Biocompatibility of High-Flux Membranes

Standard dialysis with cuprophane membranes is known to stimulate the immune system. As a result of activation of macrophages various interleukins and tumor necrosis factor (TNF) are secreted, presenting further evidence of the poor biocompatibility of cuprophane. We investigated the immunogenic properties of three modern high-flux membranes. Seven patients were studied during hemodiafiltration sessions using either a polysulfone (F60, Fresenius), a polymethylmetacrylate (BK 2.1, Toray) or a cellulose triacetate (FB-210 U, Nipro) dialyzer in a hemodiafiltration procedure. Serial measurements were made during each treatment of interleukin-1β (II-1β), TNF, soluble IL-2 receptor (sII-2r), soluble CD4 (sCD4), soluble CD8 (sCD8), interferon gamma (IFNg) and neopterin. In contrast to the known increase of IL-1β, IL-2r and TNF with cuprophane membranes, none of the modern high-flux dialyzers stimulated the production of these factors. Significant decreases of neopterin and sCD4 were observed. IFNg and sCD8 did not change significantly. Our results suggest that the modern high-flux dialyzers are non-immunogenic, and thus provide further evidence of the superior biocompatibility of synthetic or semisynthetic membranes over the conventional cuprophane.

Detection of cell proliferation in adults of the water bear Hypsibius dujardini (Tardigrada) via incorporation of a thymidine analog

The taxon Tardigrada, commonly called "water bears", consists of microscopic, eight-legged invertebrates that are well known for their ability to tolerate extreme environmental conditions. Their miniscule body size means that tardigrades possess a small total number of cells, the number and arrangement of which may be highly conserved in some organs. Although mitoses have been observed in several organs, the rate and pattern of cell divisions in adult tardigrades has never been characterized. In this study, we incubated live tardigrades over a period of several days with a thymidine analog in order to visualize all cells that had divided during this time. We focus on the midgut, the largest part of the digestive system. Our results show that new cells in the midgut arise from the anterior and posterior ends of this organ and either migrate or divide toward its middle. These cells divide at a constant rate and all cells of the midgut epithelium are replaced in approximately one week. On the other hand, we found no cell divisions in the nervous system or any other major organs, suggesting that the cell turnover of these organs may be extremely slow or dependent on changing environmental conditions.

Abstract P2-09-09: Polyligand profiling differentiates cancer patients according to their benefit of treatment

Introduction: Deconvolution of multi-nodal perturbations in cancer network architecture demands highly multiplexed profiling assays. We demonstrate the value of polyligand profiling of tumor systems states using libraries of single stranded oligodeoxynucleotides (ssODN) to distinguish between tumor tissue from breast cancer patients who did or did not derive benefit from treatment regimens containing trastuzumab.

Methods: This study included cases from women with invasive breast cancer who received chemotherapy+ trastuzumab (C+T) or trastuzumab monotherapy with available retrospective data on the time to next treatment (TTNT). A library of 2x1012 unique ssODN was exposed to FFPE tissues from patients who benefited (B) or not (NB) from trastuzumab-based regimens in several rounds of positive and negative selection. Two enriched libraries were screened on independent set of 42 B and 19 NB cases using a modified IHC protocol for detection of bound ssODNs. Poly-Ligand Profiles (PLP) were scored by a blinded pathologist. Two libraries, EL-NB and EL-B, showed significant p-values between groups of responders and non-responders. A Cox-PH model was fitted using either tumors' HER2 status or PLP test results as the independent variable. Median survival time was calculated from the Kaplan-Meier estimate. A separate group of 63 cases with TTNT data from chemotherapy without trastuzumab was used as a control to distinguish prognostic from predictive performance.

Results: The PLP scores of EL-NB and EL-B were assessed by receiver operating characteristic (ROC) curves and resulted in a combined AUC value of 0.81. EL-NB and EL-B were able to effectively classify B and NB patients with either HER2-negative/equivocal (AUC = 0.73) or HER2-positive cancers (AUC = 0.84). In contrast, HER2 status alone yielded an AUC value of 0.47. The combined PLP scores for the independent set of 63 patients treated with C excluding trastuzumab resulted in an AUC value of 0.53, indicating that the assay was predictive and not simply prognostic. Kaplan-Meier curves analysis shows that PLP+ cases have 429 days median TTNT, while PLP- cases have 129 days (HR = 0.38, log-rank p = 0.001). Analysis based on HER2 status showed no significant difference in TTNT between patients that were HER2+ (280 days) or HER2-negative/equivocal (336 days, HR = 1.27, log-rank p =0.45).

Summary: Performance of the PLP assay in differentiating patients who did or did not benefit from trastuzumab therapy outperforms the standard IHC assay for HER2 status. These results represent a promising step towards the development of a CDx to identify the 50-70% of HER2+ patients who will not benefit from trastuzumab. In addition, PLP also has the potential to identify the HER2-negative/equivocal patients who may benefit from trastuzumab-containing regimens.

Citation Format: Domenyuk V, Gatalica Z, Santhanam R, Wei X, Stark A, Kennedy P, Toussaint B, Levenberg S, Wang R, Xiao N, Greil R, Rinnerthaler G, Gampenrieder S, Heimberger AB, Berry DJ, Barker A, Demetri GD, Quackenbush J, Marshall JL, Poste G, Vacirca JL, Vidal GA, Schwartzberg LS, Halbert DD, Voss A, Miglarese MR, Famulok M, Mayer G, Spetzler D. Polyligand profiling differentiates cancer patients according to their benefit of treatment [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-09-09.

A rare case of Epstein-Barr virus-associated hepatosplenic smooth muscle tumors after kidney transplantation

A 27-year old caucasian male was diagnosed 2.7 years after kidney transplantation with Epstein-Barr virus (EBV)-associated smooth muscle tumors in liver and spleen. The reduction in immunosuppression and conversion from tacrolimus to sirolimus did not lead to a regression of the tumors. Additionally, the patient developed a cellular rejection of his renal allograft, which was successfully treated. A combined approach with stereotactic radiofrequency ablation (SRFA) and surgical resection was effective in the treatment of the tumors.

Cationic switchable lipids: pH-triggered molecular switch for siRNA delivery

A pH-sensitive molecular switch able to change its conformation upon protonation at endosomal pH values is embedded into the structure of cationic lipidoid materials, thus conferring endosomal escape properties. Involvement of the conformational switch in the endosomal escape process was confirmed and leading material identified was able to induce efficient gene knockdown both in vitro and in vivo. The lipid nanoparticles reported here are promising for therapeutic applications and this work could serve as a template for future design of stimulus-responsive (ionic, redox, light) molecular switch for drug and gene delivery.

Cerebral vasculitis in a patient with hereditary complete C4 deficiency and systemic lupus erythematosus

We describe the case of a female patient with hereditary complete C4 deficiency and systemic lupus erythematosus. She had suffered from lupus nephritis in early childhood. At the age of 23 years she developed severe lupus with skin disease and life-threateningcerebral vasculitis. Her cerebral disease was unresponsiveto high-dosesteroids, intravenousimmunoglobulin, fresh frozen plasma and plasma exchange. Improvement was achieved with immunoadsorption in combination with mycophenolate mofetil. The patient made a complete recovery and is maintained in complete remission on mycophenolate and low-dose steroids.

[Sleep and neurological diseases]

Knowledge of the physiology of sleep-wake regulation can contribute to an understanding of the pathophysiology and symptoms of neurological diseases and is helpful for initiating specific therapies for sleep-wake cycle stabilization. Based on historically important observations on the close relationship between sleep and neurological diseases, new insights and developments in selected neurological entities are presented in this review article.

The presence of biofilm structures in atherosclerotic plaques of arteries from legs amputated as a complication of diabetic foot ulcers

OBJECTIVE

Atherosclerosis, rather than microcirculatory impairment caused by endothelial cell dysfunction, is the main driver of circulatory compromise in patients with diabetic limbs. The presence of atherosclerotic plaque at the trifurcation is a significant contributor to amputation of diabetic legs. The presence of bacteria and other microorganisms in atherosclerotic plaque has long been known, however, the cause of chronic inflammation and the role of bacteria/viruses in atherosclerosis have not been studied in detail. The objective of this study was to clarify the cause of the chronic inflammation within atherosclerotic plaques, and determine if any bacteria and/or viruses are involved in the inflammatory pathway.

METHOD

This study uses fluorescence microscopy and fluorescence in-situ hybridisation (FISH) to identify components of biofilm in atherosclerotic arteries. These tools are also used to identify individual bacteria, and determine the architectural spatial location within the atherosclerotic plaque where the bacteria can be found.

RESULTS

The results indicate that the presence of biofilms in grossly involved arteries may be an important factor in chronic inflammatory pathways of atherosclerotic progression, in the amputated limbs of patients with diabetic foot ulcers and vascular disease.

CONCLUSION

While the presence of bacterial biofilm structures in atherosclerotic plaque does not prove that biofilm is the proximate cause of atherosclerosis, it could contribute to the persistent inflammation associated with it. Second, the synergistic relationship between the atherosclerotic infection and the diabetic foot ulcer may ultimately contribute to higher amputation rates in diabetics.

DECLARATION OF INTEREST

RAW and RDW have equity interest in PathoGenius, a clinical laboratory using DNA to identify microbes.

Abstract P2-01-08: Adaptive dynamic artificial poly-ligand targeting: Aptamer-based profiling of liquid biopsies to improve the accuracy of breast cancer diagnoses in women with dense breast tissue

Introduction:

Breast cancer screening relies upon mammography, but for women with dense breast tissue this method is often uninformative. Routine screening identifies suspicious breast lesions in some women, but the pain and risk associated with follow-up biopsies along with the poor accuracy of traditional histopathology urgently call for improved approaches to breast cancer screening. This is especially important for those high-risk patients for whom mammography is of limited value. We describe a non-invasive liquid biopsy method of profiling plasma exosome preps designed to improve the accuracy and safety of breast cancer screening for women with dense breast tissue.

Results:

We incubated plasma samples (300 microliters per sample) from breast cancer patients (n=60) and a control cohort (n=60) with a high-complexity DNA aptamer library using a modified SELEX scheme, termed “adaptive dynamic artificial poly-ligand targeting (ADAPTTM)”. Differentially bound (cancer vs. non-cancer) aptamers were recovered from precipitated exosomes and were identified by deep sequencing. Two thousand aptamer sequences were resynthesized and used to probe a larger set of 500 plasma samples from a patient cohort (n=206) and a control cohort comprised of self-reported healthy volunteers (n=117) and patients whose biopsies led to a diagnosis of non-cancer (n=177). We employed several statistical models to build a cancer/non-cancer predictor, including a Random Generalized Linear Model (RGLM) and a Random Forest Model (RFM). Both models yielded an equivalent classification performance with areas under the receiver-operator characteristic curve (ROC AUC) of 0.7. Testing the prediction performance by 100 Out-of-Bag permutations or by pre-filtered (read cutoff and estimated sample size) cross-validation (CV) resulted in ROC AUC values of 0.66 and 0.62, respectively. When samples were randomly assigned to groups, the aptamers were no longer able to distinguish the groups (ROC AUC = 0.54), indicating that the underlying information driving the model is truly specific to cancer. Importantly, incorporation of BIRAD results as a clinical covariate did not influence model performance, signifying that predictions by ADAPTTM were independent of breast tissue density.

Conclusions:

We have identified a set of 2000 DNA aptamers that distinguish women with breast cancer from women without breast cancer. Our liquid biopsy approach requires only 300 microliters of plasma and is amenable to high-throughput processing. By employing a number of statistical approaches including rigorous cross-validation, we consistently achieve cross validation ROC AUC values approaching 0.7. The performance of the predictor was not affected by BIRAD scores, supporting its potential utility in difficult cases where imaging is insufficient, such as in women with dense breast tissue. Further optimization of the aptamer library and testing on additional samples should improve performance. Upon complete validation, an ADAPTTM – derived breast cancer test may serve as a vital diagnostic adjunct that can be easily incorporated into standard clinical practice.

Citation Format: Domenyuk V, Zhong Z, Wang J, Stark A, Chen W, Xiao N, Miglarese MR, Famulok M, Mayer G, Spetzler DB. Adaptive dynamic artificial poly-ligand targeting: Aptamer-based profiling of liquid biopsies to improve the accuracy of breast cancer diagnoses in women with dense breast tissue. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-01-08.

Dysautonomia in prodromal α-synucleinopathy: peripheral versus central autonomic degeneration

BACKGROUND AND PURPOSE

There is an urgent need for early predictive markers for the course of disease in prodromal α-synucleinopathies such as idiopathic rapid eye movement (REM) sleep behaviour disorder. Autonomic cardiac/vascular dysfunction is a prominent feature in advanced α-synucleinopathies, but its diagnostic value as an early neurodegenerative marker remains unclear. The latter may be complicated since synuclein-mediated neurodegeneration may involve central and peripheral components of the autonomic nervous system.

METHODS

The diagnostic value of autonomic symptoms and central and peripheral autonomic markers of blood pressure and heart rate regulation were prospectively evaluated in 20 subjects with idiopathic REM sleep behaviour disorder and 20 age-matched healthy controls.

RESULTS

Although subjects with REM sleep behaviour disorder showed no clinical autonomic symptoms, blood pressure (P ≤ 0.035) and heart rate response (P ≤ 0.065) were slightly diminished during orthostatic challenge. Autonomic dysregulation was distinctively reflected in lower resting heart rate (all components, P ≤ 0.05) and blood pressure variability (low frequency component, P ≤ 0.024) indicating peripheral cardiac/vascular denervation. In contrast, baroreflex sensitivity and central cardiac autonomic outflow (sympathovagal balance) were well preserved indicating intact central autonomic regulation. Heart rate variability [very low frequency component, receiver operating characteristic (ROC) area under the curve (AUC) 0.80, P ≤ 0.001] and blood pressure variability (low frequency component ROC AUC 0.73, P ≤ 0.01) but not baroreflex sensitivity and sympathovagal balance showed an excellent diagnostic accuracy in identifying subjects with REM sleep behaviour disorder and healthy controls.

CONCLUSIONS

Cardiac/vascular dysfunction in prodromal α-synucleinopathy arises from peripheral rather than from central autonomic degeneration. Autonomic indices encoded in heart rate and blood pressure variability are precise functional markers of early synuclein-mediated neurodegeneration.

An Intrinsically Disordered Region in the Proapoptotic ASPP2 Protein Binds to the Helicobacter pylori Oncoprotein CagA

The leading risk factor for gastric cancer in humans is infection by Helicobacter pylori strains that express and translocate the oncoprotein CagA into host epithelial cells. Once inside host cells, CagA interacts with ASPP2, which specifically stimulates p53-mediated apoptosis and reverses its pro-apoptotic function to promote ASPP2-dependent degradation of p53. The X-ray crystal structure of a complex between the N-terminal domain of CagA and a 56-residue fragment of ASPP2, of which 22 residues were resolved, was recently described. Here, we present biochemical and biophysical analyses of the interaction between the additional regions of CagA and ASPP2 potentially involved in this interaction. Using size exclusion chromatography-multiangle laser light scattering, circular dichroism, and nuclear magnetic resonance analyses, we observed that the ASPP2 region spanning residues 331-692, which was not part of the ASPP2 fragment used for crystallization, is intrinsically disordered in its unbound state. By surface plasmon resonance analysis and isothermal titration calorimetry, we found that a portion of this disordered region in ASPP2, residues 448-692, binds to the N-terminal domain of CagA. We also measured the affinity of the complex between the ASPP2 fragment composed of residues 693-918 and inclusive of the fragment used for crystallization and CagA. Additionally, we mapped the binding regions between ASPP2 and CagA using peptide arrays, demonstrating interactions between CagA and numerous peptides distributed throughout the ASPP2 protein sequence. Our results identify previously uncharacterized regions distributed throughout the protein sequence of ASPP2 as determinants of CagA binding, providing mechanistic insight into apoptosis reprogramming by CagA and potential new drug targets for H. pylori-mediated gastric cancer.

[Narcolepsy]

Narcolepsy is a rare sleep disorder. The classical presentation includes the four symptoms excessive daytime sleepiness, cataplexy, sleep paralysis and hypnagogic hallucinations. As a model disease with all the transitions from awake to sleeping conditions, non-rapid eye movement (NREM) and rapid eye movement (REM), it plays an important role in neurology and sleep medicine. Patients with narcolepsy possess a reduced number of hypocretin-producing neurons in the hypothalamus and accordingly the hypocretin level in the cerebrospinal fluid is low. The neuropeptide hypocretin (orexin) has functions, such as the regulation of the sleep-wake cycle, the autonomous nerve system, motor system and metabolic processes. The delay in diagnosing narcolepsy is difficult to comprehend in modern medicine. The frequent association with other sleep-wake disorders may be responsible for the delay. Genomewide association studies have subsequently been able to prove that autoimmune mechanisms are responsible for the manifestation of narcolepsy with the HLA association being the most important for susceptibility and protection. Imaging studies have revealed neurodegenerative changes, making a multifactorial etiopathogenesis probable. The frequent occurrence of metabolic disorders has not yet been clarified. Early diagnosis of narcolepsy has the possibility to offer affected persons an adequate medication to lead an almost normal life and the future possibility to cure narcolepsy through immunomodulation therapy.