Intercellular crosstalk shapes purinergic metabolism and signaling in cancer cells

CD73-derived adenosine suppresses anti-cancer immunity, and CD73 inhibitors are currently evaluated in several clinical trials. Here, we have assessed enzyme kinetics of all key purinergic ectoenzymes in five cancer cell lines (Hodgkin lymphoma, multiple myeloma, pancreas adenocarcinoma, urinary bladder carcinoma, and glioblastoma) under normoxia and hypoxia. We found that adenosine metabolism varied considerably between individual cancer types. All cell lines investigated exhibited high ecto-adenosine deaminase (ADA) activity, which critically influenced the kinetics of adenosine accumulation. Combining kinetics data with single-cell RNA sequencing data on myeloma and glioblastoma cancerous tissue revealed that purine metabolism is not homogeneously organized, but it differs in a cancer type-specific fashion between malignant cells, stromal cells, and immune cells. Since purine metabolism in cancerous tissue is most likely spatially heterogeneous and differs between the various cell types, diffusion distances in the microenvironment as well as ADA activity may be important variables that influence the level of bioactive adenosine.

Mechanism of pro-MMP9 activation in co-culture of pro-inflammatory macrophages and cardiomyocytes

OBJECTIVE

A wide range of cardiac diseases is associated with inflammation. "Inflamed" heart tissue is infiltrated with pro-inflammatory macrophages which extensively secrete matrix metalloproteinase 9 (MMP9), a regulator of extracellular matrix turnover. As MMP9 is released from macrophages in a latent form, it requires activation. The present study addresses the role of cardiomyocytes in the course of this activation process.

METHODS AND RESULTS

In mono- and co-cultures of pro-inflammatory rat macrophages (bone marrow-derived and peritoneal) and cardiomyocytes (H9C2 cell line) gelatin zymography demonstrated that activated macrophages robustly secreted latent pro-MMP9, whereas cardiomyocytes could not produce the enzyme. Co-culturing of the two cell species was critical for pro-MMP9 activation and was also accompanied by processing of cardiomyocyte-secreted pro-MMP2. A cascade of pro-MMP9 activation was initiated on macrophage membrane with pro-MMP2 cleavage. Namely, pro-inflammatory macrophages expressed an active membrane type 1 MMP (MT1MMP), which activated pro-MMP2, which in turn converted pro-MMP9. Downregulation of MT1MMP in macrophages by siRNA abolished activation of both pro-MMP2 and pro-MMP9 in co-culture. In addition, both cell species secreted MMP13 as a further pro-MMP9 activator. In co-culture, activation of pro-MMP13 occurred on membranes of macrophages and was enhanced in presence of active MMP2. Using incubations with recombinant MMPs and isolated macrophage membranes, we demonstrated that while both MMP2 and MMP13 individually had the ability to activate pro-MMP9, their combined action provided a synergistic effect.

CONCLUSION

Activation of pro-MMP9 in a co-culture of pro-inflammatory macrophages and cardiomyocytes was the result of a complex interaction of several MMPs on the cell membrane and in the extracellular space. Both cell types contributed critically to pro-MMP9 processing.

Live Cell Imaging of ATP Levels Reveals Metabolic Compartmentalization within Motoneurons and Early Metabolic Changes in FUS ALS Motoneurons

Motoneurons are one of the most energy-demanding cell types and a primary target in Amyotrophic lateral sclerosis (ALS), a debilitating and lethal neurodegenerative disorder without currently available effective treatments. Disruption of mitochondrial ultrastructure, transport, and metabolism is a commonly reported phenotype in ALS models and can critically affect survival and the proper function of motor neurons. However, how changes in metabolic rates contribute to ALS progression is not fully understood yet. Here, we utilize hiPCS-derived motoneuron cultures and live imaging quantitative techniques to evaluate metabolic rates in fused in sarcoma (FUS)-ALS model cells. We show that differentiation and maturation of motoneurons are accompanied by an overall upregulation of mitochondrial components and a significant increase in metabolic rates that correspond to their high energy-demanding state. Detailed compartment-specific live measurements using a fluorescent ATP sensor and FLIM imaging show significantly lower levels of ATP in the somas of cells carrying FUS-ALS mutations. These changes lead to the increased vulnerability of diseased motoneurons to further metabolic challenges with mitochondrial inhibitors and could be due to the disruption of mitochondrial inner membrane integrity and an increase in its proton leakage. Furthermore, our measurements demonstrate heterogeneity between axonal and somatic compartments, with lower relative levels of ATP in axons. Our observations strongly support the hypothesis that mutated FUS impacts the metabolic states of motoneurons and makes them more susceptible to further neurodegenerative mechanisms.

Targeting inflammation in hypertension

PURPOSE OF REVIEW

Hypertension remains a global health and socioeconomic burden. Immune mechanisms are now recognized as integral part of the multifactorial etiology of hypertension and related organ damage. The present review addresses inflammatory pathways and immune targets in hypertension, which may be important for an immunomodulatory treatment of hypertension aside from lowering arterial pressure.

RECENT FINDINGS

Anti-inflammatory interventions targeting single interleukins or almost the entire immune system show different beneficial effects. While immunomodulation (targeting specific portion of immune system) shows beneficial outcomes in certain groups of hypertensives, this does not pertain to immunosuppression (targeting entire immune system). Immunomodulatory interventions improve outcomes of hypertension independent of arterial pressure. The studies reveal interleukins, such as interleukin (IL)-1β and IL-17 as targets of immunomodulation. Besides interleukins, targeting αvβ-3 integrin and matrix metalloproteinase-2 or using experimental cell-therapy demonstrate beneficial effects in hypertensive organ damage. The NLR family pyrin domain containing 3 (NLRP3) inflammasome/IL-1β/endothelial cell/T-cell axis seems to be an important mediator in sustained inflammation during hypertension.

SUMMARY

Although immunomodulation may be advantageous as a causal therapy in hypertension, targeting immune networks rather than single interleukins appears of major importance. Further research is required to better identify these networks and their links to human hypertension.

Aprotinin does not Impair Vascular Function in Patients Undergoing Coronary Artery Bypass Graft Surgery

Bleeding is a major complication in coronary artery bypass graft surgery. Antifibrinolytic agents like serine protease inhibitor aprotinin can decrease postoperative bleeding and complications of cardiac surgery. However, the effects of aprotinin on vascular function are not completely elucidated. We compared the ex vivo vascular function of left internal mammary arteries from patients undergoing coronary artery bypass graft surgery with and without intraoperative application of aprotinin using a Mulvany Myograph. Human internal mammary arteries were treated with aprotinin ex vivo and tested for changes in vascular function. We analyzed the impact of aprotinin on vascular function in rat aortic rings. Finally, impact of aprotinin on expression and activity of endothelial nitric oxide synthase was tested in human endothelial cells. Intraoperative application of aprotinin did not impair ex vivo vascular function of internal mammary arteries of patients undergoing coronary artery bypass graft surgery. Endothelium-dependent and -independent relaxations were not different in patients with or without aprotinin after nitric oxide synthase blockade. A maximum vasorelaxation of 94.5%±11.4vs. 96.1%±5.5% indicated a similar vascular smooth muscle function in both patient groups (n=13 each). Long-term application of aprotinin under physiological condition preserved vascular function of the rat aorta. In vitro application of increasing concentrations of aprotinin on human endothelial cells resulted in a similar expression and activity of endothelial nitric oxide synthase. In conclusion, intraoperative and ex vivo application of aprotinin does not impair the endothelial function in human internal mammary arteries and experimental models.

Developmental endothelial locus-1 protects from hypertension-induced cardiovascular remodeling via immunomodulation

The causative role of inflammation in hypertension-related cardiovascular diseases is evident and calls for development of specific immunomodulatory therapies. We tested the therapeutic efficacy and mechanisms of action of developmental endothelial locus-1 (DEL-1), an endogenous antiinflammatory factor, in angiotensin II– (ANGII–) and deoxycorticosterone acetate–salt–induced (DOCA-salt–induced) cardiovascular organ damage and hypertension. By using mice with endothelial overexpression of DEL-1 (EC-Del1 mice) and performing preventive and interventional studies by injecting recombinant DEL-1 in mice, we showed that DEL-1 improved endothelial function and abrogated aortic adventitial fibrosis, medial thickening, and loss of elastin. DEL-1 also protected the mice from cardiac concentric hypertrophy and interstitial and perivascular coronary fibrosis and improved left ventricular function and myocardial coronary perfusion. DEL-1 prevented aortic stiffness and abolished the progression of hypertension. Mechanistically, DEL-1 acted by inhibiting α_vβ₃ integrin–dependent activation of pro-MMP2 in mice and in human isolated aorta. Moreover, DEL-1 stabilized α_vβ₃ integrin–dependent CD25⁺FoxP3⁺ Treg numbers and IL-10 levels, which were associated with decreased recruitment of inflammatory cells and reduced production of proinflammatory cytokines in cardiovascular organs. The demonstrated effects and immune-modulating mechanisms of DEL-1 in abrogation of cardiovascular remodeling and progression of hypertension identify DEL-1 as a potential therapeutic factor.

Overexpression of dimethylarginine dimethylaminohydrolase 1 protects from angiotensin II-induced cardiac hypertrophy and vascular remodeling

Cardiovascular complications are the leading cause of death, and elevated levels of asymmetric dimethyarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, are implicated in their pathophysiology. We investigated the role of dimethylarginine dimethylaminohydrolase 1 (DDAH1), an enzyme hydrolyzing ADMA, in prevention of cardiovascular remodeling during hypertension. We hypothesized that the animals overexpressing DDAH1 will be protected from angiotensin II (ANG II)-induced end organ damage. Angiotensin II (ANG II) was infused in two doses: 0.75 and 1.5 mg/kg/day in DDAH1 transgenic mice (DDAH1 TG) and wild-type (WT) littermates for 2 or 4 wk. Echocardiography was performed in the first and fourth weeks of the infusion, systolic blood pressure (SBP) was measured weekly, and cardiac hypertrophy and vascular remodeling was assessed by histology. Increase in SBP after 1 wk of ANG II infusion was not different between the groups, whereas TG mice had lower SBP at later time points. TG mice were protected from cardiovascular remodeling after 2 wk of ANG II infusion in the high dose and after 4 wk in the moderate dose. TG mice had higher left ventricular lumen-to-wall ratio, lower cardiomyocyte cross-sectional area, and less interstitial fibrosis compared with WT controls. In aorta, TG mice had less adventitial fibrosis, lower medial thickness with preserved elastin content, lower counts of inflammatory cells, lower levels of active matrix metalloproteinase-2, and showed better endothelium-dependent relaxation. We demonstrated that overexpression of DDAH1 protects from ANG II-induced cardiovascular remodeling and progression of hypertension by preserving endothelial function and limiting inflammation.NEW & NOTEWORTHY We showed that overexpression of dimethylarginine dimethylaminohydrolase 1 (DDAH1) protects from angiotensin II-induced cardiovascular damage, progression of hypertension, and adverse vascular remodeling in vivo. This protective effect is associated with decreased levels of asymmetric dimethylarginine, preservation of endothelial function, inhibition of cardiovascular inflammation, and lower activity of matrix metalloproteinase-2. Our findings are highly clinically relevant, because they suggest that upregulation of DDAH1 might be a promising therapeutic approach against angiotensin II-induced end organ damage.

Induction of Heme Oxygenase-1 Is Linked to the Severity of Disease in Human Abdominal Aortic Aneurysm

Background

Rupture of abdominal aortic aneurysm (rAAA) is associated with high case fatality rates, and risk of rupture increases with the AAA diameter. Heme oxygenase‐1 (gene HMOX1, protein HO‐1) is a stress‐induced protein and induction has protective effects in the vessel wall. HMOX1^−/− mice are more susceptible to angiotensin II‐induced AAA formation, but the regulation in human nonruptured and ruptured AAA is only poorly understood. Our hypothesis proposed that HO‐1 is reduced in AAA and lowering is inversely associated with the AAA diameter.

Methods and Results

AAA walls from patients undergoing elective open repair (eAAA) or surgery because of rupture (rAAA) were analyzed for aortic HMOX1/HO‐1 expression by quantitative real‐time polymerase chain reaction and Western blot. Aortas from patients with aortic occlusive disease served as controls. HMOX1/HO‐1 expression was 1.1‐ to 7.6‐fold upregulated in eAAA and rAAA. HO‐1 expression was 3‐fold higher in eAAA specimen with a diameter >84.4 mm, whereas HO‐1 was not different in rAAA. Other variables that are known for associations with AAA and HO‐1 induction were tested. In eAAA, HO‐1 expression was negatively correlated with aortic collagen content and oxidative stress parameters H₂O₂ release, oxidized proteins, and thiobarbituric acid reactive substances. Serum HO‐1 concentrations were analyzed in patients with eAAA, and maximum values were found in an aortic diameter of 55 to 70 mm with no further increase >70 mm, compared with <55 mm.

Conclusions

Aortic HO‐1 expression was increased in eAAA and rAAA. HO‐1 increased with the severity of disease but was additionally connected to less oxidative stress and vasoprotective mechanisms.

Characterization of tryptophan-containing dipeptides for anti-angiogenic effects

AIMS

In the pathogenesis of several diseases, neo-angiogenesis is increased (e.g. tumour growth). The peptide L-glutamyl-L-tryptophan (EW/IM862) has been claimed to exhibit inhibitory effects on tumour growth in vivo. However, the potential role of natural peptides with respect to anti-angiogenic properties is unsettled. The current study explores anti-angiogenic effects of the dipeptides WL, EW, IW and WE.

METHODS AND RESULTS

Using a bottom-up strategy, we first evaluated the effects of the peptides on VEGFR-2 signalling and quantified their effects in different angiogenesis assays. WL consistently had the strongest effects on phosphorylation of VEGFR-2 and downstream signalling. Therefore, this peptide was chosen in comparison with EW to further assess anti-angiogenic properties. However, sprout formation in three-dimensional (3D) fibrin gel bead assay was significantly inhibited by EW only. Furthermore, vessel sprouting in the mouse aortic ring assay was decreased by the presence of WL and EW compared to control. Results from a chorioallantoic membrane assay showed that under vascular endothelial growth factor (VEGF) stimulation WL and EW decreased the number of blood vessels versus control. These results were in line with those obtained in a matrigel plug assay. The VEGF-induced increase in the haemoglobin content was nearly abolished when treatment was combined with either WL or EW application. In the murine model of oxygen-induced retinopathy, WL exhibited a small albeit significant anti-angiogenic effect.

CONCLUSION

Comprehensive screening of WL suggests an anti-angiogenic effect, demonstrated in in vitro, ex vivo and in vivo models. Thus, WL is a dipeptide with potential anti-angiogenic effects and is worthy for further exploration.

The longevity gene mIndy (I'm Not Dead, Yet) affects blood pressure through sympathoadrenal mechanisms

Reduced expression of the plasma membrane citrate transporter INDY (acronym I’m Not Dead, Yet) extends life span in lower organisms. Deletion of the mammalian Indy (mIndy) gene in rodents improves metabolism via mechanisms akin to caloric restriction, known to lower blood pressure (BP) by sympathoadrenal inhibition. We hypothesized that mIndy deletion attenuates sympathoadrenal support of BP. Continuous arterial BP and heart rate (HR) were reduced in mINDY-KO mice. Concomitantly, urinary catecholamine content was lower, and the decreases in BP and HR by mIndy deletion were attenuated after autonomic ganglionic blockade. Catecholamine biosynthesis pathways were reduced in mINDY-KO adrenals using unbiased microarray analysis. Citrate, the main mINDY substrate, increased catecholamine content in pheochromocytoma cells, while pharmacological inhibition of citrate uptake blunted the effect. Our data suggest that deletion of mIndy reduces sympathoadrenal support of BP and HR by attenuating catecholamine biosynthesis. Deletion of mIndy recapitulates beneficial cardiovascular and metabolic responses to caloric restriction, making it an attractive therapeutic target.

Deletion of mIndy reduces blood pressure and heart rate by attenuating catecholamine biosynthesis and recapitulates beneficial cardiovascular and metabolic responses to caloric restriction.

Myeloid SOCS3 Deficiency Regulates Angiogenesis via Enhanced Apoptotic Endothelial Cell Engulfment

Mononuclear phagocytes, such as macrophages and microglia, are key regulators of organ homeostasis including vascularization processes. Here, we investigated the role of the suppressor of cytokine signaling 3 (SOCS3) in myeloid cells as a regulator of mononuclear phagocyte function and their interaction with endothelial cells in the context of sprouting angiogenesis. As compared to SOCS3-sufficient counterparts, SOCS3-deficient microglia and macrophages displayed an increased phagocytic activity toward primary apoptotic endothelial cells, which was associated with an enhanced expression of the opsonin growth arrest-specific 6 (Gas6), a major prophagocytic molecule. Furthermore, we found that myeloid SOCS3 deficiency significantly reduced angiogenesis in an ex vivo mouse aortic ring assay, which could be reversed by the inhibition of the Gas6 receptor Mer. Together, SOCS3 in myeloid cells regulates the Gas6/Mer-dependent phagocytosis of endothelial cells, and thereby angiogenesis-related processes. Our findings provide novel insights into the complex crosstalk between mononuclear phagocytes and endothelial cells, and may therefore provide a new platform for the development of new antiangiogenic therapies.

Docosahexaenoic acid reduces adenosine triphosphate-induced calcium influx via inhibition of store-operated calcium channels and enhances baseline endothelial nitric oxide synthase phosphorylation in human endothelial cells

Docosahexaenoic acid (DHA), an omega-3-fatty acid, modulates multiple cellular functions. In this study, we addressed the effects of DHA on human umbilical vein endothelial cell calcium transient and endothelial nitric oxide synthase (eNOS) phosphorylation under control and adenosine triphosphate (ATP, 100 µM) stimulated conditions. Cells were treated for 48 h with DHA concentrations from 3 to 50 µM. Calcium transient was measured using the fluorescent dye Fura-2-AM and eNOS phosphorylation was addressed by western blot. DHA dose-dependently reduced the ATP stimulated Ca²⁺-transient. This effect was preserved in the presence of BAPTA (10 and 20 µM) which chelated the intracellular calcium, but eliminated after withdrawal of extracellular calcium, application of 2-aminoethoxy-diphenylborane (75 µM) to inhibit store-operated calcium channel or thapsigargin (2 µM) to delete calcium store. In addition, DHA (12 µM) increased ser1177/thr495 phosphorylation of eNOS under baseline conditions but had no significant effect on this ratio under conditions of ATP stimulation. In conclusion, DHA dose-dependently inhibited the ATP-induced calcium transient, probably via store-operated calcium channels. Furthermore, DHA changed eNOS phosphorylation suggesting activation of the enzyme. Hence, DHA may shift the regulation of eNOS away from a Ca²⁺ activated mode to a preferentially controlled phosphorylation mode.

Endothelial-Specific Deficiency of ATG5 (Autophagy Protein 5) Attenuates Ischemia-Related Angiogenesis

Objective—

Pathological angiogenesis, such as exuberant retinal neovascularization during proliferative retinopathies, involves endothelial responses to ischemia/hypoxia and oxidative stress. Autophagy is a clearance system enabling bulk degradation of intracellular components and is implicated in cellular adaptation to stressful conditions. Here, we addressed the role of the ATG5 (autophagy-related protein 5) in endothelial cells in the context of pathological ischemia-related neovascularization in the murine model of retinopathy of prematurity.

Approach and Results—

Autophagic vesicles accumulated in neovascular tufts of the retina of retinopathy of prematurity mice. Endothelium-specific Atg5 deletion reduced pathological neovascularization in the retinopathy of prematurity model. In contrast, no alterations in physiological retina vascularization were observed in endothelial-specific ATG5 deficiency, suggesting a specific role of endothelial ATG5 in pathological hypoxia/reoxygenation–related angiogenesis. Consistently, in an aortic ring angiogenesis assay, endothelial ATG5 deficiency resulted in impaired angiogenesis under hypoxia/reoxygenation conditions. As compared to ATG5-sufficient endothelial cells, ATG5-deficient cells displayed impaired mitochondrial respiratory activity, diminished production of mitochondrial reactive oxygen species and decreased phosphorylation of the VEGFR2 (vascular endothelial growth factor receptor 2). Consistently, ATG5-deficient endothelial cells displayed decreased oxidative inactivation of PTPs (phospho-tyrosine phosphatases), likely due to the reduced reactive oxygen species levels resulting from ATG5 deficiency.

Conclusions—

Our data suggest that endothelial ATG5 supports mitochondrial function and proangiogenic signaling in endothelial cells in the context of pathological hypoxia/reoxygenation–related neovascularization. Endothelial ATG5, therefore, represents a potential target for the treatment of pathological neovascularization-associated diseases, such as retinopathies.

Hematopoietic hypoxia-inducible factor 2α deficiency ameliorates pathological retinal neovascularization via modulation of endothelial cell apoptosis

A hallmark of proliferative retinopathies, such as retinopathy of prematurity (ROP), is a pathological neovascularization orchestrated by hypoxia and the resulting hypoxia-inducible factor (HIF)-dependent response. We studied the role of Hif2α in hematopoietic cells for pathological retina neovascularization in the murine model of ROP, the oxygen-induced retinopathy (OIR) model. Hematopoietic-specific deficiency of Hif2α ameliorated pathological neovascularization in the OIR model, which was accompanied by enhanced endothelial cell apoptosis. That latter finding was associated with up-regulation of the apoptosis-inducer FasL in Hif2α-deficient microglia. Consistently, pharmacological inhibition of the FasL reversed the reduced pathological neovascularization from hematopoietic-specific Hif2α deficiency. Our study found that the hematopoietic cell Hif2α contributes to pathological retina angiogenesis. Our findings not only provide novel insights regarding the complex interplay between immune cells and endothelial cells in hypoxia-driven retina neovascularization but also may have therapeutic implications for proliferative retinopathies.-Korovina, I., Neuwirth, A., Sprott, D., Weber, S., Sardar Pasha, S. P. B., Gercken, B., Breier, G., El-Armouche, A., Deussen, A., Karl, M. O., Wielockx, B., Chavakis, T., Klotzsche-von Ameln, A. Hematopoietic hypoxia-inducible factor 2α deficiency ameliorates pathological retinal neovascularization via modulation of endothelial cell apoptosis.

Abstract 287: Transgenic Overexpression of Dimethylarginine Dimethylaminohydrolase 1 Protects From Angiotensin II - Induced Cardiac Hypertrophy and Vascular Remodeling

Background: Dimethylarginine dimethylaminohydrolase 1 (DDAH1) hydrolyzes the endogenous inhibitor of nitric oxide synthases asymmetric dimethylarginine (ADMA). DDAH1 is also suggested to have ADMA-independent effects. DDAH1 overexpression lowers ADMA levels and protects from renal interstitial fibrosis and vascular oxidative stress in angiotensin-II-induced hypertension. The current study was designed to test the hypothesis that DDAH1 overexpression protects from angiotensin II-induced cardiac hypertrophy and vascular remodeling.

Methods: Angiotensin II (AngII) was infused in the doses of 0.75 and 1.5 mg/kg/day, respectively, in DDAH1 transgenic mice (TG) and wild type (WT) littermates via osmotic minipumps. Echocardiography was performed in the first and fourth week after start of the infusion. Systolic blood pressure was measured by the tail-cuff method. Cardiac hypertrophy and vascular remodeling was assessed by histology after 4 weeks of AngII infusion.

Results: TG mice had decreased plasma and tissue ADMA. Infusion of Ang II resulted in an increase in systolic blood pressure, which was similar between TG and WT mice at week 1, however, TG mice were protected from a further increase in blood pressure. After 4-weeks infusion of AngII TG mice had significantly higher left ventricular lumen to wall ratio, smaller size of cardiomyocytes and reduced myocardial collagen expression compared to WT littermates. TG mice had lower left ventricular posterior wall thickness in systole and diastole as compared to WT controls. The vasomotor function of aortic rings in response to acetylcholine was improved in the TG mice as compared to the WT mice. TG mice had less aortic hypertrophy and fibrosis and more elastin in aorta as compared to WT mice. Aortic infiltration of CD45 + , CD3 + , CD8 + and CD4 + T-cells was significantly lower in TG than in WT mice.

Conclusion: This study shows that upregulation of DDAH1 protects from AngII-induced cardiac hypertrophy and vascular remodeling. Upregulation of DDAH1 might be a potential therapeutic approach for protection from AngII – induced end organ damage. We are currently investigating, whether protective effects of DDAH1 are ADMA-dependent or ADMA-independent.

Fetal middle cerebral artery Doppler to time intrauterine transfusion in red-cell alloimmunization: a randomized trial

OBJECTIVES

To evaluate whether Doppler measurement of middle cerebral artery peak systolic velocity (MCA-PSV) for timing subsequent intrauterine transfusions (IUTs) in fetuses that had undergone one IUT for anemia secondary to red-cell alloimmunization is non-inferior to timing based on expected decrease in fetal hematocrit (Hct) or fetal hemoglobin level, without compromising infant hemoglobin at birth.

METHODS

This was an international, pragmatic multicenter randomized controlled trial. Women with a pregnancy complicated by fetal anemia secondary to red-cell alloimmunization (due to any antibody alone or in combination), as indicated by the need to undergo a single IUT, were eligible for inclusion. Women were randomized to the determination of timing of further transfusion(s) by Doppler measurement of MCA-PSV (MCA-PSV Group), with a serial upward trend of values >1.5 multiples of the median considered indicative of the need for another IUT, or timing of transfusion by a decrease in fetal Hct (fetal Hct Group), with subsequent IUTs timed according to an estimated fall in fetal Hct of 1% per day or fetal hemoglobin of 0.3 g/dL per day, to maintain fetal hemoglobin level between 7 and 10 g/dL. The primary outcome was infant hemoglobin level measured at birth.

RESULTS

A total of 71 women were randomized, 36 to the MCA-PSV Group and 35 to the fetal Hct Group. Median gestational age at randomization was 30.3 weeks, the majority of women were Caucasian and non-smokers, 9.9% of women had Kell alloimmunization, and 14% of fetuses were hydropic at their first IUT. No statistically significant differences between the two treatment groups were observed with regard to mean hemoglobin levels at birth (MCA-PSV Group, 10.36 ± 3.82 g/dL vs fetal Hct Group, 12.03 ± 3.14 g/dL; adjusted mean difference -1.56 g/dL (95% CI, -3.24 to 0.13 g/dL); P = 0.070), or the number of IUTs performed after randomization (MCA-PSV Group, 1.75 ± 1.79 vs fetal Hct Group 1.80 ± 1.32; adjusted relative risk 0.88 (95% CI, 0.61-1.26); P = 0.474). There was no statistically significant difference between the two groups with respect to the risk of adverse infant outcomes related to alloimmunization or procedure-related complications.

CONCLUSION

Both Doppler measurement of MCA-PSV and estimation of the decrease in fetal Hct or hemoglobin can be used to determine the timing of second and subsequent IUTs in fetuses with red-cell alloimmunization. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.