Charles N. Durfor

Low molecular weight hyaluronic acid effects on murine macrophage nitric oxide production.

Hyaluronic acid (HA) is increasingly used for a number of medical device applications. Since the chemical structure of HA is identical no matter its bacterial or animal origin, it should be the ideal biomaterial. However, short term transient inflammatory reactions are common, while rare long-term adverse events may correlate with subclinical chronic inflammation. Concern has been raised that low molecular weight components or degradation fragments from implanted HA may directly stimulate inflammatory reactions. This study examined a panel of HA molecular weights from the unitary disaccharide up to 1.7 x 10(6) Dalton lengths, in which endotoxin was assayed at a very low level (less than 0.03 EU/mg). The murine cell line RAW 264.7, rat splenocytes, and rat adherent differentiated primary macrophages were assayed for nitric oxide production under a variety of inflammatory conditions plus or minus HA. Under the highest inflammatory states, nitric oxide production was mildly suppressed by HMW-HA while slightly augmented by LMW-HA at mg/mL concentrations. However, at micromolar concentrations fragments below 5000 Daltons, thought to have drug-like qualities, were without effect. These data support the hypothesis that if endotoxin is reduced to an extremely low level, LMW-HA may not directly provoke normal tissue macrophage-mediated inflammatory reactions.

Overview of the FDA Regulatory Process

Publisher Summary This chapter provides a brief historical review of the Food and Drug Administration (FDA) and its organizational structure and discusses topics pertaining to the regulation of regenerative medicine products including possible regulatory pathways for combination products and relevant jurisdictional issues. FDA regulations are contained in the Code of Federal Regulations (CFR). Regulations for drugs, biologics, devices, and tissues, along with related regulations, may be found in various parts of Title 21 of the CFR. Guidance documents are nonbinding publications that describe the FDAs interpretation of policy pertaining to a regulatory issue or set of issues related to the design, production, labeling, promotion, manufacturing, and testing of regulated products, the processing, content, and evaluation, or approval of submissions inspection, and enforcement policies. Guidance documents, which are developed in accordance with Good Guidance Practices found at 21 CFR §10.115, are intended to clarify the FDAs current thinking related to regulatory issues and procedures. The FDA has issued “Guidance for Industry: Eligibility Determination for Donors of Human Cells, Tissues, and Cellular and Tissue-Based Products to assist establishments making donor eligibility determinations with complying with the Donor Eligibility rule (21 CFR 1271 Subpart C).” This guidance also incorporates and finalizes the content of “Guidance for Industry, Preventive Measures to Reduce the Possible Risk of Transmission of Creutzfeldt–Jakob Disease (CJD) and Variant Creutzfeldt–Jakob Disease (vCJD) by Human Cells, Tissues, and Cellular and Tissue-Based Products (HCT/Ps).” The US Public Health Service (PHS) agencies including the FDA, National Institutes of Health (NIH), Centers for Disease Control and Prevention (CDC), and Health Resources and Services Administration (HRSA) have worked together to address the risk of infectious disease transmission, publishing the “PHS Guideline on Infectious Disease Issues in Xenotransplantation.”

Screening biomaterials for stimulation of nitric oxide‐mediated inflammation

Inflammatory reactions to biomaterials may include macrophage-mediated generation of nitric oxide (NO), which may harm patient tissue or potentially interfere with proper function of an implanted device. RAW 264.7 cells were grown in culture and treated at various times with lipopolysaccharide (LPS, endotoxin), murine recombinant gamma-interferon (mrIFN-gamma), and different preparations of hyaluronic acid (HA). Increase in fluorescence of 2,3-diaminonaphthalene (DAN) allowed for detection of initial (24 h or less) NO inflammatory responses of RAW 264.7 to LPS from E. coli O26:B6. By looking at early time points, mrIFN-gamma augmentation of the LPS effect was observed, simulating a complex immune reaction. Activation through nuclear factor-kappaB (NF-kappaB), was confirmed in this system by parthenolide inhibition of LPS stimulation. Stimulation of RAW 264.7 by different HA preparations resulted in NO responses that correlated with the amount of LPS present. In the presence of mrIFN-gamma, a significant inflammatory reaction to HA was observed when the concentration of contaminating LPS was as low as 0.15 EU/mL. NO production in the presence of mrIFN-gamma by RAW 264.7 may serve as a convenient in vitro system to routinely screen biomaterials for potentially harmful macrophage-mediated inflammation whereby the safety of implanted medical devices might be compromised.

Chapter II.17 – Tissue Engineering: Product Applications and Regulatory Issues

Publisher Summary The Food and Drug Administration (FDA) recognizes that an important segment of the products that it regulates arises from new technological achievements and innovations. One example is products developed through tissue engineering (TE) technology, i.e., tissue engineered medical products. Tissue engineering is the application of the principles of life sciences and engineering to develop biological substitutes for the restoration, maintenance, modification, improvement, or replacement of tissue or organ function. In the broadest sense, tissue engineered medical products span a spectrum of products including transplanted human tissues or organs (i.e., autologous or allogeneic tissue); animal tissues or organs (e.g., transgenic animals or xenotransplants); processed, selected, or expanded mammalian cells (e.g., somatic and genetic cellular therapies) in combination with or without biomaterials; and totally synthetic materials of biomimetic design. Both the range of products and the rapid evolution in product design have generated a certain degree of ambiguity in the definition of tissue engineered medical products. There is no precise and globally accepted definition for tissue-engineered products (TEPs).

Translation of Regenerative Medicine Products Into the Clinic in the United States: FDA Perspective

Abstract The field of regenerative medicine encompasses a breathtaking array of interdisciplinary scientific approaches with the promise of delivering future therapies to meet current unmet medical needs for patients. Increasingly more of these innovative products are being translated into human clinical trials in the United States, and general familiarity of the FDA is important to efficiently navigate the process. The basics of FDA history, organization, and processes are described herein for those new to clinical translation, with more detailed content added regarding approval pathways, regulations, guidances, and select special topics of relevance to regenerative medicine. In addition to the cumulative experience of previous products, the FDA regulatory approach to medical products evaluation includes an ongoing assessment of how the science of those products informs regulatory policy. FDA engages in ongoing dialogue with the scientific community and product sponsors to continue to develop science-based regulatory review policies that are robust and predictable in order to meet the needs of the challenging array of products that are on the horizon.

Chapter 41 – Overview of the FDA Regulatory Process

Regenerative medicine encompasses a breathtaking array of interdisciplinary scientific approaches which address a broad spectrum of clinical needs. Recent advances in scientific knowledge related to cell biology, gene transfer therapy, biomaterials, immunology, and engineering principles applicable to biological systems place this community in a position to address a number of challenging and critical health needs. These include treatment of disease conditions resulting from pancreas, liver, and kidney failure; structural cardiac valve repair; skin and wound repair; and orthopedic applications. Scientific challenges include expanding the knowledge base in each discipline as well as developing an interdisciplinary approach for identifying and resolving key questions. The Food and Drug Administration’s (FDA’s) regulatory review process mirrors the scientific challenges with regard to the development of review paradigms that cross scientific disciplines. This chapter provides a brief historical review of the FDA and its organizational structure, and discusses topics pertaining to the regulation of regenerative medicine products.

Chapter 83 – Overview of the FDA Regulatory Process

This chapter provides a brief historical review of the Food and Drug Administration (FDA) and its organizational structure and discusses topics pertaining to the regulation of regenerative medicine products including possible regulatory pathways for combination products and relevant jurisdictional issues. FDA regulations are contained in the Code of Federal Regulations (CFR). Regulations for drugs, biologics, devices, and tissues, along with related regulations, may be found in various parts of Title 21 of the CFR. Guidance documents are nonbinding publications that describe the FDAs interpretation of policy pertaining to a regulatory issue or set of issues related to the design, production, labeling, promotion, manufacturing, and testing of regulated products, the processing, content, and evaluation, or approval of submissions inspection, and enforcement policies. Guidance documents, which are developed in accordance with Good Guidance Practices found at 21 CFR §10.115, are intended to clarify the FDAs current thinking related to regulatory issues and procedures. The FDA has issued “Guidance for Industry: Eligibility Determination for Donors of Human Cells, Tissues, and Cellular and Tissue-Based Products to assist establishments making donor eligibility determinations with complying with the Donor Eligibility rule (21 CFR 1271 Subpart C).” This guidance also incorporates and finalizes the content of “Guidance for Industry, Preventive Measures to Reduce the Possible Risk of Transmission of Creutzfeldt–Jakob Disease (CJD) and Variant Creutzfeldt–Jakob Disease (vCJD) by Human Cells, Tissues, and Cellular and Tissue-Based Products (HCT/Ps).” The US Public Health Service (PHS) agencies including the FDA, National Institutes of Health (NIH), Centers for Disease Control and Prevention (CDC), and Health Resources and Services Administration (HRSA) have worked together to address the risk of infectious disease transmission, publishing the “PHS Guideline on Infectious Disease Issues in Xenotransplantation.”