Biocompatibility and toxicity of novel iron chelator Starch-Deferoxamine (S-DFO) compared to zinc oxide nanoparticles to zebrafish embryo

Abstract

Objectives

Clinically approved iron chelators are effective in decreasing significant transfusional iron accumulation. Starch-Deferoxamine (S-DFO), a novel high molecular weight iron chelator, was produced to increase binding capacity to iron and reduce toxicity. Although its efficacy was established in one small cohort clinical trial, its potential adverse effect was not adequately addressed.

Methods

We utilized zebrafish model to assess S-DFO toxicity using following assays: mortality, teratogenicity, hatching rate, tail flicking, Acridine Orange staining for apoptosis detection, o-dianisidine staining for hemoglobin synthesis, and the level of Hsp70 as a general stress indicator. Embryos were exposed to different concentrations of S-DFO, Zinc Oxide nanoparticle (ZnO) (positive control), along with untreated control (UC).

Results

S-DFO showed no significant mortality nor deformities at all tested concentrations (0.0–1000 μM). Thus, the LC50 is expected to >1000 μM. 100 μM S-DFO treatment did not affect embryo development (as judged by hatching rate); neuromuscular activity (as judged by tail flicking); and hemoglobin synthesis. Neither apoptosis, nor increase in Hsp70 level was noticed upon S-DFO treatment.

Conclusion

Our assays demonstrate that S-DFO does not induce cellular or biochemical stress and has no adverse effect on organ development of zebrafish embryos, suggesting its safe use as an iron chelator.https://www.sciencedirect.com/science/article/abs/pii/S0892036218301338

Role of Zebrafish in medical research

In biomedical research always it is a challenge to find an experimental model to test various innovative drugs. In modern-day hematology, research zebrafish demonstrated its suitability and complex nature of known physiological functions of zebrafish has some resemblance to humans that makes these tiny fish in the forefront of cutting edge modern research. The blood of zebrafish is curious if we look at the RBC. In human RBC in peripheral blood is non-nucleated cells, but in these tiny fish blood has nucleated  RBCs. Zebrafish are commonly used as a vertebrate model to study multiple human diseases including cardiovascular disease. Zebrafish model is suitable for drug discovery research because its genome is homologous to the human genome by 70%. Besides, zebrafish develop rapidly during a short period where reaches to adulthood phase. In research zebrafish embryos and adult zebrafish are widely used to study metabolic and neurological functions.

Zebrafish larvae as a model to demonstrate secondary iron overload

Abstract

Objectives

Thalassemia is the most common genetically inherited blood disorder arising from a defect in hemoglobin production, resulting in ineffective erythropoiesis and severe hemolytic anemia. While transfusion therapy corrects the anemia, it gives rise to secondary iron overload. Current iron chelation therapy performed using deferoxamine, and the efficiency of this drug was demonstrated here using the zebrafish animal model.

Methods

Zebrafish larvae were exposed for 3 days to iron [100 μmol L−1 ferric ammonium citrate; 3‐6 days post fertilization (dpf)]. Then, iron treated larvae were exposed to 100 μmol L−1 deferoxamine for 3 days (6‐9 dpf). Total tissue iron concentration in the whole larvae, assessed by three different assays; inductively coupled plasma mass spectrometry, colorimetry (spectrophotometry), and microscopy using iron staining followed by imaging and quantification.

Results

The three assays showed that iron treatment alone resulted in a significant increase in total iron. Deferoxamine treatment of the iron‐loaded zebrafish larvae showed a significant decrease in total iron concentration.

Conclusion

This study presented a clear evidence of the effectiveness of zebrafish larvae to use as a tool to study iron overload and open the door for studying the efficiency of potential new iron chelating compounds other than commercially available ones.https://onlinelibrary.wiley.com/doi/abs/10.1111/ejh.13035

Time Dependent Assessment of Morphological Changes: Leukodepleted Packed Red Blood Cells Stored in SAGM

Usually packed red blood cells (pRBCs) require specific conditions in storage procedures to ensure the maximum shelf life of up to 42 days in 2–6°C. However, molecular and biochemical consequences can affect the stored blood cells; these changes are collectively labeled as storage lesions. In this study, the effect of prolonged storage was assessed through investigating morphological changes and evaluating oxidative stress. Samples from leukodepleted pRBC in SAGM stored at 4°C for 42 days were withdrawn aseptically on day 0, day 14, day 28, and day 42. Morphological changes were observed using scanning electron microscopy and correlated with osmotic fragility and hematocrit. Oxidative injury was studied through assessing MDA level as a marker for lipid peroxidation. Osmotic fragility test showed that extended storage time caused increase in the osmotic fragility. The hematocrit increased by 6.6% from day 0 to day 42. The last 2 weeks show alteration in the morphology with the appearance of echinocytes and spherocytes. Storage lesions and morphological alterations appeared to affect RBCs during the storage period. Further studies should be performed to develop strategies that will aid in the improvement of stored pRBC quality and efficacy. http://www.hindawi.com/journals/bmri/2016/4529434/

 

Incidence of blood groups among blood donors in Maldives

Prevalence of blood groups among different ethnic groups have variation in different part of the world. There is no published data about the prevalence of blood groups in Maldives. The data shown here is the incidence trend among blood donors in blood bank at Maldivian Blood Services. As expected O Rh+ blood group is most common blood group among Maldivians.

Blood group

Cancer Awareness Program in Hulhmeedhoo

Cancer is alarmingly increasing in Hulhumeedho for the last decade the data shows.

Cancer awareness workshop held in Adducity Hulhumeedhoo on 22-23rd June 2012. The target audience was women of age group 21-45. The areas covered on this workshop were introduction of cancer, and common predisposing factors for cancer. Major areas covered among most common female cancers were cervical cancer, uterine and breast cancer.

The Crisis of Iron in Transfusion Medicine: Improved Iron Chelation Therapy and its Implications For Clinical Practice in the Maldives

Name: Ibrahim Mustafa

Date: Monday, July 18, 2011 at 9:00 AM

Place: Room 203 of the Graduate Student Centre

Abstract
The Maldives has one of the highest incidences of ß thalassemia in the world. Treatment of ß thalassemia is characterized by two distinct phases: treatment of nature’s disease (anemia) and the secondary treatment of transfusional iron overload, a side effect of our cure. Interestingly, excess iron may also exert a negative effect on immune competence thus explaining the recurrent bacterial infections in these patients. Current iron chelation therapy using DesferalÒ (DFO) is challenging due to its short vascular half-life, frequency of injections, toxicity and expense. To address this problem, we have tested novel, low toxicity, high molecular weight (HMW) iron chelators. The utility of these chelators was tested in vitro using iron loaded (0-500 μM ferric (Fe3+) ammonium citrate, FAC; 0- 48 hours) HepG2 and dendritic cells (DC). Iron chelation studies utilized either single or combinational treatment with deferiprone (L1) or DFO (both low molecular weight chelators) and S-DFO (a HMW derivative of DFO) for 0-48 hrs. The efficacy of treatment was assessed by cellular ferritin, Perl’s iron stain, transmission electron microscopy (TEM), antigen presentation assays and cell viability assays. Iron treatment alone resulted in a significant increase in intracellular ferritin, histochemical iron staining and also resulted in a ~65.2% reduction in PBMC proliferation in response to the tetanus toxoid following 14 days of incubation.

Treatment with either L1 or S-DFO alone demonstrated modestly decreased ferritin levels and iron staining. Importantly, combination therapy (L1+S-DFO), resulted in an additive effect resulting in a 79% decrease in FAC-driven ferritin levels after 48 hours and TEM studies of FAC treated, but not control, cells.  FAC treated cells also demonstrated organellular and structural changes with electron dense iron deposits. As hypothesized, iron chelators (e.g., 200 μM DFO or L1) restored the PBMC proliferation in a concentration dependent manner and reversed the ultra structural changes in organelles. The development of HMW chelators may provide better therapeutic value (less toxic and less frequent administration) in developing nations. Consequent to this, iron mediated pathology in patients would be diminished resulting in less cost to already strained public health budgets such as in Maldives.

http://www.pathology.ubc.ca/pathology/News.htm