Recommendations for mRNA analysis of micro-dissected glomerular tufts from paraffin-embedded human kidney biopsy samples.

Background: Glomeruli are excellent pre-determined natural structures for laser micro-dissection. Compartment-specific glomerular gene expression analysis of formalin-fixed paraffin-embedded renal biopsies could improve research applications. The major challenge for such studies is to obtain good-quality RNA from small amounts of starting material, as applicable for the analysis of glomerular compartments.

Glomerular mRNA expression of prothrombotic and antithrombotic factors in renal transplants with thrombotic microangiopathy.

Background: Thrombotic microangiopathy (TMA) in renal transplants (rTx-TMA) is a serious complication and is usually either recurrent TMA (RecTMA) due to humoral rejection (HR-TMA) or due to calcineurin inhibitor toxicity (CNI-TMA). Although the triggers are known, our knowledge about the thrombogenic transcriptome changes in the microvessels is rudimentary.

Methods: We examined the expression of several prothrombotic and antithrombotic genes in 25 biopsies with rTx-TMA (6 RecTMA, 9 HR-TMA, and 10 CNI-TMA) and 8 controls.

Arteriolar vascular smooth muscle cell differentiation in benign nephrosclerosis.

Background: Benign nephrosclerosis (bN) is the most prevalent form of hypertensive damage in kidney biopsies. It is defined by early hyalinosis and later fibrosis of renal arterioles. Despite its high prevalence, very little is known about the contribution of arteriolar vascular smooth muscle cells (VSMCs) to bN.

Optimized RNA extraction from non-deparaffinized, laser-microdissected material.

mRNA extraction and subsequent RT-polymerase chain reaction (PCR)-based expression analysis from laser-microdissected material is by now a well-established and reproducible method. Most routinely stored tissue samples are preserved as formalin-fixed, paraffin-embedded materials. While this allows for a convenient storage and stable preservation of nucleic acids, deparaffinization before staining for laser microdissection may result in a significant loss of mRNA quality and consequently of PCR sensitivity.

Diminished met signaling in podocytes contributes to the development of podocytopenia in transplant glomerulopathy.

Transplant glomerulopathy (TxG) can show secondary focal and segmental glomerulosclerosis (FSGS). FSGS in native kidneys is caused by podocytopenia. This study examines podocytopenia and the role of decreased paracrine Met activation on podocytes by decreased glomerular hepatocyte growth factor (HGF) levels in the development of podocytopenia in TxG.

ADAMTS13--marker of contractile phenotype of arterial smooth muscle cells lost in benign nephrosclerosis.

Background: Hypertensive nephrosclerosis alone and in combination with other renal diseases is a leading cause of terminal renal insufficiency. Histologic lesions manifest as benign nephrosclerosis (bN) with arteriolar hyalinosis and later fibrosis. Procoagulant micromilieus have been implicated in fibrosis.

Podocytic PKC-alpha is regulated in murine and human diabetes and mediates nephrin endocytosis.

Background: Microalbuminuria is an early lesion during the development of diabetic nephropathy. The loss of high molecular weight proteins in the urine is usually associated with decreased expression of slit diaphragm proteins. Nephrin, is the major component of the glomerular slit diaphragm and loss of nephrin has been well described in rodent models of experimental diabetes as well as in human diabetic nephropathy.