Stewart Fleming

Renin-1 is essential for normal renal juxtaglomerular cell granulation and macula densa morphology.

The secretion of renin from granules stored in renal juxtaglomerular cells plays a key role in blood pressure homeostasis. The synthesis and release of renin and the extent of granulation is regulated by several mechanisms including signaling from the macula densa, neuronal input, and blood pressure. Through the use of a gene-targeting vector containing homology arms generated using the polymerase chain reaction, we have inactivated theRen-1 d gene, one of two mouse genes encoding renin, and report that lack of renin-1 d results in altered morphology of the macula densa of the kidney distal tubule and complete absence of juxtaglomerular cell granulation. Furthermore,Ren-1 d−/− mice exhibit sexually dimorphic hypotension. The altered growth morphology of the macula densa in Ren-1d -null mice should provide a tool for the investigation of the JG cell-macula densa signaling. Furthermore, the current data indicate that expression of theRen-1 d gene is a prerequisite for the formation of storage granules, even though the related protein renin-2 is present in these mice, suggesting that renin-1 d and renin-2 are secreted by distinct pathways in vivo.

Malignant hypertension – the role of the paracrine renin–angiotensin system

Malignant hypertension remains one of the life‐threatening complications of blood pressure elevation. It is a clinico‐pathological syndrome of severe blood pressure elevation combined with malignant vascular injury. This is a characteristic form of vascular damage, with two elements: fibrinoid necrosis and endarteritis proliferans. Although the morphology of these has been well described, the molecular events are not fully understood. This review summarizes the evidence from transgenic animals for a role for the activation of a local paracrine renin–angiotensin system in the pathogenesis of malignant vascular injury. These animal models provide pathological, pharmacological, and genetic evidence supporting the hypothesis that intra‐renal generation of angiotensin 2 and exposure of the microcirculation to elevated blood pressure co‐operate in causing tissue damage in malignant hypertension. Copyright

Immunopathology of the placenta in pemphigoid gestationis and linear IgA disease

We have investigated the immunopathology of the placenta in bullous diseases by studying the deposition of immune complexes and expression of MHC class II subregion products by immunohistological methods. Placentae from seven patients with pemphigoid gestationis (PG) and two patients with linear IgA disease were studied. In PG immune complexes containing IgG1 and C3 were identified in six cases. In linear IgA disease IgA1 containing immune complexes were found in both cases. Placentae from patients with PG showed aberrant expression of MHC Class II products. This was not seen in the placentae from patients with linear IgA disease. In PG there was incoordinate expression of the subregion products, DP and DR being more extensively and consistently expressed than DQ. These results and previous immunogenetic studies suggest that PG may be unique among organ specific autoimmune disease, the autoantibodies forming during an allogeneic response rather than target cells behaving as antigen presenting cells.

Association of the D allele of the angiotensin I converting enzyme polymorphism with malignant vascular injury

Aims: To determine whether there is an association between the insertion/deletion (I/D) polymorphism of the human angiotensin I converting enzyme (ACE) gene and malignant vascular injury (MVI). Methods: The polymerase chain reaction was used to genotype DNA extracted from archival, paraffin wax embedded renal biopsy material from 48 patients with MVI, made up from cases of malignant hypertension (n = 23), scleroderma (n = 10), and haemolytic uraemic syndrome (n = 15), and from whole blood samples from 191 healthy controls. Results: The D allele was found more frequently in cases of MVI than in healthy controls, (65% v 52%). Both the DD and I/D genotypes occurred significantly more frequently in patients with MVI than did the II genotype (χ2 = 7.26, p = 0.007; and χ2 = 4.06, p = 0.04, respectively). Conclusions: Possession of at least one copy of the D allele is associated with an increased risk of developing MVI. Our data support a dominant mode of effect for the D allele. Use of the I/D polymorphism as a genetic marker for MVI may be of value clinically in identifying at risk individuals before the development of target end organ damage. Furthermore, those at risk may benefit from early ACE inhibition.

Morphological evidence for calcium-dependent association of calgranulin with the epidermal cytoskeleton in inflammatory dermatoses

The association of calgranulins. intracellular calcium‐binding proteins, with the keratinocyte cytoskeleton has been studied. These molecules are expressed in various inflammatory dermatoses and in organ‐culture explants. Triton X‐100 extraction in the presence of calcium or EDTA suggested that calgranulins are detergent insoluble in the presence of calcium. The molecules were localized in a plaque‐like structure at the cell periphery in lesional skin and in organ‐culture explants. Following induction of calgranulins in vitro there was a redistribution of the intermediate filament cytoskeleton into a perinuclear halo, although desmosomes remained intact. These various features suggest that these members of the S‐100 protein family have a role in cytoskeletal changes seen in various skin diseases.

Antigen‐presenting cells in the skin and placenta in pemphigoid gestationis

In pemphigoid gestationis (PG), one of the major initiating events is the aberrant expression of the class II molecules of the major histocompatibility complex in the placenta. We used a panel of 13 monoclonal antibodies to investigate the phenotype of the MHC class II positive antigen‐presenting cells (APC) in the skin and placenta in PG. In the skin, the APC show reactivity with a variety of macrophage markers and the CDi marker of Langerhans cells. By contrast, the MHC class II positive cells in the placenta showed no reactivity with macrophage or Langerhans cell markers, but were the cytokeratin‐positive trophoblast or vimentin‐positive stromal cells.

Isolated basal keratinocytes express pemphigoid gestationis antigen

Basal keratinocytes were isolated from epidermal cell suspensions prepared by trypsinization of normal human skin. Cells were identified as basal cells by their adherence to collagen and confirmed as basal cells by the presence of pemphigoid antigen. Using an indirect immunofluorescence assay, cells wee found to express pemphigoid gestationis‐related antigen. Sera from patients with pemphigoid gestations reacted in one of two immunofluorescence patterns: either polar, in a pattern similar to that observed with bullous pemphigoid serum, or with uniform staining around the cell periphery.

Changes in autofluorescence based organoid model of muscle invasive urinary bladder cancer.

Muscle invasive urinary bladder cancer is one of the most lethal cancers and its detection at the time of transurethral resection remains limited and diagnostic methods are urgently needed. We have developed a muscle invasive transitional cell carcinoma (TCC) model of the bladder using porcine bladder scaffold and the human bladder cancer cell line 5637. The progression of implanted cancer cells to muscle invasion can be monitored by measuring changes in the spectrum of endogenous fluorophores such as reduced nicotinamide dinucleotide (NADH) and flavins. We believe this could act as a useful tool for the study of fluorescence dynamics of developing muscle invasive bladder cancer in patients. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

Challenges in pathologic staging of renal cell carcinoma: A study of interobserver variability among urologic pathologists

Staging criteria for renal cell carcinoma differ from many other cancers, in that renal tumors are often spherical with subtle, finger-like extensions into veins, renal sinus, or perinephric tissue. We sought to study interobserver agreement in pathologic stage categories for challenging cases. An online survey was circulated to urologic pathologists interested in kidney tumors, yielding 89% response (31/35). Most questions included 1 to 4 images, focusing on: vascular and renal sinus invasion (n=24), perinephric invasion (n=9), and gross pathology/specimen handling (n=17). Responses were collapsed for analysis into positive and negative/equivocal for upstaging. Consensus was regarded as an agreement of 67% (2/3) of participants, which was reached in 20/33 (61%) evaluable scenarios regarding renal sinus, perinephric, or vein invasion, of which 13/33 (39%) had ≥80% consensus. Lack of agreement was especially encountered regarding small tumor protrusions into a possible vascular lumen, close to the tumor leading edge. For gross photographs, most were interpreted as suspicious but requiring histologic confirmation. Most participants (61%) rarely used special stains to evaluate vascular invasion, usually endothelial markers (81%). Most agreed that a spherical mass bulging well beyond the kidney parenchyma into the renal sinus (71%) or perinephric fat (90%) did not necessarily indicate invasion. Interobserver agreement in pathologic staging of renal cancer is relatively good among urologic pathologists interested in kidney tumors, even when selecting cases that test the earliest and borderline thresholds for extrarenal extension. Disagreements remain, however, particularly for tumors with small, finger-like protrusions, closely juxtaposed to the main mass.

Periprostatic Fat Adipokines Expression Correlated with Prostate Cancer Aggressiveness in Men Undergoing Radical Prostatectomy for Clinically Localised Disease

To investigate the relationship between periprostatic adipose tissue (PPAT) adipokine expression and prostate cancer (PCa) aggressiveness using both pathological features of radical prostatectomy (RP) and multiparametric magnetic resonance imaging ( MRI) variables.