Proximal tubular cells contain a phenotypically distinct,scattered cell population involved in tubular regeneration

Regeneration of injured tubular cells occurs after acute tubular necrosis primarily from intrinsic renal cells. This may occur from a pre‐existing intratubular stem/progenitor cell population or from any surviving proximal tubular cell. In this study, we characterize a CD24‐, CD133‐, and vimentin‐positive subpopulation of cells scattered throughout the proximal tubule in normal human kidney. Compared to adjacent ‘normal’ proximal tubular cells, these CD24‐positive cells contained less cytoplasm, fewer mitochondria, and no brush border. In addition, 49 marker proteins are described that are expressed within the proximal tubules in a similar scattered pattern. For eight of these markers, we confirmed co‐localization with CD24. In human biopsies of patients with acute tubular necrosis (ATN), the number of CD24‐positive tubular cells was increased. In both normal human kidneys and the ATN biopsies, around 85% of proliferating cells were CD24‐positive – indicating that this cell population participates in tubular regeneration. In healthy rat kidneys, the novel cell subpopulation was absent. However, upon unilateral ureteral obstruction (UUO), the novel cell population was detected in significant amounts in the injured kidney. In summary, in human renal biopsies, the CD24‐positive cells represent tubular cells with a deviant phenotype, characterized by a distinct morphology and marker expression. After acute tubular injury, these cells become more numerous. In healthy rat kidneys, these cells are not detectable, whereas after UUO, they appeared de novo – arguing against the notion that these cells represent a pre‐existing progenitor cell population. Our data indicate rather that these cells represent transiently dedifferentiated tubular cells involved in regeneration. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Absence of long‐term analgesic effect from a short‐term S‐ketamine infusion on fibromyalgia pain: A randomized,prospective, double blind,active placebo‐controlled trial

To assess the analgesic efficacy of the N‐methyl‐D‐aspartate receptor antagonist S(+)‐ketamine on fibromyalgia pain, the authors performed a randomized double blind, active placebo‐controlled trial. Twenty‐four fibromyalgia patients were randomized to receive a 30‐min intravenous infusion with S(+)‐ketamine (total dose 0.5 mg/kg, n=12) or the active placebo, midazolam (5 mg, n =12). Visual Analogue Pain Scores (VAS) and ketamine plasma samples were obtained for 2.5‐h following termination of treatment; pain scores derived from the fibromyalgia impact questionnaire (FIQ) were collected weekly during an 8‐week follow‐up. Fifteen min after termination of infusion the number of patients showing a reduction in pain scores >50% was 8 vs. 3 (P<0.05), at t=180 min 6 vs. 2 (ns), at the end of week‐1 2 vs. 0 (ns) and at end of week‐8 2 vs. 2 in the ketamine and midazolam groups, respectively. Ketamine effect on VAS closely followed ketamine plasma concentrations. For VAS and FIQ scores no significant differences in treatment effects were observed in the 2.5‐h following infusion or during the 8‐week follow‐up. Side effects as measured by the Bowdle questionnaire (which scores for 13 separate psychedelic symptoms) were mild to moderate in both study groups and declined rapidly, indicating adequate blinding of treatments. Efficacy of ketamine was limited and restricted in duration to its pharmacokinetics. The authors argue that a short‐term infusion of ketamine is insufficient to induce long‐term analgesic effects in fibromyalgia patients.     

Oral magnesium supplementation reduces insulin resistance in non-diabetic subjects - a double-blind, placebo-controlled, randomized trial

The incidence of insulin resistance and metabolic syndrome correlates with the availability of magnesium (Mg). We studied the effect of oral Mg supplementation on insulin sensitivity and other characteristics of the metabolic syndrome in normomagnesemic, overweight, insulin resistant, non-diabetic subjects. Subjects were tested for eligibility using oral glucose tolerance test (OGTT) and subsequently randomized to receive either Mg-aspartate-hydrochloride (n = 27) or placebo (n = 25) for 6 months. As trial endpoints, several indices of insulin sensitivity, plasma glucose, serum insulin, blood pressure and lipid profile were determined. Mg supplementation resulted in a significant improvement of fasting plasma glucose and some insulin sensitivity indices (ISIs) compared to placebo. Blood pressure and lipid profile did not show significant changes. The results provide significant evidence that oral Mg supplementation improves insulin sensitivity even in normomagnesemic, overweight, non-diabetic subjects emphasizing the need for an early optimization of Mg status to prevent insulin resistance and subsequently type 2 diabetes.     

No increase in C-reactive protein levels during intranasal compared to oral hormone therapy in healthy post-menopausal women

BACKGROUND: Inflammation plays an important role in the development of atherosclerotic disease. Oral post-menopausal hormone therapy increases serum C-reactive protein (CRP) levels. This study compared the effects of intranasal and oral administration of 17beta-estradiol (E2) combined with norethisterone acetate (NETA) on markers of inflammation in healthy post-menopausal women. METHODS: Ninety healthy post-menopausal women (age 56.6 +/- 4.7 years) participated in this 1-year trial. After computerized block randomization, they daily received, in a double-blind fashion, either intranasal E2/NET [175 microg/275 microg (n = 47)] or oral E2/NETA [1 mg/0.5 mg (n = 43)]. Concentrations of high sensitivity CRP and adhesion molecules were measured at baseline and after 12, 24 and 52 weeks of treatment. RESULTS: CRP levels were increased (P = 0.001) in the oral but not in the intranasal group. The increase in the oral group was highest at week 12 (64.9%) and was larger (P < 0.01) compared with the non-significant increase (8.6%) found in the intranasal group. Both groups showed decreases (P < 0.001) in soluble vascular cell adhesion molecule (sVCAM), soluble intracellular adhesion molecule (sICAM) and sE-selectin. The decreases were larger (P < 0.01) in the oral than in the intranasal group. CONCLUSION: Intranasal E2/NET therapy did not significantly increase CRP levels, in contrast to the increase observed in the oral E2/NETA treatment group. Both intranasal and oral therapy lowered plasma concentrations of adhesion molecules, however, more so in the oral group.     

Physicochemical and Immunological Characterization of N,N,N-Trimethyl Chitosan-Coated Whole Inactivated Influenza Virus Vaccine for Intranasal Administration

Purpose  The purpose of this study was the development and physicochemical and immunological characterization of intranasal (i.n.) vaccine formulations of whole inactivated influenza virus (WIV) coated with N,N,N-trimethyl chitosan (TMC). Methods  Synthesized TMCs with a degree of quarternization of 15% (TMC15) or 37% (TMC37) were tested in vitro for their ability to decrease the transepithelial resistance (TEER) of an epithelial cell monolayer. TMC15- and TMC37-coated WIV (TMC15-WIV and TMC37-WIV) were characterized by zeta potential measurements, dynamic light scattering, electron microscopy and gel permeation chromatography. Mice were vaccinated i.n. with selected vaccine formulations and immunogenicity was determined by measuring serum hemagglutination inhibition (HI) and serum IgG, IgG1 and IgG2a/c titers. Also a pulse-chase study with TMCs in solution administered i.n. 2 h prior to WIV was performed. Protective efficacy of vaccination was determined by an aerosol virus challenge. Results  TMC37 induced a reversible decrease in TEER, suggesting the opening of tight junctions, whereas TMC15 did not affect TEER. Simple mixing of (negatively charged) WIV with TMC15 or TMC37 resulted in positively charged particles with TMCs being partially bound. Intranasal immunization with TMC37-WIV or TMC15-WIV induced stronger HI, IgG, IgG1 and IgG2a/c titers than WIV alone. TMC37-WIV induced the highest immune responses. Both TMC15-WIV and TMC37-WIV provided protection against challenge, whereas WIV alone was not protective. Intranasal administration of TMC prior to WIV did not result in significant immune responses, indicating that the immunostimulatory effect of TMC is primarily based on improved i.n. delivery of WIV. Conclusions  Coating of WIV with TMC is a simple procedure to improve the delivery and immunogenicity of i.n. administered WIV and may enable effective i.n. vaccination against influenza.     

Prevalence of congenital heart defects and persistent pulmonary hypertension of the neonate with Down syndrome

The aim of this study was to assess the prevalence of congenital heart defects (CHDs) and persistent pulmonary hypertension of the neonate (PPHN) in children with Down syndrome (DS) and to assess its impact on neonatal factors. It was a prospective study of a birth cohort of children with DS born between 2003 and 2006 registered by the Dutch Paediatric Surveillance Unit (DPSU). A CHD occurred in 43% of 482 children with trisomy 21. Atrioventricular septal defect was found in 54%, ventricular septal defect in 33.3% and patent ductus arteriosus in 5.8%. The incidence of PPHN in DS was 5.2%, which is significantly higher than the general population (p < 0.001). The reported mortality in newborns with DS was overall 3.3% and was still significant higher in children with a CHD versus no CHD (5.8% versus 1.5%) (p = 0.008). The presence of CHD in children with DS had no influence on their birth weight, mean gestational age and Apgar score. In neonates with DS, we found not only a 43% prevalence of CHD, but also a high incidence of PPHN at 5.2%. Early recognition of the cardiac condition of neonates with DS seems justified.     

Homocysteine in postmenopausal women and the importance of hormone replacement therapy.

Homocysteine (Hcy) has been shown to damage the vascular endothelial cells, contributing to atherothrombosis. The increase in plasma Hcy levels with natural menopause suggests a close relationship between Hcy metabolism and estrogen status and proposes one of the mechanisms through which menopause unfavorably affects cardiovascular disease risk in women. In addition to the prevention of osteoporosis, hormone replacement therapy (HRT) lowers Hcy levels in postmenopausal women. The first report by van der Mooren et al., demonstrated in an uncontrolled study a significant reduction (11%) in fasting serum Hcy level after 6 months of treatment with sequentially combined estradiol-dydrogesterone therapy in 21 healthy postmenopausal women. This effect was particularly evident in women with initially elevated baseline serum Hcy concentrations. Similar results were found in other studies in which women were treated with various transdermal as well as oral HRT regimens, although two studies could not confirm these findings. All these studies were uncontrolled, and three of them consisted of a relatively small number of participants. Therefore, they remained inconclusive. Three randomized controlled trials on HRT and Hcy were published to date, confirming that postmenopausal HRT reduces circulating levels of Hcy. Current and recent HRT use is associated with a slight increased risk of breast cancer. As a result of this, research has centered on finding compounds that can prevent the consequences of estrogen deficiency, without the potential risk of HRT. Raloxifene, referred to as a Selective Estrogen Receptor Modulator (SERM), has the potential as a viable alternative to HRT. Recently, two randomized controlled trials demonstrated that raloxifene lowers plasma Hcy levels in postmenopausal women, similar to the reduction obtained with HRT. Little is known about the mechanisms underlying the HRT-associated lowering of plasma Hcy. Proposed mechanisms relate to an increase in kidney methionine synthase activity or may be related to the transamination of methionine. We conclude that HRT decreases plasma Hcy levels in postmenopausal women and that the strongest reductions can be achieved in women with the highest concentrations.