Pressure elevation slows the fibroblast response to wound healing

Krüppel-like factor 15 is a key suppressor of podocyte fibrosis under rotational force-driven pressure

Krüppel-like factor 15 (KLF15) is a well-known transcription factor associated with podocyte injury and fibrosis. Recently, hypertensive nephropathy was discovered to be closely related to podocyte injury and fibrosis. However, methods to stimulate hypertension in vitro are lacking. Here, we constructed an in vitro model mimicking hypertension using a rotational force device to identify the role of KLF15 in fibrosis due to mechanically induced hypertensive injury. First, we found that KLF15 expression was decreased in patients with hypertensive nephropathy. Then, an in vitro study of hypertension due to rotational force was conducted, and an increase in fibrosis markers and decrease in KLF15 levels were determined after application of 4 mmHg pressure in primary cultured human podocytes. KLF15 and tight junction protein levels increased with retinoic acid treatment. siRNA-mediated inhibition of KLF15 exacerbated pressure-induced fibrosis injury, and KLF15 expression after treatment with angiotensin II was similar to that observed after treatment with the blood pressure modeling device. Furthermore, the reduced KLF15 levels after mechanical pressure application were restored after the administration of an antihypertensive drug. KLF15 expression was also low in vivo. We confirmed the protective role of KLF15 in fibrosis using a mechanically induced in vitro model of hypertensive injury.

Transilluminated powered phlebectomy in the treatment of large area venous leg ulcers: A case-control study with 3 years follow-up

OBJECTIVE

To evaluate the efficacy, safety and long-term outcome of TIPP for the adjunct therapy of superficial venous reflux-related VLUs.

METHODS

A total of 93 consecutive patients (104 legs) with superficial venous insufficiency-related VLUs who underwent TIPP (53 legs) or conventional phlebectomy (51 legs) between January 2010 and December 2013 were retrospectively studied.

RESULTS

Compared to patients in the conventional phlebectomy group, TIPP patients had larger ulcer areas before surgery (P < 0.005). However, TIPP group required a significantly shorter operation time (P < 0.005), fewer incisions (P < 0.005) but less ulcer healing time (1.25 month vs 2.5 months, P < 0.05). No significant difference in in-hospital and follow-up complications was found between the two groups. For long-term outcome, TIPP group leaded a lower ulcer recurrence rate at 36 months (13.2% vs 29.4%, P < 0.05).

CONCLUSION

TIPP may be an adjunct surgical method contributes to healing of VLUs, especially for large ulcer areas.

Chronic Venous Insufficiency

Varicose veins are a common manifestation of chronic venous disease and affect approximately 25% of adults in the western hemisphere. The historical standard treatment has been surgery, with high ligation and stripping, combined with phlebectomies. In the past decade, alternative treatments such as endovenous ablation of the great saphenous vein (GSV) with laser, radiofrequency ablation, and ultrasonography-guided foam sclerotherapy have gained popularity. Performed as office-based procedures using tumescent local anesthesia, the new minimally invasive techniques have been shown in numerous studies to obliterate the GSV, eliminate reflux, and improve symptoms safely and effectively.

Role of elevated pressure in TRAIL-induced apoptosis in human lung carcinoma cells

TNF-related apoptosis-inducing ligand (TRAIL, Apo2L) is a promising anticancer agent with high specificity for cancer cells. Many strategies have been proposed to enhance the sensitivity of cancer cells to TRAIL-mediated apoptosis, including the use of combination treatment with conventional cancer therapies. However, few reports have evaluated the effects of TRAIL in combination with mechanical stress, which can also cause apoptosis of cancer cells. In the present study, we describe a custom-designed culture system that delivers two atmospheres of elevated pressure (EP) by using compressed air, and which enhances the sensitivity of cancer cells to TRAIL-mediated apoptosis. The combination of TRAIL and EP significantly increased apoptosis of human H460 lung cancer cells more than hyperbaric normoxia or normobaric mild hyperoxia. EP-potentiating TRAIL-mediated apoptosis of H460 cells was accompanied by up-regulated death receptor 5 (DR5), activation of caspases, decreased mitochondrial membrane potential, and reactive oxygen species production. We also observed EP-induced sensitization of TRAIL-mediated apoptosis in other cancer cell types. In contrast, human normal cells showed no DNA damage or cell death when exposed to the combined treatment. In a chicken chorioallantoic membrane model, EP enhanced TRAIL-mediated apoptosis of tumors that developed from transplanted H460 cells. Collectively, EP enhanced TRAIL-induced apoptosis of human lung carcinoma cells in vitro and in vivo. These findings suggest that EP is a mechanical and physiological stimulus that might have utility as a sensitizing tool for cancer therapy.

Comparison of the effects of 40% oxygen and two atmospheric absolute air pressure conditions on stress-induced premature senescence of normal human diploid fibroblasts

The pressure during hyperbaric oxygen treatment may increase oxygen toxicity via an augmented oxygen pressure in the gas. Nevertheless, only a few reports have been published on the effect of cells grown under 2 atmospheric absolute (ATA) pressure. To evaluate the effect of pressure on oxygen toxicity and to study effects in addition to oxygen toxicity, we designed an experiment to compare the effects of normobaric mild hyperoxia (NMH, 40% oxygen) and hyperbaric air condition (HA, air with 2 ATA) on human diploid fibroblasts (HDF) in a hyperbaric incubator. HDFs in both the NMH and the HA condition had a similar oxidative stress response and exhibited premature senescence. To investigate differences in gene profiling in cells grown in the NMH and HA conditions, samples from cells exposed to each condition were applied to microarrays. We found no expression difference in genes related to aging and deoxyribonucleic acid damage, but the expression of genes including cell adhesion, stress response, and transcription were significantly increased in fibroblasts that were responsive to pressure. Among 26 statistically reliable genes, the expression of apoptosis related genes such as ADAM22, Bax, BCL2L14, and UBD, as well as tumor suppressor-related genes like Axin2 and ATF, and also mitogen-activated protein kinase-related genes like mitogen-activated protein kinase kinase kinase 1, histamine receptor, and RAB24, were significantly changed in cells responsive to pressure-induced oxidative stress.