The role of reactive oxygen species in apoptosis of the diabetic kidney

Increased levels of reactive oxygen species (ROS) by hyperglycemia can induce apoptosis of renal cells and diabetic nephropathy. The redox balance in the renal cell seems, therefore, of the utmost importance. ROS-mediated apoptosis may be further aggravated by an inadequate cytoprotective response against ROS. When there are insufficient cytoprotective and ROS scavenging molecules, ROS lead to considerable cellular damage and to a point of no return in apoptosis. Induction of cytoprotective proteins may prevent or attenuate apoptosis, renal cell injury, and finally diabetic nephropathy. Here, we discuss some mechanisms of apoptosis and several strategies that have been probed to ameliorate, or to prevent apoptosis in the diabetic kidney

Synchronized turbo apoptosis induced by cold-shock

In our research on the role of apoptosis in the pathogenesis of the autoimmune disease systemic lupus erythematosus (SLE), we aim to evaluate the effects of early and late apoptotic cells and blebs on antigen presenting cells. This requires the in vitro generation of sufficiently large and homogeneous populations of early and late apoptotic cells. Here, we present a quick method encountered by serendipity that results in highly reproducible synchronized homogeneous apoptotic cell populations. In brief, granulocytic 32Dcl3 cells are incubated on ice for 2 h and subsequently rewarmed at 37°C. After 30–90 min at 37°C more than 80–90% of the cells become early apoptotic (Annexin V positive/propidium iodide negative). After 24 h of rewarming at 37°C 98% of the cells were late apoptotic (secondary necrotic; Annexin V positive/propidium iodide positive). Cells already formed apoptotic blebs at their cell surface after approximately 20 min at 37°C. Inter-nucleosomal chromatin cleavage and caspase activation were other characteristics of this cold-shock-induced process of apoptosis. Consequently, apoptosis could be inhibited by a caspase inhibitor. Finally, SLE-derived anti-chromatin autoantibodies showed a high affinity for apoptotic blebs generated by cold-shock. Overall, cold-shock induced apoptosis is achieved without the addition of toxic compounds or antibodies, and quickly leads to synchronized homogeneous apoptotic cell populations, which can be applied for various research questions addressing apoptosis

Polymorphism of human haptoglobin and its clinical importance

Haptoglobin (Hp) is a plasma glycoprotein, the main biological function of which is to bind free hemoglobin (Hb) and prevent the loss of iron and subsequent kidney damage following intravascular hemolysis. Haptoglobin is also a positive acute-phase protein with immunomodulatory properties. In humans, the HP locus is polymorphic, with two codominant alleles (HP1 and HP2) that yield three distinct genotypes/phenotypes (Hp1-1, Hp2-1 and Hp2-2). The corresponding proteins have structural and functional differences that may influence the susceptibility and/or outcome in several diseases. This article summarizes the available data on the structure and functions of Hp and the possible effects of Hp polymorphism in a number of important human disorders