Dorota Gruber

Stabilization and Functional Modulation of Microtubules by Microtubule-Associated Protein 4

Microtubules (MTs) are hollow cytoplasmic fibers that are composed of a dimeric protein called tubulin, as well as several MT-associated proteins (MAPS) bound along their surface. MTs are believed to play important roles in a variety of cellular processes, including mitosis, cell motility, and intracellular vesicle transport. Both in vitro and in vivo, individual MTs are dynamic; that is, they undergo alternating periods of polymerization and depolymerization from their ends, a process known as dynamic instability. The dynamic behavior of MTs is thought to play an important role both in cell cycle events and in cell differentiation. MAPS have been postulated to function as in vivo regulators of the dynamics and functions of MTs. Based on in vitro studies, several MAPS have been classified as

Recipient Genotype Is a Predictor of Allograft Cytokine Expression and Outcomes After Pediatric Cardiac Transplantation

OBJECTIVES This study sought to investigate the influence of recipient renin-angiotensin-aldosterone system (RAAS) genotype on cardiac function, rejection, and outcomes after heart transplantation. BACKGROUND The RAAS influences cardiac function and up-regulates inflammatory/immune pathways. Little is known about the effect of recipient RAAS polymorphisms in pediatric cardiac transplantation. METHODS Patients <25 years of age, after cardiac transplantation, were enrolled (2003 to 2008) and genotyped for polymorphisms in genes associated with RAAS upregulation: AGT-G, ACE-D, AGTR1-C, CYP11B2-G, and CMA-A. Presence of at least 1 high-risk allele was defined as a high-risk genotype. Univariable and multivariable associations between genotypes and outcomes were assessed in time-dependent models using survival, logistic, or linear regression models. Biopsy samples were immunostained for interleukin (IL)-6, transforming growth factor (TGF)-beta, and tumor necrosis factor (TNF)-alpha during rejection and quiescence. RESULTS A total of 145 patients were studied, 103 primary cohort and 42 replication cohort; 81% had rejection, 51% had graft dysfunction, and 13% had vasculopathy, 7% died and 8% underwent re-transplantation. A higher number of homozygous high-risk RAAS genotypes was associated with a higher risk of graft dysfunction (hazard ratio [HR]: 1.5, p = 0.02) and a higher probability of death (HR: 2.5, p = 0.04). The number of heterozygous high-risk RAAS genotypes was associated with frequency of rejection (+0.096 events/year, p < 0.001) and rejection-associated graft dysfunction (+0.37 events/year, p = 0.002). IL-6 and TGF-beta were markedly upregulated during rejection in patients with >/=2 high-risk RAAS genotypes. CONCLUSIONS Recipient RAAS polymorphisms are associated with a higher risk of rejection, graft cytokine expression, graft dysfunction, and a higher mortality after cardiac transplantation. This may have implications for use of RAAS inhibitors in high-risk patients after transplantation.

Identification of kinesin-like molecules in myogenic cells

Numerous organelles are repositioned during myogenic differentiation and are maintained in an asymmetric distribution throughout the life span of a myotube. It is likely that members of the kinesin superfamily may be responsible for some or all of these microtubule-dependent movements. Consequently, we have attempted to identify kinesin-like molecules expressed throughout myogenesis. Using a standard PCR-based strategy, we cloned two kinesin-like molecules from a rat myogenic cell line, L6. Sequence analysis of the first of these, KIF3C, defines it as a novel member of the KIF3 subfamily of kinesin-like proteins. KIF3C is expressed throughout myogenesis as well as in numerous rat tissues. Like other members of the KIF3 subfamily, KIF3C has an N-terminal motor domain. The second molecule identified is a rat homolog of murine KIF1B, a putative mitochondrial transporter. KIF1B is also expressed ubiquitously both in myogenic cells at all stages and in a variety of rat tissues.

Relationship between a validated molecular cardiac transplant rejection classifier and routine organ function parameters

Cadeiras M, Shahzad K, John MM, Gruber D, von Bayern M, Auerbach S, Sinha A, Latif F, Unniachan S, Memon S, Mital S, Restaino S, Marboe CC, Addonizio LJ, Deng MC. Relationship between a validated molecular cardiac transplant rejection classifier and routine organ function parameters.
Clin Transplant 2010: 24: 321–327.

Brain injury with systemic inflammation in newborns with congenital heart disease undergoing heart surgery

The potential role of systemic inflammation on brain injury in newborns with congenital heart disease (CHD) was assessed by measuring levels of central nervous system (CNS)-derived proteins in serum prior to and following cardiac surgery. A total of 23 newborns (gestational age, 39±1 weeks) with a diagnosis of CHD that required cardiac surgery with cardiopulmonary bypass (CPB) were enrolled in the current study. Serum samples were collected immediately prior to surgery and 2, 24 and 48 h following CPB, and serum levels of phosphorylated neurofilament-heavy subunit (pNF-H), neuron-specific enolase (NSE) and S100B were analyzed. Systemic inflammation was assessed by measuring serum concentrations of complement C5a and complement sC5b9, and the following cytokines: Interleukin (IL)-1β, IL-6, IL-8, IL-10, IL12p70, interferon γ and tumor necrosis factor (TNF)-α. Analysis of cord blood from normal term deliveries (n=26) provided surrogate normative values for newborns. pNF-H and S100B were 2.4- to 2.8-fold higher (P<0.0001) in patient sera than in cord blood prior to surgery and remained elevated following CPB. Pre-surgical serum pNF-H and S100B levels directly correlated with interleukin (IL)-12p70 (ρ=0.442, P<0.05). pNF-H was inversely correlated with arterial pO2 prior to surgery (ρ=−0.493, P=0.01) and directly correlated with arterial pCO2 post-CPB (ρ=0.426, P<0.05), suggesting that tissue hypoxia and inflammation contribute to blood brain barrier (BBB) dysfunction and neuronal injury. Serum IL12p70, IL-6, IL-8, IL-10 and TNF-α levels were significantly higher in patients than in normal cord blood and levels of these cytokines increased following CPB (P<0.001). Activation of complement was observed in all patients prior to surgery, and serum C5a and sC5b9 remained elevated up to 48 h post-surgery. Furthermore, they were correlated (P<0.05) with low arterial pO2, high pCO2 and elevated arterial pressure in the postoperative period. Length of mechanical ventilation was associated directly with post-surgery serum IL-12p70 and IL-8 concentrations (P<0.05). Elevated serum concentrations of pNF-H and S100B in neonates with CHD suggest BBB dysfunction and CNS injury, with concurrent hypoxemia and an activated inflammatory response potentiating this effect.

Endothelial function evaluation in patients with anorexia nervosa

Introduction: This study evaluated endothelial function in patients with anorexia nervosa (AN) using Endothelial Pulse Amplitude Testing (Endo-PAT) and correlated findings with the patients’ history and biochemical data. Method: Twenty-one patients age 13-21 years diagnosed with AN by the Division of Adolescent Medicine at Cohen Children’s Medical Center of New York between 6/1/2012 and 5/31/2013 were studied along with 19 healthy controls similar in age and gender distribution. Digital pulse amplitude was examined using Endo-PAT. Raw data were automatically transferred into a reactive hyperemia index (RHI) and the natural log transformation of RHI (LnRHI). Subjects’ and controls’ electrocardiograms and biochemical markers were obtained. Results: AN and controls had similar RHI (P=0.7542) and LnRHI (P=0.9497). AN had lower mean weight (P<0.0001), height (P=0.0207), BMI (P<0.0001), resting HR (P<0.0001), systolic (P<0.0001) and diastolic BP (P=0.0141). AN also had lower mean HR during EndoPAT testing (P<0.0001), triiodothyronine (T3) (P<0.0001), luteinizing hormone (LH) (P=0.0055) and estradiol (E2) (P=0.0052). Total cholesterol (Chol) (P=0.0004) was higher in AN subjects. No correlation was observed between RHI and other parameters. Conclusion: No significant differences in RHI or LnRHI were found between the two groups. There were significantly higher Chol and lower HR, T3, LH and E2 levels in the AN group compared to controls. There were no correlations of these parameters to RHI. Abbreviations: AN: anorexia nervosa; BMI: body mass index; Chol: total cholesterol; DBP: diastolic blood pressure; E2: estradiol; ECG: electrocardiogram; Endo-PAT: Endothelial Pulse Amplitude Testing; FSH: follicle-stimulating hormone; Hcy: homocysteine; HDL: high-density lipoprotein; LDL: low-density lipoprotein; LH: luteinizing hormone; LnRHI: natural logarithm transformation of Reactive Hyperemia Index; ln(Lp(a)): natural logarithm transformation of lipoprotein A; Lp(a): lipoprotein A; PAT: Peripheral Arterial Tone; PRL: prolactin; RHI: Reactive Hyperemia Index; SBP: systemic blood pressure; T3: triiodothyronine; TG: triglyceride; TSH: thyroid stimulating hormone