Amyloid deposition plays a significant, albeit overlooked, role in neurologic disorders. Deposition of amyloid proteins in both the central and peripheral nervous systems lead to debilitating, and often deadly, organ dysfunction, including cerebral amyloid angiopathy, familial amyloid neuropathy, and Alzheimer’s disease (AD). Alzheimer’s disease is discussed in some detail in a separate chapter within this book, and therefore will not be discussed in detail in this chapter. In this chapter, we present the pathological mechanisms, disease manifestations, diagnostic approach, and treatment modalities for diseases of the nervous system caused by amyloid deposition. While significant strides have been made over the years in identifying key underlying pathologic mechanisms, the medical community’s understanding of these rare conditions remain limited. The primary goal of this chapter is to provide additional resources and information for clinicians to help identify these disorders early in their course before they cause irreparable damage to their patients.

The amyloidoses are a heterogenous group of clinical disorders that share the common finding of the abnormal deposition of insoluble proteins into various organs, with the result that these proteinaceous deposits disrupt cellular function and impair the integrity of the organs involved. Most typically, the abnormal protein deposition is the consequence of abnormal three dimensional folding of the culprit protein. The abnormal folding of the protein, in turn, may be due to a germ line mutation, may be due to an acquired mutation, or may be due to a polymorphism or characteristic of a normal protein that leads to abnormal folding, precipitation, and deposition of the protein, particularly when that protein is expressed at unusually high levels for a prolonged period of time. The clinical manifestations of an amyloid disorder are the consequences of the array of organs involved, the extent of amyloid deposition, and co-morbid conditions present in the individual patient. The array of organs involved, and the extent of organ involvement, in turn, depend in large part on the specific protein that is responsible for the amyloid deposition, and the process driving that protein’s production. In this chapter, a chronological overview is intended to summarize the critical insights into the patho-biology of amyloid accumulation of various types. These insights have allowed an improved understanding over time of the of the major subgroups and disease entities of the amyloidoses, leading to some degree of improvement in diagnosis and treatment outcomes. Unfortunately, as of this writing, treatment outcomes still remain poor for a large fraction of patients, and there is need for improvement in all aspects of the evaluation and management of these diseases.

Primary central nervous system (CNS) marginal zone B-cell lymphoma (MZBCL) arising from the dural meninges is a rare but indolent disease. This malignancy can present in various ways, hence making it difficult to diagnose. Biopsy results dictate an appropriate treatment plan, which commonly consists of a combination of surgical resection, whole brain radiotherapy and systemic therapy.

Amyloidosis is a group of disorders that share a common pathobiology: in each case, a protein that exhibits misfolding is deposited in one or multiple organs leading to disruption in organ function. These amyloid proteins are recognized as amorphous pink material in Hematoxylin and Eosin staining, with confirmation by staining with Congo red and yellow or green birefringence under polarized light microscope. To date at least 36 different types of amyloid proteins have been identified. Worldwide, AA amyloidosis is the most common type, and this occurs secondary to chronic inflammatory disease states—such as chronic infections and rheumatological disorders. In western countries, the incidence of AA amyloidosis is decreasing, and AL is the most common type of amyloidosis, characterized by amyloid due to light chain deposition. ATTR amyloidosis, which can be either hereditary or acquired, is a unique variant of systemic amyloidosis that results from mutations in the transthyretin (TTR) gene. Our review will focus on clinical features of the most common systemic amyloidosis, with a detailed review on evaluation and management of AA, AL and ATTR amyloidosis.

Acute myeloid leukemia (AML) has a poor prognosis and requires new approaches for treatment. We have reported that a combination of vitamin D‐based cell differentiation agents (doxercalciferol/carnosic acid [D2/CA]) added following the cytotoxic drug arabinocytosine (AraC) increases AML cell death (CD), a model for improved therapy of this disease. Because AraC‐induced CD is known to involve reactive oxygen species (ROS) generation, here we investigated if the modulation of cellular REDOX status plays a role in the enhancement of cell death (ECD) by D2/CA. Using thiol antioxidants, such as N‐acetyl cysteine (NAC), we found a significant inhibition of ECD, yet this occurred in the absence of any detectable change in cellular ROS levels. In contrast, NAC reduced the vitamin D receptor (VDR) abundance and its signaling of ECD. Importantly, VDR knockdown and NAC similarly inhibited ECD without producing an additive effect. Thus, the proposed post‐AraC therapy may be compromised by agents that reduce VDR levels in AML blasts.

BACKGROUND The educational objective of this study was to describe 2 case reports in which patients were found to have an autoimmune disease concomitantly with a rare, benign histiocytic disorder known as Rosai-Dorfman disease (RDD). It is unclear if there is an underlying association between autoimmune disease and RDD. Lymphadenopathy, although most frequently seen bilaterally in the cervical region in RDD, may be present anywhere. A biopsy with histologic confirmation is required to not only evaluate for malignancy in these cases, but also necessary to diagnose RDD. CASE REPORT We describe 2 cases in which RDD was found incidentally in 2 patients who concomitantly had known autoimmune diseases. The first patient's history included Factor II deficiency, antiphospholipid syndrome, and autoimmune hemolytic anemia; whereas the second patient had a positive antinuclear antibody test, elevated rheumatoid factor, positive lupus anticoagulant, and positive beta-2 glycoprotein 1 antibodies, as well as positive anticardiolipin antibody panel, immune mediated thrombocytopenia, and pernicious anemia. Lymphadenopathy and an enlarged mass were seen in these cases respectively, which were histologically proven to be RDD. Steroid therapy was the mainstay of treatment. CONCLUSIONS Autoimmune diseases are relatively common in the general population and it appears that RDD coexists more often than suspected. When lymphadenopathy or a mass is seen, especially in those with other autoimmune diseases, RDD should remain within the differential diagnosis. Further research is required to determine characteristics and optimal management of RDD. We have observed in the cases presented, that if the autoimmune disease is well controlled, RDD can be an indolent disease.

Abstract Acute Myeloid Leukemia (AML) is a disease with a grim prognosis and limited curative treatment options. The principal agent used to induce disease remissions is Cytarabine (AraC), typically combined with an anthracycline, though multiple other combinations have been explored. We have previously reported that the exposure of AML blasts, in which the DNA is already damaged by AraC, to the Vitamin D2 analog Doxercalciferol combined with Carnosic Acid (D2/CA) enhances AraC cytotoxicity, resulting in an increased cell kill of the blasts. To obtain an understanding of the underlying mechanisms, and thus facilitate the translation of this finding to the clinic, we conducted in vitro studies on HL60, U937 cell lines and on AML blasts in primary culture. The initial findings were that the kinases BRAF and JNK1 and the pro-apoptotic protein BIM participate in the enhancement of AraC action. We now report that the kinase activity of ASK1 (MAP3K5) is upregulated by both AraC and D2/CA, and this appears to be additive thus increasing the apoptosis by this sequential combination regimen. Interestingly, we also noted that BRAF directly binds to ASK1, and since it is a kinase, this raises the possibility that it activates ASK1 in this experimental system. This possibility is strengthened by the report that JNK activation which leads to apoptosis is dependent on BRAF. The ongoing investigation of additional details of the molecular events responsible for enhanced cell death may provide clues for the improvement of the therapy of AML. (Supported by NIH grant R01CA044722-26 from NCI). Citation Format: Xuening Wang, Jonathan S. Harrison, George P. Studzinski. Cell death of AML blasts induced by cytarabine and enhanced by the Vitamin D2/Carnosic acid cell differentiating combination involves apoptosis signal-regulating kinase 1 (ASK1) activation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 315.

Thrombotic Thrombocytopenic Purpura (TTP), first described in the early twentieth century, was fatal in the majority of cases until the advent of plasma therapy. Mortality has declined dramatically since the 1980s, and in the 1990s the pathophysiology was elucidated through the discovery and understanding of the central role of a deficiency of the metalloprotease ADAMTS13. The vast majority of cases occur due to an autoimmune process, with a minority of cases due to an underlying mutation. Since the turn of this century, Rituximab, a monoclonal antibody targeting CD20 expressed on B-lymphocytes, has become widely used to treat patients with a wide spectrum of autoimmune diseases, including TTP. However, Rituximab remains “off-label” in the setting of TTP. We recently encountered a patient with chronic relapsing TTP, whose clinical relapses have responded to Rituximabbased therapy without need to resort to plasmapheresis. The clinical course of this patient is described, and the literature focusing on the use of Rituximab in prophylaxis to prevent recurrent TTP is reviewed.

Standard therapy for Acute Myeloid Leukemia (AML) is rarely curative, and several suggested improvements have had little success so far. We have reported that in an in vitro model of a potential therapeutic regimen for AML, the activity of cytarabine (AraC) is enhanced by a sequential treatment with a combination of the vitamin D2 analog Doxercalciferol (D2) and the plant-derived antioxidant carnosic acid (CA). Importantly, the enhancement occurred selectively in patient-derived AML blasts, but not in the normal bone marrow cells. We now demonstrate that TXNIP, previously known as Vitamin D up-regulated protein 1 (VDUP1) [PMID 808674] plays a part in signaling cell death (CD) in this regimen. This is shown by the reduced CD when TXNIP protein levels are decreased by the CRISPR/CAS9 or RNAi technology. Further, we show that direct activation of ASK1 kinase by TXNIP is required for the optimal transmission of the CD signal to apoptotic machinery, regulated by JNK and BIM. These studies provide a rationale for a projected clinical trial of this vitamin D-based new therapeutic regimen for AML.

Autoimmune polyglandular syndrome type 1 (APS1) is a rare autosomal recessive disorder, and large granular lymphocytic leukemia (LGLL) may, even more rarely, complicate APS1. LGLL may be subtle in presentation, but it is imperative to recognize LGLL in APS1 promptly, as outcome may otherwise be fatal, as described herein.

: Acquired coagulopathies are common; uncommonly, adsorption of coagulation factors from the circulation into the tissues by pathologic amyloid exceeds the body's ability to produce factor and results in acquired factor deficiency. When amyloidosis does cause a coagulopathy, it is most often acquired factor X deficiency, but there are rare reports of amyloidosis being associated with other acquired factor deficiencies. We investigated a case of a severe bleeding diathesis, the cause of which was combined acquired factor V deficiency and concomitant acquired von Willebrand syndrome. Studies revealed prolonged prothrombin time and activated partial thromboplastin time. Mixing patient plasma with normal plasma corrected both the prothrombin time and activated partial thromboplastin time. Assays showed decreased factor V activity of 27%; Ristocetin cofactor activity was decreased at 49%, but von Willebrand antigen was elevated at 213%. Multimer analysis was consistent with type 2 von Willebrand syndrome. Lymph node biopsy documented amyloid light chain type (AL) amyloidosis; extraction of protein from the lymph node documented AL lambda light chain amyloid. Marrow biopsy documented IgG lambda myeloma. Immunohistochemical staining of the lymph node, using investigational polyvalent antibodies, demonstrated that both von Willebrand factor and factor V were identifiable in areas of amyloid deposition, providing evidence that these coagulation factors were adsorbed to the amyloid protein, resulting in accelerated clearance from the circulation, previously reported to be the mechanism of cases of acquired factor X deficiency in the setting of amyloidosis. Although there are case reports of acquired von Willebrand syndrome because of amyloidosis and case reports of acquired factor V deficiency because of amyloidosis, this appears to be the first reported case of concomitant acquired von Willebrand syndrome and acquired factor V deficiency because of amyloidosis, and the first report of localization of both von Willebrand protein and factor V protein to AL amyloid as a cause of a severe bleeding diathesis.

A model of increased toxicity of AraC to AML cells when AraC is followed by carnosic acid (CA) and vitamin D analog.

Numerous clinical studies of vitamin D, its derivatives or analogs, have failed to clearly demonstrate sustained benefits when used for the treatment of human malignant diseases. However, given the strong preclinical evidence of anti-neoplastic activity and the epidemiological associations suggesting that vitamin D compounds may have a place in cancer therapy, attempts are continuing to devise new approaches to their therapeutic use. This laboratory has developed a strategy to enhance the effectiveness of the currently standard therapy of Acute Myeloid Leukemia (AML) by the immediate addition of the vitamin D2 analog Doxercalciferol combined with the plant polyphenol-derived Carnosic acid to AML cells previously treated with Cytarabine (AraC). Enhancement of AML cell death was noted to be dependent on VDR and BRAF kinase. Here we document that the stress-related kinase JNK is an important additional component of cell death enhancement in this protocol. Either the Knock-down or the inhibition of JNK activity reduced the enhancement of AraC-induced cell death, and we show that JNK signaling to the apoptosis regulator BIM and Caspase executioners of cell death are downstream of VDR and BRAF. A clear understanding of the molecular basis for the increased efficacy of AraC in the therapy of AML is expected to bring this regimen to a clinical trial.

To evaluate the diagnostic performance of contrast-enhanced ultrasound (CEUS) in differential diagnosis of inflammatory bowel disease (IBD) and colon cancer, we enrolled 51 patients with thickened bowel walls (13 with IBD and 38 with colon cancer). Ultrasound and CEUS were performed and both qualitative and quantitative features were analyzed. The intestinal wall stratification was preserved in 63.6% of the IBD group but in only 2.6% of the colon cancer group (p <0.01). On CEUS, disordered enhancement and heterogeneous enhancement were shown in only 9.1% and 0%, respectively, of the IBD group while in 94.7% and 78.9%, respectively, of the colon cancer group (p <0.01). For quantitative analysis, compared to IBD, colon cancer showed later enhancement and slower wash-out with less speed to reach peak intensity (p <0.05). In conclusion, CEUS may prove useful for the differential diagnosis of IBD and colon cancer, but more studies are required.

Abstract Cytarabine (AraC) is an important component of AML therapy, but like other DNA damaging therapeutic agents it is rarely curative. Exploratory studies suggest that therapy outcomes may be improved by combining AraC with other compounds. In this context, we have recently reported that the addition of a vitamin D-based differentiating agent combination following AraC damage to AML cells in established culture, increases the cell kill. Here we present data obtained with AML blasts cells freshly obtained from patients with this disease which demonstrate that HL60 and U937 cell lines provide a good model to supplement studies of the mechanisms underlying this potential therapeutic regimen. Importantly, in contrast to malignant cells, mononuclear cells isolated from normal human bone marrow do not show the enhancement of AraC-induced cell death by combinations of differentiation agents. The cells were exposed to AraC at concentrations which produced approximately 30-40% cell kill, followed by a combination of 100 nM 1alfa-hydroxyvitamin D2 (D2) and 10 uM carnosic acid (CA), which together serve as a powerful differentiating agent combination (D2/CA) for AML cells, but are minimally toxic alone. Increased cell death, measured by Annexin V/Propidium Iodide, compared to AraC alone, was selective for malignant cells, occurred by both apoptosis and necrosis, and was associated with increased levels of vitamin D receptor (VDR), DNA damage, and higher levels of DNA damage response marker P-H2AX. The knock-down of VDR with siRNA markedly reduced the potentiating effect of D2/CA on the AraC- induced cell death and the associated cellular changes. Since several caspases showed increased expression, and a caspase 3-specific inhibitor markedly reduced the enhancement of cell death, we measured the levels of the pro-apoptotic member of the Bcl family, Bim, which prominently increased following the addition of D2/CA to cells previously exposed to AraC. The increased Bim expression occurred at both mRNA and protein levels. Consistent with a role in the enhancement of cell death in this system, knock down of Bim by siRNA abrogated the effect of adding D2/CA to AraC-treated cells. Thus, our data indicate that in AML cells with pre-existing DNA damage activated VDR can interact with apoptotic pathways, and rather than promoting differentiation, leads to increased leukemia cell kill. (Supported by grant R01CA044722-25 from the National Cancer Institute, NIH, and grant 10A049 from American Institute for Cancer Research, both to GPS; JSH received support from the Nellie B. Smith Endowment at the University of Missouri and the Ellis Fischel Cancer Research Fund at the University of Missouri). Citation Format: Xuening Wang, Jonathan Harrison, George P. Studzinski. Translational study of the enhancement of cytarabine toxicity to AML blasts by a differentiation agent combination. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1185.

Acute Myeloid Leukemia (AML) has grave prognosis due to aggressive nature of the disease, the toxicity of standard treatment, and overall low cure rates. We recently showed that AML cells in established culture treated with Cytarabine (AraC) and a differentiation agent combination show enhancement of AraC cytotoxicity. Here we elucidate molecular changes which underlie this observation with focus on AML blasts in primary culture. The cells were treated with AraC at concentrations achievable in clinical settings, and followed by the addition of Doxercalciferol, a vitamin D2 derivative (D2), together with Carnosic acid (CA), a plant-derived antioxidant. Importantly, although AraC is also toxic to normal bone marrow cell population, the enhanced cell kill by D2/CA was limited to malignant blasts. This enhancement of cell death was associated with activation of the monocytic differentiation program as shown by molecular markers, and the increased expression of vitamin D receptor (VDR). Apoptosis elicited by this treatment is caspase-dependent, and the optimal blast killing required the increased expression of the apoptosis regulator Bim. These data suggest that testing of this regimen in the clinic is warranted.

Multiple small-molecule inhibitors of the β-secretase enzyme (BACE1) are under preclinical or clinical investigation for Alzheimer's disease (AD). Prior work has illustrated robust lowering of central amyloid β (Aβ) after acute administration of BACE1 inhibitors. However, very few studies have assessed the overall impact of chronically administered BACE1 inhibitors on brain amyloid burden, neuropathology, and behavioral function in aged preclinical models. We investigated the effects of a potent nonbrain-penetrant BACE1 inhibitor, delivered directly to the brain using intracerebroventricular infusion in an aged transgenic mouse model. Intracerebroventricular infusion of the BACE1 inhibitor (0.3-23.5 μg/d) for 8 weeks, initiated in 17-month-old Tg2576 mice, produced dose-dependent increases in brain inhibitor concentrations (0.2-13 μm). BACE1 inhibition significantly reversed the behavioral deficit in contextual fear conditioning, and reduced brain Aβ levels, plaque burden, and associated pathology (e.g., dystrophic neurites), with maximal effects attained with ∼1 μg/d dose. Strikingly, the BACE1 inhibitor also reversed amyloid pathology below baseline levels (amyloid burden at the start of treatment), without adversely affecting cerebral amyloid angiopathy, microhemorrhages, myelination, or neuromuscular function. Inhibitor-mediated decline in brain amyloid pathology was associated with an increase in microglial ramification. This is the first demonstration of chronically administered BACE1 inhibitor to activate microglia, reverse brain amyloid pathology, and elicit functional improvement in an aged transgenic mouse model. Thus, engagement of novel glial-mediated clearance mechanisms may drive disease-modifying therapeutic benefit with BACE1 inhibition in AD.

It is now well known that in the mammalian body vitamin D is converted by successive hydroxylations to 1,25‐dihydroxyvitamin D (1,25D), a steroid‐like hormone with pleiotropic properties. These include important contributions to the control of cell proliferation, survival and differentiation, as well as the regulation of immune responses in disease. Here, we present recent advances in current understanding of the role of 1,25D in myelopoiesis and lymphopoiesis, and the potential of 1,25D and analogs (vitamin D derivatives; VDDs) for the control of hematopoietic malignancies. The reasons for the unimpressive results of most clinical studies of the therapeutic effects of VDDs in leukemia and related diseases may include the lack of a precise rationale for the conduct of these studies. Further, clinical trials to date have generally used extremely heterogeneous patient populations and, in many cases, small numbers of patients, generally without controls. Although low calcemic VDDs have been used and combined with agents that can increase the leukemia cell killing or differentiation effects in acute leukemias, the sequencing of agents used for combination therapy should to be more clearly delineated. Most importantly, it is recommended that in future clinical trials the rationale for the basis of the enhancing action of drug combinations should be clearly articulated and the effects on anticancer immunity should also be evaluated. J. Cell. Biochem. 116: 1500–1512, 2015. © 2015 Wiley Periodicals, Inc.

Arabinocytosine (AraC, also known as cytarabine) is one of the mainstays of AML therapy, but like other DNA damaging therapeutic agents it is rarely curative by itself. There is an emerging realization that the therapeutic outcomes may be improved by combining AraC with other compounds. Here we report that the addition of, a differentiating agent combination immediately following AraC damage to AML blasts, selectively increases the cell kill. The experiments were performed using cultured cells from established cell lines of AML (HL60 and U937). The cells were exposed to 100 nM AraC, a concentration which produced approximately 25-50% cell kill, followed by a combination of 100 nM 1alpha-hydroxyvitamin D2 (1-D2) and 10 mu M carnosic acid (CA), which together can serve as a powerful differentiating agent combination for AML cells, but are not toxic alone. AraC-induced cell death, measured by annexin V/propidium iodide, was significantly (p < 0.01) increased by the 1-D2/CA combination in both cell lines, but not by 1-D2 or CA alone. The enhancement of cell death occurred by both apoptosis and necrosis, was associated with increased DNA damage and with higher levels of DNA damage response (DDR) activated marker Chk1, but the expression of p27, a cell cycle inhibitor protein, was not enhanced by 1-D2/CA. The principal finding is that a vitamin D analog 1-D2 combined with a plant-derived antioxidant CA can markedly augment the cytotoxic action of AraC, an anti-leukemia therapeutic agent. (C) 2015 Elsevier Ltd. All rights reserved.