Human in vitro studies

Treatment of PCMOs with islet-conditioning medium (ICM) containing EGF, HGF and nicotinamide (IM) for 4-10 days resulted in the appearance of characteristic cell aggregates resembling pancreatic islets (Fig. 3A). Immuno-histochemical analysis of these three-dimensional cellular cluster formations reveals exhibition of all four endocrine cell entities defining normal human islets. As depicted in Fig. 3B, glucagon, insulin, somatostatin and pancreatide-peptide staining cell types can be...

Clinical Applications of Novel Adult Stem Cell Derived Therapy

In 2001 a study was published claiming that stem cells derived from bone marrow could be used to repair damaged heart muscle following a severe cardiac event.33 This sparked a number of clinical studies involving intra-coronary injection of autologous bone-marrow-cells.34 The leap into clinical action has been criticized on several counts. Although, historically, drugs have been approved for general use without any knowledge of their mechanism of action, nowadays regulators prefer to see some...

Pancreatic stem cells

Endocrine pancreas, as well as the nervous system and heart, are organs with a very limited proliferative capacity compared to epidermis of the skin, intestinal epithelium, muscle, liver (after hepatectomy) and the very well studied bone marrow tissue (responsible for blood cell generation and osteoarticular turnover). Nevertheless, an interesting finding is that the tissues with no proliferation, such as the nervous system, bear progenitor stem cells. This is a key finding, because the...

Discussion

An attractive theoretical concept is to introduce the glucose sensing human insulin gene into stable autologous cells of the patient, so avoiding the need for immunosuppression, provided the immune target in the case of type I diabetes does not reside in these cells. The goal is similar to that outlined for the treatment of hemophilia A. Unanswered is the question, whether enough insulin could be produced at the right time for long enough to be of therapeutic use. These matters are likely to be...

Info

BFGF basic fibroblast growth factor EGF epidermal growth factor FBS fetal bovine serum KGF keratinocyte growth factor MEF* mitotically inactivated mouse embryonic fibroblasts neor neomycin resistance gene NIC nicotinamide. rat and human pancreatic islets.13 However, cell-lineage tracing strategies suggest that nestin-positive progenitors contribute to the formation of the microvasculature of the islet.14 The first protocol was developed by the group of McKay15 and comprised 5 stages 1)...

In vitro differentiation of MSCs

Cells are generally cultured in basal medium such as Dulbecco's modified Eagle's medium (high glucose) in the presence of 10 fetal bovine serum (FBS). The optimal expansion of MSCs from bone marrow requires the preselection of FBS.16'46 MSCs in culture have a fibroblastic morphology and adhere to the tissue culture substrate. Primary cultures are usually maintained for 12-16 days, during which time the nonadherent hematopoietic cell fraction is depleted. The addition of growth factor...

Biliary Epithelial Cells Rodent studies

When either massive damage is inflicted upon the liver or regeneration after damage is compromised, a potential stem cell compartment located within the smallest branches of the intrahepatic biliary tree is activated. This so-called oval cell or ductular reaction amplifies the biliary population before these cells differentiate into either hepatocytes or cholangiocytes.34-38 Careful studies in rats indicate that oval cells are predominantly derived from the canal of Hering, and thus this is the...

The Provenance of Stem Cells Does Source Matter

In spite of the fact that good scientific reasons can be supplied to support the claim that adult, ES and EG cell research should be carried out in parallel, ethical concerns over the provenance of the latter two cell types has resulted in outright bans or policy restrictions on their use, in many nations. Does the source of stem cells matter morally quite as much as people tend to think Embryonic germ (EG) cells are obtained by laboratory cultivation of primordial germ cells found in the fetal...

Microtubule and mitotic spindle defects in clones

The embryo formed during nuclear transfer must successfully complete many of the same functions during the first cell cycle that an embryo formed by normal fertilization must perform. While knowledge of the cytoplasmic events of the mammalian zygotic first cell cycle is far from complete, we do know a great deal about the necessary microtubule regulation during the first cell cycle of the fertilized zygote. Except for the mouse, all mammals studied41-46 adhere to the paternal inheritance of the...

Ocular Surface Disease Arising from Stem Cell Deficiency

Limbal stem cell deficiency can be caused by a variety of hereditary or acquired disorders.1'3 Possible inherited disorders in which limbal stem cells may be congenitally absent or dysfunctional are shown in Table 1. Limbal stem cells may also be deficient or destroyed by various acquired conditions. Acquired disorders form the majority of cases seen in the clinical setting. Limbal stem cell deficiency results in abnormal healing and epithelization of the cornea. It is characterized by...

The Tendon and Ligament Specific Progenitors and Differentiation Factors

Many of the recent studies have demonstrated that the bMSCs accelerate and improve tendon repair. However, these studies also verified that it is difficult to fully regenerate a tendon. The neo-tendons were similar to the native tendon but were not identical to the native tendon. This outcome may be due to two reasons. One is that the regeneration ability of tendon tissue is limited, unlike bone which can heal by regenerating normal bone in most instances, as an injured tendon often heal by...

Recent Progress in Recipient Immunosuppression

While the Edmonton immunosuppressive protocol represents a major step forward, the medications used in this protocol are associated with significant side effects that unfavorably alter the risk benefit ratio of islet transplantation. The therapy is currently unsuitable for the majority of patients with type 1 diabetes that are adequately stabilized on insulin. Approximately 10 of patients with type 1 diabetes, however, have severe forms of glycemic lability or recurrent hypoglycemia, and...

Cultural Persuasion

Grow cells in culture in the presence of differentiation factors that are known to be present in the embryonic development of the tissue in question. The sources of such cells could vary, for example A popular choice with the media attracted by the idea that ES cells can change into any cell type. To take an ESC all the way to a cell may involve numerous changing differentiation environments in normal development, probably influenced by what is going on in adjacent tissues. Currently, we have...

References

WolpertL, Hicklin J, HornbruchA. (1971) Positional information and pattern regulation in regeneration of hydra. Symp Soc Exp Biol 25 391-415. 2. Brockes JP. (1997) Amphibian limb regeneration Rebuilding a complex structure. Science 276 81-87. 3. Kiessling AA, Anderson SC. (2003) Human embryonic stem cells. Boston Jones and Bartlett. 4. Anderson DJ, Gage FH, Weissman IL. (2001) Can stem cells cross lineage boundaries Nature 7 393-395. 5. Bongso A, Richards M. (2004) History and perspective of...

The Edmonton Protocol

A new protocol was developed in Edmonton, Canada in 1999 that radically changed the face of clinical islet transplantation. The first seven patients treated under the Edmonton Protocol all achieved and maintained insulin independence beyond one year, demonstrating for the first time that islet transplantation could achieve insulin independence with rates similar to whole pancreas transplantation, but without a need for a major inter-ventional surgery.32 The success of this protocol has been...