Drug-associated disease: hematologic dysfunction

The Relationship of Drug Therapy to Aplastic Anemia in Pakistan: A Hospital-Based Case Control Study

Introduction

Drug-induced aplastic anemia has long been a menacing outcome of modern pharmacotherapy. The incidence of idiosyncratic, drug-induced aplastic anemia varies depending on the genetic susceptibility and the associated drug. Only scarce studies have explained the epidemiology and actual incidence of this reaction.

Purpose

The aim of the study was to establish the association between drugs and aplastic anemia.

Methods

A case-control study was conducted with 191 cases and 696 controls at a tertiary hospital for blood diseases in Karachi-Pakistan. Cases were patients of aplastic anemia diagnosed through bone marrow biopsy. The controls did not have either AA or chronic diseases. Each case was paired with four sex and age group match controls. Cases and controls were compared with respect to the drugs used. Univariate and multivariate analysis were performed in order to delineate the association.

Results

Median age of the study-participants was 27 years (04-69 years). The majority 84 (44%) were from age group 16 to 30 years. The male-to-female ratio was 2:1. Among study participants, various drugs were significantly associated with aplastic anemia. Treatment of epilepsy with carbamazepine showed a positive association (OR=2.7, 95% C.I, 1.0-6.8). An increased risk of aplastic anemia was noted with exposure to thiazide (OR=3.1, 95% C.I, 1.3-7.4) and mebendazole (OR=3.7, 95% C.I, 1.5-9.2). However, risks were not increased with chloramphenicol, trimethoprim/sulfamethoxazole, benzodiazepines, antihistamines, oral contraceptives, and herbal medicine.

Conclusion

This large-scale case-control study provide association of aplastic anemia with exposure to carbamazepine, thiazides and mebendazole in population of Pakistan. Patients should be monitored with complete blood indices for early detection of drug toxicity.

Evolving Role of Pharmacogenetic Biomarkers to Predict Drug-Induced Hematological Disorders

ABSTRACT

Drug-induced hematological disorders constitute up to 30% of all blood dyscrasias seen in the clinic. Hematologic toxicity from drugs may range from life-threatening marrow aplasia, agranulocytosis, hemolysis, thrombosis to mild leukopenia, and thrombocytopenia. Pathophysiologic mechanisms underlying these disorders vary from an extension of the pharmacological effect of the drug to idiosyncratic and immune-mediated reactions. Predicting these reactions is often difficult, and this makes clinical decision-making challenging. Evidence supporting the role of pharmacogenomics in the management of these disorders in clinical practice is rapidly evolving. Despite the Clinical Pharmacology Implementation Consortium and Pharmacogenomics Knowledge Base recommendations, few tests have been incorporated into routine practice. This review aims to provide a comprehensive summary of the various drugs which are implicated for the hematological adverse events, their underlying mechanisms, and the current evidence and practical recommendations to incorporate pharmacogenomic testing in clinical care for predicting these disorders.

The molecular basis of immune-based platelet disorders

Platelets have a predominant role in haemostasis, the maintenance of blood volume and emerging roles as innate immune cells, in wound healing and in inflammatory responses. Platelets express receptors that are important for platelet adhesion, aggregation, participation in inflammatory responses, and for triggering degranulation and enhancing thrombin generation. They carry a cargo of granules bearing enzymes, adhesion molecules, growth factors and cytokines, and have the ability to generate reactive oxygen species. The platelet is at the frontline of a host of cellular responses to invading pathogens, injury, and infection. Perhaps because of this intrinsic responsibility of a platelet to rapidly respond to thrombotic, pathological and immunological factors as part of their infantry role; platelets are susceptible to targeted attack by the adaptive immune system. Such attacks are often transitory but result in aberrant platelet activation as well as significant loss of platelet numbers and platelet function, paradoxically leading to elevated risks of both thrombosis and bleeding. Here, we discuss the main molecular events underlying immune-based platelet disorders with specific focus on events occurring at the platelet surface leading to activation and clearance.

Iron in infection and immunity

Iron is an essential micronutrient for virtually all living cells. In infectious diseases, both invading pathogens and mammalian cells including those of the immune system require iron to sustain their function, metabolism and proliferation. On the one hand, microbial iron uptake is linked to the virulence of most human pathogens. On the other hand, the sequestration of iron from bacteria and other microorganisms is an efficient strategy of host defense in line with the principles of 'nutritional immunity'. In an acute infection, host-driven iron withdrawal inhibits the growth of pathogens. Chronic immune activation due to persistent infection, autoimmune disease or malignancy however, sequesters iron not only from infectious agents, autoreactive lymphocytes and neoplastic cells but also from erythroid progenitors. This is one of the key mechanisms which collectively result in the anemia of chronic inflammation. In this review, we highlight the most important interconnections between iron metabolism and immunity, focusing on host defense against relevant infections and on the clinical consequences of anemia of inflammation.

Aplastic anemia in a patient with advanced lung adenocarcinoma during first line osimertinib: A case report and literature review

OBJECTIVES

Osimertinib is a third-generation, irreversible tyrosine kinase inhibitor of the epidermal growth factor receptor (EGFR-TKI) showing longer progression free survival and overall survival than other EGFR-TKI with an improvement in tolerability.

MATERIALS AND METHODS

We report about an advanced lung adenocarcinoma patient with severe aplastic anemia during first line osimertinib.

RESULTS AND CONCLUSION

Severe hematologic toxicity is extremely rare but possible with osimertinib and clinicians should be careful about changes in blood cell count during the use of it.

Role of epigenetic mechanisms in cisplatin-induced toxicity

Cisplatin (CDDP) is a highly effective antineoplastic agent, widely used in the treatment of various malignant tumors. However, its major problems are side effects associated to toxicity. Considerable inter-individual differences have been reported for CDDP-induced toxicity due to genetic and epigenetic factors. Genetic causes are well described; however, epigenetic modifications are not fully addressed. In the last few years, many evidences were found linking microRNA to the development of CDDP-mediated toxicity, particularly nephrotoxicity. In this review, we described how genetic and epigenetic modifications can be important determinants for the development of toxicity in patients treated with CDDP, and how these alterations may be interesting biomarkers for monitoring toxicity induced by CDDP. Considering the validation in different studies, we suggest that miR-34a, -146b, -378a, -192, and -193 represent an attractive study group to evaluate potential biomarkers to detect CDDP-related nephrotoxicity.

Emergency Medicine Evaluation and Management of Anemia

Anemia is a common condition and is diagnosed on laboratory assessment. It is defined by abnormally low hemoglobin concentration or decreased red blood cells. Several classification systems exist. Laboratory markers provide important information. Acute anemia presents with symptoms owing to acute blood loss; chronic anemia may present with worsening fatigue, dyspnea, lightheadedness, or chest pain. Specific treatments depend on the underlying anemia and etiology. Iron is an alternative treatment for patients with microcytic anemia owing to iron deficiency. Hyperbaric oxygen is an option for alternative rescue therapy. Most patients with chronic anemia may be discharged with follow-up if hemodynamically stable.

Unfolding the mechanism of cisplatin induced pathophysiology in spleen and its amelioration by carnosine

cis-Diamminedichloroplatinum (cisplatin) is an effective chemotherapeutic and is widely used for the treatment of various types of solid tumors. Bio-distribution of cisplatin to other organs due to poor targeting towards only cancer cells constitutes the backbone of cisplatin-induced toxicity. The adverse effect of this drug on spleen is not well characterized so far. Therefore, we have set our goal to explore the mechanism of the cisplatin-induced pathophysiology of the spleen and would also like to evaluate whether carnosine, an endogenous neurotransmitter and antioxidant, can ameliorate this pathophysiological response. We found a dose and time-dependent increase of the pro-inflammatory cytokine, TNF-α, in the spleen tissue of the experimental mice exposed to 10 and 20 mg/kg body weight of cisplatin. The increase in inflammatory cytokine can be attributed to the activation of the transcription factor, NF-ĸB. This also aids in the transcription of other pro-inflammatory cytokines and cellular adhesion molecules. Exposure of animals to cisplatin at both the doses resulted in ROS and NO production leading to oxidative stress. The MAP Kinase pathway, especially JNK activation, was also triggered by cisplatin. Eventually, the persistence of inflammatory response and oxidative stress lead to apoptosis through extrinsic pathway. Carnosine has been found to restore the expression of inflammatory molecules and catalase to normal levels through inhibition of pro-inflammatory cytokines, oxidative stress, NF-ĸB and JNK. Carnosine also protected the splenic cells from apoptosis. Our study elucidated the detailed mechanism of cisplatin-induced spleen toxicity and use of carnosine as a protective agent against this cytotoxic response.

Active exercise in critically ill adults affected by thrombocytopaenia

Introduction

Thrombocytopaenia (TCP), or low platelet count, is a haematological disorder that commonly occurs in critically ill patients and is defined as a platelet count below 100 000/μL. Patients are at higher risk of muscular atrophy and other complications after prolonged bed rest. This literature review aims to clarify the appropriateness of active exercise in critically ill adult patients with TCP.

Methods

A review of the literature was conducted using the following key words that are PubMed medical subheading (MeSH) terms: ‘critical illness’, ‘exercise therapy’, ‘manual therapy’, ‘physical therapy’, ‘physiotherapy’, ‘postoperative care’, ‘rehabilitation’, ‘thrombocytopenia’, and ‘thrombopenia’. The search was limited by publication date (2000 to 2013) and language (English only) in three main databases: PubMed, SCOPUS, and CINAHL.

Results

The key word searches found a total of 78 citations. Of these, only those meeting the inclusion criteria were selected after reading the title and abstract. Two studies were included after reading the full-texts. Exercise is used to treat muscular atrophy in critically ill adult patients, and rehabilitation plays an important role in the care pathway. Results of our analysis do not support evidence for or against exercise in critically ill adult patients with TCP; therefore, health professionals must pay close attention to the presence of signs of bleeding in these patients when proposing exercise.

Discussion

Surprisingly, no study was found that directly covered this issue. Aggressive exercise may not be appropriate in patients with very low platelet counts. On the other hand, critically ill patients are at high risk of muscular atrophy due to the forced bed rest, especially after complex surgery or in prolonged hospitalisation. Physiotherapists and those providing care must share their observations with the rest of the multidisciplinary team before treatment starts.

Conclusions

Active exercise in critically ill adult patients with severe TCP must be personalised and platelet count carefully monitored before proposing physical activity. Physical recovery can be challenging in critically ill adult patients, and it can be limited by severe TCP, mostly when bleeding is present.

Specific hemosiderin deposition in spleen induced by a low dose of cisplatin: altered iron metabolism and its implication as an acute hemosiderin formation model

Cisplatin is one of the commonly-used chemotherapeutic drugs to efficiently treat malignant tumors in clinic, however, the adverse effects of cisplatin such as nephrotoxicity, neurotoxicity, and hemolytic uremic syndrome are often observed at its clinical doses (approximately 60 mg/m(2)), which limit its broader application. In earlier studies, little attention was paid to the subtle changes in the architecture of lymphatic organs after low doses of cisplatin treatment. This paper reviews current understanding of cisplatin-induced erythrocyte injury, and presents our latest finding that a low dose of cisplatin (3.6 mg/m(2)/day, 14 days) could induce specific hemosiderin deposition in spleen of both normal and hepatoma-22 (H22) inoculated Balb/C mice. This dose of cisplatin significantly inhibited H22-induced acute ascites development. No significant toxicity was induced by this dose of cisplatin to tissues except for hemosiderin accumulation in the spleen of both normal and H22 tumor-bearing mice. Increased splenic iron content and erythrocyte injury were observed after treatment with the low dose of cisplatin. The mRNA levels of ferroportin (FPN1) and ferritin were upregulated by 25 and 5-fold in spleen, respectively. Overexpression of FPN1 and ferritin protein were also been observed at protein levels by Western blotting analysis. In addition, the mRNA expression of hepcidin was also increased, suggesting blockage of iron recycling through FPN1 in spleen with cisplatin treatment. In conclusion, cisplatin treatment damages the erythrocytes which accumulate in the red pulp of spleen with defective recycling of FPN1 and ferritin protein. Hepcidin inhibits the function of FPN1 as iron-exporter leading to iron overloaded inside ferritins of splenic cells, which are stained with abnormal hemosiderin accumulation. These results demonstrate that cisplatin-caused hemosiderin deposition in spleen provides a valuable clue for understanding the molecular basis of toxicity of cisplatin and hemosiderin accumulation and iron metabolism in vivo.

Drug-induced Hemolytic Anemia and Thrombocytopenia Associated with Alterations of Cell Membrane Lipids and Acanthocyte Formation

CXCR3 is a chemokine receptor, upregulated upon activation of T cells and expressed on nearly 100% of T cells in sites of inflammation. SCH 900875 is a selective CXCR3 receptor antagonist. Thrombocytopenia and severe hemolytic anemia with acanthocytosis occurred in rats at doses of 75, 100, and 150 mg/kg/day. Massively enlarged spleens corresponded histologically to extramedullary hematopoiesis, macrophages, and hemosiderin pigment and sinus congestion. Phagocytosed erythrocytes and platelets were within splenic macrophages. IgG and/or IgM were not detected on erythrocyte and platelet membranes. Ex vivo increased osmotic fragility of RBCs was observed. Lipid analysis of the RBC membrane revealed modifications in phosphatidylcholine, overall cholesterol, and/or sphingomyelin. Platelets exhibited slender filiform processes on their plasma membranes, analogous to those of acanthocytes. The presence of similar morphological abnormalities in acanthocytes and platelets suggests that possibly similar alterations in the lipid composition of the plasma membrane have taken place in both cell types. This phenotype correlated with alterations in plasma lipids (hypercholesterolemia and low triglycerides) that occurred after SCH 900875 administration, although other factors cannot be excluded. The increased cell destruction was considered triggered by alterations in the lipid profile of the plasma membranes of erythrocytes and platelets, as reflected morphologically.

Suicidal erythrocyte death triggered by cisplatin

Cisplatin, a cytotoxic drug for the treatment of cancer, induces suicidal death or apoptosis of nucleated cells. Side effects of cisplatin include anemia, which, at least in theory, could similarly result from suicidal cell death. Erythrocyte suicidal death or eryptosis is characterized by cell shrinkage and cell membrane scrambling, the latter leading to exposure of phosphatidylserine (PS) at the cell surface. PS-exposing cells are rapidly cleared from circulating blood. The present experiments explored whether cisplatin could trigger eryptosis. According to forward scatter in FACS analysis, a 48 h exposure to cisplatin (> or =1 microM) indeed decreased cell volume and, according to annexin V-binding, cisplatin (> or =1 microM, 48 h) indeed increased PS exposure at the cell surface. Cisplatin did not induce hemolysis. According to Fluo3 fluorescence, cisplatin increased cytosolic Ca2+ activity, a known stimulator of eryptosis. In the absence of extracellular Ca2+, the effect of cisplatin on annexin V-binding was blunted. Cisplatin did not significantly modify the formation of ceramide, another stimulator of eryptosis. Cisplatin moderately decreased the cellular concentration of ATP, which is known to favour eryptosis. In conclusion, cisplatin triggers suicidal erythrocyte death at least partially by increasing cytosolic Ca2+ activity. The effect contributes to or even accounts for the development of anemia during cisplatin treatment.

Toxicity as a result of immunostimulation by biologics

The immune system has evolved highly effective mechanisms of surveillance and defense against foreign pathogens, and is also thought to act in surveillance and suppression of cancer. Thus, a predominant goal of immune system-based therapies is to normalize or enhance the host immune response in the areas of infectious disease and oncology. This review considers general approaches used for therapeutic immunostimulation, alterations in immune response mechanisms that occur with these treatments and the syndromes that commonly arise as a result of these changes. Because nonclinical studies of these therapies are conducted in animal models as the basis for predicting potential human toxicities, this review also considers the value of nonclinical testing to predict human toxicity.

Case report: cefazolin-induced hemolytic anemia

Antibiotic-induced hemolytic anemia is a rare complication. Prophylactic cephalosporins are widely used in patients having orthopaedic procedures. When there is a precipitous drop in hemoglobin levels, it is important for the clinician to consider the possibility of drug-induced anemia when other causes of blood loss have been excluded. We present a patient with no prior drug allergies who had antibiotic-induced hemolytic anemia develop after total knee arthroplasty.