Ventilatory acclimatization to hypoxia is a time-dependent increase in ventilation and the hypoxic ventilatory response (HVR) that involves neural plasticity in both carotid body chemoreceptors and brainstem respiratory centers. The mechanisms of such plasticity are not completely understood but recent animal studies show it can be blocked by administering ibuprofen, a nonsteroidal anti-inflammatory drug, during chronic hypoxia. We tested the hypothesis that ibuprofen would also block the increase in HVR with chronic hypoxia in humans in 15 healthy men and women using a double-blind, placebo controlled, cross-over trial. The isocapnic HVR was measured with standard methods in subjects treated with ibuprofen (400mg every 8 hrs) or placebo for 48 hours at sea level and 48 hours at high altitude (3,800 m). Subjects returned to sea level for at least 30 days prior to repeating the protocol with the opposite treatment. Ibuprofen significantly decreased the HVR after acclimatization to high altitude compared to placebo but it did not affect ventilation or arterial O2 saturation breathing ambient air at high altitude. Hence, compensatory responses prevent hypoventilation with decreased isocapnic ventilatory O2-sensitivity from ibuprofen at this altitude. The effect of ibuprofen to decrease the HVR in humans provides the first experimental evidence that a signaling mechanism described for ventilatory acclimatization to hypoxia in animal models also occurs in people. This establishes a foundation for the future experiments to test the potential role of different mechanisms for neural plasticity and ventilatory acclimatization in humans with chronic hypoxemia from lung disease.

The scale of the COVID-19 pandemic forced urgent measures for the development of new therapeutics. One of these strategies is the use of convalescent plasma (CP) as a conventional source for passive immunity. Recently, there has been interest in CP-derived exosomes. In this report, we present a structural, biochemical, and biological characterization of our proprietary product, convalescent human immune plasma-derived exosome (ChipEXO), following the guidelines set forth by the Turkish Ministry of Health and the Turkish Red Crescent, the Good Manufacturing Practice, the International Society for Extracellular Vesicles, and the Gene Ontology Consortium. The data support the safety and efficacy of this product against SARS-CoV-2 infections in preclinical models.

Pulmonary arterial hypertension (PAH) is a life‐threatening disease characterized by a constant high pulmonary artery pressure and the remodeling of the vessel. Chloroquine (CLQ) has been observed to inhibit calcium influx. The aim of this study is to investigate the effect of CLQ on transient receptor cationic proteins (TRPC1 and TRPC6) and extracellular calcium‐sensitive receptor (CaSR) in a hypoxic PAH model. In this study, 8‐ to 12‐week‐old 32 male Wistar albino rats, weighing 200 to 300 g, were used. The rats were studied in four groups, including normoxy control, n = 8; normoxy CLQ (50 mg/kg/28 d), n = 8; hypoxia (HX; 10% oxygen/28 d) control, n = 8; and HX (10% oxygen/28 d) + CLQ (50 mg/kg), N = 8. Pulmonary arterial medial wall thickness, pulmonary arteriole wall, TRPC1, TRPC6, and CaSR expressions were evaluated by immunohistochemistry, polymerase chain reaction, and enzyme‐linked immunosorbent assay methods. At the end of the experiment, a statistically significant increase in the medial wall thickness was observed in the hypoxic group as compared with the control group. However, in the HX + CLQ group, there was a statistically significant decrease in the vessel medial wall as compared with the HX group. In the TRPC1‐, TRPC6‐, and CaSR‐immunopositive cell numbers, messenger RNA expressions and biochemical results showed an increase in the HX group, whereas they were decreased in the HX + CLQ group. The inhibitory effect of CLQ on calcium receptors in arterioles was observed in PAH.

Chronic hypoxia negatively affects male fertility by causing pathological changes in male reproductive system. However, underlying mechanisms of this damage are unknown. Chloroquine (CLQ) is an anti‐inflammatory agent that is widely used in the treatment of inflammation‐related diseases such as malaria and rheumatoid arthritis. This study aimed to investigate the therapeutic effects of CLQ in the hypoxia‐induced testicular damage via assessment of hypoxic response, endoplasmic reticulum stress and apoptosis. For this purpose, 32 Wistar albino rats were divided into 4 groups as control (given 20%‐21% O2, no treatment), CLQ (given 50 mg/kg and 20%‐21% O2 for 28 days), hypoxia (HX) (given 10% O2 for 28 days) and HX + CLQ (given 50 mg/kg and 10% O2 for 28 days). After the experiment, blood samples and testicular tissues were taken. Histopathological evaluation was performed on testicular tissues and hypoxia‐inducible factor 1‐α (HIF1‐α), heat shock proteins (HSPs) HSP70, HSP90 and growth arrest and DNA damage‐inducible gene 153 (GADD153) expression levels were detected via immunohistochemistry. Moreover, apoptotic cells were detected via terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) staining and serum testosterone levels were determined by enzyme‐linked immunosorbent assay (ELISA) assay. Histopathological changes, apoptotic cell numbers and HIF1‐α, HSP70, HSP90 and GADD153 expressions significantly increased in HX group (P < .05). Moreover, serum testosterone levels decreased in this group (P > .05). However, CLQ exerted a strong ameliorative effect on all parameters in HX + CLQ group. According to our results, we suggested that CLQ can be considered as an alternative protective agent for eliminating the negative effects of hypoxic conditions on male fertility.