Effect of PCSK9 inhibitors on remnant cholesterol and lipid residual risk: The LIPID-REAL registry.

BACKGROUND: Monoclonal antibodies that inhibit the proprotein convertase subtilisin/kexin type 9 (PCSK9) reduce low-density lipoprotein cholesterol (LDLc) by 55%, regardless of baseline treatments. Nonetheless, the effect of other lipid parameters, such as cholesterol remnants or, the so-called lipid residual risk, is unknown. METHODS: Multicenter and retrospective registry of patients treated with PCSK9 inhibitors from 14 different hospitals in Spain. Before and on-treatment lipid parameters were recorded. Residual lipid risk was estimated by (1) cholesterol remnants, (2) triglycerides/HDLc ratio (TG/HDL), (3) total cholesterol/HDLc (TC/HDL) and (4) the triglycerides-to-glucose index (TGGi). RESULTS: Six hundred fifty-two patients were analysed, mean age of 60.2 (9.63) years, 24.69% women and mean LDLc before treatment 149.24 (49.86) mg/dl. Median time to second blood determination was 187.5 days. On-treatment LDLc was 67.46 (45.78) mg/dl, which represented a 55% reduction. Significant reductions were observed for TG/HDL ratio, cholesterol remnants, TC/HDL ratio and TGGi. As consequence, 34.61% patients had LDLc <55 mg/dl and cholesterol remnants <30 mg/dl; additionally, 31.95% had cholesterol remnants <30 mg/dl but LDLc >55 mg/dl. Patients who had levels of cholesterol remnants >30 mg/dl before initiating the treatment with PCSK9 had higher reductions in cholesterol remnants, TG/HDL ratio, TC/HDL and TGGi. By contrast, no reduction differences were observed according to baseline LDLc (< or > the mean), age, gender or obesity. CONCLUSIONS: This multicenter and retrospective registry of real-world patients treated with PCSK9 inhibitors demonstrates a positive effect on cholesterol remnants and lipid residual risk beyond LDLc reductions.

Sex Differences in Low-Density Lipoprotein Cholesterol Reduction With PCSK9 Inhibitors in Real-world Patients: The LIPID-REAL Registry.

BACKGROUND: Previous evidence supports that monoclonal antibodies that inhibit the proprotein convertase subtilisin/kexin type 9 (PCSK9) reduce low-density lipoprotein cholesterol (LDLc) by 50%-65%, regardless of baseline treatments. We tested possible sex differences in a multicentre registry of real-world patients treated with PCSK9 inhibitors. METHODS: This is a multicentre and retrospective study of 652 patients initiating treatment with any PCSK9 inhibitor in 18 different hospitals. Before-treatment and on-treatment LDLc and medical treatments, clinical indication, and clinical features were recorded. RESULTS: Women represented 24.69% of the cohort. The use of statins was similar in both sexes, but women were receiving most frequently ezetimibe. Before-treatment median LDLc was 135 (interquartile range 115-166) mg, and it was higher in women. The median on-treatment LDLc was 57 (interquartile range 38-84) mg/dL, which represented a mean 54.5% reduction. On-treatment LDLc was higher in women, and the mean LDLc reduction was lower in women (47.4% vs. 56.9%; P = 0.0002) receiving evolocumab or alirocumab. The percentage of patients who achieved ≥50% LDLc reduction was higher in men (71.36% vs. 57.62%; P = 0.002). According to LDLc before-treatment quartiles, LDLc reduction was statistically lower in women in the 2 highest and a significant interaction of women and baseline LDLc >135 mg/dL was observed. Women were negatively associated with lower rates of LDLc treatment target achievement (odds ratio: 0.31). Differences were also observed in women with body mas index >25 kg/m2. Only 14 patients (2.14%) presented side effects. CONCLUSIONS: This multicentre and retrospective registry of real-world patients treated with PCSK9 inhibitors highlights significant gender differences in LDLc reduction.

Cytogenetic Analysis of the Asian Box Turtles of the Genus Cuora (Testudines, Geoemydidae).

The Asian box turtle genus Cuora currently comprises 13 species with a wide distribution in Southeast Asia, including China and the islands of Indonesia and Philippines. The populations of these species are rapidly declining due to human pressure, including pollution, habitat loss, and harvesting for food consumption. Notably, the IUCN Red List identifies almost all species of the genus Cuora as Endangered (EN) or Critically Endangered (CR). In this study, we explore the karyotypes of 10 Cuora species with conventional (Giemsa staining, C-banding, karyogram reconstruction) and molecular cytogenetic methods (in situ hybridization with probes for rDNA loci and telomeric repeats). Our study reveals a diploid chromosome number of 2n = 52 chromosomes in all studied species, with karyotypes of similar chromosomal morphology. In all examined species, rDNA loci are detected at a single medium-sized chromosome pair and the telomeric repeats are restricted to the expected terminal position across all chromosomes. In contrast to a previous report, sex chromosomes are neither detected in Cuoragalbinifrons nor in any other species. Therefore, we assume that these turtles have either environmental sex determination or genotypic sex determination with poorly differentiated sex chromosomes. The conservation of genome organization could explain the numerous observed cases of interspecific hybridization both within the genus Cuora and across geoemydid turtles.

Interstitial Telomeric Repeats Are Rare in Turtles.

Telomeres are nucleoprotein complexes protecting chromosome ends in most eukaryotic organisms. In addition to chromosome ends, telomeric-like motifs can be accumulated in centromeric, pericentromeric and intermediate (i.e., between centromeres and telomeres) positions as so-called interstitial telomeric repeats (ITRs). We mapped the distribution of (TTAGGG)n repeats in the karyotypes of 30 species from nine families of turtles using fluorescence in situ hybridization. All examined species showed the expected terminal topology of telomeric motifs at the edges of chromosomes. We detected ITRs in only five species from three families. Combining our and literature data, we inferred seven independent origins of ITRs among turtles. ITRs occurred in turtles in centromeric positions, often in several chromosomal pairs, in a given species. Their distribution does not correspond directly to interchromosomal rearrangements. Our findings support that centromeres and non-recombining parts of sex chromosomes are very dynamic genomic regions, even in turtles, a group generally thought to be slowly evolving. However, in contrast to squamate reptiles (lizards and snakes), where ITRs were found in more than half of the examined species, and birds, the presence of ITRs is generally rare in turtles, which agrees with the expected low rates of chromosomal rearrangements and rather slow karyotype evolution in this group.

Author Correction: Sex is determined by XX/XY sex chromosomes in Australasian side-necked turtles (Testudines: Chelidae).

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Sex is determined by XX/XY sex chromosomes in Australasian side-necked turtles (Testudines: Chelidae).

Turtles demonstrate variability in sex determination and, hence, constitute an excellent model for the evolution of sex chromosomes. Notably, the sex determination of the freshwater turtles from the family Chelidae, a species-rich group with wide geographical distribution in the southern hemisphere, is still poorly explored. Here we documented the presence of an XX/XY sex determination system in seven species of the Australasian chelid genera Chelodina, Emydura, and Elseya by conventional (karyogram reconstruction, C-banding) and molecular cytogenetic methods (comparative genome hybridization, in situ hybridization with probes specific for GATA microsatellite motif, the rDNA loci, and the telomeric repeats). The sex chromosomes are microchromosomes in all examined species of the genus Chelodina. In contrast, the sex chromosomes are the 4th largest pair of macrochromosomes in the genera Emydura and Elseya. Their X chromosomes are submetacentric, while their Y chromosomes are metacentric. The chelid Y chromosomes contain a substantial male-specific genomic region with an accumulation of the GATA microsatellite motif, and occasionally, of the rDNA loci and telomeric repeats. Despite morphological differences between sex chromosomes, we conclude that male heterogamety was likely already present in the common ancestor of Chelodina, Emydura and Elseya in the Mesozoic period.

Turtles of the genera Geoemyda and Pangshura (Testudines: Geoemydidae) lack differentiated sex chromosomes: the end of a 40-year error cascade for Pangshura.

For a long time, turtles of the family Geoemydidae have been considered exceptional because representatives of this family were thought to possess a wide variety of sex determination systems. In the present study, we cytogenetically studied Geoemyda spengleri and G. japonica and re-examined the putative presence of sex chromosomes in Pangshura smithii. Karyotypes were examined by assessing the occurrence of constitutive heterochromatin, by comparative genome hybridization and in situ hybridization with repetitive motifs, which are often accumulated on differentiated sex chromosomes in reptiles. We found similar karyotypes, similar distributions of constitutive heterochromatin and a similar topology of tested repetitive motifs for all three species. We did not detect differentiated sex chromosomes in any of the species. For P. smithii, a ZZ/ZW sex determination system, with differentiated sex chromosomes, was described more than 40 years ago, but this finding has never been re-examined and was cited in all reviews of sex determination in reptiles. Here, we show that the identification of sex chromosomes in the original report was based on the erroneous pairing of chromosomes in the karyogram, causing over decades an error cascade regarding the inferences derived from the putative existence of female heterogamety in geoemydid turtles.

Tyrosine hydroxylase haploinsufficiency prevents age-associated arterial pressure elevation and increases half-life in mice.

Catecholamines are essential for the maintenance of physiological homeostasis under basal and stress conditions. We aim to determine the impact of deletion of a single allele of the tyrosine hydroxylase (Th) gene might have on aging arterial pressure and life-span. We found that Th haploinsufficiency prevents age-associated increase of arterial pressure (AP) in mature adult mice, and it results in the extension of the half-life of Th-heterozygous (TH-HET) mice respect to their wild-type (WT) littermates. Heart performance was similar in both genotypes. To further investigate the lack of increase in AP with age in TH-HET mice, we measured the AP response to intra-peritoneal administration of substances involved in AP regulation. The response to acetylcholine and the basal sympathetic tone were similar in both genotypes, while norepinephrine had a greater pressor effect in TH-HET mice, which correlated with altered adrenoreceptor expression in blood vessels and the heart. Furthermore, sympatho-adrenomedular response to stress was attenuated in TH-HET mice. Plasma catecholamine levels and urine glucose increased markedly in WT but not in TH-HET mice after stress. Our results showed that TH-HET mice are resistant to age-associated hypertension, present a reduction in the sympathetic response to stress and display an extended half-life.

Increased oxidative stress, the renin-angiotensin system, and sympathetic overactivation induce hypertension in kidney androgen-regulated protein transgenic mice.

Gender differences in the incidence and severity of hypertension have suggested the involvement of a sex-dependent mechanism. Transgenic (Tg) mice overexpressing kidney androgen-regulated protein (KAP) specifically in kidney showed hypertension associated with oxidative stress. Reactive oxygen species (ROS) are strongly implicated in the pathological signaling leading to hypertension in a framework that includes renin-angiotensin system (RAS) activation, increased sympathetic activity, and cardiac remodeling. In this report, we observed that plasma levels of angiotensin II and catecholamines were increased in KAP Tg mice, compared with wild-type animals. Systemic administration of Tempol, a membrane-permeative superoxide dismutase mimetic, reduced arterial pressure as well as urinary excretion of oxidative stress markers and reduced both angiotensin II and norepinephrine plasma levels in KAP Tg mice. Intracerebroventricular administration of Tempol also reduced arterial pressure in Tg mice. Moreover, administration of apocynin and DPI, inhibitors of NADPH oxidase, a major source of ROS, also reduced arterial pressure and both angiotensin II and norepinephrine plasma levels in Tg mice. Thus, we analyzed the involvement of the RAS and sympathetic nervous system in KAP Tg mouse hypertension. Both captopril and losartan reduced arterial blood pressure in Tg mice, as also occurred after ß-adrenergic blockade with atenolol. Also, intracerebroventricular losartan administration reduced arterial pressure in KAP Tg mice. Our data demonstrate that hypertension in male KAP Tg mice is based on increased oxidative stress, increased sympathetic activity, and RAS activation. Moreover, our results suggest a role for increased oxidative stress in the CNS as a major cause of hypertension in these animals.