Shortage of cholesterol linked to neurodegenerative diseases

This post includes a synopsis of a paper published in Neurobiology of Disease 2009 May;34(2):212-20

Study title and authors:
Aneuploidy in the normal, Alzheimer's disease and ataxia-telangiectasia brain: differential expression and pathological meaning.

Iourov IY, Vorsanova SG, Liehr T, Yurov YB.

National Research Center of Mental Health, Russian Academy of Medical Sciences, Moscow, Russia.ivan_iourov@yahoo.com

This paper can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/19344645

Aneuploid cells have an abnormal number of chromosomes and may form because of a shortage of cholesterol. See here.

The study measured the number of aneuploid cells in the brains of people with:
(a) No disease
(b) Alzheimer's disease
(c) Ataxia Telangiectasia

The study revealed that:
(1) The overall proportion of aneuploid cells in the normal brain is approximately 10%.
(2) The overall proportion of aneuploid cells in the brain of ataxia telangiectasia individuals was estimated at approximately 20-50%.
(3) A dramatic 10-fold increase of chromosome 21-specific aneuploidy was detected in individuals with Alzheimer's disease.

Iourov concluded that neural aneuploidy to be a feature of neurodegenerative diseases.

Cholesterol is essential for renewal of cells and wound healing

This study was published in Experimental Cell Research Volume 300, Issue 1, 15 October 2004, Pages 109-120

Study title and authors:
Cholesterol is essential for mitosis progression and its deficiency induces polyploid cell formation
Carlos Fernández, María del Val T. Lobo, c, Diego Gómez-Coronado and Miguel A. Lasunción, d,
Servicio de Bioquímica-Investigación, Hospital Ramón y Cajal, Madrid, Spain

This paper can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/15383319

Fernández notes that cholesterol is an essential component of cell membranes.

Mitosis is a process of cell division which results in the production of two daughter cells from a single parent cell. The daughter cells are identical to one another and to the original parent cell. Mitosis plays a role in cell replacement and wound healing. Cytokinesis is the final stage of mitosis where a single parent cell forms the two new cells.

The aim of the study was to determine the role of cholesterol in mitosis. For this human cells were incubated in a cholesterol free medium and the results observed were:

(a) Prolonged cholesterol starvation inhibitied cytokinesis and caused the formation of polyploid cells, which were multinucleated (cells which have more than one nucleus per cell and are implicated in tumour formation) and had other abnormalities.
(b) Supplementing with cholesterol completely abolished these adverse effects, demonstrating they were specifically due to cholesterol deficiency.

Polyploid cells are implicated in cancer, Alzheimer's disease and ataxia telangiectasia (Ataxia-telangiectasia is rare childhood disease that affects the brain and other parts of the body such as uncoordinated movements and retarded mental ability)

Fernández concluded: "Cholesterol is essential for mitosis completion and that, in the absence of cholesterol, the cells fail to undergo cytokinesis... generating polyploid cells".