Mesenchymal Stem Cells and Exosomes: A Novel Therapeutic Approach for Corneal Diseases.

The cornea, with its delicate structure, is vulnerable to damage from physical, chemical, and genetic factors. Corneal transplantation, including penetrating and lamellar keratoplasties, can restore the functions of the cornea in cases of severe damage. However, the process of corneal transplantation presents considerable obstacles, including a shortage of available donors, the risk of severe graft rejection, and potentially life-threatening complications. Over the past few decades, mesenchymal stem cell (MSC) therapy has become a novel alternative approach to corneal regeneration. Numerous studies have demonstrated the potential of MSCs to differentiate into different corneal cell types, such as keratocytes, epithelial cells, and endothelial cells. MSCs are considered a suitable candidate for corneal regeneration because of their promising therapeutic perspective and beneficial properties. MSCs compromise unique immunomodulation, anti-angiogenesis, and anti-inflammatory properties and secrete various growth factors, thus promoting corneal reconstruction. These effects in corneal engineering are mediated by MSCs differentiating into different lineages and paracrine action via exosomes. Early studies have proven the roles of MSC-derived exosomes in corneal regeneration by reducing inflammation, inhibiting neovascularization, and angiogenesis, and by promoting cell proliferation. This review highlights the contribution of MSCs and MSC-derived exosomes, their current usage status to overcome corneal disease, and their potential to restore different corneal layers as novel therapeutic agents. It also discusses feasible future possibilities, applications, challenges, and opportunities for future research in this field.

Current Advances in Regenerative Strategies for Dry Eye Diseases: A Comprehensive Review.

Dry eye disease (DED) is an emerging health issue affecting millions of individuals annually. Ocular surface disorders, such as DED, are characterized by inflammation triggered by various factors. This condition can lead to tear deficiencies, resulting in the desiccation of the ocular surface, corneal ulceration/perforation, increased susceptibility to infections, and a higher risk of severe visual impairment and blindness. Currently, the clinical management of DED primarily relies on supportive and palliative measures, including the frequent and lifelong use of different lubricating agents. While some advancements like punctal plugs, non-steroidal anti-inflammatory drugs, and salivary gland autografts have been attempted, they have shown limited effectiveness. Recently, there have been promising developments in the treatment of DED, including biomaterials such as nano-systems, hydrogels, and contact lenses for drug delivery, cell-based therapies, biological approaches, and tissue-based regenerative therapy. This article specifically explores the different strategies reported so far for treating DED. The aim is to discuss their potential as long-term cures for DED while also considering the factors that limit their feasibility and effectiveness. These advancements offer hope for more effective and sustainable treatment options in the future.

Trephine Transverse Colostomy Is Effective for Patients Who Have Previously Undergone Rectal Surgery.

PURPOSE: Colostomy creation is an essential procedure for colorectal surgeons, but the preferred method of colostomy varies by surgeon. We compared the outcomes of trephine colostomy creation with open those for the (laparotomy) and laparoscopic methods and evaluated appropriate indications for a trephine colostomy and the advantages of the technique. METHODS: We retrospectively evaluated 263 patients who had undergone colostomy creation by trephine, open and laparoscopic approaches between April 2006 and March 2016. We compared the clinical features and the operative and postoperative outcomes according to the approach used for stoma creation. RESULTS: One hundred sixty-three patients (62%) underwent colostomy surgery for obstructive causes and 100 (38%) for fistulous problems. The mean operative time was significantly shorter with the trephine approach (trephine, 46.0 ± 1.9 minutes; open, 78.7 ± 3.9 minutes; laparoscopic, 63.5 ± 5.0 minutes; P < 0.001), as was the time to flatus (1.8 ± 0.1 days, 2.1 ± 0.1 days, 2.2 ± 0.3 days, P = 0.025). Postoperative complications (<30 days) were not different among the 3 approaches (trephine, 4.3%; open, 1.2%; laparoscopic, 0%; P = 0.828). In patients who underwent rectal surgery, a trephine colostomy was feasible for a diversion colostomy (P < 0.001). CONCLUSION: The trephine colostomy is safe and can be implemented quickly in various situations, and compared to other colostomy procedures, the patient's recovery is faster. Previous laparotomy history was not a contraindication for a trephine colostomy, and a trephine transverse colostomy is feasible for patients who have undergone previous rectal surgery.

Outcomes of patients with abdominoperineal resection (APR) and low anterior resection (LAR) who had very low rectal cancer.

We compared the oncological outcomes of sphincter-saving resection (SSR) and abdominoperineal resection (APR) in 409 consecutive patients with very low rectal cancer (i.e., tumors within 3 cm from the anal verge); 335 (81.9%) patients underwent APR and 74 (18.1%) underwent SSR. The APR group comprised higher proportions of men (67.5% vs 55.4%, P = .049) and advanced-stage patients (P < .001). Preoperative chemoradiotherapy (PCRT) was more frequently administered in the SSR group (83.8% vs 52.8%, P < .001). Overall, the systemic and local recurrence rates were 29.1% and 6.1%, respectively. On stratification according to PCRT and pathologic stage, the mode of surgery did not affect the recurrence type. Moreover, recurrence-free survival (RFS) did not differ according to the mode of surgery in different cancer stages. RFS was associated with ypT and ypN stages in patients who received PCRT, while pN stage, lymphovascular invasion (LVI), and circumferential resection margin (CRM) involvement were risk factors for RFS in those who did not receive PCRT. Notably, SSR was not found to be a risk factor for RFS in either subgroup. Patients who were stratified according to cancer stage and PCRT also showed no differences in RFS according to the mode of surgery. Our results demonstrate that, regardless of PCRT administration, SSR is an effective treatment for very low rectal cancer, while CRM is an important prognostic factor for patients who did not receive PCRT.

Association of immunologic markers from complete blood counts with the response to preoperative chemoradiotherapy and prognosis in locally advanced rectal cancer.

We investigated retrospectively whether immunologic markers from a complete blood count (CBC) are associated with the responsiveness to preoperative chemoradiotherapy (PCRT) and oncologic outcomes in 984 patients with locally advanced rectal cancer (LARC) who also underwent radical surgery from 2005 to 2013. CBC parameters including the neutrophil to lymphocyte ratio (NLR), lymphocyte to monocyte ratio (LMR), and platelet to lymphocyte ratio (PLR) were recorded. Pathologic responses to PCRT were evaluated in the resected specimens using the tumor regression grade system. The cut-off values of the immunologic markers were calculated to analyze their association with recurrence-free survival (RFS). One hundred ninety-five patients achieved total regression of their primary tumor. By receiver operating characteristic analysis, NLR, PLR, and LMR could not distinguish total regression from residual disease after PCRT. The NLR, LMR and PLR cut-off values were 1.7, 6.8 and 92.88, respectively. By univariate analysis, low NLR (≤1.7), high LMR (>6.8) and high PLR (>92.88) were indicators of a favorable RFS outcome. By multivariate analysis, high PLR was associated with an improved RFS (HR, 0.649; 95% CI, 0.473-0.89; P=0.007). High NLR (>1.7) was an independent negative prognostic factor for RFS in stage II (HR, 1.868; 95% CI, 1.08-3.109; P=0.025) and high PLR was a positive prognostic factor in stage III (HR, 0.675; 95% CI, 0.421-0.957; P=0.03). Immunologic markers derived from CBCs are independently associated with the RFS outcome in LARC patients treated with PCRT followed by radical resection. However, these markers are not predictive of total primary tumor regression after PCRT.

Postoperative changes of manometry after restorative proctocolectomy in Korean ulcerative colitis patients.

AIM: To investigate the changes of postoperative anal sphincter function and bowel frequency in Korean patients with ulcerative colitis (UC). METHODS: A total of 127 patients with UC who underwent restorative proctocolectomy (RPC) during 20 years were retrospectively analyzed. The parameters of anal manometry and bowel frequency were compared according to the 6-mo intervals until 24 mo postoperatively. Manometry was used to measure the maximal squeezing pressure (MSP) and maximal resting pressure (MRP). RESULTS: MSP decreased after surgery until 6 mo (157 to 142 mmHg); thereafter, it improved and was recovered to and maintained at the preoperative value at 12 mo postoperatively (142-170 mmHg, P < 0.001). Although the decreased MRP (65 to 56 mmHg) improved after 18 mo (62 mmHg), it did not completely recover to the preoperative value. The decreased rectal capacity after surgery (90 to 82 mL) gradually increased up to 150 mL at 24 mo. Although bowel frequency showed significant gradual decreases at each interval, it was stabilized after 12 mo postoperatively (6.5 times/d). CONCLUSION: Postoperative changes of manometry and bowel frequency after restorative proctocolectomy in Korean patients with UC were not different from those in Western patients with UC.

A case of rectal cancer in a patient with neurofibromatosis type 1.

A rectal cancer was found in a 67-year-old man with a history of neurofibromatosis type 1. A low anterior resection was performed, and he received concurrent chemoradiation for 6 months. Twelve months after the surgery, a tumor was found at the anastomotic site by positron emission tomography-computed tomography and colonoscopy and was mistaken as anastomotic site recurrence. The tumor was confirmed as an inflammatory myofibroblastic tumor through transanal excision.

Bezoar-induced Small Bowel Obstruction.

PURPOSE: The aim of this study was to observe the clinical features of a bezoar-induced small bowel obstruction and to investigate the role of abdominal computed tomography (CT) in establishing the diagnosis. METHODS: We retrospectively reviewed 20 cases of bezoar-induced small bowel obstruction in our hospital from 1996 to 2010. RESULTS: Thirteen patients (65%) had a history of abdominal surgery. Nine patients (45%) were diagnosed with a bezoar before surgery, seven patients were diagnosed by using abdominal CT, and two patients were diagnosed with a small bowel series. Abdominal CT was performed in 15 patients, and the diagnostic accuracy was 47% (7/15). Surgery revealed ten bezoars in the jejunum and 11 in the ileum. Two patients had bezoars found concurrently in the stomach. Spontaneous removal took place in two patients. An enterotomy and bezoar extraction was performed in 15 patients. Fragmentation and milking, a small bowel resection, and a Meckel's diverticulectomy were performed in one patient each. Early operative treatment was possible (P = 0.036) once the bezoar had been diagnosed by using abdominal CT. There tended to be fewer postoperative complications in patients who were diagnosed with a bezoar by using abdominal CT, but the result was not statistically significant (P = 0.712). CONCLUSION: A preoperative diagnosis of bezoar-induced small bowel obstruction by using clinical features was difficult. Increased use of abdominal CT led to a more accurate diagnosis and to earlier surgery for bezoar-induced small bowel obstructions, thereby reducing the rate of complications.