http://gene-quantification.net/giulietti-2001.pdf

An overview of real-time quantitative PCR: applications to quantify cytokine gene expression.

Collagen is the most widely distributed class of proteins in the human body. The use of collagen-based biomaterials in the field of tissue engineering applications has been intensively growing over the past decades. Multiple cross-linking methods were investigated and different combinations with other biopolymers were explored in order to improve tissue function. Collagen possesses a major advantage in being biodegradable, biocompatible, easily available and highly versatile. However, since collagen is a protein, it remains difficult to sterilize without alterations to its structure. This review presents a comprehensive overview of the various applications of collagen-based biomaterials developed for tissue engineering, aimed at providing a functional material for use in regenerative medicine from the laboratory bench to the patient bedside.

/pdf/collagen-based-biomaterials-for-tissue-engineering-37yrr8an7e.pdf

Collagen-Based Biomaterials for Tissue Engineering Applications

Professor Titmuss, an eminent English social theorist, believes that man is inherently altruistic and that the duty of government is to create that social and economic climate which best channels man's drive to work together for the common good. In support of this belief, he has written a book about the procurement, distribution, and transfusion of human blood, a medical topic which he employs as an illustrative social and economic microcosm. The conclusion he reaches is foregone: "The voluntary socialized system in Britain is economically, professionally, administratively and qualitatively more efficient than the mixed, commercialized, and individualistic American system" (Titmuss, R.M: "Why Give to Strangers?" Lancet 1 :123-125, 1971). As the book was written with a bias, so will it be read with bias. My own bias is that of an American and a blood-banker. I am only too conscious of many deficiencies in the American complex of arrangements—it isn't

The Gift Relationship: From Human Blood to Social Policy

IL-10, IL-6, and TNF-α: Central factors in the altered cytokine network of uremia—The good, the bad, and the ugly

Calcification of tissue heart valve substitutes: progress toward understanding and prevention.

Interleukin (IL)-6 is a pleiotropic cytokine, produced by different cells. There is accumulating evidence that IL-6 promoter polymorphisms impact substantially on various diseases and we identified kidney transplant recipients carrying the IL-6 GGG/GGG −597/−572/−174genotype to have superior graft survival. To prove a functional impact on gene expression, we analysed systematically IL-6 production in healthy individuals with respect to the IL-6 −597/−572/−174genotype. IL-6 was determined in 100 healthy blood donors at protein and mRNA levels upon specific stimulation in monocytes and T lymphocytes under whole blood conditions. GGG/GGG individuals showed a lower IL-6 secretion upon lipopolysaccharide (LPS)-stimulation versus all others (P = 0·039). This link was even stronger when −597 and −174GG genotypes were reanalysed separately (P = 0·008, P = 0·017). However, we found neither a difference at the mRNA level or percentage of CD14+ cells nor after T cell stimulation. We found evidence for the IL-6 −597/−572/−174genotype to affect IL-6 synthesis, i.e. lower levels of IL-6 protein upon LPS-stimulation in GGG/GGG individuals. Further studies are needed in kidney transplant recipients to investigate the potential link between the GGG/GGG genotype and graft survival. In line with this, determination of the genetic risk profiles might be promising to improve the transplant outcome in the individual patient.

The impact of interleukin-6 promoter −597/−572/−174genotype on interleukin-6 production after lipopolysaccharide stimulation

BACKGROUND AND OBJECTIVES Inflammatory cytokines in platelet concentrates (PC) may cause side-effects such as febrile non-haemolytic transfusion reactions. The maximum white blood cell (WBC) content tolerable to avoid the accumulation of cytokines, and whether these cytokines originate from degranulating leucocytes or de novo synthesis during storage, had not been investigated prior to this study. MATERIAL AND METHODS We investigated the secretion of interleukin (IL)-1beta, IL-2, IL-6, IL-8, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) and quantified the appropriate expression of corresponding mRNA in PC with regard to different levels of WBC contamination and storage times. In addition we tested the viability of WBCs during PC storage (by staining with 7-aminoactinomycin D) and their ability to perform de novo cytokine synthesis (by using superantigen stimulation). RESULTS We detected a statistically significant increase of IL-1beta, IL-6, IL-8 and TNF-alpha in PC with > or = 108 WBCs. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) showed increasing mRNA expression of the respective cytokines depending on the number of WBC present. On day 5 of storage, WBC viability was > 80% and the leucocytes were still able to produce cytokines de novo. CONCLUSIONS These data show clear evidence for de novo synthesis of cytokines in PC. The cytokine pattern supports the hypothesis that activated monocytes are responsible for this cytokine synthesis. PC with a WBC contamination of > or = 108 contain inflammatory mediators in clinically relevant concentrations.

Evidence for de novo synthesis of cytokines and chemokines in platelet concentrates.

The interleukin-6 -174 promoter polymorphism is associated with extrapulmonary bacterial dissemination in Streptococcus pneumoniae infection.

Platelet concentrates (PC) prepared from pooled buffy coat (BC-PC) contain a variable number of leukocytes from different donors. We questioned whether storage of BC-PC can lead to a lymphocyte activation in the sense of a mixed lymphocyte reaction. BC-PC were prepared from four ABO-identical buffy coats and we undertook leukocyte analyses and measurement of different cyto- kines on days 1,3 and 5 of PC storage (n = 72). Cytokine content was also deter- mined in freshly prepared plasma (n = 48) and PC prepared by thrombapheresis (SD-PC) (n = 12). As control, we studied lymphoproliferation of pooled periph- eral blood mononuclear cells from four individuals in 10 mixed lymphocyte cul- tures (MLCs) under optimal conditions. In the BC-PC, whole blood count and lymphocyte analysis showed a mean leukocyte contamination of 64f28 x 10' per unit with a proportion of lymphocytes of 66.7+13%. In the MLC, levels of in- terleukin-2 (IL-2) and interferon-y (IFN-y) were increased on day 3 and 5 of storage (p<O.OOl). In a proportion of BC-PC, tumor necrosis factor-a (72.2%) and IL-2 (43.1%) were detectable immediately after preparation, whereas IFN-y (4.2%), interleukin-lg (4.2%) and interleukin-8 (11.1%) were only found in some BC-PC. In all cases, initial values of cytokines did not increase during storage. Cytokine measurement in FFP and SD-PC showed similar results. The study demonstrates that cytokines are detectable in a variety of blood products immedi- ately after preparation. Levels of cytokines did not increase in the preparations. BC-PC can be stored for up to 5 days without any signs of lymphocyte activation.

Michael Müller-Steinhardt

Papers

The impact of interleukin-6 promoter −597/−572/−174genotype on interleukin-6 production after lipopolysaccharide stimulation

Evidence for de novo synthesis of cytokines and chemokines in platelet concentrates.

The interleukin-6 -174 promoter polymorphism is associated with extrapulmonary bacterial dissemination in Streptococcus pneumoniae infection.

Cytokines in Platelet Concentrates Prepared from Pooled Buffy Coats

Rapid screening of granulocyte antibodies with a novel assay: flow cytometric granulocyte immunofluorescence test.