the pineal gland_3rd - eye

8/14/2019 The Pineal Gland_3rd - Eye

1/5

17

J. Anat. Soc. India 50(1) 17-18 (2001)

Dixit, D.P. et al

J Anat. Soc. India 50(1) 17-18 (2001)

Varying Appearances of Calcification in Human Pineal Gland: ALight Microscopic StudyKoshy, S. and Vettivel S.K.

Department of Anatomy, Christian Medical College, Vellore, INDIA

For Reprints, request the first author.

Abstract.Pineal glands were collected from accident deads during autopsy. The subjects were South Indians. There were nohistological postmortum changes. The glands were processed for light microscopy. Eight micron sections were cut and stained. Capsule,septa, lobules, and corpora aranacea were observed. The pineal parenchyma had light and dark pinealocytes. Intrapineal and extrapinealcalcified concretions were present. Intrapineal concretions were in the parenchyma, where in younger age groups and among the

pinealocytes, the concretions were of globular pattern but in older age groups and among glial fibres, these were of concentric lamellarpattern. Extrapineal concretions were adjacent to the capsule and were concentric lamellar only.

Key words : Calcification, concretions, corpora aranacea, glial fibres, parenchyma, pineal gland, pinealocytes.

Introduction :

The pineal gland (epiphysis cerebri) containscords and follicles of pinealocytes and neuroglia.Septa extend into it from the surrounding piamater.

Pinealocytes form the pineal parenchyma.Neuroglial cells, partially separating thepinealocytes, are like astrocytes (Williams et al.1989). Brain sands, corpora aranacea, or acervuliare calcified concretions in the pineal gland,presence of which is known since the discovery ofthe pineal gland and have been investigated over400 years in animals and in human. They are visiblein imaging techniques and help as a midlinelandmark. There are intrapineal calcifications as wellas extrapineal calcifications. Calcified deposits seenin the choroid plexus of lateral ventricles, meninges,and elsewhere in the habenular commissure are

extrapineal calcification; and those within the pinealparenchyma are intrapineal calcification.Occasionally these are absent in some specimens.Only a few studies on the concretions, suggested afresh study. Therefore, the morphology of the pinealcalcified concretions were studied.

Materials and Methods :

Forty pineal glands were collected fromaccident deads within five to six hours after deathduring autopsy. There were no histologicalpostmortum changes. Age of the subjects rangedfrom one to eighty years. The subjects were SouthIndians in decade wise age groups.

Pineal glands were removed from the brainalong with the superior colliculus, so that the pinealrecess of the third ventricle was also included.Pineal glands were put in Bouins fluid. Afterfixation, the specimens were processed for lightmicroscopy. Eight micron serial sections were cutand stained. Staining methods used were(1) Haematoxylin and eosin, (2) Massons fontannamethod for melanin, (3) Heidenhains iron

haemotoxylin for secretory materials, and (4)Mallorys phosphotungstic acid haematoxylin forneuroglial cells and nerve fibres.

Observations :

Pineal gland had a well defined capsule(piamater) and from the capsule septa extended intothe parenchyma dividing it into lobules (Fig. 1). Thelobular pattern was not well defined in older agegroups. Parenchyma consisted of mainly two typesof pinealocytes, light pinealocytes and darkpinealocytes (Fig 2). Besides these cells, there wereglial cells (Fig. 2). Corpora aranacea were aconstant feature as age advanced.

Corpora aranacea were in two locations,intrapineal in the pineal parenchyma and extrapineal

in the pineal capsule (Fig. 3). These calcifieddeposits were of two patterns, one was a globularpattern and the other was a concentric lamellatedpattern. The extrapineal were of concentriclamellated pattern only. The intrapineal were of twotypes, the globular type seen, where pinealocyteswere present and in younger age groups, and theconcentric lamellated type seen around glial fibresand in older age groups. Corpora aranaceaappeared in a gland of 12 year. Globular pattern ofcalcification was chiefly in younger age groups andamong large amount of pinealocytes (Fig. 4). As age

advanced, there were areas of more glial fibres, andof glial cyst with central coagulum and surroundingglial fibres (Fig. 5). Peripheral to the glial fibre tissue

were areas of pinealocytes. In the areas of moreglial fibres, large amount of concentric lamellatedcrystals of corpora aranacea were present in areas

of less pinealocytes and more glial fibres (Fig. 6).

Discussion :

Corpora aranacea are composed of calcium

and magnesium salts, Polypeptide hormones,


2/5

produced by pineal neuroglia and neurons,

combined with specific protein carriers. They are

released by exocytosis, together with fragments of

vasicular membranes, the latter forming exocytotic

debris. When released, the complex is believed to

dissociate, hormones being exchanged for calcium

ions. The calcium carrier complex so formed is, in

the pineal, deposited concentrically aroundexocytotic debris as corpora aranacea (Lukaszyk

and Rieter, 1975). Presence of calcified concretions

need not reflect a pathological state as these pineal

glands were collected from accident deads, whose

health status was unknown and who probably were

of normal health.

The degree of calcification invariably increases

from younger to older age groups and occasionally,

corpora aranacea are absent in some adult

specimens as according to Krabbe (1955). The

morphology of corpora aranacea shows variations in

the present study. Calcification occurs not only inthe pineal gland but also in the capsule. Vigh et al.

(1998) reported the presence of calcium alongside

the cell membranes and that meningeal corpora

aranacea are in the form of concentric lamellae &

intrapineal as globular. But in the present study, as

age advances, the intrapineal concretions are of

concentric lamellar pattern. Thus, probably the

morphology of intrapineal conceretions changes as

age advances, globular pattern in younger age

groups & concentric lamellar pattern in older age

groups. As age advances, the number of

pinealocytes decreases and glial fibres increase.

The pattern of intrapineal concretions also changes.Globular type of calcified deposits are seen

where large amount of pineal parenchyma is present

and in younger age groups; whereas concentric

lamellated type of calcified deposits are usually

associated with large amounts of glial fibres and in

older age groups. Humbert and Pevet (1995)

observed in aging rats two types of calcification by

electron microscopic and electron diffraction

methods, an amorphous type with concentric layers

and crystalline type with needle shaped crystals and

stated that the genesis takes place in dark

pinealocytes, which contains more calcium and thatonce formed the concretions reach extracellular

space.

The amount of calcarous deposits do not seem

to significantly increase as age advanced but the

pattern of deposit differs. Kodaka et al (1994) stated

that initial human calcification is as calcified

pinealocytes, which grow appositionally forming

concentric laminations and then simple

calcospherulites aggregated with each other and

that some of them become numerous aggregated

concretions, others individually develop scallop-

shaped concentric laminations and become lobated

calcospherulites. Cytoplasmic microacervuli are

localized ultrastructurally in pineal gland from age of

2 days to 86 years; microacervuli are barely present

or frequently absent in the oldest subjects; their

involvement in the secretory activity rather than in

gland atrophy suggests a close relationship betweencytoplasmic microacervuli and intermediate

microfilaments and a possible role of the

cytoskeleton in the formation of corpora aranacea

(Gallinai et al. 1989).

Where the concretions occur adjacent to

pinealocytes, it is crystalline, needle shaped &

globular (Fig. 3) while adjacent to glial fibres or

other connective tissue, it is amorphous, concentric

& lamellar (Fig. 6).

To conclude, (1) Pinealocytes are abundant in

younger age groups, where the concretions are in

the form of crystalline globular pattern. (2) As ageadvances, pinealocytes decrease and glial fibres

increase. Secretory products of pinealocytes are

less so that the concretions are modified to

amorphous concentric lamellar pattern.

References :

1. Galliani, I., Frank, F., Gobbi, P., Giangaspero, F. and Falcieri,

E. (1989): Histochemical and ultrastructural study of human

pineal gland in the course of aging. Journal of

Submicroscopic Cytology and Pathology. 21(3): 571-8.

2. Humbert, W. and Pevet, P. (1995): Calcium concretions in

the pineal gland of aged rats: an ultrastructural and

microanalytical study of their biogenesis: Cell & Tissue

Research 279(3): 565-73.

3. Kodaka, T., Mori, R., Debari, K. and Yamada, M. (1940):

Scanning electron microscopy and electron probe

microanalysis studies of human pineal concretions. Journal

of Electron Microscopy (Tokyo)43(5): 307-17.

4. Krabbe, K.H. (1995): Development of the pineal organ and a

rudimentary parietal eye in some birds Journal of

Comparative Neurology103: 139-49.

5. Lukaszyk, A. and Rieter, R.J. (1975): Histophysiological

evidence for the secretion of polypeptides by the pineal gland.

American Journal of Anatomy103: 139-149.

6. Vigh, B., Szel, A., Debreceni, K., Fejer, Z., Manzano e Silva,

M.J. and Vigh-Teichmann, I. (1998): Comparative histology of

pineal calcification: History and Histopathology13(3): 851-

70.

7. Willaims, P.L., Warwick, R., Dyson, M. and Bannister, L.H.:

Grays Anatomy. In: The Endocrine System. 37th Edn,

Churchill Livingstone, London, pp. 1450-475. (1989).

18

J. Anat. Soc. India 50(1) 17-18 (2001)

Calcification in Pineal Gland


3/5

Opp. 18 Calcification in Pineal Gland

Fig. 1. Lobular appearance of pineal parenchyma (100 X).

Capsule C

Septa S

Lobule L

Fig. 2. Cells in parenchyma (1000 X).

Dark pinealocyte Square

Light pinealocyte Thick arrow

Glial cell Thin arrow


4/5


Fig. 3. Extrapineal calcification in capsule (100 X).

Concentric lamellar pattern Thick arrow (LC)

Fig. 4. Intrapineal calcification in parenchyma (100 X).

Globular pattern (arrow) surrounded by pinealocytes


5/5


Fig. 5. Increased glial fibres with glial cyst (100 X)

Area of glial fibres F

Glial cyst C

Fig. 6. Intrapineal calcification in parenchyma (100 X)

Concentric lamellar pattern (arrow) surrounded by glial fibres (F)

the pineal gland_3rd - eye

Documents