Difference between revisions of "Alopecia - Hair Loss"

Revision as of 19:50, 16 August 2007

Rationale

• "Medication for men plagued by hair loss has become a topic of interest in Japan since a drug company began marketing it at the end of last year." March 5th, 2006 – source

• "An increasing number of companies are apparently turning the Chinese fear of a bald spot into big bucks with some doing so well they are branching out into other countries." February 16, 2006 – [1]

• "There is something in the air, or should we say in the hair, these days. Scientific research into hair loss remedies has never been more active or more exciting." June 7, 2006 - [2]

Alopecia IPMap

Dolcera IPMap for Alopecia

Introduction

Hair basics

• Hair is a complex and delicate part of the body.
• Keeping it healthy and beautiful is a challenge.
• Hair grows everywhere on the body with the exception of lips, eyelids, palms of the hands and soles of the feet.
• Hair is basically a form of skin.
• Hair is made up of a protein called keratin.
• Each shaft of hair is made of two or three inter-twined layers of keratin which grow from a follicle beneath the skin.
• Hair Structure - [3]
• Hair Cycle - [4]

What causes hair loss?

• Decrease in growth of hair
• Increase in shedding of hair
• Breakage of hair
• Conversion of thick terminal hairs to thin vellus hairs

Survey results from Japan

Both men and women lose hair for similar reasons. Hair loss in men is often more dramatic, and follows a specific pattern of loss, one of which has been termed “Male Pattern Baldness" or "Androgenetic Alopecia".

Types of alopecia

• Alopecia Areata (AA): Hair loss occurring in patches anywhere on the body.
• Alopecia Totalis (AT): Total loss of the hair on the scalp.
• Alopecia Universalis (AU): Total loss of all hair on the body.
• Alopecia Barbae: Loss of facial hair (for a man) especially in the beard area.
• Alopecia Mucinosa: A type of alopecia which results in scaley patches.
• Androgenetic Alopecia (AGA): Also known as male pattern baldness. It is a thinning of the hair to an almost transparent state, in both men or women. It is thought to be a hereditary form of hair loss.
• Traction Alopecia: Traction alopecia is usually due to excessive pulling or tension on hair shafts as a result of certain hair styles. It is seen more often in women, particularly those of East Indian and Afro-Caribbean origin. Hair loss depends on the way the hair is being pulled. Prolonged traction alopecia can stop new hair follicles from developing and leads to permanent hair loss.
• Anagen Effluvium: This hair loss is generally caused by chemicals such as those used to treat cancer. Initially it causes patchy hair loss, which often then leads to total hair loss. The good news is that when you stop using these chemicals the hair normally grows back (usually about 6 months later). Other drugs also can cause hair loss. Many medicines used to treat even common diseases can cause hair loss.
• Scarring Alopecia: A form of alopecia which leaves scarring on the area of hair loss.
• Telogen Effluvium: A form of hair loss where more than normal numbers of hair fall out. There is a general 'thinning' of the hair. Unlike some other hair and scalp conditions, it is temporary and the hair growth usually recovers. (Source)

Androgenetic alopecia

• Gradual onset
• Transition from large, thick, pigmented terminal hairs to thinner, shorter, indeterminate hairs and finally to short, wispy, non-pigmented vellus hairs in the involved areas
• Characterized by a receding hairline and/or hair loss on the top of the head

Main causes

• Genetic predisposition
• Hormonal effect of androgen
• Reduction of blood circulation around hair follicle
• Deactivation of hair matrix cells

Some facts from Japan

• Market size: ¥ 30 Billion
• Number of products: more than 100

(JICST-EPlus - Japanese Science & Technology)

IP activity over the years

The graph indicates:

• Number of patents filed every 5 years (except for first 7 years).
• First solution proposed in 1973
• Filing trend indicates steep rise in activity recently.

IP Activity over years

Major players

Assignees with more than 20 patents

Assignees with fewer than 20 patents

• Active assignees

Assignees currently active with more than 5 patents to their credit during 2000-2005.

• Warner with 9 patents,
• Bristol with 6 and
• Abbott with 5.

Active Assignees

Treatment Approaches

Composition of treatment for causes are identified and categorized as follows:

• Anti-androgens (Finasteride) source
• Vasodilators (Minoxidil) source
• Double action (Anti-androgen + Vasodilator)
• Hair matrix cells activator

Anti-androgens

• Anti-androgens are used in hormone therapy.
• Anti-androgens are designed to affect the hormones made in the adrenal glands. They don't stop the hormones from being made, but they stop them from having an effect leading to hair loss.

What causes hair loss?

• Testosterone is reduced to its active metabolite, Dihydrotestosterone (DHT) by the enzyme 5 alpha reductase.
• DHT attaches to androgen receptor sites at the hair follicle.
• DHT causes gradual miniaturization of the follicle, which eventually results in hair loss.

How do anti-androgens treat hair loss?

• Anti-androgens compete with DHT to bind to the androgen receptor.
• Upon binding of anti-androgen in place of DHT, follicle miniaturization is lowered and hair loss prevented.

Functions of Anti-androgen

Anti-androgen

Functions of Anti-androgen

IP Map for anti-androgen

Minoxidil (Vasodilators)

• Minoxidil is a "potassium channel opener" that leads to vasodilation.
• The drug is available in two forms. Oral minoxidil is used to treat high blood pressure and the topical solution form is used to treat hair loss and baldness.

What causes hair loss?

• A thick network of tiny veins and arteries line the outer wall of the follicle. Blood pumps through the bulb and hair via this network.
• DHT accumulates in the hair follicles and roots, constricting the blood supply of oxygen and nutrients to the hair roots; which is also seen to possibly contribute towards hair loss.

How does Minoxidil treat hair loss?

• Minoxidil is applied to the scalp topically, where it dilates blood vessels in the scalp and sustains the hair follicles for longer period of time.
• Minoxidil is thought to have a direct mitogenic effect on epidermal cells, as has been observed both in vitro and in vivo. Though the mechanism of its action for causing cell proliferation is not very clear, minoxidil is thought to prevent intracellular calcium entry. Calcium normally enhances epidermal growth factors to inhibit hair growth, and Minoxidil by getting converted to minoxidil sulfate acts as a potassium channel agonist and enhances potassium ion permeability to prevent calcium ions from entering into cells. (Source)
• Minoxidil sulfate (MS) appears to be the active metabolite responsible for hair growth stimulation.

Functions of Vasodilators

Functions of Monoxidil source

IP Map for Vasodilators

Double action (Anti-androgen + Vasodilator)

• Combination of Vasodilator + Anti-androgen (double action) composition for effective treatment of Male-Pattern Baldness.

What is the problem with using only Anti-androgen therapy?

• Anti-androgen is not effective in addressing the issue of vasocontriction around hair follicles due to sebum oil build up.
• Anti-androgen only prevents binding of DHT to androgen receptors. However, the effects of improper oxygen and nutrient supply to the brain due to vasocontriction still remains and gradually causes hair loss.

What is the problem with using only Vasodilator (or Minoxidil only) therapy?

• Vasodilator or Minoxidil-based products are generally not effective in stopping hair loss as vasodilators (or Minoxidil) do not block the harmful effects of DHT in the scalp and hair follicles.
• Vasodilators or Minoxidil simply dilate blood vessels in the scalp. However, the harmful DHT still gets produced in the body, enters the scalp and hair follicles causing hair loss.

How is the combination of Anti-androgens and Vasodilator (or Minoxidil) effective?

• Anti-androgens target the problem of DHT binding to androgen receptors and prevents follicle miniaturization.
• Vasodilators like Minoxidil cause vasodilation and therefore improve supply of oxygen and nutrients to the hair follicle and roots.
• Combination therapy therefore proves to be much more effective than individual therapy.

Functions of (Anti-androgen + Vasodilators)

Anti-androgen and Minoxidil

Functions of (Anti-androgen + Vasodilators)

IP Map for (Anti-androgen + Vasodilators)

Hair matrix cell activator

Hair matrix cell activator is a substance that acts at the matrix cells in the hair follicle preventing their degradation.

What causes hair loss?

• Stem cells are interspersed within the basal layer of the outer root sheath and in an area called the bulge.
• Stem cells migrate to hair matrix where they start to divide and differentiate, under the influence of substances produced by cells of the dermal papilla.
• Perifollicular matrix cells undergo slow degradation which prevents follicle stimulation.
• Hair follicle activation is required for hair growth and thus inhibition of follicle activation eventually leads to hair loss.

How does hair cell matrix activator treat hair loss?

• Hair cell matrix activator slows down and inhibits degradation of the perifollicular matrix.
• This leads to an increase in hair follicle matrix cells that differentiate from progenitor stem cells.
• Matrix activator allows activation of hair matrix cells and therefore follicle stimulation leading to hair growth.

Functions of Hair matrix cell activator

Hair matrix cell activator

Functions of Hair matrix cell activator

IP Map for Hair matrix cell activator

Technology mapping based on patents analyzed

IPMap: Composition nature matrix

Focus of patents

Technology focus

Technology focus

Distribution of patents

By patent types

Distribution based on patent types

By key ingredients

Distribution of key ingredients

By target disease

Distribution based on target diseases

Key ingredients vs. Target disease

Key ingredients vs. Target disease

Target species

Target species

Mode of administration

Mode of administration

Product type vs. Product form

Product type vs. Product form

Patents by target diseases

Patents by application

Distribution of patents based on application

List of patents

Pathways and linkages

Pathways associated with hair matrix cell activation

Molecular mediators of hair follicle embryogenesis: Identification of the molecular pathways controlling differentiation and proliferation in mammalian hair follicles provides the crucial link to understanding the regulation of normal hair growth, the basis of hereditary hair loss diseases, and the origin of follicle-based tumors. Homeobox (hox), hedgehog (hh), patched (ptc), wingless (wg}/wnt, disheveled (dsh), engrailed (en), Notch 1 and armadillo/B-catenin genes are all critical for hair follicle.

• Wnt pathway: Maintains hair-inducing activity of the dermal papilla.
• Hedgehog pathway: Sonic hedgehog (SHH) signaling plays a critical role in hair follicle development. Sonic hedgehog gene. Sonic hedgehog, SHH for short, helps guide hair follicles from a resting stage into growth activity. SHH is particularly important in the embryonic formation of hair follicles.
• STAT pathway
• TGF beta/BMP Pathway: Bone morphogenetic protein (BMP) signaling have been implicated in the regulation of both proliferation and differentiation in the hair follicle. BMP2 is expressed in the embryonic ectoderm, but then localizes to the early hair follicle placode and underlying mesenchyme. BMP4 is expressed in the early dermal condensate. Research results show that BMPs are a key component of the signaling network controlling hair development and are required to induce the genetic program regulating hair shaft differentiation in the anagen hair follicle. Transforming growth factor beta (TGF-beta), inhibits mitogen - induced dermal papilla cell proliferation
• FGF Pathway: Fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF) potentiate the growth of dermal papilla cells. It is proposed that these proteins increase the synthesis of stromelysin (an enzyme, matrix metalloproteinase) which acts on the papilla cells and accelerates their growth.
• MAPK Pathway: Mitogen-activated protein kinase (MAPK) activation, increases keratinocyte turnover.
• NOTCH Pathway: Notch-1 is expressed in ectodermal-derived cells of the follicle, in the inner cells of the embryonic placode and the follicle bulb, and in the suprabasal cells of the mature outer root sheath. Delta-1, one of the three ligands is only expressed during embryonic follicle development and is exclusive to the mesenchymal cells of the pre-papilla located beneath the follicle placode, and appears to promote and accelerate placode formation, while suppressing placode formation in surrounding cells. Other ligands, Serrate 1 and Serrate 2, are expressed in matrix cells destined to form the inner root sheath and hair shaft.

Pathways associated with Anti Androgen

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Alopecia pathways

Players of WNT inhibition Pathway

Wnt inhibition

Role of Pyrazole compounds in Wnt Pathway

Pyrazole

• Pyrazole (C3H4N2) refers both to the class of simple aromatic ring organic compounds of the heterocyclic series characterized by a 5-membered ring structure composed of three carbon atoms and two nitrogen atoms in adjacent positions and to the unsubstituted parent compound. Being so composed and having pharmacological effects on humans, they are classified as alkaloids although they are not known to occur in nature.
• Pyrazoles are produced synthetically through the reaction of α,β-unsaturated aldehydes with hydrazine and subsequent dehydrogenation

Pyrazole (C3H4N2)

• Pyrazoles are used for their analgesic, anti-inflammatory, antipyretic, antiarrhythmic, tranquilizing, muscle relaxing, psychoanaleptic, anticonvulsant, monoamineoxidase inhibiting, antidiabetic and antibacterial activities.
• Structurally related compounds are pyrazoline and pyrazolidine.

Structurally related compounds

GSK3 inhibition by pyrazole compounds

Inhibition by amine derivatives

Patent Number: US6989385 Applicant: Vertex Pharmaceuticals Incorporated Title: Pyrazole compounds useful as protein kinase inhibitors

Basic Structure:

Derivatives of pyrimidine-pyrazole amine disclosed in US6989385 patent

Patent Number: US7008948 Applicant: Vertex Pharmaceuticals Incorporated Title: Fused pyrimidyl pyrazole compounds useful as protein kinase inhibitors

Basic Structure

Derivatives of pyrimidine-pyrazole amine disclosed in US7008948 patent

Patent Number: US6977262 Assignee: Mitsubishi Pharma Corporation Title: Dihydropyrazolopyridine compounds and pharmaceutical use thereof

Basic Structure:

Derivatives of pyrimidine-pyrazole amine disclosed in US6977262 patent

Patent Number: US6664247 Assignee: Vertex Pharmaceuticals Incorporated Title: Pyrazole compounds useful as protein kinase inhibitors

Basic Structure:

Derivatives of pyrimidine-pyrazole amine disclosed in US6664247 patent

Patent Number: US2004224944 Assignee: VERTEX PHARMACEUTICALS INC Title: Pyrazole compounds useful as protein kinase inhibitors

Basic Structure:

Derivatives of pyrimidine-pyrazole amine disclosed in US2004224944 patent

Other derivates for alopecia

GSK-3 Inhibition Mechanism - Phosphorylation

• GSK-3 inhibition targets treatment of chemotherapy-induced alopecia source
• In the canonical Wnt signaling cascade, adenomatous polyposis coli (APC), axin, and GSK3 constitute the so-called destruction complex, which controls the stability of beta-catenin. It is generally believed that four conserved Ser/Thr residues in the N terminus of beta-catenin are the pivotal targets for the constitutively active serine kinase GSK3. GSK3 covalently modifies beta-catenin by attaching phosphate groups (from ATP) to serine, and threonine residues. In so doing, the functional properties of the protein kinase’s substrate (beta-catenin) are modified.

• In the absence of Wnt signals, glycogen synthase kinase (GSK) is presumed to phosphorylate the N-terminal end of beta-catenin, thus promote degradation of beta-catenin and subsequent ubiquitination and proteasomal targeting.

• Exposure of cells to Wnts leads to inactivation of GSK-3 through an as yet unclear mechanism.The phosphoprotein Dishevelled is required, after receptor-ligand interaction, to transduce the signal that results in the inactivation of GSK-3. As a result, beta-catenin is dephosphorylated and escapes the ubiqduitylation-dependent destruction machinery.

• Unphosphorylated beta-catanin accumulates in the cytoplasm and translocates to the nucleus, where it can associate with the TCF/LEFs and become a transcriptional transactivator.

More details on GSK-3

Key points

• Beta-catenin phosphorylation at serine 45 (Ser45), threonine 41 (Thr41), Ser37, and Ser33 is critical for beta-catenin degradation. source
• Regulation of beta-catenin phosphorylation is a central part of the canonical Wnt signaling pathway. source
• Ser-X-X-X-Ser (X is any amino acid) motif is obligatory for beta-catenin phosphorylation by GSK3.source
• Beta-catenin phosphorylation/degradation and its regulation by Wnt can occur normally in the absence of Thr41 as long as the Ser-X-X-X-Ser motif/spacing is preserved. [httSp://pubs.acs.org/cgi-bin/abstract.cgi/bichaw/2006/45/i16/abs/bi0601149.html source]

GK3 Inhibition:

• GSK3 is regulated by phosphorylation.
• Phosphorylation of GSK3beta on Ser9 (Ser21 in GSK3alpha) by protein kinase B (PKB) causes its inactivation is the primary mechanism responsible for growth factor inhibition of this kinase. Activation of GSK3beta is dependent upon the phosphorylation of Tyr216 (Tyr279 in GSK3alpha). Upon activation, it has been shown to phosphorylate a number of different cellular proteins, including p53, c-Myc, c-Jun, heat shock factor-1 (HSF-1), beta-catenin and cyclin D1. source
• GSK3 is inhibited by phosphorylation of serine-9 or serine-21 in GSK3beta and GSK3alpha, respectively. source
• GSK3’s substrate specificity is unique in that phosphorylation of substrate only occurs if a phosphoserine or phosphotyrosine is present four residues C-terminal to the site of GSK phosphorylation. source
• A phosphorylation cascade starts from GSK3 itself and initiates it in beta-catenin. source
• Thus our goal is to stop the phosphorylation of the serine and threonine residue of GSK3.
• The figure below illustrates the phosphorylation mechanism of serine and threonine by ATP.

Phosphorylation mechanism source

• We can't stop conversion of ADP to ATP that relaseas Phosphorous group causing Phosphorylation.
• We can only block the oxygen atom on serine and threonine as a result which will in turn stop Phosphorylation.
• The two probable ways of blocking the oxygen atom are (a) As oxygen is a Lewis acid with strong electron donating capacity, so usually a strong electron pair acceptor can easily bind to oxygen atom and preventing phosphorylation or (b) breaking of the -OH bond with the carbon atom.

Serine - pyrazole reaction

Serine and Pyrazole reaction source

• The T-loop of GSK-3 is tyrosine phosphorylated at Y216 and Y279 in GSK-3b and GSK-3a, respectively, but not threonine phosphorylated. Y216/Y279 phosphorylation could play a role in forcing open the substrate (e.g, beta-catanin)-binding site.

• Thus, T-loop tyrosine might facilitate substrate phosphorylation but is not strictly required for kinase activity.

• Stimulation of cells with pyrazole compounds cause inactivation of GSK-3 through phosphorylation (S9 of GSK-3 beta and S21 of GSK-3 alpha), which inhibits GSK-3 activity. Thus leading to dephosphorylation of substrates (e.g., beta-catanin) resulting in their functional activation and consequent increased hair follicle morphogenisis.

• Phosphorylation of S9/S21 creates a primed pesudosubstrate that binds intramolecularly to the positively charged pocket of the GSK-3. This folding precludes phosphorylation of substrates (eg., beta-catanin) because the catalytic groove is occupied. The mechanism of inhibition is competitive.

• A consequence of this is that primed substrates, in high enough concentrations, out-compete the pesudosubstrate and thus become phosphorylated.

• Thus, small molecule inhibitors modeled to fit in the positively charged pocket of the GSK-3 kinease domain could potentially be very effective for selective inhibition of primed substrates.

Proposed mechanisms to regulate GSK-3 source

1. inactivation of GSK-3 through serine phosphorylation
2. activation of GSK-3 through tyrosine phosphorylation
3. inactivation of GSK-3 through tyrosine dephosphorylation
4. Covalant modifications of substrates through priming phosphorylation
5. inhibition or facilation of GSK-3 mediated substrate phosphorylation thriugh interation of GSK-3 with binding or scaffolding proteins
6. targeting of GSK-3 to different subcellular localizations
7. differential usage of isoforms or splice variants to alter subcellular localization or substrate specificity
8. integration of parellel signals conveyed by a signal stimulus.

Key Finding

• Pyrazole compounds with inhibition constant (Ki) of <0.1 mM are a good starting point for developing molecules that can inhibit serine/threonine protein kinase (such as GSK-3) and the proteins they help to regulate. source

Pathway associated with anti-androgen

• Dihydrotestosterone
  • Formed by peripheral conversion of testosterone by 5-alpha reductase
  • Binds to androgen receptor on susceptible hair follicles
• Hormone-receptor complex activates genes responsible for gradual transformation of large terminal follicles to miniaturized (progressive diminution of hair shaft diameter and length in response to systemic androgens) follicles

Structure-Activity Relationships(SARs)

Pathway associated with Minoxidil (vasodilators)

Minoxidil is a well know drug used for the treatment of alopecia. A co-relation between Sesquiterpene lactone (Helenalin) produced from Arnica montana and Minoxidil is illustrated in the figure below. Arnica montana, a Vasodilator, acts on the NO/cGMP Pathway through T-cells, B-cells and epithelial cells & abrogates kappa B-driven gene expression.