Pulmonary Langerhans cell histiocystosis (PLCH) and lymphangioleiomyomatosis (LAM) have circulating cells with loss of heterozygosity of the TSC2 gene

Lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is an ultra-rare, slowly progressive neoplastic cystic disease, belonging to the group of PEComas. It can occur sporadically or associated to tuberous sclerosis complex disease and affects mainly women in child-birth age. Dyspnoea is the most frequent symptom referred to the time of diagnosis, however spontaneous pneumothorax may be a typical presentation associated to extrathoracic manifestations, such as renal angiomyolipomas. In the last decade, important advances in understanding molecular mechanisms underlying the LAM pathogenesis have been reached. It has allowed to obtain improvements in the research of novel biomarkers, treatment and a better management of the disease.

The world of rare interstitial lung diseases

The world of rare interstitial lung diseases (ILDs) is diverse and complex. Diagnosis and therapy usually pose challenges. This review describes a selection of rare and ultrarare ILDs including pulmonary alveolar proteinosis, pulmonary alveolar microlithiasis and pleuroparenchymal fibroelastosis. In addition, monogenic ILDs or ILDs in congenital syndromes and various multiple cystic lung diseases will be discussed. All these conditions are part of the scope of the European Reference Network on rare respiratory diseases (ERN-LUNG). Epidemiology, pathogenesis, diagnostics and treatment of each disease are presented.

Rapamycin nanoparticles improves drug bioavailability in PLAM treatment by interstitial injection

BACKGROUND

Pulmonary lymphangiomyomatosis (PLAM) is a rare interstitial lung disease characterized by diffuse cystic changes caused by the destructive proliferation of smooth muscle-like cells or LAM cells. PLAM is more common in young women than other people, and a consensus is lacking regarding PLAM treatment. The clinical treatment of PLAM is currently dominated by rapamycin. By inhibiting the mTOR signaling pathway, rapamycin can inhibit and delay PLAM's occurrence and development. However, the application of rapamycin also has shortcomings, including the drug's low oral bioavailability and a high binding rate to hemoglobin, thus significantly decreasing the amount of drug distributed to the lungs.

METHODS AND RESULTS

Here, we developed a new mode of rapamycin administration in which the drug was injected into the intrathecal space after being nanosized; the directional flow characteristics of the liquid in the intrathecal space were exploited to increase the drug content in the interstitial fluid to the greatest extent possible. We studied the rapamycin content in the interstitial fluid and blood after intervaginal space injection (ISI). Compared with oral administration, ISI significantly increased the drug concentration in the lung interstitial fluid.

CONCLUSIONS

These results provided new ideas for treating PLAM and optimizing the dosing regimens of drugs with similar characteristics to rapamycin.