The NAD-Booster Nicotinamide Riboside Potently Stimulates Hematopoiesis through Increased Mitochondrial Clearance

It has been recently shown that increased oxidative phosphorylation, as reflected by increased mitochondrial activity, together with impairment of the mitochondrial stress response, can severely compromise hematopoietic stem cell (HSC) regeneration. Here we show that the NAD⁺-boosting agent nicotinamide riboside (NR) reduces mitochondrial activity within HSCs through increased mitochondrial clearance, leading to increased asymmetric HSC divisions. NR dietary supplementation results in a significantly enlarged pool of progenitors, without concurrent HSC exhaustion, improves survival by 80%, and accelerates blood recovery after murine lethal irradiation and limiting-HSC transplantation. In immune-deficient mice, NR increased the production of human leucocytes from hCD34+ progenitors. Our work demonstrates for the first time a positive effect of NAD⁺-boosting strategies on the most primitive blood stem cells, establishing a link between HSC mitochondrial stress, mitophagy, and stem-cell fate decision, and unveiling the potential of NR to improve recovery of patients suffering from hematological failure including post chemo- and radiotherapy.

Cellular endogenous NAD(P)H fluorescence as a label-free method for the identification of erythrocytes and reticulocytes

Reticulocytes and erythrocytes are the ultimate differentiated stages of erythropoiesis. In addition to being anucleate cells, they are characterized by the clearance of their mitochondrial pool or lack thereof. Given that for most research-oriented flow cytometry experiments erythrocytes and reticulocytes are often undesirable cell types, their identification and exclusion from analyses can be essential. Here, we describe a flow cytometric method based on cellular NAD(P)H-related autofluorescence, whose localization is mainly associated with mitochondria. By increasing the sensitivity of the specific NAD(P)H-fluorescence detector, we discovered a population with weak levels of NAD(P)H fluorescence signals whose immunophenotypical and physiological characterization in mouse bone marrow led to its identification as both erythrocytes and reticulocytes. Our method showed comparable sensitivity and specificity to the detection of red blood cells based on the absorption of light by oxyhemoglobin. This NAD(P)H-based approach consistently identified over 95% of the total pool of erythrocytes and reticulocytes in bone marrow samples and revealed robust as over 93% of these two erythropoietic subsets were identified in melanoma tumor samples with the same method. The measurement of cellular endogenous NAD(P)H fluorescence, therefore, offers a reliable and straightforward alternative to identify erythrocytes and reticulocytes without additional immunostaining or the need to modify the cytometer's optical configuration. © 2018 International Society for Advancement of Cytometry.

Alterations in viscoelastic properties following premature birth may lead to hypertension and cardiovascular disease development in later life

The aim of this review was to identify the underlying relationship between preterm birth and the development of cardiovascular diseases. Preterm birth significantly affects the elastin content and viscoelastic properties of the vascular extracellular matrix in human arteries. Inadequate elastin synthesis during early development may cause a permanent increase in arterial stiffness in adulthood.

CONCLUSION

Early and permanent alterations in viscoelastic properties may lead to hypertension and cardiovascular disease development in adults born prematurely.

Impact de l'âge gestationnel et du poids de naissance sur le devenir cardiovasculaire à long terme

PURPOSE

Intra-uterine growth restriction and preterm birth can lead to cardiovascular diseases in adulthood.

CURRENT KNOWLEDGE AND KEY POINTS

Preterm birth and intra-uterine growth restriction induce long-term changes in organ development such as arterial system and kidney function. Among these changes, the impairment of arterial wall structure or properties occurring in low birth weight babies, as a result of preterm birth and intra-uterine growth restriction, may lead on a long-term to an elevation of arterial pressure and arterial stiffness. These notions are still not completely understood and seem of high importance in regard to the high frequency in preterm birth and intra-uterine growth restriction.

FUTURE PROSPECTS AND PROJECTS

Identifying clinical, paraclinical markers and better understanding a link between adverse perinatal conditions and cardiovascular diseases might improve actions for preventing cardiovascular diseases in adulthood in this population.

Enhanced ceramide-induced apoptosis in ceramide kinase overexpressing cells

We evaluated how increased levels of ceramide kinase (CerK) would impact the growth of COS-1 fibroblasts and RBL-2H3 basophils. The low CerK activity in these cells was strongly up-regulated upon recombinant expression of CerK. CerK-overexpressing COS-1 cells depended on higher concentrations of serum for their growth and displayed many filipodia. The two CerK-overexpressing cell lines were more sensitive to C2-ceramide-mediated apoptosis, and this correlated with the production of C2-ceramide-1-phosphate by CerK. This study indicates that ceramide kinase may participate in the control of cell growth, and establishes a novel assay that will be valuable for testing ceramide kinase inhibitors.

Effects of ceramide-1-phosphate on cultured cells: dependence on dodecane in the vehicle

Ceramide-1-phosphate (C1P), the product of ceramide kinase, is a sphingophospholipid with recently recognized signaling properties. In particular, it was reported to be mitogenic and capable of direct stimulation of cytosolic phospholipase A(2alpha). Much of the present knowledge has relied on the use of C1P of various acyl chain lengths, together with diverse protocols to deliver it to cultured cells. A mixture of ethanol (or methanol) with dodecane, as the vehicle, has become popular. However, the contribution of this solvent to the observed effects of C1P has not been documented. Here, we show that addition of C1P in ethanol-dodecane to culture medium leads to irreversible cytotoxic effects. These culminate in mitochondrial swelling, vacuole formation, and cell death. Not only the toxicity of C1P, but also its ability to trigger prostaglandin E2 release, is fully dependent upon addition of a premade C1P-dodecane mixture. Furthermore, we show that these effects are not restricted to C1P. They result from the capacity of dodecane to interact with phospholipids; hence, they go undetected with a vehicle control. This study should raise awareness about the use of dodecane for phospholipid delivery and, in turn, help in unraveling C1P signaling, which is still poorly understood.

[Arterial blood pressure and arterial stiffness in adolescents are related to gestational age]

BACKGROUND

Recent studies show that low birth weight (LBW) infants are at risk of increased arterial blood pressure (BP) in adulthood. Previous work from our centre and others suggests that arterial stiffness (AS) is increased in such patients. However, the respective roles of preterm birth and of intrauterine growth restriction (IUGR) are unclear.

AIM

To characterize AS and BP in adolescents who were: born at term with an appropriate birth weight for gestational age (GA) (group 1, n=41); born preterm with an appropriate birth weight for GA (group 2, n=25); born at term and small for GA (group 3, n=24).

PATIENTS AND METHODS

Systemic BP was measured with an automated oscillometric device. AS was assessed by measuring pulse wave velocity (PWV) between carotid and radial arteries.

RESULTS

90 adolescents were studied at a mean (SD) age of 13.9 (1.2) years. Subjects from group 2 were born with a 33.6 (1.5) GA. Systolic BP, mean BP, and PWV were significantly increased in group 2 subjects in comparison to both group 1 (123 +/- 11 vs. 117 +/- 11 mmHg, p = 0.04; 88 +/- 7 vs. 83 +/- 7 mmHg, p = 0.03; 7.7 +/- 1.0 vs. 7.0 +/- 0.9 m/s, p = 0.02 respectively) and to group 3 (114 +/- 15 mmHg, p = 0.03: 79 +/- 8 mmHg, p = 0.001; 6.8 +/- 0.9 m/s, p = 0.005 respectively) subjects. Systolic BP, mean BP, and PWV were similar in group 1 and group 3 subjects.

CONCLUSION

BP and AS are increased during adolescence in subjects born with a LBW due to preterm birth, while they are not altered in subjects when LBW is related to IUGR. It may be speculated that such changes predispose to long term hypertension and that preterm birth is involved in the early programming of arterial diseases in adulthood.

Vascular mechanisms in the developmental programming of cardio-vascular disease

Several studies suggest that adverse events during foetal life can program cardiovascular diseases in adulthood. Barker et al. identified a relationship between low birth weight and an increased risk of arterial hypertension, carotid arteriosclerosis, and mortality by coronary heart disease or stroke in adulthood. These findings led to the "foetal origins" hypothesis, which is that cardiovascular disease originates in the adaptations to an adverse intrauterine environment. Such adaptations may permanently alter the cardiovascular structure and physiology through the process of programming. Several factors, such as impaired foetal growth, premature birth or postnatal growth of low birth weight infants may be involved, but to which extent is still unclear.

Brûlure néonatale accidentelle à l'isopropanol

Antiseptic solutions are commonly used for skin care but are not always safe. In preterm infants, application of antiseptic solutions can lead to serious burns. We report the case of a premature newborn who developed severe burns at 35 weeks post-conceptional age, after his mother used disposable antiseptic towels containing isopropyl alcohol for his skin care. Burns outcome led to diffuse skin burn and death of the baby. Several cases of isopropyl alcohol poisoning through skin absorption have been reported in neonate and infants. Because of its neonatal toxicity, isopropyl alcohol has been excluded from composition of antiseptic solutions commonly used in neonatology. However, isopropyl alcohol is still available in many housecleaning and cosmetic products, while its toxic effects in children are not clearly mentioned. A specific mention "toxic for infants and children" should appear on mass consumption products containing isopropyl alcohol. Moreover, health workers may individually inform parents about possible hazards of poisoning through skin absorption.

Étude de la circulation artérielle périphérique par échographie-doppler conventionnelle : faisabilité et reproductibilité

Ultrasonography Doppler in the assessment of arterial peripheral circulation.

PURPOSE

The ultrasonography-Doppler study of peripheral arterial circulation requires measurements of arterial area and arterial blood flow. The aim of this study was to assess their variabilities, intra- and interobserver.

METHODS

We studied brachial arterial circulation of 13 volunteers. Two experimented investigators carried out the examinations. Arterial blood pressure measurements were obtained at the level of the brachial artery of the left arm by means of a semi automated oscillometric device. The brachial artery was approached by ultrasound scan in semi-decubitus position, the arm in exterior rotation and abduction. Brachial artery cross-sectional areas were obtained by a transversal view with a depth of 4-15-cm upstream the antecubital fossa of the forearm. Cross sectional areas were measured at end diastole (SD) and end systole (SS). We measured maximal systolic and diastolic velocities (Vmax and Vmin), mean velocity (Vmoy) and velocity integral (ITV) of the blood flow. We deduced brachial output (D), resistance and pulsatility index (IR, IP), cross-sectional compliance coefficient (C).

RESULTS

Intra- and interoperator variability as assessed by the Bland-Altman approach was acceptable SS, SD, ITV, D, Vmax, Vmoy, Vmin C, IR, and IP, in regard with values of variation coefficient, biais, and concordance limits.

CONCLUSION

Conventional B-mode ultrasonography may offer a reliable method for arterial peripheral circulation evaluation.

[Short and medium-term results of the Norwood intervention (first stage)]

We report the short and mid-term results of the Norwood procedure (Stage one) in 20 patients with hypoplastic left heart syndrome or univentricular heart with aortic obstruction. Seven patients were prenatally diagnosed. Preoperatively there was obstruction to pulmonary venous return in 6 cases, a mild to moderate tricuspid regurgitation in 6 cases, and 11 patients were supported by mechanical ventilation with multiorgan failure in 5 cases. The surgery was performed under cardiopulmonary bypass at a mean age and weight of 12.9 days and 3 kg, respectively. Nine patients (45%) died within 30 days postoperatively, whereas 5 had delayed sternal closure. The mean duration of mechanical ventilation and ICU stay were 5.7 and 11 days, respectively. Two patients were reoperated for bronchial compression and tracheotomy. Systemic venous thrombosis occurred in 5 patients. In multivariate analysis, an older age at surgery was correlated with postoperative hospital death (p = 0.03). Among the 11 patients discharged home after Stage one procedure, 5 patients underwent balloon dilation for recoarctation and one patient died at home. A bidirectional cavopulmonary anastomosis was performed in 8 patients at a mean age of 0.76 year, with one postoperative death. After a mean follow-up of 1 year (+/- 1.97 years), the 9 remaining patients are all in NYHA class I, at a mean age of 2.2 years. Their mean transcutaneous saturation is 81%. The Norwood procedure (Stage one) is associated with high hospital mortality. However, the functional status of the survivors is correct, like in patients with other type of univentricular hearts. Moreover, although the causes of death in our patients are often not clarified, other studies show that the leading causes of deaths in our patients are often not clarified, other studies show that the leading causes of death in those patients are correctable. In conclusion, the option of a Norwood procedure (Stage one) should be proposed in patients with hypoplastic left heart syndrome (or variant).