Platelets in Early Antibody-Mediated Rejection of Renal Transplants

Antibody-mediated rejection is a major complication in renal transplantation. The pathologic manifestations of acute antibody-mediated rejection that has progressed to functional impairment of a renal transplant have been defined in clinical biopsy specimens. However, the initial stages of the process are difficult to resolve with the unavoidable variables of clinical studies. We devised a model of renal transplantation to elucidate the initial stages of humoral rejection. Kidneys were orthotopically allografted to immunodeficient mice. After perioperative inflammation subsided, donor-specific alloantibodies were passively transferred to the recipient. Within 1 hour after a single transfer of antibodies, C4d was deposited diffusely on capillaries, and von Willebrand factor released from endothelial cells coated intravascular platelet aggregates. Platelet-transported inflammatory mediators platelet factor 4 and serotonin accumulated in the graft at 100- to 1000-fold higher concentrations compared with other platelet-transported chemokines. Activated platelets that expressed P-selectin attached to vascular endothelium and macrophages. These intragraft inflammatory changes were accompanied by evidence of acute endothelial injury. Repeated transfers of alloantibodies over 1 week sustained high levels of platelet factor 4 and serotonin. Platelet depletion decreased platelet mediators and altered the accumulation of macrophages. These data indicate that platelets augment early inflammation in response to donor-specific antibodies and that platelet-derived mediators may be markers of evolving alloantibody responses.     

Use of a dual lumen port for automated red cell exchange in adults with sickle cell disease

Red cell exchange (RCE) is a common procedure in adults with sickle cell disease (SCD). Implantable dual lumen Vortex (DLV) ports can be used for RCE in patients with poor peripheral venous access. We performed a retrospective cohort study of RCE procedures performed in adults with SCD. The main objective of the study was to compare the inlet speed, duration of procedures and rate of complications performed through DLV ports to those performed through temporary central venous and peripheral catheters. Twenty‐nine adults with SCD underwent a total of 318 RCE procedures. Twenty adults had DLV ports placed and 218 procedures were performed using DLV ports. Mean length of follow‐up after DLV port placement was 397 ± 263 days. Six DLV ports were removed due to infection and 1 for malfunction after a mean of 171 ± 120 days. Compared to temporary central venous and peripheral catheters, DLV port procedures had a greater rate of procedural complications, a longer duration, and a lower inlet speed (all P < 0.01). When accounting for the maximum allowable inlet speed to avoid citrate toxicity, 40% of DLV port procedures were greater than 10% below maximum speed, compared to 7 and 14% of procedures performed through temporary central venous and peripheral catheters (P < 0.0001). In conclusion, DLV ports can be used for RCE in adults with SCD, albeit with more procedural complications and longer duration. The smaller internal diameter and longer catheter of DLV ports compared to temporary central venous catheters likely accounts for the differences noted. J. Clin. Apheresis 30:353–358, 2015. © 2015 Wiley Periodicals, Inc.     

Orthogonally oriented scaffolds with aligned fibers for engineering intestinal smooth muscle

Controlling cellular alignment is critical in engineering intestines with desired structure and function. Although previous studies have examined the directional alignment of cells on the surface (x–y plane) of parallel fibers, quantitative analysis of the cellular alignment inside implanted scaffolds with oriented fibers has not been reported. This study examined the cellular alignment in the x–z and y–z planes of scaffolds made with two layers of orthogonally oriented fibers. The cellular orientation inside implanted scaffolds was evaluated with immunofluorescence. Quantitative analysis of coherency between cell orientation and fiber direction confirmed that cells aligned along the fibers not only on the surface (x–y plane) but also inside the scaffolds (x–z & y–z planes). Our study demonstrated that two layers of orthogonally aligned scaffolds can generate the histological organization of cells similar to that of intestinal circular and longitudinal smooth muscle.     

A multi-institutional experience in vascular Ehlers-Danlos syndrome diagnosis

ObjectiveVascular Ehlers-Danlos syndrome (vEDS) is a rare disorder and 1 of 13 types of EDS. The syndrome results in aortic and arterial aneurysms and dissections at a young age. Diagnosis is confirmed with molecular testing via skin biopsy or genetic testing for COL3A1 pathogenic variants. We describe a multi-institutional experience in the diagnosis of vEDS from 2000 to 2015.MethodsThis is a multi-institutional cross-sectional retrospective study of individuals with vEDS. The institutions were recruited through the Vascular Low Frequency Disease Consortium. Individuals were identified using the International Classification of Diseases-9 and 10-CM codes for EDS (756.83 and Q79.6). A review of records was then performed to select individuals with vEDS. Data abstraction included demographics, family history, clinical features, major and minor diagnostic criteria, and molecular testing results. Individuals were classified into two cohorts and then compared: those with pathogenic COL3A1 variants and those diagnosed by clinical criteria alone without molecular confirmation.ResultsEleven institutions identified 173 individuals (35.3% male, 56.6% Caucasian) with vEDS. Of those, 11 (9.8%) had nonpathogenic alterations in COL3A1 and were excluded from the analysis. Among the remaining individuals, 86 (47.7% male, 68% Caucasian, 48.8% positive family history) had pathogenic COL3A1 variants and 76 (19.7% male, 19.7% Caucasian, 43.4% positive family history) were diagnosed by clinical criteria alone without molecular confirmation. Compared with the cohort with pathogenic COL3A1 variants, the clinical diagnosis only cohort had a higher number of females (80.3% vs 52.3%; P < .001), mitral valve prolapse (10.5% vs 1.2%; P = .009), and joint hypermobility (68.4% vs 40.7%; P < .001). Additionally, they had a lower frequency of easy bruising (23.7% vs 64%; P < .001), thin translucent skin (17.1% vs 48.8%; P < .001), intestinal perforation (3.9% vs 16.3%; P = .01), spontaneous pneumothorax/hemothorax (3.9% vs 14%, P.03), and arterial rupture (9.2% vs 17.4%; P = .13). There were no differences in mortality or age of mortality between the two cohorts.ConclusionsThis study highlights the importance of confirming vEDS diagnosis by testing for pathogenic COL3A1 variants rather than relying on clinical diagnostic criteria alone given the high degree of overlap with other forms genetically triggered arteriopathies. Because not all COL3A1 variants are pathogenic, the interpretation of the genetic testing results by an individual trained in variant assessment is essential to confirm the diagnosis. An accurate diagnosis is critical and has serious implications for lifelong screening and treatment strategies for the affected individual and family members.