Early detection of cardiac involvement in thalassemia: From bench to bedside perspective

Myocardial siderosis is known as the major cause of death in thalassemia major(TM) patients since it can lead to iron overload cardiomyopathy.Although this condition can be prevented if timely effective intensive chelation is given to patients,the mortality rate of iron overload cardiomyopathy still remains high due to late detection of this condition.Various direct and indirect methods of iron assessment,including serum ferritin level,echocardiogram,non-transferrin-bound iron,cardiac magnetic resonance T2*,heart rate variability,and liver biopsy and myocardial biopsy,have been proposed for early detection of cardiac iron overload in TM patients.However,controversial evidence and limitations of their use in clinical practice exist.In this review article,all of these iron assessment methods that have been proposed or used to directly or indirectly determine the cardiac iron status in TM reported from both basic and clinical studies are comprehensively summarized and presented.Since there has been growing evidence in the past decades that cardiac magnetic resonance imaging as well as cardiac autonomic status known as the heart rate variability can provide early detection of cardiac involvement in TM patients,these two methods are also presented and discussed.The existing controversy regarding the assessment of cardiac involvement in thalassemia is also discussed.

Hyperhomocysteinemia dysregulates plasma levels of polyunsaturated fatty acids-derived eicosanoids

Hyperhomocysteinemia(HHcy)contributes to the incidence of many cardiovascular diseases(CVD).Our group have previously established crucial roles of eicosanoids and homocysteine in the incidence of vascular injury in diabetic retinopathy and renal injury.Using cystathionine-β-synthase heterozygous mice(cβs^(+/-))as a model of HHcy,the current study was designed to determine the impact of homocysteine on circulating levels of lipid mediators derived from polyunsaturated fatty acids(PUFA).Plasma samples were isolated from wild-type(WT)and cβs^(+/-)mice for the assessment of eicosanoids levels using LC/MS.Plasma 12/15-lipoxygenase(12/15-LOX)activity significantly decreased in cβs^(+/-)vs.WT control mice.LOX-derived metabolites from both omega-3 and omega-6 PUFA were also reduced in cβs^(+/-)mice compared to WT control(P<0.05).Contrary to LOX metabolites,cytochrome P450(CYP)metabolites from omega-3 and omega-6 PUFA were significantly elevated in cβs^(+/-)mice compared to WT control.Epoxyeicosatrienoic acids(EETs)are epoxides derived from arachidonic acid(AA)metabolism by CYP with anti-inflammatory properties and are known to limit vascular injury,however their physiological role is limited by their rapid degradation by soluble epoxide hydrolase(sEH)to their corresponding diols(DiHETrEs).In cβs^(+/-)mice,a significant decrease in the plasma EETs bioavailability was obvious as evident by the decrease in EETs/DiHETrEs ratio relative to WT control mice.Cyclooxygenase(COX)metabolites were also significantly decreased in cβs^(+/-)vs.WT control mice.These data suggest that HHcy impacts eicosanoids metabolism through decreasing LOX and COX metabolic activities while increasing CYP metabolic activity.The increase in AA metabolism by CYP was also associated with increase in sEH activity and decrease in EETs bioavailability.Dysregulation of eicosanoids metabolism could be a contributing factor to the incidence and progression of HHcy-induced CVD.

Gasdermin D-mediated pyroptosis in myocardial ischemia and reperfusion injury:Cumulative evidence for future cardioprotective strategies

Cardiomyocyte death is one of the major mechanisms contributing to the development of myocardial infarction(MI)and myocardial ischemia/reperfusion(MI/R)injury.Due to the limited regenerative ability of cardiomyocytes,understanding the mechanisms of cardiomyocyte death is necessary.Pyroptosis,one of the regulated programmed cell death pathways,has recently been shown to play important roles in MI and MI/R injury.Pyroptosis is activated by damage-associated molecular patterns(DAMPs)that are released from damaged myocardial cells and activate the formation of an apoptosisassociated speck-like protein containing a CARD(ASC)interacting with NACHT,LRR,and PYD domains-containing protein 3(NLRP3),resulting in caspase-1 cleavage which promotes the activation of Gasdermin D(GSDMD).This pathway is known as the canonical pathway.GSDMD has also been shown to be activated in a non-canonical pathway during MI and MI/R injury via caspase-4/5/11.Suppression of GSDMD has been shown to provide cardioprotection against MI and MI/R injury.Although the effects of MI or MI/R injury on pyroptosis have previously been discussed,knowledge concerning the roles of GSDMD in these settings remains limited.In this review,the evidence from in vitro,in vivo,and clinical studies focusing on cardiac GSDMD activation during MI and MI/R injury is comprehensively summarized and discussed.Implications from this review will help pave the way for a new therapeutic target in ischemic heart disease.

Maternal milk ILCs and adaptive immune cells populate neonatal organs

How does the neonatal immune system decide which of the millions and millions of microbes it encounters during and soon after birth are commensal and which are pathological?This is not a trivial issue.Excessively vigorous responses to commensal bacteria cause unnecessary collateral tissue damage and loss of the potentially beneficial microbial flora needed for host metabolism.On the other hand,insufficient immune defense against invading,harmful,microbes is also very problematic,if not lethal.1 While the mechanisms for self-tolerance have been the subject of extensive investigations since the mid-1950s,such is not the case for selective unresponsiveness to commensal microbial flora residing on the skin or the mucosa of the gastrointestinal track.