Biomarkers of Inflammation and Axonal Degeneration/Damage in Patients with Newly Diagnosed Multiple Sclerosis: Contributions of the Soluble CD163 CSF/Serum Ratio to a Biomarker Panel

Background

Expression of soluble CD163 (sCD163), a macrophage/microglia biomarker, is increased in inflammatory conditions, and sCD163 levels in the cerebrospinal fluid (CSF) have recently been shown to be elevated in patients with multiple sclerosis (MS): the sCD163 CSF/serum ratio was elevated in patients with relapsing-remitting MS (RRMS), primary progressive MS (PPMS), and clinically isolated syndrome (CIS) compared with symptomatic controls.

Objective

To investigate the contributions of the sCD163 CSF/serum ratio to a biomarker panel focusing on inflammation and axonal degeneration in newly diagnosed MS; thus optimising a diagnostic biomarker panel for MS.

Methods

After a full MS diagnostic work-up, including collection of paired samples of CSF and serum, 125 patients were included in this study. Patients were divided into groups based on their diagnosis, and patients with normal clinical and paraclinical findings were defined as symptomatic controls. Serum and CSF levels, ratios, and indices of sCD163, CXCL13, osteopontin, neopterin, and CSF levels of neurofilament light polypeptide were determined by enzyme-linked immunosorbent assays (ELISAs). For sCD163 the results constitute a post-hoc analysis of already published data.

Results

All tested biomarkers, notably the sCD163 ratio, the CXCL13 ratio, the NEO ratio, the CSF level of NfL, the IgG index, and the serum level of OPN, were significantly correlated to RRMS, PPMS, and/or CIS. The individual biomarkers in single tests had a lower performance than the IgG index, however, their combined receiver operating characteristic (ROC) curve demonstrated excellent diagnostic discriminatory power.

Conclusion

The biomarker panel showed distinct profiles for each patient group and could be a valuable tool for clinical differentiation of MS subgroups. The combined ROC analysis showed that sCD163 contributes positively as a diagnostic marker to a panel of established MS biomarkers. Patients with PPMS were demonstrated to have significantly elevated levels of both inflammatory and degenerative markers.     

Simulating viability of a spadefoot toad Pelobates fuscus metapopulation in a landscape fragmented by a road

A stochastic simulation model allowing for demographic and environmental stochasticity was developed in order to predict the dynamics of a Pelobates fuscus metapopulation. The metapopulation (consisting of ca 1000 adult individuals) was intensively studied in the field for a period of four years and the simulation model was parameterised (sex ratio, age‐specific survival rates, fecundity and dispersal between subpopulations) using field data. A sensitivity analysis revealed that a change in the juvenile yearly survival rate has a relatively larger effect on subpopulation persistence than adult survival rate and fecundity rate have. The probability of subpopulation persistence for one hundred years increased from 0 to 0.6 with a change in juvenile yearly survival rate from 0.35 to 0.40. Varying dispersal rate (from 0 to 1% of the individuals in a subpopulation moving to another subpopulation within a year) showed that four of the five subpopulations are dependent on the last one for persistence, indicating a source‐sink structure of the metapopulation. The subpopulation with the highest estimated juvenile survival has a far higher persistence probability than the others; they in turn would go extinct were it not for the occasional input of individuals from the source subpopulation. The source‐sink structure was also apparent when simulating the isolation effect of the road: persistence of the subpopulation isolated by the road decreases markedly with only a 20% decrease in the number of individuals dispersing to this pond. Environmental stochasticity decreases persistence time of the source subpopulation, but increases persistence time of the unstable ones. This is probably due to the presence of overcompensating density‐dependent factors affecting the subpopulations and to the more general effect of stochasticity: it may temporarily change reproduction and mortality rates, increase time to extinction for unstable subpopulations through a rescue effect; and decrease time to extinction for the more stable subpopulations.     

Progesterone and levonorgestrel regulate expression of 17βHSD-enzymes in progesterone receptor positive breast cancer cell line T47D

The use of combined hormone replacement therapy (HRT) with oestrogens and progestins in postmenopausal women has been associated with an increased risk for developing breast cancer. The reasons are not fully understood, but influence of HRT on endogenous conversion of female sex hormones may be involved. The expression of 17β hydroxysteroid dehydrogenases (17βHSD), which are enzymes catalysing the conversion between more or less potent oestrogens, may partly be regulated by progestins. The breast cancer cell lines T47D, MCF7 and ZR75-1 were treated with progesterone, medroxyprogesterone acetate (MPA) or levonorgestrel for 48 and 72 h at 10(-7) and 10(-9)M to investigate influence on 17βHSD1, 17βHSD2 and 17βHSD5 mRNA expression measured by real time PCR. The expression of 17βHSD1 increased in progesterone and levonorgestrel treated T47D cells (48 h 10(-7)M P=0.002; P<0.001) and 17βHSD5 increased after progesterone treatment (48 h 10(-7)M P=0.003), whereas the expression of 17βHSD2 decreased after the (48 h 10(-7)M P=0.003; P<0.001). Similar, but less prominent effects were seen in MCF7 and ZR75-1. The progestin effects on 17βHSD-expression were lost when T47D cells were co-treated with progestins and the progesterone receptor (PgR) inhibitor mifprestone. We show that both reductive (17βHSD1 and 17βHSD5) and oxidative (17βHSD2) members of the 17βHSD-family are under control of progesterone and progestins in breast cancer cell lines. This is most clear in T47D cells which have high PgR expression. 17βHSD-enzymes are important players in the regulation of sex steroids locally in breast tumours and tumoural expression of various 17βHSD-enzymes have prognostic and treatment predictive relevance. We propose a mechanism for increased breast cancer risk after HRT in which hormone replacement affects the expression of 17βHSD-enzymes, favouring the expression of reductive enzymes, which in turn could increase levels of bioactive and mitogenic estrogens in local tissue, e.g. breast tissue.     

The potential for selection on pollen colour dimorphisms in Nigella degenii: morph-specific differences in pollinator visitation, fertilisation success and siring ability

Two subspecies of Nigella degenii (Ranunculaceae) possess a dimorphism in pollen colour and vary extensively in frequency of the two morphs in natural populations. Here we investigate the role of selection on pollen colour during the pollination phase in the two subspecies and its potential contribution to the maintenance of this colour variation. In a combination of common garden experiments and field observations, we obtained data on pollinator visitation rates and explored the effect of pollen colour on fertilisation success and siring ability under conditions of low vs. high pollen competition. In experimental gardens, naïve pollinators responded differently to plants with different pollen colour, but the favoured morph varied between dates and locations, and colour morphs were not visited in a frequency-dependent manner. Donor plants with dark pollen had a reproductive advantage (higher seed set) in single-donor pollinations, but the realised siring ability (measured by progeny morph ratio) was highly variable between different two-donor crosses with no general bias towards the light or dark morph. Therefore, although the dark pollen type appears to have a general selective advantage in terms of fertilisation success, our data are also consistent with a scenario involving the maintenance of both colour morphs, particularly under conditions of high pollen competition, a variable genetic background and/or spatial or temporal variation in the pollinator fauna.     

Evolution of the Arctic Calanus complex: an Arctic marine avocado?

Before man hunted the large baleen whales to near extinction by the end of the nineteenth century, Arctic ecosystems were strongly influenced by these large predators. Their main prey were zooplankton, among which the calanoid copepod species of the genus Calanus, long considered key elements of polar marine ecosystems, are particularly abundant. These herbivorous zooplankters display a range of adaptations to the highly seasonal environments of the polar oceans, most notably extensive energy reserves and seasonal migrations to deep waters where the non-feeding season is spent in diapause. Classical work in marine ecology has suggested that slow growth, long lifespan and large body size in zooplankton are specific adaptations to life in cold waters with short and unpredictable feeding seasons. Here, we challenge this understanding and, by using an analogy from the evolutionary and contemporary history of the avocado, argue that predation pressure by the now nearly extinct baleen whales was an important driving force in the evolution of life history diversity in the Arctic Calanus complex.     

Conformation dependent depolymerisation kinetics of polysaccharides studied by viscosity measurements

Degradation of single- and multiple-stranded polysaccharides by acid hydrolysis or free radical depolymerisation with H₂O₂/Fe²⁺ was monitored by viscosity measurements. Single-stranded polysaccharides (alginate, hydroxyethyl cellulose, carboxymethyl cellulose and κ-carrageenan in its disordered conformation) gave the expected linear relationship between 1/η_sp^(1/a) and the degradation time, where a is the Mark-Houwink-Sakurada exponent. Double-stranded xanthan and triple-stranded scleroglucan showed a different pattern. Following an initial period with apparently slow degradation, a second regime was entered where the apparent degradation rate was much higher, and where η_sp followed the power law, η_sp t^−va. However, the estimated values of the parameter v differed from those calculated by a Monte Carlo method for double- (xanthan) and triple-(scleroglucan) stranded polymers. κ-Carrageenan in its iodide-induced ordered conformation was very stable in acid as compared to the disordered conformation. In the ordered state the apparent degradation rate was initially constant, but increased in later stages. However, the double-logarithmic plot of η_sp versus time showed that there was neither a pronounced stable regime nor a regime following the power law. The degradation of gellan resulted in a rapid and linear increase in 1/η_sp with degradation time, both in the ordered and disordered conformation. The same type of degradation kinetics was obtained for welan.