Vitreous TIMP-1 levels associate with neovascularization and TGF-β2 levels but not with fibrosis in the clinical course of proliferative diabetic retinopathy

In proliferative diabetic retinopathy (PDR), vascular endothelial growth factor (VEGF) and CCN2 (connective tissue growth factor; CTGF) cause blindness by neovascularization and subsequent fibrosis. This angio-fibrotic switch is associated with a shift in the balance between vitreous levels of CCN2 and VEGF in the eye. Here, we investigated the possible involvement of other important mediators of fibrosis, tissue inhibitor of metalloproteinases (TIMP)-1 and transforming growth factor (TGF)-β2, and of the matrix metalloproteinases (MMP)-2 and MMP-9, in the natural course of PDR. TIMP-1, activated TGF-β2, CCN2 and VEGF levels were measured by ELISA in 78 vitreous samples of patients with PDR (n = 28), diabetic patients without PDR (n = 24), and patients with the diabetes-unrelated retinal conditions macular hole (n = 10) or macular pucker (n = 16), and were related to MMP-2 and MMP-9 activity on zymograms and to clinical data, including degree of intra-ocular neovascularization and fibrosis. TIMP-1, CCN2 and VEGF levels, but not activated TGF-β2 levels, were significantly increased in the vitreous of diabetic patients, with the highest levels in PDR patients. CCN2 and the CCN2/VEGF ratio were the strongest predictors of degree of fibrosis. In diabetic patients with or without PDR, activated TGF-β2 levels correlated with TIMP-1 levels, whereas in PDR patients, TIMP-1 levels, MMP-2 and proMMP-9 were associated with degree of neovascularization, like VEGF levels, but not with fibrosis. We confirm here our previous findings that retinal fibrosis in PDR patients is significantly correlated with vitreous CCN2 levels and the CCN2/VEGF ratio. In contrast, TIMP-1, MMP-2 and MMP-9 appear to have a role in the angiogenic phase rather than in the fibrotic phase of PDR.     

Testable but not falsifiable?

We are puzzled by a recent comment that suggested that historical hypotheses can be tested but are unfalsifiable. We argue that phylogenetic hypotheses are falsifiable without the aid of a time machine and that they are like any other hypothesis: they are tentative knowledge propositions capable of falsification with character evidence.     

Serum levels of IL-32 in patients with coronary artery disease and its relationship with the serum levels of IL-6 and TNF-α

Molecular Biology Reports - The coronary artery disease (CAD) is a chronic inflammatory disease caused by atherosclerosis, in which arteries become clogged due to plaque formation, fat...     

Iron-dependent binding of bovine milk α-casein with holo-lactoferrin, but not holo-transferrin

Bovine milk α-casein has been identified as an iron- and heme-binding protein. However, the physiological role of its iron-binding remains to be elucidated in more detail. α-Casein was immobilized on CNBr-activated Sepharose 4B beads, and the α-casein agarose beads efficiently bound hemin as well as ferrous ammonium sulfate (Fe(2+)) as compared with control beads. Additionally, α-casein-beads bound bovine holo-lactoferrin (Lf), but not holo-transferrin. Lf caused the release of Fe(2+) which had bound to the α-casein-agarose beads beforehand. These results suggest that bovine α-casein iron-dependently binds holo-bovine Lf more strongly than Fe(2+), and that strong binding between them may play a physiological role in regulating iron homeostasis in the bovine mammary gland.     

IL-6, but not TNF-α, increases plasma YKL-40 in human subjects

Plasma levels of YKL-40 are elevated in patients with systemic infection, inflammatory disorders and cancer. Both monocytes/macrophages, neutrophils, and cancer cells have the capacity to produce YKL-40, but the regulation during the inflammatory response is unknown. To study the possible role of interleukin-6 (IL-6) and tumor necrosis factor (TNF)-α in the regulation of YKL-40 plasma levels, we included healthy men, who received either recombinant human (rh)IL-6 (n=6), rhTNF-α (n=8) or vehicle (n=7) for 3h. The plasma levels of IL-6 and TNF-α reached ～ 150 and ～ 18 pg/ml, respectively, during the infusions. Following the IL-6 infusion, the plasma level of YKL-40 increased from ～ 30 to ～ 57 ng/ml (p<0.05) at 24h, and returned to normal values after 48 h. The plasma level of YKL-40 did not change during TNF-α infusion or infusion of vehicle. These data demonstrate that IL-6, but not TNF-α, has a key-role in the regulation of plasma YKL-40 levels during inflammation.     

Changes in function but not oligomeric size are associated with αB-crystallin lysine substitution

αB-Crystallin, ubiquitously expressed in many tissues including the ocular lens, is a small heat shock protein that can prevent protein aggregation. A number of post-translation modifications are reported to modify αB-crystallin function. Recent studies have identified αB-crystallin lysine residues are modified by acetylation and ubiquitination. Therefore, we sought to determine the effects of lysine to alanine substitution on αB-crystallin functions including chaperone activity and modulation of actin polymerization. Analysis of the ten substitution mutants as recombinant proteins indicated all the proteins were soluble and formed oligomeric complexes similar to wildtype protein. Lysozyme aggregation induced by chemical treatment indicated that K82, K90, K121, K166 and K174/K175 were required for efficient chaperone activity. Thermal induction of γ-crystallin aggregation could be prevented by all αB-crystallin substitution mutants. These αB-crystallin mutants also were able to mediate wildtype levels of actin polymerization. Further analysis of two clones with either enhanced or reduced chaperone activity on individual client substrates or actin polymerization indicated both retained broad chaperone activity and anti-apoptotic activity. Collectively, these studies show the requirements for lysine residues in αB-crystallin function.     

Maternal serum cell-free fetal DNA levels are increased in cases of trisomy 13 but not trisomy 18

Cell-free fetal DNA in the maternal circulation is a potential noninvasive marker for fetal aneuploidies. In previous studies with Y DNA as a fetal-specific marker, levels of circulating fetal DNA were shown to be elevated in women carrying trisomy 21 fetuses. The goal of this study was to determine whether cell-free fetal DNA levels in the serum of pregnant women carrying fetuses with trisomies 13 or 18 are also elevated. Archived maternal serum samples from five cases of male trisomy 13 and five cases of male trisomy 18 were studied. Each case was matched for fetal gender, gestational age, and duration of freezer storage to four or five control serum samples presumed to be euploid after newborn medical record review. Real-time quantitative polymerase chain reaction amplification of DYS1 was performed to measure the amount of male fetal DNA present. Unadjusted median serum fetal DNA concentrations were 97.5 GE/ml (genomic equivalents per milliliter; 29.2-187.0) for the trisomy 13 cases, 31.5 GE/ml (18.6-77.6) for the trisomy 18 cases, and 40.3 GE/ml (3.7-127.4) for the controls. Fetal DNA levels in trisomy 13 cases were significantly elevated ( P=0.016) by analysis of variance of the ranks of values within each matched set. In contrast, fetal DNA levels in trisomy 18 cases were no different from the controls ( P=0.244). Second trimester maternal serum analytes currently used in screening do not identify fetuses at high risk for trisomy 13. Fetal DNA may facilitate noninvasive screening for trisomy 13 provided that a gender-independent fetal DNA marker can be developed.     

Asymmetry in genitalia is in sync with lateralized mating behavior but not with the lateralization of other behaviors

Asymmetries in bilateral organisms attract a lot of curiosity given that they are conspicuous departures from the norm.They allow the investigation of the integration at different levels of biological organization.Here we study whether and how behavioral and asymmetrical anatomical traits coevolved and work together.We ask if asymmetry is determined locally for each trait or at a whole individual level in a species bearing conspicuous asymmetrical genitalia.Asymmetric genitalia evolved in many species;however,in most cases the direction of asymmetry is fixed.Therefore,it has been rarely determined if there is an association between the direction of asymmetry in genitalia and other traits.In onesided livebearer fish of the genus Jenynsia(Cyprinodontiformes,Anablepidae),the anal fin of males is modified into a gonopodium,an intromittent organ that serves to inseminate females.The gonopodium shows a conspicuous asymmetry,with its tip bending either to the left or the right.By surveying 13 natural populations of Jenynsia lineata,we found that both genital morphs are equally common in wild populations.In a series of experiments in a laboratory population,we discovered asymmetry and lateralization for multiple other traits;yet,the degree of integration varied highly among them.Lateralization in exploratory behavior in response to different stimuli was not associated with genital morphology.Interestingly,the direction of genital asymmetry was positively correlated with sidedness of mating preference and the number of neuromasts in the lateral line.This suggests integration of functionally linked asymmetric traits;however,there is no evidence that asymmetry is determined at the whole individual level in our study species.     

“x” is not a bias,but a number with real biological significance

Recent literature criticized the use of the symbol “x” to denote basic chromosome number in cytotaxonomy. I show here that this criticism is superfluous and is based on historical confusion between the concepts of basic chromosome number (or monoploid chromosome number), which is objective, and ancestral basic chromosome number, which is always inferred, by means of several – more or less reliable – methods. The most relevant literature is discussed and, in the end, I propose the use of x for basic chromosome number and p for (hypothetical) ancestral basic chromosome number.     

Screening for naturally occurring apolipoprotein A-I variants: apo A-I(ΔK107) is associated with low HDL-cholesterol levels in men but not in women

Isoelectric focussing (IEF) in carrier ampholyte-generated pH gradients and hybrid isoelectric focussing (HIEF) in immobilized pH gradients under nondenaturing conditions were used in parallel to screen 5,500 plasma samples for naturally occurring variants of apolipoprotein A-I (apo A-I). The following defects were identified in four unrelated subjects heterozygous for apo A-I variants: apo A-I(K107)(2 ×), apo A-I(K107M)(1 ×), and apo A-I(E41R)(1 ×). The later variant is a novel finding. Family studies did not reveal any association of apo A-I(K107M) and apo A-I(E41R) with dyslipidemia, but identified several heterozygotes for apo A-I(K107) who had low levels of high density lipoprotein (HDL)cholesterol. Therefore, and since the apo A-I(K107) is the most frequent apo A-I variant in Germany (1 5,000) we evaluated our data and that reported from 11 families with 32 heterozygous carriers and 30 unaffected controls. This analysis revealed that apo A-I(K107) is associated with lower HDL-cholesterol (-30%) and higher triglycerides (+ 48%) in men but not in women as compared with unaffected family members as well as with controls from the Prospective Cardiovascular Münster (PROCAM) study. Moreover, 11 of 15 male apo AI(K107) heterozygotes but only 2 of 17 female apo AI(K107) heterozygotes had HDL-cholesterol levels below the 20th percentile of sex-matched controls from the PROCAM study. We conclude that heterozygosity for apo A-I(K107) decreases HDL-cholesterol and increases triglycerides in men but not in women.     

Estradiol-17β stimulates proliferation of uterine epithelial cells cultured with stromal cells but not cultured separately

Summary There is indirect evidence that the in vivo proliferative response of rodent uterine epithelium to estrogen requires interaction with the underlying stroma in pre- and post-pubescent animals. To examine this potential requirement directly, the proliferative response of epithelium to 17β-estradiol in the presence or absence of stroma was measured in vitro. Uterine epithelial and stromal cells were isolated separately from immature or adult mice, and were maintained as monocultures or cocultures in defined, serum-free medium with or without 8 × 10⁻⁹ M 17β-estradiol. Incorporation of bromodeoxyuridine into the DNA was determined by immunolabeling to assay proliferation in individual cells. Cell morphology and immunolabeling of cytokeratin were used to distinguish epithelial from stromal cells. Treatment of cocultures with 17β-estradiol for 24 h increased the proliferation of epithelial cells relative to controls approximately threefold, whereas, in monocultures of epithelial or stromal cells 17β-estradiol decreased the number of bromodeoxyuridine-incorporating cells by approximately half. Furthermore, cell contact between epithelial and stromal cells was important for the effects of 17β-estradiol on cells in cocultures. Approximately three quarters of the 17β-estradiol-induced proliferation of epithelial cells in cocultures was produced by epithelial cells within colonies that were also contacting stromal cells. These results are consistent with the hypothesis that stromal cells mediate the estrogenic proliferative response, and provide evidence that this mediation involves cell contact or stroma-mediated changes in the microenvironment immediately around the epithelial cell.     

An almond-enriched diet increases plasma α-tocopherol and improves vascular function but does not affect oxidative stress markers or lipid levels

Abstract

Vascular dysfunction is one of the major causes of cardiovascular (CV) mortality and increases with age. Epidemiological studies suggest that Mediterranean diets and high nut consumption reduce CV disease risk and mortality while increasing plasma α-tocopherol. Therefore, we have investigated whether almond supplementation can improve oxidative stress markers and CV risk factors over 4 weeks in young and middle-aged men.

Healthy middle-aged men (56 ± 5.8 years), healthy young men (22.1 ± 2.9 years) and young men with two or more CV risk factors (27.3 ± 5 years) consumed 50 g almond/day for 4 weeks. A control group maintained habitual diets over the same period.

Plasma α-tocopherol/cholesterol ratios were not different between groups at baseline and were significantly elevated by almond intervention with 50 g almond/day for 4 weeks (p < 0.05). Plasma protein oxidation and nitrite levels were not different between groups whereas, total-, HDL- and LDL-cholesterols and triglycerides were significantly higher in healthy middle-aged and young men with CV risk factors but were not affected by intake. In the almond-consuming groups, flow-mediated dilatation (FMD) improved and systolic blood pressure reduced significantly after 50 g almonds/day for 4 weeks, but diastolic blood pressure reduced only in healthy men.

In conclusion, a short-term almond-enriched diet can increase plasma α-tocopherol and improve vascular function in asymptomatic healthy men aged between 20 and 70 years without any effect on plasma lipids or markers of oxidative stress.     

Magic traits in speciation: 'magic' but not rare?

Speciation with gene flow is greatly facilitated when traits subject to divergent selection also contribute to non-random mating. Such traits have been called 'magic traits', which could be interpreted to imply that they are rare, special, or unrealistic. Here, we question this assumption by illustrating that magic traits can be produced by a variety of mechanisms, including ones in which reproductive isolation arises as an automatic by-product of adaptive divergence. We also draw upon the theoretical literature to explore whether magic traits have a unique role in speciation or can be mimicked in their effects by physically linked trait-complexes. We conclude that magic traits are more frequent than previously perceived, but further work is needed to clarify their importance.     

Autophagy is decreased in mesenteric fat tissue but not in intestinal mucosae of patients with Crohn’s disease

Crohn??s disease (CD) is a chronic intestinal disease with a multifactorial etiology. Recently, a role for mesenteric fat has been proposed in CD pathophysiology, since fat hypertrophy is detected close to the affected intestinal area; however, there are few studies regarding autophagy and the hypertrophied mesenteric tissue in CD. To evaluate autophagy-related proteins in intestinal mucosae and mesenteric fat of patients with CD and controls, patients with ileocecal CD (CD Group) and with non-inflammatory disease (FC Group) selected for surgery were studied. Expression of LC3-II was determined by immunoblotting of protein extracts. In addition, beclin-1, LC3 and Atg16-L1 RNA levels were measured using RT-PCR. The expression of LC3-II was significantly lower in the mesenteric tissue and higher in intestinal mucosae of CD when compared to controls. However, mRNA expression of autophagy-related proteins was similar when comparing the mesenteric fat groups. These findings suggest a defect in autophagy activation in the mesenteric fat tissue of CD individuals, which could be involved in the maintenance of the inflammatory process.