Stability of Naked Nucleic Acids under Physical Treatment and Powder Formation: Suitability for Development as Dry Powder Formulations for Inhalation.

A number of functional nucleic acids, including plasmid DNA (pDNA) and small interfering RNA (siRNA), have been attracting increasing attention as new therapeutic modalities worldwide. Dry pDNA and siRNA powder formulations for inhalation are considered practical in clinical applications for respiratory diseases. However, physical stresses in the powder-forming process may destabilize nucleic acids, particularly when vectors with stabilizing effects are not used. We herein compare the stability of naked pDNA and siRNA through various physical treatments and two powder-forming processes. The structural and functional integrities of pDNA were markedly reduced via sonication, heating, and atomization, whereas those of siRNA were preserved throughout all of the physical treatments investigated. Spray-dried and spray-freeze-dried powders of siRNA maintained their structural and functional integrities, whereas those of pDNA did not. These results demonstrate that siRNA is more suitable for powder formation in the naked state than pDNA due to its higher stability under physical treatments. Furthermore, a spray-freeze-dried powder with a high content of naked siRNA (12% of the powder) was successfully produced that preserved its structural and functional integrities, achieving high aerosol performance with a fine particle fraction of approximately 40%.

Bowel perforation associated with Cushing's disease: a case report with literature review.

Although rare, endogenous hypercortisolemia, including Cushing's disease (CD), is known to cause bowel perforation and to mask typical symptoms of bowel perforation, leading to delayed diagnosis. Additionally, elderly patients with CD are considered to be at a higher risk for bowel perforation because intestinal tissue fragility tends to increase in the elderly. Herein, we describe a rare case in which a young adult patient with CD was diagnosed with bowel perforation associated with CD following severe abdominal pain. A 24-year-old Japanese man was admitted to the hospital for the evaluation of ACTH-dependent Cushing's syndrome. He suddenly complained of severe abdominal pain on the 8th day of hospitalization. Computed tomography revealed free air around the sigmoid colon. The patient was diagnosed with bowel perforation, underwent emergency surgery, and was saved. He was subsequently diagnosed with CD, and the pituitary adenoma was resected transsphenoidally. To date, eight cases of bowel perforation due to CD had been reported, with a median age of 61 years at the time of bowel perforation. Hypokalemia was detected in half of the patients, and all had a history of diverticular disease. Nevertheless, not many patients complained of peritoneal irritation. In conclusion, this is the youngest reported case with bowel perforation due to CD and the first report of bowel perforation in a patient without a history of diverticular disease. Bowel perforation may occur in patients with CD, irrespective of age and the presence of hypokalemia, diverticular disease, or peritoneal irritation.

An elderly patient with 17α-hydroxylase deficiency misdiagnosed as primary aldosteronism: a case report.

BACKGROUND: 17α-hydroxylase deficiency (17OHD) is a rare autosomal recessive disorder. Aldosterone levels are usually low in patients with 17OHD. However, among the approximately 150 cases of 17OHD reported to date, aldosterone levels were not low in all cases. Therefore, some 17OHD cases may have been misdiagnosed as primary aldosteronism (PA) cases. Often before puberty, 17OHD is diagnosed because of abnormal genital morphology and menstrual irregularities. However, we report a very rare case of 17OHD in an elderly patient with a high aldosterone/renin ratio (ARR) similar to that in PA. CASE PRESENTATION: A 63-year-old Japanese woman was transferred to our medical facility for the evaluation of bilateral adrenal hypertrophy, which was incidentally discovered during an abdominal examination after cholecystectomy. The patient had hypokalemia and a high aldosterone/renin ratio. Her medical history included hypertension and right intracerebral capsular hemorrhage at the age of 30 years. Additional testing revealed low cortisol, high adrenocorticotropic hormone, and low testosterone and dehydroepiandrosterone sulfate, indicating congenital adrenal hyperplasia. Genetic analysis revealed a mutation in the CYP17A1 gene and a karyotype of 46, XY; hence, she was diagnosed with 17OHD. CONCLUSION: 17OHD can resemble PA. The combination of a high ARR and low cortisol level should trigger the consideration of 17OHD.

Development of spray-freeze-dried siRNA/PEI powder for inhalation with high aerosol performance and strong pulmonary gene silencing activity.

In the present study, a novel dry small interfering RNA (siRNA) powder for inhalation, containing polyethyleneimine (PEI) as a delivery vector, was produced by spray freeze drying (SFD). The powder had spherical and highly porous structure of approximately 10 µm in diameter with high aerosol performance for emission and lung delivery. The reconstituted siRNA/PEI complex after dissolution of the powder had almost the same physicochemical properties and in vitro gene silencing activity as the original one constituted in the sample solution before SFD, showing that the integrity of the siRNA was maintained. In in vivo studies of intratracheal administration into lung metastasis mice and healthy mice, powder with a low dose of 3 µg siRNA exhibited strong and specific gene silencing activity against tumors metastasized to the lungs, whereas it caused no significant histological changes, lactate dehydrogenase leakage, or inflammatory cytokine induction in the lungs. These results strongly indicated that inhalable dry siRNA/PEI powders can provide effective pulmonary gene silencing without severe lung injury and that SFD can be applied to the production of such powders.