Human fetal tissue research: practice, prospects, and policy

Propaedeutic, Basis for Constitution, and Statute of the Bank of Human Embryonic and Fetal Cells

Article without abstract

A Mathematical Model for the Estimation of Human Embryonic and Fetal Age

Precise determination of donor age in human embryonic and fetal tissue is crucial for cell transplantation due to the existence of distinct time windows within which successful grafting is possible. This study demonstrates that between 4-12 wk postconception embryonic and fetal age can be estimated based on various morphometric parameters measured on a routine basis in suction abortion material. The greatest length, the neck-rump length, the foot length, and the proximal and distal arm and leg length were correlated with the anamnestic and ultra-sonographically estimated age. Multivariate regression analyses showed a linear correlation between age and the logarithmic value of the various morphometric parameters. The best correlation was found for a mathematical model combining the limb parameters (r = 0.904; p < 0.001; n −37). A prospective follow-up study (n = 40) was carried out to test the validity of the mathematical model. A high correlation was found between the calculated age and the estimated age based on anamnestic data (r = 0.749, p < 0.001). Outliers due to errors in the anamnestic data were readily identified by comparing anamnestic with calculated age. This method allows determination of embryonic and fetal age within and beyond the age group of the Carnegie classification and may, therefore, be useful for the needs of experimental and clinical cell transplantation.

Xenogeneic Cell Therapy: Current Progress and Future Developments in Porcine Cell Transplantation

The multitude of distinct cell types present in mature and developing tissues display unique physiologic characteristics. Cellular therapy is a novel technology with the promise of utilizing this diversity to treat a wide range of human degenerative diseases. Intractable diseases, disorders, and injuries are characterized by cell death or aberrant cellular function. Cell transplantation can replace diseased or lost tissue to provide restorative therapy for these conditions. The limited use of cell transplants as a basis for current therapy can, in part, be attributed to the lack of available human cells suitable for transplantation. This has prevented further realization of the promise of cell transplantation as a platform technology. Accordingly, cell-based therapies such as blood transfusions, for which the cells are readily available, are a standard part of current medical practice. Despite numerous attempts to expand primary human cells in tissue culture, current technological limitations of this approach in regard to proliferative capacity and maintenance of the differentiated phenotype has prevented their use for transplantation. Further, use of human stem cells for the derivation of specific cell types for transplantation is an area of future application with great potential, but hurdles remain in regard to deriving and sufficiently expanding these multi-potential cells. Thus, it appears that primary cells are at present a superior source for transplantation. This review focuses on pigs as a source of a variety of primary cells to advance cell therapy to the clinic and implement achievement of its full potential. We outline the advantages and disadvantages of xenogeneic cell therapy while underscoring the utility of transplantable porcine cells for the treatment of human disease. © 1998 Elsevier Science Inc.

Human central nervous system tissue culture: a historical review and examination of recent advances

Tissue culture has been and continues to be widely used in medical research. Since the beginning of central nervous system (CNS) tissue culture nearly 100 years ago, the scientific community has contributed innumerable protocols and materials leading to the current wide variety of culture systems. While nonhuman cultures have traditionally been more widely used, interest in human CNS tissue culture techniques has accelerated since the middle of the last century. This has been fueled largely by the desire to model human physiology and disease in vitro with human cells. We review the history of human CNS tissue culture summarizing advances that have led to the current breadth of options available. The review addresses tissue sources, culture initiation, formats, culture ware, media, supplements and substrates, and maintenance. All of these variables have been influential in the development of culturing options and the optimization of culture survival and propagation.

Transplantation of hematopoietic stem cells in utero

Hematopoietic stem cell (HSC) transplantation in children and adults with congenital lymphohematopoietic disorders is limited by donor availability, graft failure, graft-versus-host disease (GVHD) and delayed immunological reconstitution. These problems may be circumvented by transplanting the patient before birth. Prenatal cellular therapy for the treatment of congenital diseases has tremendous theoretical appeal. Potential advantages of prenatal transplantation include: A) fetal immunologic immaturity and the potential for induction of donor-specific tolerance; B) available space in the developing bone marrow for engraftment of donor cells; C) the sterile, protective, fetal environment which provides isolation from environmental pathogens, and D) prevention of clinical manifestations of the disease. Normal hematopoietic and immunologic development during ontogeny creates a "window of opportunity" during which events favor the engraftment of transplanted allogeneic (and xenogeneic) HSC and their proliferation. This is a period in which the fetus is immunologically naive and thus incapable of rejecting the foreign HSC, and the expanding bone marrow spaces allow homing and engraftment of HSC without the need for myeloablation. Experiments in sheep have established the optimal age of the recipient, route of donor cell administration, sources of HSC, and other parameters necessary for the successful engraftment and long-term expression of donor HSC. In preclinical studies, transplantation of CD34-enriched or highly purified populations of human adult bone marrow cells in utero resulted in the long-term engraftment and expression of donor HSC without graft failure and GVHD. The strategies developed in allogeneic and xenogeneic fetal sheep models were used to successfully treat human fetuses with X-linked recessive severe combined immunodeficiency.

A mathematical model for the estimation of human embryonic and fetal age

Precise determination of donor age in human embryonic and fetal tissue is crucial for cell transplantation due to the existence of distinct time windows within which successful grafting is possible. This study demonstrates that between 4-12 wk postconception embryonic and fetal age can be estimated based on various morphometric parameters measured on a routine basis in suction abortion material. The greatest length, the neck-rump length, the foot length, and the proximal and distal arm and leg length were correlated with the anamnestic and ultrasonographically estimated age. Multivariate regression analyses showed a linear correlation between age and the logarithmic value of the various morphometric parameters. The best correlation was found for a mathematical model combining the limb parameters (r = 0.904; p < 0.001; n = 37). A prospective follow-up study (n = 40) was carried out to test the validity of the mathematical model. A high correlation was found between the calculated age and the estimated age based on anamnestic data (r = 0.749, p < 0.001). Outliers due to errors in the anamnestic data were readily identified by comparing anamnestic with calculated age. This method allows determination of embryonic and fetal age within and beyond the age group of the Carnegie classification and may, therefore, be useful for the needs of experimental and clinical cell transplantation.