluid flow in the array is achieved by surface tension-generated pressure as a result of inlet and outlet size differences. Flow properties are character
• PMID 27534648

• Immune Intervention and Preservation of Pancreatic Beta Cell Function in Type 1 Diabetes.

• Simmons KM1, Gottlieb PA1, Michels AW2.
• Current diabetes reports.Curr Diab Rep.2016 Oct;16(10):97. doi: 10.1007/s11892-016-0793-8.
• Type 1 diabetes (T1D) results from the immune-mediated destruction of insulin-producing β cells located within the pancreatic islets of Langerhans. The autoimmune process leads to a deficiency in insulin production and resultant hyperglycemia requiring lifelong treatment with insulin administration
• PMID 27558810

• Reproducible preparation of spheroids of pancreatic hormone positive cells from human iPS cells: An in vitro study.

• Konagaya S1, Iwata H2.
• Biochimica et biophysica acta.Biochim Biophys Acta.2016 Sep;1860(9):2008-16. doi: 10.1016/j.bbagen.2016.05.012. Epub 2016 May 11.
• BACKGROUND: Transplantation of islets of Langerhans is regarded as a promising therapy for type 1 diabetes. A large number of β-cells are required for the treatment of human type 1 diabetes. Pluripotent stem cells, such as embryonic stem cells and induced pluripotent stem cells, have been considere
• PMID 27180174

Related Links

• 膵島 - Insulae pancreaticae

膵島 - Insulae pancreaticae Langerhans Quick Links 画像 この解剖学的部位を含む画像はまだありません。 説明 The pancreas contains tissue with an endocrine and exocrine role, and this division is also visible when the pancreas ...

• MEDO 組織学用語 (2012/02/16)

*pancreatic islet「膵島」(=insulae pancreaticae[L][pl]) *papilla「乳頭」 ⇒lingual papilla「舌乳頭」 *parafollicular cell「傍濾胞細胞」 *parathyroid gland「傍甲状腺」 *parathyroid hormone「傍甲状腺ホルモン」 *palatine tonsil ...

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★リンクテーブル★

リンク元	「膵島」
関連記事	「pancreatic」「insulae」

「膵島」

　　[★]

英

pancreatic islet (Z), pancreatic islets

ラ

insula pancreatica, insulae pancreaticae

同

ランゲルハンス島 islets of Langerhans Langerhans island、ラ島

関

膵臓、膵島細胞

• ホルモン分泌

• グルカゴン：α細胞
• インスリン：β細胞
• ソマトスタチン：δ細胞

「pancreatic」

　　[★]

• adj.

• 膵臓の、膵性の、膵の

関

pancreas、pancreata

　 　

「insulae」

　　[★]

島

関

insula、islet