Surface modulation of extracellular vesicles with cell-penetrating peptide-conjugated lipids for improvement of intracellular delivery to endothelial cells

Exosomes (diameter 30-200 nm) are a subtype of extracellular vesicles secreted by cells containing DNA, microRNA (miRNA), and proteins. Exosomes are expected to be valuable as a means of delivering drugs or functional miRNAs in treatment of diseases. However, the delivery of exosomes is not sufficiently effective, even though exosomes have intrinsic delivery functions. Cell-penetrating peptides (CPPs) are short peptide families that facilitate cellular intake of molecules and vesicles. We previously reported that the modification of cells, and liposomes with CPP-conjugated-lipids, CPPs conjugated with poly (ethylene glycol)-conjugated phospholipids (PEG-lipid), that induce adhesion by CPPs, can be useful for cell-based assays and harvesting liposomes. In this study, we aimed to modulate the exosome surface using Tat peptide (YGRKKRRQRRR)-PEG-lipids to improve intracellular delivery to endothelial cells. We isolated and characterized exosomes from the medium of HEK 293 T cell cultures. Tat conjugated PEG-lipids with different spacer molecular weights and lipid types were incorporated into exosomes using fluorescein isothiocyanate labeling to optimize the number of Tat-PEG-lipids immobilized on the exosome surface. The exosomes modified with Tat-PEG-lipids were incubated with human umbilical vein endothelial cells (HUVECs) to study the interaction. Tat conjugated with 5 kDa PEG and C16 lipids incorporated on the exosome surface were highly detected inside HUVECs by flow cytometry. Fluorescence was negligible in HUVECs for control groups. Thus, Tat-PEG-lipids can be modified on the exosome surface, improving the intracellular delivery of exosomes.

Impact of spontaneous liposome modification with phospholipid polymer-lipid conjugates on protein interactions

Liposome surface coating has been studied to avoid the immunological responses caused by the complement system, and alternative materials to poly(ethylene glycol) (PEG) have been explored recently since the production of anti-PEG IgM antibodies has been found in humans. We previously reported a liposome coating with poly(2-methacryloyloxyethyl phosphorylcholine) (poly(MPC))-conjugated lipids (PMPC-lipids) and demonstrated its protective effect on blood protein interactions. Here, we attempted to modify the liposome surface by exogenously adding PMPC-lipids, which were spontaneously incorporated into the outer membrane via hydrophobic interactions. The polymerization degree of the PMPC segment was regulated from 10 to 100. The incorporated ratio of PMPC-lipid increased with a decrease in the degree of PMPC polymerization. Due to surface modification with PMPC-lipids, increase in the length of the PMPC-chain increased the size of the liposomes. The modified liposomes were kept stable for 14 d in terms of their size, polydispersity, and surface properties, where approximately 70% of PMPC-lipids were incorporated into the liposome surface. We demonstrated that liposome surface modification with PMPC-lipids can inhibit protein adsorption when exposed to serum, regardless of the degree of polymerization of PMPC. In addition, the PMPC-lipid modified surface was not recognized by the anti-PEG IgM antibody, whereas PEG-lipid was recognized by the antibody. Thus, we successfully fabricated an inert liposome surface via spontaneous modification with PMPC-lipids, where only the outer bilayer surface was modified. This technique can be available for full loading of water-soluble active pharmaceutical ingredient inside the modified liposome.

Quantitative assessment of water diffusion changes in brains of children with neurofibromatosis type I using apparent diffusion coefficient

We measured diffusion changes in the brains of children with neurofibromatosis type 1 (NF1). Using diffusion-weighted and conventional magnetic resonance (MR) images of 42 children with NF1 (19 girls, 23 boys; 7 months-16 years, mean 6.8 years) and 42 age-matched controls (20 boys, 22 girls; 6 months-17 years, mean, 6.9 years), we calculated the apparent diffusion coefficient (ADC) from the automatically generated ADC maps and placed regions of interest in the pons, middle cerebellar and cerebral peduncles, thalami, globus pallidi and frontal white matter. Evaluating only normal-appearing regions on conventional images, we compared mean ADCs using the unpaired Student t test. Means were not significantly different in frontal white matter but were larger in the other regions in the NF1 (P < 0.01). Although conventional MR showed normal intensity, ADCs of the pons, middle cerebellar and cerebral peduncles, thalami and globus pallidi were significantly larger in the NF1.

Use of the curved linear-array echo endoscope to identify gastrorenal shunts in patients with gastric fundal varices

BACKGROUND AND STUDY AIMS

: Balloon-occluded retrograde transvenous obliteration (B-RTO) has emerged as an effective, minimally invasive treatment for fundal varices. B-RTO requires a spontaneously developed gastrorenal shunt as a pathway for the balloon catheter to reach the fundal varices. We used a curved linear-array (CLA) echo endoscope in patients with fundal varices to identify gastrorenal shunts, and compared the detection rate with the gold standard, contrast-enhanced computed tomography (CECT).

PATIENTS AND METHODS

A total of 40 patients with fundal varices were examined with both CLA echo endoscopy and CECT. The CECT images were retrospectively and independently evaluated by two gastroenterologists who were unaware of the clinical details, including the results of the CLA echo endoscopy.

RESULTS

CLA echo endoscopy identified gastrorenal shunts in 26/40 patients with fundal varices. It visualized the shunt in a longitudinal direction and provided images of the connections of the shunt at both ends, the fundal varices and the left renal vein/branch of the inferior adrenal vein. The kappa index for CLA echo endoscopy and CECT for the identification of gastrorenal shunt was 0.9 (95 % CI, 0.6 to 1.0). When the cutoff point for the diameter of the gastrorenal shunt detected by the CLA echo endoscope was set at equal to or greater than 5 mm, the kappa index was 1.0 (95 % CI, 0.7 to 1.0).

CONCLUSIONS

These results suggest that CLA echo endoscopy can successfully identify gastrorenal shunt and provide detailed morphological information. It also efficiently identifies patients suitable for B-RTO, particularly in cases of acute bleeding. It also has considerable potential for providing detailed information with regard to the treatment of gastric varices.

[The effects of percutaneous endoscopic gastrostomy feeding in patients with swallowing disturbance]

BACKGROUND AND PURPOSE

Because the number of patients who need home healthcare has recently increased in Japan, Percutaneous endoscopic gastrostomy (PEG) will soon become more popular. This study aims to examine the effects of enteral alimentation via PEG.

MATERIAL AND METHODS

The subjects were 18 patients who underwent PEG instead of receiving total parental nutrition (TPN) (TPN-to-PEG group), 13 patients who underwent PEG instead of receiving enteral nutrition through a naso gastric tube (NG-to-PEG group), and 11 healthy volunteers (control). Morphological changes of the small bowel mucosa and activities of daily life (ADL) after PEG were also investigated.

RESULTS

In the TPN-to-PEG group, the serum level of total protein and albumin, length of duodenal villi, ration of positive proliferative cells, width of duodenal microvilli and ADL markedly increased. In the NG-to-PEG group, body weight and ADL were markedly improved after PEG.

CONCLUSION

Nutrition via PEG is superior to TPN or enteral nutrition with an NG tube. I conclude that PEG will become the first choice for improving nutrition in patients with dysphasia and will contribute to continuous enteral nutrition for home care.

Low power diode laser treatment using indocyanine green for eradication of esophageal varices

BACKGROUND AND STUDY AIMS

Endoscopic variceal ligation (EVL) is an alternative to sclerotherapy for the treatment of esophageal varices, but is associated with higher rates of recurrence and subsequent bleeding than sclerotherapy. To prevent recurrence of varices after EVL, we have developed a low-dose diode laser therapy combined with the injection of indocyanine green, which allows enhanced tissue absorption of the laser beam selectively around varices. In this study we investigated the efficacy and safety of this technique.

PATIENTS AND METHODS

Eight patients with F2 or F3 esophageal varices were enrolled. At 1 week after EVL, indocyanine green solution (1 mg/ml) was injected submucosally around the remaining varices. A diode laser (power 10 watts) was applied to the surface from the esophagogastric junction to 5 cm above it. The spot size was kept to 5 mm in diameter.

RESULTS

Laser irradiation was performed safely, without bleeding from the varices, or perforation. There were no major complications. Endoscopy 1 month later showed F0 forms in seven patients, F1 in one patient, and no red color sign in any patient. No recurrence of varices has been observed in any of the patients during the follow-up period of at least 12 months.

CONCLUSION

This technique may provide a simple, safe and effective procedure, as an additional treatment to EVL, for the prevention of recurrence of esophageal varices.

Hemodynamic analysis of esophageal varices using color Doppler endoscopic ultrasonography to predict recurrence after endoscopic treatment

BACKGROUND AND STUDY AIMS

The time to recurrence of esophageal varices may vary greatly between patients even after the same endoscopic therapy. To clarify the factors which contribute to recurrence after endoscopic treatment, the hemodynamics and morphology of the left gastric vein (LGV) were investigated using color Doppler endoscopic ultrasonography (EUS).

PATIENTS AND METHODS

A total of 31 patients with high-risk esophageal varices underwent color Doppler-EUS before receiving endoscopic variceal ligation and endoscopic injection sclerotherapy combined therapy. Endoscopic examination was performed every 3 months after the treatment to evaluate recurrence of varices.

RESULTS

A total of 18 patients responded to the therapy, while 13 patients did not respond, and had recurrence within 12 months. The hepatofugal flow velocity in the LGV trunk was significantly lower in the responders (9.9 vs. 13.9 cm/sec; P = 0.02). The branch pattern of the LGV was categorized into three groups: anterior branch dominant, posterior branch dominant, and no-dominant type. The incidence of the anterior branch dominant type was significantly less in responders (17 vs. 70 %; P = 0.01). There was no significant difference in the LGV trunk diameter and the size of the paraesophageal vein between the two groups.

CONCLUSION

Risk factors for recurrence can be analyzed in detail using color Doppler-EUS. Further investigation using color Doppler-EUS may enable us to select the optimal way to treat esophageal varices to prevent recurrence.

[Squamous cell carcinoma and basal cell carcinoma]

Both basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are very common in skin malignancy. Operative therapy is the first choice at the treatment for SCC and BCC in early stage. After excision for large skin tumor, occasionally we use skin flap or musculocutaneous flap or free flap. At the old patient of Stage III and IV SCC and BCC, sometimes reduction surgery is useful at the combination therapy. Radiation as adjuvant therapy is sometimes useful for not only SCC but also BCC. The clinical efficacy of CA (C' A') chemotherapy (CDDP, ADM or CBDCA, EPI-ADM), was evaluated on Stage III, IV SCC and BCC. The response rate was 63% in SCC and 75% in BCC.

Lupus susceptibility loci in New Zealand mice

Susceptibility to systemic lupus erythematosus has been unequivocally established to be an inherited trait, but the exact genes and how they confer susceptibility remain largely unknown. In this study of (NZB x NZW)F2 intercross mice, we used linkage analysis of markers covering > 90% of the autosomal genome and identified eight susceptibility loci (Lbw1 to -8, chromosomes 17, 4-7, 18, 1, 11, respectively) associated with antichromatin autoantibody production, glomerulonephritis, and/or mortality. Only one locus, the major histocompatibility complex, was linked to all three traits. Two other loci were associated with both glomerulonephritis and mortality, whereas the remaining loci were linked to one of the above traits. Two additional loci (Sbw1 and -2) that contributed to splenomegaly were also identified. The Sbw2 locus mapped to the identical region as Lbw2, a locus on chromosome 4 linked to glomerulonephritis and mortality, suggesting a single locus with pleiotropic effects. The results indicate that the immunopathologic features of lupus are affected by distinct, but additive, genetic contributions. Studies to determine the nature of the genes associated with these loci should help define the genetic mechanisms involved in this systemic autoimmune disease.

[Squamous cell carcinoma, basal cell carcinoma]

In Japan the regimen with peplomycin has been mainly used for the treatment of squamous cell carcinoma (SCC). But recently, a regimen with cisplatin, particularly the combination of cisplatin and adriamycin (CA chemotherapy) has been used for the treatment of SCC, and a better prognosis has resulted Since CA chemotherapy is very effective for not only SCC, but also basal cell carcinoma (BCC), we think it is a prominent neoadjuvant therapy for SCC and BCC. We have used CA chemotherapy for multiple lung metastasis of BCC over the past six years, and three times PR was obtained, with survival so far.