Plasma fractionation in countries with limited infrastructure and low-/medium income: How to move forward?

Although therapeutic drivers are changing over the years, and innovative biotech products are continuously modifying the clinical landscape, there is an increasing need for plasma protein therapies obtained by the fractionation of human plasma. Plasma-derived protein products therefore continue to play vital roles in the therapeutic management of various immunological disorders, deficiencies in coagulation factors or protease inhibitors, viral or bacterial infections, and trauma. Plasma fractionation is a biotechnology industry that has increased in complexity over the last 30 years to ensure that plasma-derived protein therapies exhibit optimal quality and pathogen safety profiles. Plasma-derived products are among the safest biological therapies available; in industrialized countries they are strictly and efficiently regulated in all aspects of their production chain and clinical use. Conversely, due to some technological complexities and strict adherence to regulatory requirements, a substantial barrier to entry into the field of plasma fractionation exists. Although various plasma-derived protein products are on the WHO model list of essential medicines, dramatic shortages of these products exist, especially in low-/medium income countries, while at the same time more than 9 million liters of recovered plasma in these countries are wasted annually. Lack of plasma protein products results mainly from three factors: (a) cost of imported products, (b) insufficient local supply of quality plasma for fractionation, or (c) lack of domestic industrial fractionation capacity. As the understanding of critical quality and safety factors has dramatically improved over the years, there is a need to rethink how affordable, scalable, and reliable purification and virus inactivation technologies could be introduced in countries with poor relevant infrastructures and low-/medium income. Such technologies, when properly validated and implemented, could help ensure local availability of essential plasma protein therapies and gradually fill the gap in product supply, safety and affordability that exists relative to advanced economies.

Minipool caprylic acid fractionation of plasma using disposable equipment: a practical method to enhance immunoglobulin supply in developing countries.

BACKGROUND: Immunoglobulin G (IgG) is an essential plasma-derived medicine that is lacking in developing countries. IgG shortages leave immunodeficient patients without treatment, exposing them to devastating recurrent infections from local pathogens. A simple and practical method for producing IgG from normal or convalescent plasma collected in developing countries is needed to provide better, faster access to IgG for patients in need. METHODOLOGY/PRINCIPAL FINDINGS: IgG was purified from 10 consecutive minipools of 20 plasma donations collected in Egypt using single-use equipment. Plasma donations in their collection bags were subjected to 5%-pH5.5 caprylic acid treatment for 90 min at 31°C, and centrifuged to remove the precipitate. Supernatants were pooled, then dialyzed and concentrated using a commercial disposable hemodialyzer. The final preparation was filtered online by gravity, aseptically dispensed into storage transfusion bags, and frozen at <-20°C. The resulting preparation had a mean protein content of 60.5 g/L, 90.2% immunoglobulins, including 83.2% IgG, 12.4% IgA, and 4.4% IgM, and residual albumin. There was fourfold to sixfold enrichment of anti-hepatitis B and anti-rubella antibodies. Analyses of aggregates (<3%), prekallicrein (5-7 IU/mL), plasmin (26.3 mU/mL), thrombin (2.5 mU/mL), thrombin-like activity (0.011 U/g), thrombin generation capacity (< 223 nM), and Factor XI (<0.01 U/mL) activity, Factor XI/XIa antigen (2.4 ng/g) endotoxin (<0.5 EU/mL), and general safety test in rats showed the in vitro safety profile. Viral validation revealed >5 logs reduction of HIV, BVDV, and PRV infectivity in less than 15 min of caprylic acid treatment. CONCLUSIONS/SIGNIFICANCE: 90% pure, virally-inactivated immunoglobulins can be prepared from plasma minipools using simple disposable equipment and bag systems. This easy-to-implement process could be used to produce immunoglobulins from local plasma in developing countries to treat immunodeficient patients. It is also relevant for preparing hyperimmune IgG from convalescent plasma during infectious outbreaks such as the current Ebola virus episode.

Platelets effects on tumor growth.

Unlike other blood cells, platelets are small anucleate structures derived from marrow megakaryocytes. Thought for almost a century to possess solely hemostatic potentials, platelets, however, play a much wider role in tissue regeneration and repair and interact intimately with tumor cells. On one hand, tumor cells induce platelet aggregation (TCIPA), known to act as the trigger of cancer-associated thrombosis. On the other hand, platelets recruited to the tumor microenvironment interact, directly, with tumor cells, favoring their proliferation, and, indirectly, through the release of a wide palette of growth factors, including angiogenic and mitogenic proteins. In addition, the role of platelets is not solely confined to the primary tumor site. Indeed, they escort tumor cells, helping their intravasation, vascular migration, arrest, and extravasation to the tissues to form distant metastasis. As expected, nonspecific or specific inhibition of platelets and their content represents an attractive novel approach in the fight against cancer. This review illustrates the role played by platelets at primary tumor sites and in the various stages of the metastatic process.

Platelet microparticles: detection and assessment of their paradoxical functional roles in disease and regenerative medicine.

There is increasing research on and clinical interest in the physiological role played by platelet microparticles (PMPs). PMPs are 0.1-1-µm fragments shed from plasma membranes of platelets that are undergoing activation, stress, or apoptosis. They have a phospholipid-based structure and express functional receptors from platelet membranes. As they are the most abundant microparticles in the blood and they express the procoagulant phosphatidylserine, PMPs likely complement, if not amplify, the functions of platelets in hemostasis, thrombosis, cancer, and inflammation, but also act as promoters of tissue regeneration. Their size and structure make them instrumental in platelet-cell communications as a delivery tool of platelet-borne bioactive molecules including growth factors, other signaling molecules and micro (mi)RNA. PMPs can therefore be a pathophysiological threat or benefit to the cellular environment when interacting with the blood vasculature. There is also increasing evidence that PMP generation is triggered during blood collection, separation into components, and storage, a phenomenon potentially leading to thrombotic and inflammatory side effects in transfused patients. Evaluating PMPs requires strict pre-analytical and analytical procedures to avoid artifactual generation and ensure accurate assessment of the number, size repartitioning, and functional properties. This review describes the physical and functional methods developed for analyzing and quantifying PMPs. It then presents the functional roles of PMPs as markers or triggers of diseases like thrombosis, atherosclerosis, and cancer, and discusses the possible detrimental immunological impact of their generation in blood components. Finally we review the potential function of PMPs in tissue regeneration and the prospects for their use in therapeutic strategies for human health.

Platelet-cancer interactions.

Platelets play a crucial role in the pathophysiological processes of hemostasis and thrombosis. Increasing evidence indicates that they fulfill much broader roles in balancing health and disease. The presence of tumor cells affects platelets both numerically, through a wide variety of mediators and cytokines, or functionally through tumor cell-induced platelet activation, the first step toward cancer-induced thrombosis. This induction results from signaling events through the different platelet receptors, or may be cytokine-mediated. Reciprocally, upon activation, the platelets will release a myriad of growth factors from their dense and α-granules and peroxisomes; these will directly impact tumor growth, tethering, and spread. A similar cross-talk is initiated between tumor microvesicles stimulating the platelets and platelet microparticles, promoting both thrombosis and tumor growth. A vicious loop of activation thereafter takes place. Platelets directly and indirectly promote tumor growth, and enable a molecular mimicry coating the malignant growth and allowing metastasizing cells to escape T-cell-mediated immunity and natural killer cell surveillance. Breaking this vicious activation loop with nonspecific platelet inhibitors, such as aspirin, or by targeting specific sites on the activation cascade may offer a mean to reduce both the risks of development and progression of cancer and the risk of thrombosis.

Blood-derived biomaterials and platelet growth factors in regenerative medicine.

Several biomaterials can be obtained from human blood. Some are used for clinical indications requiring a high content in fibrinogen, while others are used because they contain multiple platelet growth factors. Mimicking thrombin-induced physiological events of coagulation leading to fibrino-formation and platelet activation, blood biomaterials have critical advantages of being devoid of tissue necrotic effects and of being biodegradable by body enzymes. Fibrin-based biomaterials, known as fibrin glues or fibrin sealants, have been used for more than 30 years as surgical hemostatic and sealing agents, demonstrating benefits in essentially all surgical fields, including reconstructive plastic surgery and wound treatment. Clinical interest in platelet growth factor-rich biomaterials (often known as platelet gels or platelet-rich-plasma) has emerged more recently. Platelet gels are used in clinical situations to achieve wound healing and repair soft and hard tissues. Applications include the healing of recalcitrant ulcers and burns, and stimulation of osseous tissue regeneration in dentistry, implantology, and maxillofacial and plastic surgery. They were evaluated recently in knee osteoarthritis and for the repair of musculoskeletal tissue lesions in sports medicine. Platelet lysates are now used as a substitute for fetal bovine serum and for ex vivo clinical-scale expansion of stem cells, opening new perspectives in regenerative medicine. We present the scientific rationale that prevailed in the development of blood biomaterials, describe their modes of production and biochemical and functional characteristics, and present clinical applications in regenerative medicine.

The platelet-cancer loop.

The relationship between cancer and thrombosis has been established since 1865 when Armand Trousseau described superficial thrombophlebitis as forewarning sign of occult visceral malignancy. Platelets are the primary hemostatic tool and play a primordial role in cancer-induced thrombosis. Tumor-induced numerical and functional platelet abnormalities have been described in conjunction to changes in coagulation. Such changes are reported even in the absence of clinically detectable thrombosis and correlate with tumor progression and metastasis. Reciprocally, platelets seem to interplay with the tumors and the immune system, both directly and indirectly favoring tumor progressions, tethering and distant spread. A number of growth factors supporting tumor growth, angiogenesis and metastasis are released from the platelets. A reciprocating loop of tumor-induced platelet activation/platelet-induced tumor growth and dissemination is initiated, acting as a thrombosis trigger/tumor amplifier. Recent studies have demonstrated that the use of anti-platelet agents can break this loop resulting in a reduction of short-term risk for incident cancer, cancer mortality and metastasis. The beneficial effect in reduction in cancer-induced thrombosis remains to be established. The current review aims at shedding the light on the intimate reciprocal cross-talk between platelets and cancer and on exploring the potential beneficial effect of anti-platelet agents in breaking the deadly loop of tumor amplification.

[Performance Assessment Tool for Quality Improvement in Hospitals (PATH): first experiences in Croatia]. / Alat za ocjenu rada u cilju poboljsanja kvalitete u bolnicama: prva iskustva u provodenju programa PATH u hrvatskim bolnicama.

PATH (Performance Assessment Tool for Quality Improvement in Hospitals), a project of the World Health Organization (WHO) for Europe offers hospitals a comprehensive and standardized tool (a set of indicators) to evaluate their own performance and development of measures for quality improvement. PATH Program was launched in Croatia in 2008, and it was conducted in 2009 in hospitals that have voluntarily decided to be involved. Here we present the results of the first phase of pilot experience of establishing the program, based on data collected in 22 Croatian hospitals. Analysis of the first results indicated the existence of marked differences among the hospitals that have taken the example of the percentage of cesarean sections ranging from 1.1% to 21.4%. The mortality rate of myocardial infarction ranged from 1.9 to 21.4%, while the mortality of stroke ranged from 12.5 to 45.5%. The highest percentage of needle-stick injuries reported for physicians was 16.2% of entire hospital staff in one year, 6.1% for nurses and 4.6% for the supportive staff. The result suggests the existence of many problems and limitations in data collection at hospital level, limitations in their analysis and creates recommendations for quality improvements, which must be taken into account when hospitals are compared on the national or international level.