Human cloning is the creation of a genetically identical copy of a human. The term is generally used to refer to artificial human cloning, which is the reproduction of human cells and tissue. It does not refer to the natural conception and delivery of identical twins. The possibilities of human cloning have raised controversies. These ethical concerns have prompted several nations to pass laws regarding human cloning.
In multicellular organisms, stem cells are undifferentiated or partially differentiated cells that can change into various types of cells and proliferate indefinitely to produce more of the same stem cell. They are the earliest type of cell in a cell lineage. They are found in both embryonic and adult organisms, but they have slightly different properties in each. They are usually distinguished from progenitor cells, which cannot divide indefinitely, and precursor or blast cells, which are usually committed to differentiating into one cell type.
Hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body. Typically at least the head is involved. The severity of hair loss can vary from a small area to the entire body. Inflammation or scarring is not usually present. Hair loss in some people causes psychological distress.
The hair follicle is an organ found in mammalian skin. It resides in the dermal layer of the skin and is made up of 20 different cell types, each with distinct functions. The hair follicle regulates hair growth via a complex interaction between hormones, neuropeptides, and immune cells. This complex interaction induces the hair follicle to produce different types of hair as seen on different parts of the body. For example, terminal hairs grow on the scalp and lanugo hairs are seen covering the bodies of fetuses in the uterus and in some newborn babies. The process of hair growth occurs in distinct sequential stages: anagen is the active growth phase, catagen is the regression of the hair follicle phase, telogen is the resting stage, exogen is the active shedding of hair phase and kenogen is the phase between the empty hair follicle and the growth of new hair.
The management of hair loss, includes prevention and treatment of alopecia, baldness, and hair thinning, and regrowth of hair.
Regenerative medicine deals with the "process of replacing, engineering or regenerating human or animal cells, tissues or organs to restore or establish normal function". This field holds the promise of engineering damaged tissues and organs by stimulating the body's own repair mechanisms to functionally heal previously irreparable tissues or organs.
Hair transplantation is a surgical technique that removes hair follicles from one part of the body, called the 'donor site', to a bald or balding part of the body known as the 'recipient site'. The technique is primarily used to treat male pattern baldness. In this minimally invasive procedure, grafts containing hair follicles that are genetically resistant to balding are transplanted to the bald scalp.
Pattern hair loss is a hair loss condition that primarily affects the top and front of the scalp. In male-pattern hair loss (MPHL), the hair loss typically presents itself as either a receding front hairline, loss of hair on the crown and vertex of the scalp, or a combination of both. Female-pattern hair loss (FPHL) typically presents as a diffuse thinning of the hair across the entire scalp.
Follicular unit extraction is one of two primary methods of obtaining hair follicles, naturally occurring groups of one to four hairs, for hair transplantation. The other method is called strip harvesting. In 2018, Mejia published the updated guidelines adopted by the International Society of Hair Restoration Surgery. This name change came about to accurately describe the procedure which involves surgically cutting or incising a full thickness hair follicle skin graft with a circular scalpel, punch or motorized drill and subsequently carefully extracting it from the scalp to be placed in the donor balding scalp. Due to the new developments of incision punches and devices and a variety of different extraction techniques, it was necessary to more accurately define the procedure. Additionally, many places were incorrectly marketing the extraction procedure as a simple plucking of hairs and deceiving the public.
Desmocollin-3 is a protein that in humans is encoded by the DSC3 gene.
Embryomics is the identification, characterization and study of the diverse cell types which arise during embryogenesis, especially as this relates to the location and developmental history of cells in the embryo. Cell type may be determined according to several criteria: location in the developing embryo, gene expression as indicated by protein and nucleic acid markers and surface antigens, and also position on the embryogenic tree.
Anagen effluvium is the pathologic loss of anagen or growth-phase hairs. Classically, it is caused by radiation therapy to the head and systemic chemotherapy, especially with alkylating agents.
Scarring hair loss, also known as cicatricial alopecia, is the loss of hair which is accompanied with scarring. This is in contrast to non scarring hair loss.
The growth of human hair occurs everywhere on the body except for the soles of the feet, the palms of the hands, the inside of the mouth, the lips, the backs of the ears, some external genital areas, the navel, and, apart from eyelashes, the eyelids. Hair is a stratified squamous keratinized epithelium made of multi-layered flat cells whose rope-like filaments provide structure and strength to the hair shaft. The protein called keratin makes up hair and stimulates hair growth. Hair follows a specific growth cycle with three distinct and concurrent phases: anagen, catagen, and telogen. Each phase has specific characteristics that determine the length of the hair.
Regeneration in humans is the regrowth of lost tissues or organs in response to injury. This is in contrast to wound healing, or partial regeneration, which involves closing up the injury site with some gradation of scar tissue. Some tissues such as skin, the vas deferens, and large organs including the liver can regrow quite readily, while others have been thought to have little or no capacity for regeneration following an injury.
Valerie Horsley is an American cell and developmental biologist. She currently works as an associate professor at Yale University, where she has extensively researched the growth, restoration, and maintenance of skin cells. She is a currently a member of the Yale Cancer Center and Yale Stem Cell Center. She received a Presidential Early Career Award for Scientists and Engineers in 2012 and in 2013 she was the recipient of the Rosalind Franklin Young Investigator Award.
RepliCel Life Sciences is a Canadian regenerative medicine company based in Vancouver, British Columbia. The company focuses on development of cell therapies using a patient's own cells. The company has treatment development activities targeting chronic tendon injuries which have failed to heal properly, and hair restoration. The company's expertise lies in isolation and exploitation of different cell populations found in the human hair follicle.
Protein Transduction Domain-fused Dishevelled Binding Motif (PTD-DBM) is a man-made peptide which interacts with the mechanism of the hair loss linked endogenous protein, CXXC5, which is a negative feedback regulator of the Wnt/β-catenin pathway. Application of the peptide to bald laboratory mice resulted in new hair follicle growth.
Cheng-Ming Chuong is a Taiwanese-American biomedical scientist.
Angela M. Christiano is a molecular geneticist in the field of dermatology. Her research focuses on genes involved in hair and skin growth, as well as treatments for hair loss and skin cancers. She is the Richard and Mildred Rhodebeck Professor of Dermatology and Professor of Genetics and Development at Columbia University Vagelos College of Physicians and Surgeons.
