■ Abstract Apoptosis is a genetically programmed, morphologically distinct form of cell death that can be triggered by a variety of physiological and pathological stimuli. Studies performed over the past 10 years have demonstrated that proteases play critical roles in initiation and execution of this process. The caspases, a family of cysteine-dependent aspartate-directed proteases, are prominent among the death proteases. Caspases are synthesized as relatively inactive zymogens that become activated by scaffold-mediated transactivation or by cleavage via upstream proteases in an intracellular cascade. Regulation of caspase activation and activity occurs at several different levels: ( a) Zymogen gene transcription is regulated; ( b) antiapoptotic members of the Bcl-2 family and other cellular polypeptides block proximity-induced activation of certain procaspases; and ( c) certain cellular inhibitor of apoptosis proteins (cIAPs) can bind to and inhibit active caspases. Once activated, caspases cleave a variety of intracellular polypeptides, including major structural elements of the cytoplasm and nucleus, components of the DNA repair machinery, and a number of protein kinases. Collectively, these scissions disrupt survival pathways and disassemble important architectural components of the cell, contributing to the stereotypic morphological and biochemical changes that characterize apoptotic cell death.

Mammalian caspases: structure ,a ctivation ,s ubstrates, and functions during apoptosis

Hemophilia is a rare disorder that is complex to diagnose and to manage. These evidence-based guidelines offer practical recommendations on the diagnosis and general management of hemophilia, as well as the management of complications including musculoskeletal issues, inhibitors, and transfusion-transmitted infections. By compiling these guidelines, the World Federation of Hemophilia aims to assist healthcare providers seeking to initiate and/or maintain hemophilia care programs, encourage practice harmonization around the world and, where recommendations lack adequate evidence, stimulate appropriate studies.

/pdf/guidelines-for-the-management-of-hemophilia-1x6t2d999b.pdf

Guidelines for the management of hemophilia.

WFH Guidelines for the Management of Hemophilia, 3rd edition

https://onlinelibrary.wiley.com/doi/pdf/10.1111/jth.12672

Definitions in hemophilia: communication from the SSC of the ISTH.

Recessively inherited coagulation disorders

Antibodies against factor VIII coagulant activity can appear in haemophiliacs who are treated with factor VIII preparations but also spontaneously in non-haemophiliacs. The Bethesda assay is the most commonly used method to detect these antibodies, but it lacks specificity especially in the lower range resulting in unreliable data. Two modifications are proposed and tested to resolve the imperfections: 1. Buffering the normal plasma used in the assay- and control mixture with 0.1 M imidazole to pH 7.4. 2. Replacing the imidazole buffer in the control mixture by immunodepleted factor VIII deficient plasma. These modifications allow better discrimination between positive and negative samples and improve reliability.

/pdf/the-nijmegen-modification-of-the-bethesda-assay-for-factor-1dtc3qtd6q.pdf

The Nijmegen Modification of the Bethesda Assay for Factor VIII : C Inhibitors: Improved Specificity and Reliability

The effects of postponing prophylactic treatment on long-term outcome in patients with severe hemophilia.

Studies have shown that joint bleeding leads to cartilage degradation independent of concurrent synovitis We hypothesized that the blood-induced cartilage damage is because of increased chondrocyte apoptosis after short-term exposure of whole blood or isolated mononuclear cells plus red blood cells to cartilage Human cartilage tissue samples were co-cultured for 4 days with whole blood (50% v/v) or with mononuclear cells plus red blood cells (50% v/v equivalents) Cartilage matrix proteoglycan synthesis ((35)SO(4)(2-) incorporation) was determined after 4 days as well as at day 16 (after a 12-day recovery period in the absence of any additions) To test the involvement of apoptosis a specific caspase-3 inhibitor (acDEVDcho, 0 to 500 micro mol/L) as well as a pan-caspase inhibitor (zVADfmk, 0 to 500 micro mol/L) were added Chondrocyte apoptosis was evaluated by immunohistochemical staining of single-strand DNA and by terminal dUTP nick-end labeling Cartilage co-cultured with whole blood as well as mononuclear cells plus red blood cells induced a long-term inhibition of proteoglycan synthesis (74% and 78% inhibition on day 16, respectively) Immunohistochemistry showed a threefold increase in apoptotic chondrocytes in cultures with 50% whole blood as well as with mononuclear cells plus red blood cells Both the specific caspase-3 inhibitor and the pan-caspase inhibitor partially restored proteoglycan synthesis in the cartilage after blood exposure This effect was accompanied by a decrease in the number of apoptotic chondrocytes These data suggest that a single joint hemorrhage (a 4-day exposure of cartilage to 50% v/v blood) results in induction of chondrocyte apoptosis, responsible for the observed inability of the chondrocytes to restore the proteoglycan synthesis during recovery from a short-term exposure to blood This reduced restoration could eventually lead to cartilage degeneration and ultimately joint destruction

/pdf/short-term-exposure-of-cartilage-to-blood-results-in-4mxximlbt8.pdf

Short-Term Exposure of Cartilage to Blood Results in Chondrocyte Apoptosis

OBJECTIVE: We previously showed that 4-day in vitro exposure of human cartilage to blood, as well as a single experimental joint bleeding in dogs, resulted in a disturbed cartilage matrix turnover lasting at least 2 weeks. We now evaluate the longterm outcome of the adverse in vitro and in vivo effects of blood on cartilage matrix turnover. METHODS: Human and canine articular cartilage tissue was cultured in the presence of homologous whole blood during 4 days. The in vitro cartilage matrix turnover was analyzed directly after blood exposure or following culture for additional periods of 2, 5, and 10 weeks in the absence of blood. The in vivo longterm effects were determined by injecting autologous blood into the right knee of 12 Beagle dogs. Six dogs were killed shortly after blood injections; the 6 remaining dogs were killed 10 weeks later. Cartilage matrix turnover and the cartilage destructive properties of the synovial tissue were analyzed. RESULTS: Short term (4 days) in vitro exposure of human or canine cartilage to whole blood inhibited proteoglycan synthesis by more than 98% (day 4), an inhibition which lasted until week 10 (70 and 75% inhibition, respectively). Also the in vivo short term exposure of cartilage to blood induced the adverse changes in cartilage proteoglycan turnover seen shortly after exposure. However, in vivo 10 weeks after the last injection, normalization of cartilage matrix turnover was observed. Synovial inflammation was absent and no destructive activity was found. CONCLUSION: These data show a discrepancy between the in vitro and in vivo longterm effects of blood on cartilage. A possible explanation for the in vivo recovery after experimental joint bleeding in dogs could be that the observed changes in cartilage only predispose to acute damage but that additional (e.g., mechanical) factors are needed to induce permanent joint damage.

https://www.jrheum.org/content/jrheum/30/2/339.full.pdf

Marijke van den Berg

Papers

The Nijmegen Modification of the Bethesda Assay for Factor VIII : C Inhibitors: Improved Specificity and Reliability

The effects of postponing prophylactic treatment on long-term outcome in patients with severe hemophilia.

Short-Term Exposure of Cartilage to Blood Results in Chondrocyte Apoptosis

Blood-induced joint damage: longterm effects in vitro and in vivo.

Five novel mutations in the gene for human blood coagulation factor V associated with type I factor V deficiency.