Effectiveness and safety of PCSK9 inhibitors in real-world clinical practice. An observational multicentre study. The IRIS-PCSK9I study

Background and aims

The benefits of the PCSK9 inhibitors, alirocumab and evolocumab, in lowering LDL-cholesterol and preventing major adverse cardiac events (MACE) have been demonstrated in pivotal clinical trials. However, few studies of routine clinical practice have been conducted to analyse and compare the efficacy and safety of the two drugs.

Methods

Retrospective observational study of patients treated with a PCSK9 inhibitor in five hospitals in Andalusia (southern Spain). Baseline demographic and clinical data, LDL-cholesterol levels and the occurrence of MACEs during the follow-up period were recorded.

Results

A total of 141 patients were included in the study: 90 were treated with alirocumab and 51 with evolocumab. The patients' mean age (IQR) was 58 (11) years and 58 (41%) were women. The most frequent concomitant medications were statins, 94 (66.7%), followed by antiplatelet therapy (66%) and ezetimibe (65.2%). The median (IQR) follow-up period was 18 (18) months, with 18 (24) for alirocumab and 11 (18) for evolocumab. At the six-month follow-up visit, LDL-cholesterol values had decreased to pre-treatment levels and remained significantly decreased (p < 0.05) over time, for both drugs, and a greater reduction was achieved in patients with established cardiovascular disease and concomitant treatment with statins. With respect to adverse effects, there were nine MACEs (6.4%), of which seven were with alirocumab (7.8%) and two with evolocumab (3.9%) (p NS). Other adverse effects (9.2%) included local erythema (3.5%), muscle cramps (2.1%), respiratory symptoms (2.1%) and asthaenia (1.4%).

Conclusions

The efficacy and safety of alirocumab and evolocumab in routine clinical practice are consistent with the findings of the pivotal clinical trials.

HIV infection and multiple sclerosis: a case with unexpected "no evidence of disease activity" status

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system whose etiology remains unclear. It has been suggested that MS can be triggered by certain viruses; however, human immunodeficiency virus (HIV) infection is associated with reduced incidence of MS. We present the case of a young patient diagnosed with active relapsing-remitting MS whose clinical course substantially improved following HIV infection and treatment. The patient achieved no evidence of disease activity status without any disease-modifying drugs. Both HIV-induced immunosuppression and antiretroviral therapy may have attenuated the clinical course in this patient.

Ionic coupling and mitotic synchrony of siblings in a Drosophila cell line

Following mitosis in many cell lines, siblings remain adjoined in dyads until further cell division. We report here a series of experiments designed to ascertain the nature of this apposition in the embryonic Kc cell line of Drosophila melanogaster. We have found that (1) cell division in siblings is highly synchronized when compared to that in nonsiblings: (2) siblings in dyads are dye coupled with respect to Lucifer Yellow, but intercellular diffusion of larger molecules (FITC-dextran at 6 and 24 kDa) is retarded: (3) siblings are electrically coupled by an ungated low-resistance intercellular connection which is resistant to treatment with octanol and CO2, both known to close gap junction channels: and (4) members of a dyad are joined by a cytoplasmic bridge. Structures resembling septate junctions are also found between siblings and between cells in aggregates. The evidence accumulated here suggests that cytokinesis in Kc dyads is incomplete, resulting in an intercellular pathway that may provide for the passage of a molecular or electrical signal that regulates subsequent mitosis.

Electrophysiological properties of gap junctions between dissociated pairs of rat hepatocytes

Physiological properties of isolated pairs of rat hepatocytes were examined within 5 h after dissociation. These cells become round when separated, but cell pairs still display membrane specializations. Most notably, canaliculi are often present at appositional membranes which are flanked by abundant gap and tight junctions. These cell pairs are strongly dye-coupled; Lucifer Yellow CH injected into one cell rapidly diffuses to the other. Pairs of hepatocytes are closely coupled electrically. Conductance of the junctional membrane is not voltage sensitive: voltage clamp studies demonstrate that gj is constant in response to long (5 s) transjunctional voltage steps of either polarity (to greater than +/- 40 mV from rest). Junctional conductance (gj) between hepatocyte pairs is reduced by exposure to octanol (0.1 mM) and by intracellular acidification. Normal intracellular pH (pHi), measured with a liquid ion exchange microelectrode, was generally 7.1-7.4, and superfusion with saline equilibrated with 100% CO2 reduced pHi to 6.0-6.5. In the pHi range 7.5-6.6, gj was constant. Below pH 6.6, gj steeply decreased and at 6.1 coupling was undetectable. pHi recovered when cells were rinsed with normal saline; in most cases gj recovered in parallel so that gj values were similar for pHs obtained during acidification or recovery. The low apparent pK and very steep pHi-gj relation of the liver gap junction contrast with higher pKs and more gradually rising curves in other tissues. If H+ ions act directly on the junctional molecules, the channels that are presumably homologous in different tissues must differ with respect to reactive sites or their environment.

Cell junctions in early embryos of squid (Loligo pealei)

Squid embryos examined by freeze-fracture and thin-section electron microscopy exhibit identifiable gap junctions during mid-cleavage stages (stages 7-8), and junctional complexes composed of adherent appositions, elaborate septate junctions and gap junctions at slightly later stages (stages 12-13). During germinal layer establishment (stages 12-13) cytoplasmic bridges frequently link the embryonic cells. The presence of gap junctions in cleavage-stage embryos provides the morphological substrate for a demonstrated pathway of direct cell-cell communication that is modifiable by experimental treatments and may be physiologically regulatable. The existence of septate junctions and adherent contacts at later stages suggests that some functional specialization, perhaps the establishment of a strongly joined framework of cells at the surface of the embryo, accompanies the formation of germinal layers.