Inhalation treatment of cystic fibrosis with lumacaftor and ivacaftor co-delivered by nanostructured lipid carriers

Cystic fibrosis (CF), a most deadly genetic disorder, is caused by mutations of CF transmembrane receptor (CFTR) - a chloride channel present at the surface of epithelial cells. In general, two steps have to be involved in treatment of the disease: correction of cellular defects and potentiation to further increase channel opening. Consequently, a combinatorial simultaneous treatment with two drugs with different mechanisms of action, lumacaftor and ivacaftor, has been recently proposed. While lumacaftor is used to correct p.Phe508del mutation (the loss of phenylalanine at position 508) and increase the amount of cell surface-localized CFTR protein, ivacaftor serves as a CFTR potentiator that increases the open probability of CFTR channels. Since the main organ that is affected by cystic fibrosis is the lung, the delivery of drugs directly to the lungs by inhalation has a potential to enhance the efficacy of the treatment of CF and limit adverse side effects upon healthy tissues and organs. Based on our extensive experience in inhalation delivering of drugs by different nanocarriers, we selected nanostructured lipid carriers (NLC) for the delivery both drugs directly to the lungs by inhalation and tested NLC loaded with drugs in vitro (normal and CF human bronchial epithelial cells) and in vivo (homozygote/homozygote bi-transgenic mice with CF). The results show that the designed NLCs demonstrated a high drug loading efficiency and were internalized in the cytoplasm of CF cells. It was found that NLC-loaded drugs were able to restore the expression and function of CFTR protein. As a result, the combination of lumacaftor and ivacaftor delivered by lipid nanoparticles directly into the lungs was highly effective in treating lung manifestations of cystic fibrosis.

Migraine in the Andes and Headache at Sea Level

In Cerro de Pasco (CP), Peru (altitude 4338 m) 24% of men have migraine with aura. We studied 30 men. Twenty CP natives, examined in CP, were rated using a chronic mountain sickness (CMS) score to separate controls (10) from those with CMS (10), a maladaptation syndrome in natives to altitude which includes severe, recurring headache. We collected white cells in CP and, from the same men, within 1 h of arrival in Lima (150 m above sea level). Ten normal US men volunteered white cells for comparison. After RNA extraction we assessed gene expression by reverse transcription-polymerase chain reaction. Low ATP1A1 subunit of the ATPase gene mRNA expression in CP was correlated with headache ( P = 0.002), acral paraesthesias ( P = 0.004) and CMS score ( P < 0.001). ATP1A1 subunit expression was increased in all Andeans in Lima ( P < 0.001). There were no differences between Andean controls in Lima and US controls. Manipulation of Na+/K+ATPase could offer relief for migraineurs at sea level.

Selected contribution: Lung hypoxia: antioxidant and antiapoptotic effects of liposomal alpha-tocopherol

The aim of this study is to examine the antioxidant and antiapoptotic activity of liposomal alpha-tocopherol (LAT) in anesthetized rats exposed to severe hypoxia. It was shown that intratracheal application of LAT normalized lung phospholipid composition and inhibited lipid peroxidation in lung tissues, which in turn decreased lung edema and damage and improved breathing pattern, oxygen diffusion, and lung gas exchange. LAT also limited the overexpression of genes encoding hypoxia inducible factor-1alpha and both studied forms of phospholipase A(2), and it increased the power of cellular antioxidant and antiapoptotic defense by overexpressing genes encoding Mn- and Cu-Zn-cofactored superoxide dismutases, Bcl-2, and heat shock 70 proteins. The overexpression of studied caspases and their activity were downregulated, which significantly (1.6-2 times) limited apoptosis in lung cells. Finally, all these positive changes decreased mortality during hypoxia from approximately 60% in untreated animals to approximately 30% in the group of rats treated with LAT. The data obtained indicate that LAT may be useful for the correction of hypoxic lung injury.

The influence of cytotoxicity of macromolecules and of VEGF gene modulated vascular permeability on the enhanced permeability and retention effect in resistant solid tumors

PURPOSE

To study the influence of cytotoxicity of macromolecules, VEGF gene expression, and vascular permeability on the enhanced permeability and retention (EPR) effect.

METHODS

Mice bearing xenografts of A2780 multidrug resistant human ovarian carcinoma were treated by free doxorubicin (DOX) and N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-bound DOX (P(GFLG)-DOX), Texas Red (P-TR), and FITC (P-FITC). Antitumor activity, drug distribution in tumor, vascular permeability, VEGF gene expression, and DNA fragmentation were studied.

RESULTS

The accumulation of free DOX led to the VEGF gene overexpression and increased the vascular permeability, which in turn enhanced the drug accumulation in the same location. This positive feedback loop led to a highly inhomogeneous distribution of the drug within the tumor. In contrast, P(GFLG)-DOX down-regulated the VEGF gene and decreased vascular permeability. This negative feedback seemed to prevent additional drug accumulation in dead necrotic tissue, resulting in a more uniform drug distribution and enhanced the antitumor activity P(GFLG)-DOX.

CONCLUSIONS

The EPR effect significantly differed for macromolecules containing DOX when compared to macromolecules without drug. The cytotoxicity of P(GFLG)-DOX amplified the EPR effect, led to a more homogenous distribution of the drug, increased the average drug concentration in tumor and augmented its efficacy.

Familial hypercholesterolemia kindred in Utah with novel C54S mutations of the LDL receptor gene

In the course of investigations of coronary artery disease in Utah, we identified a family whose proband showed elevated plasma levels of LDL cholesterol. To determine the genetic etiology of the lipoprotein abnormalities, we screened DNA samples for mutations in all 18 exons and the exon- intron boundaries of the low-density lipoprotein (LDL) receptor gene. Novel point mutations were identified in the proband: a T-to-A transversion at nucleotide position 223, causing substitution of Ser for Cys at codon 54 in exon 3 of the receptor gene. This amino acid replacement would disrupt one of the disulfide bonds necessary for maintenance of the secondary structure of the repeat at the N-terminal of the receptor, prevent correct folding of the receptor, and result in defective intracellular transport of the receptor.

HPMA copolymer bound adriamycin overcomes MDR1 gene encoded resistance in a human ovarian carcinoma cell line

N-(2-Hydroxypropyl)methacrylamide (HPMA) copolymer-adriamycin (ADR) conjugate containing lysosomally degradable oligopeptide (GFLG) side chains terminated in ADR was synthesized. The effect of free and HPMA copolymer-bound ADR on the viability of A2780 sensitive and A2780/AD multidrug resistant human ovarian carcinoma cells was studied in vitro. As expected, the IC50 dose for the HPMA copolymer-ADR conjugate was higher than for free ADR reflecting the difference in the mechanism of cell entry. The resistant A2780/AD cells demonstrated about 40-times higher resistance to free ADR than the sensitive A2780 cells. On the contrary, there was only a small difference in cytotoxicity of the HPMA copolymer-ADR conjugate toward sensitive A2780 or MDR resistant A2780/AD cells. The IC50 value for A2780/AD was only about 20% higher than the value for sensitive A2780 cells. These data seem to indicate that the HPMA copolymer-ADR conjugate may, at least partially, avoid the ATP driven P-glycoprotein (Pgp) efflux pump. The analysis of the expression of the MDR1 gene which encodes the Pgp, has shown that free ADR in high doses stimulated MDR1 gene expression in sensitive A2780 cells. At the same time both free and HPMA copolymer-ADR conjugate partially inhibited the expression of the MDR1 and beta 2 m genes in multidrug resistant A2780/AD cells.

Superresistance against hypoxia after preliminary adaptation to repeated stress

The study investigated the influence of adaptation to stress on resistance to hypoxia. After rats were adaptated to moderate restraint stress, they were anesthetized and exposed to 6% O2. Adaptation increased tidal volume by 2.6-fold, lung and alveolar ventilation by 1.6- and 1.8-fold, respectively, and O2 consumption by 1.6-fold; limited lactate accumulation in the liver by 2-fold, in the heart by 34%, in the lung by 36%, and in the blood by 36%; and elevated pH. At the same time, preliminary adaptation to stress inhibited the hypoxic activation of lipolysis and peroxidation in all tissues. The concentration of lipid peroxides decreased after adaptation by 1.3- to 1.5-fold in different organs, whereas the content of free fatty acids diminished by 1.7- to 2.3-fold. Finally, after adaptation, mortality decreased under severe hypoxia by 6.5-fold. Thus, the data suggest that the cross-protective effect of adaptation was achieved by the economization of respiration and circulation, by marked augmentation in the ability of tissue to utilize blood O2, and by the limitation of processes that are able to damage tissue membranes, namely, acidosis, lipolysis, and lipid peroxidation.