Pradeep KumarM.Sc. Biotechnology

Tissue engineering using stem cellas regenerative medicine

Introduction

Tissue engineering is an interdisciplinary field that applies the

principles of engineering and the life sciences toward the

development of biological substitutes that restore, maintain, or

improve tissue function.

In mid 1960s, artificial skin was being used.

In the, early 1970s, there were concerted efforts to treat artificialsurfaces to be used in implants in ways that would enable themto avoid causing blood coagulation, by applying special heparincomplex coatings.

In the late 1970s, researchers experimented with collagen basedartificial skin for use in oral mucosa injuries.

In the, 1980s, R&D in tissue engineering and biomaterials tookoff. As part of this interest, several biomedical engineeringdepartments were established at major universities around theworld.

o In 1981, a skin equivalent consisting of a silicon covers a sponge

of porous collagen cross linked with chondriotin was used

successfully to treat severe burn.

o The term “tissue engineering” was first used by Eugene Bell of

MIT in 1984, and later was also referred to extensively by

Wolter and Meyer in 1984.

o Interpore's Pro-Osteon coral-derived bone graft material was

introduced in 1993.

o In 1996, Integra's Artificial Skin was approved for as an in

vivo, nonbiological tissue regeneration product.

o 1998 the general and plastic surgery approval of ‘Apligraf’,

human skin equivalent for the treatment of venous leg ulcers.

Prerequisite for tissue engineering

• Growth of cell in three dimensional systems

• Delivery systems for protein therapeutics

• Cell cultivation methods for culturing recalcitrant cells

• Transgenic protein expression in transplantable cells

• Vehicles for delivering transplantable cells

• Avoiding immunogenicity in transplantation systems

• Development of markers for tracking transplanted cell

• Developing in vivo and ex vivo biosensors for monitoring cell behaviour during tissueproduction.

• Tissue engineering and cell therapy

aims to provide therapies for diseases

such as Neurodegenerative diseases,

Cardiovascular disease, Diabetes, and

Musculoskeletal disease.

• It is also used in regeneration of the

lost organs due to accident.

STEM CELLS

1. Blood

2. Skin

3. Pancreas

4. Heart

5. Liver

6. Muscle

7. Brain

Why stem cell used as regenerative

medicine

• Stem cells are unspecialized cells

that can self-renew indefinitely

and that can also differentiate

into more mature cells with

specialized functions.

• Self-renewal – the ability to go

through numerous cycles of cell

division while maintaining the

undifferentiated state.

Sir John B. GurdonShinya Yamanaka

The Nobel Prize in Physiology or Medicine 2012 was awarded jointly

to Sir John B. Gurdon and Shinya Yamanaka "for the discovery that

mature cells can be reprogrammed to become pluripotent"

Hematopoietic stem cells

Mesenchymal stem cell

Tissue specific stem cell

Embryonic stem cell

Major Source of stem cell

common myeloid

progenitors

common lymphoid progenitors

In an individual Formation of

all blood cell form embryonic to

adult phase of life through

Hematopoiesis process.

All blood cells arise from a type

of cell called the hematopoietic stem

cell (HSC).

• Failure of Hematopoiesis leads todevelopment of leukemia.

• Transplants of hematopoietic stem cellscould replace a cancerous blood system inhumans and hence cure leukemia.

• Bollywood celebrity Lisa Ray to undergostem cell transplant for blood cancer.

• Mesenchymal stem / multipotent stromal cells (MSCs)

are capable of differentiating into multiple types of

connective tissues like bone, cartilage, muscle neuron.

• MSCs have potential utility for treating a variety of

diseases and disorders, including graft versus host

disease, organ transplantation, cardiovascular disease,

brain and spinal cord injury, lung, liver and kidney

diseases, and skeletal injuries.

• Stem cell are throught to exist in many other niches

throught the body apart from the bone marrow but are

perhaps best studied in the brain and the skin.

• NSCs as they become to be known, could be isolated

from these neurospheres and selectively differentiated

into the three main cells of the brain neurons, glial cells

and oligodendrocytes.

Germ-line

Tissue-specific stem

cells:

• ESCs have the potential to grow indefinitely and candifferentiate into all cell types of the adult.

• ESCs are found in the inner cell mass of the humanblastocyst(64 cell), an early stage of the developing embryolasting from the 4th to 7th day after fertilization.

• ESCs have the advantage over other cell types of being trulypluripotent, i.e., ESCs have the potential to develop into allthree germ layers.

Stem cell therapies

• Cardiovascular disease causes40% of all death in the unitedstates each year.

• Many treatments, includingpharmacological, lifestyle,and surgical, are available forcoronary heart disease, but asyet there is no treatment otherthan transplantation that cancause repair of damaged heartmuscle.

Alternatives to transplant are being considered, including

Xenotransplantation and artificial mechanical hearts but new

treatments that can repair or replace damaged tissue in the heart

are desperately needed.

• Stem cell research into the

generation of bone and

cartilage is linked

intrinsically to tissue

engineering.

• MSCs can differentiate into

both osteoblasts and

chondrocytes, that a

combination of MSCs and a

suitable scaffold can rectify

bone injuries in animals.

Cell therapy Neurodegenerative disease

• Parkinson’s

• Huntington’s

• Alzheimer’s

• Amyotrophic lateral sclerosis (ALS)

• Spinal cord injury

• Multiple sclerosis (MS)

Cont…Approaches to Stem Cell Therapies For Neurological Disease

1. Transplantation of neural stem cells

Donor: fetal brain

• Cell therapies that replace pancreatic β-cells in type I diabetesand augment their effect in type II diabetes would lighten theeconomical and social burden considerably.

• The insulin producing cells obtained in such experiments maybe more closely related to nerve cells than to endocrine cells.

• The most recent study at the time of writing claimed thateuglycemia was restored in 30% of streptozotocin treated miceimplanted with ESC derived β-cells.

• Pancreatic tissue produced from ESCs are better defined, theapplication of ESCs for clinical correction of type I diabetesremains a distant prospect.

Recent Invention

• Technion researchers have

succeeded in constructing a

three-dimensional

polymeric scaffold array

with pancreatic islets

surrounded by a vascular

network, reports the

scientific journal PLoSONE. ”July ,15th, 2012”

Growing a nose on a forehead or an ear on an arm is a revolutionary approach tosurgical reconstruction.

This patient suffered irreparabledamage to his nose from a caraccident and subsequentinfection. Now surgeons aregrowing a replacement on hisforehead.

One of the most complicated ear constructions in theU.S., involves removing cartilage from the rib cage toform a new ear, which is then placed under the skin ofthe forearm to grow.

• Dr. Harald Ott and his

team grew a kidney by

using an experimental

technique that has

previously been used to

create working hearts,

lungs and livers.

• Their work was published

on Sunday, “14th April,

2013 in “Nature Medicine”

3-D Printer Makes A Bionic Ear

• Their work was published on

thursday “ 2, May, 2013 in

“Nano Letters”.

Tissue engineering provides long term and much safer

solution than other options.

The traditional transplantation complications are

minimized.

The donar can be patients himself or herself.

The need for donar tissue is minimal.

Immuno suppression problem can be minimized.

The presence of residual foreign material can be

minimized.

Cell isolation and preparation , biomaterial of nutrients transport

and transplantation is very complex process.

It is difficult to achieve cell diffrentiation into desired cell type and

ensuring their nutrient supply after implantation into the body.

There may be obstacles to growing cells in sufficient quantities.

The time necessary to develops cells in culture before they can be used

and possible lack of function at the donar site are some other

limitations.

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Shunping Wang, Cynthia C. Morton, Andrew P. McMahon, Doug Powers, and Douglas A. Melton.

(2004). Derivation of Embryonic Stem-Cell Lines from Human Blastocysts. The new england journal

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• Paolo Bianco & Pamela Gehron Robey.(2001). Stem cells in tissue engineering. Nature, 414. 118-121.

• Krishnarao Appasani, Raghu K. Appasani : Stem Cells & Regenerative Medicine: From Molecular

Embryology to Tissue Engineering.19: 45: 103:195.

• Stock, U. A. & Vacanti, J. P. Tissue engineering: current state and prospects. Annu. Rev. Med. 52, 443–

451 (2001).

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biology, and potential applications. Stem Cells 19, 180–192.

• Langstaff, S. et al. (1999). Resorbable bioceramics based on stabilized calcium phosphates. Part I:

rational design, sample preparation and material characterization. Biomaterials 20, 1727–1741.

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