Persistence of Chronic Lymphocytic Leukemia Stem-like Populations under Simultaneous In Vitro Treatment with Curcumin, Fludarabine, and Ibrutinib: Implications for Therapy Resistance.

Leukemic stem cells (LSCs) possess similar characteristics to normal hematopoietic stem cells, including self-renewal capacity, quiescence, ability to initiate leukemia, and drug resistance. These cells play a significant role in leukemia relapse, persisting even after apparent remission. LSCs were first described in 1994 by Lapidot et al. Although they have been extensively studied in acute leukemia, more LSC research is still needed in chronic lymphocytic leukemia (CLL) to understand if reduced apoptosis in mature cells should still be considered as the major cause of this disease. Here, we provide new evidence suggesting the existence of stem-like cell populations in CLL, which may help to understand the disease as well as to develop effective treatments. In this study, we identified a potential leukemic stem cell subpopulation using the tetraploid CLL cell line I83. This subpopulation is characterized by diploid cells that were capable of generating the I83 tetraploid population. Furthermore, we adapted a novel flow cytometry analysis protocol to detect CLL subpopulations with stem cell properties in peripheral blood samples and primary cultures from CLL patients. These cells were identified by their co-expression of CD19 and CD5, characteristic markers of CLL cells. As previously described, increased alkaline phosphatase (ALP) activity is indicative of stemness and pluripotency. Moreover, we used this method to investigate the potential synergistic effect of curcumin in combination with fludarabine and ibrutinib to deplete this subpopulation. Our results confirmed the effectiveness of this ALP-based analysis protocol in detecting and monitoring leukemic stem-like cells in CLL. This analysis also identified limitations in eradicating these populations using in vitro testing. Furthermore, our findings demonstrated that curcumin significantly enhanced the effects of fludarabine and ibrutinib on the leukemic fraction, exhibiting synergistic effects (combination drug index, CDI 0.97 and 0.37, respectively). Our results lend support to the existence of potential stem-like populations in CLL cell lines, and to the idea that curcumin could serve as an effective adjuvant in therapies aimed at eliminating these populations and improving treatment efficacy.

Homocysteine, C-reactive protein, lipid peroxidation and mortality in haemodialysis patients.

BACKGROUND: Cardiovascular disease (CVD) is common in haemodialysis patients with chronic renal insufficiency and is the leading cause of death. The accelerated state of atherosclerosis found in these patients is due to a combination of different mechanisms. Recent studies confirm that inflammation plays an important role in the development of atherosclerosis. However, the role of hyperhomocysteinaemia and the immune response to oxidation of low-density lipoproteins (LDL) remains unclear and studies show contradictory results. The objective of this study was to determine whether there is a relationship between inflammation, hyperhomocysteinaemia and oxidative stress and whether these CVD risk factors are predictors of mortality in haemodialysis patients. METHODS: A prospective follow-up study was carried out in 94 stable, chronic haemodialysis patients for 24 months (July 1999-July 2001). All the patients were given folic acid and vitamin B complex supplements. Homocysteine was determined by fluorescence polarization immunoassay. C-reactive protein (CRP) levels were determined by chemiluminescent enzyme-labelled immunometric assay. Plasma copper oxidized anti-LDL (oxLDL) antibodies were measured by ELISA using native LDL and oxLDL as antigens. RESULTS: Thirty-two patients died during the study and 59.3% of the deaths could be attributed to CVD (eight to acute myocardial infarction and 11 to non-coronary vascular disease). The patients had slight hyperhomocysteinaemia (25.8 +/- 7.82 micromol/l), evidence of inflammation (CRP 5.16 mg/l (0.35-88.7)) and oxidative stress (oxLDL antibodies = 162 +/- 77 optical density at 495 nm x 1000). Age (P < 0.01), CRP (P = 0.03) and the oxLDL antibody titre (P < 0.01) were predictive of mortality. The patients who died from heart disease showed higher oxLDL antibody titres (P = 0.03). No correlation was found between homocysteine, CRP and the oxLDL antibody titre, or between serum homocysteine levels and the different causes of mortality. CONCLUSIONS: These results suggest that lipid peroxidation and inflammation, but not hyperhomocysteinaemia, are the main risk factors for mortality in haemodialysis patients receiving vitamin supplements. As the study was carried out in a relatively limited number of patients, our findings need to be confirmed in a larger patient population.