Pericytes: A newly recognized player in wound healing

Pericytes have generally been considered in the context of stabilizing vessels, ensuring the blood barriers, and regulating the flow through capillaries. However, new reports suggest that pericytes may function at critical times to either drive healing with minimal scarring or, perversely, contribute to fibrosis and ongoing scar formation. Beneficially, pericytes probably drive much of the vascular involution that occurs during the transition from the regenerative to the resolution phases of healing. Pathologically, pericytes can assume a fibrotic phenotype and promote scarring. This perspective will discuss pericyte involvement in wound repair and the relationship pericytes form with the parenchymal cells of the skin. We will further evaluate the role pericytes may have in disease progression in relation to chronic wounds and fibrosis.     

Two-level posterior lumbar interbody fusion for degenerative disc disease: improved clinical outcome with restoration of lumbar lordosis

BACKGROUND CONTEXT: Although posterior lumbar interbody fusion (PLIF) for degenerative lumbar diseases is routine, there are few reports on double-level PLIF. PURPOSE: To evaluate the clinical outcomes of double-level PLIF. STUDY DESIGN/SETTING: A retrospective study of operated cases in Gifu, Japan. PATIENT SAMPLE: Nineteen patients (8 men and 11 women, 59.5+/-10.2 years) who underwent double-level PLIF between 1996 and 2001. OUTCOME MEASURES: Operation time, blood loss, complications, the Japanese Orthopaedic Association (JOA) score for back pain and lumbar sagittal alignment were evaluated. METHODS: Patients were examined retrospectively at follow-ups of 3.6+/-1.7 years. Primary diseases were spondylolisthesis, spinal canal stenosis, degenerative scoliosis and herniated intervertebral disc. Fusion areas were L3 to L5 in 15 cases and L4 to S1 in 4 cases. RESULTS: The mean JOA score increased from an initial score of 12.9+/-3.5 to 21.3+/-4.9 at the final follow-up. There was a positive correlation (R=0.718, p<.001) between the increase in lordotic angle and the increase in the JOA score. Several parameters suggested that the surgical invasiveness was not minimal. CONCLUSION: Double-level PLIF provided satisfactory results and preserved lumbar spine lordosis.     

Prematurity Reduces Functional Adaptation to Intestinal Resection in Piglets

Background: Necrotizing enterocolitis and congenital gastrointestinal malformations in infants often require intestinal resection, with a subsequent risk of short bowel syndrome (SBS). We hypothesized that immediate intestinal adaptation following resection of the distal intestine with placement of a jejunostomy differs between preterm and term neonates. Methods: Preterm or term piglets were born by cesarean section and fed enterally for 2 days. On day 2, piglets were subjected to 50% distal intestinal resection with placement of a jejunostomy. On the following 4–5 days, piglets received parenteral nutrition with gradually increasing doses of enteral nutrition (bovine colostrum). Intestinal tissue samples were collected at delivery and 2 and 6–7 days after birth for histological examination and assessment of digestive enzyme activities. Results: Preterm and term piglets showed similar increases in intestinal weight and digestive enzyme activities from birth to 2 days. On days 6–7 after birth, the remnant intestine showed a similar density (g/cm) and mucosal mass in term and preterm piglets, but villus height, crypt depth, enzyme activities (sucrase, maltase, dipeptidyl peptidase IV [DPPIV]), and hexose uptake capacity were significantly higher in term piglets (P < .05). Preterm piglets were more prone to develop hypoglycemia, respiratory distress syndrome, dehydration, and circulatory instability after surgery compared with term piglets. Conclusion: Studies on intestinal adaptation after resection are feasible in both preterm and term piglets, but intensive clinical support is required when rearing preterm piglets with SBS. Physiological instability and immaturity of the intestine may explain the fact that immediate adaptation after resection is reduced in preterm vs term neonates.     

Effects of pentoxifylline on the vascular response to injury after angioplasty in rabbit iliac arteries

Pentoxifylline (PTX) inhibits the effects of several cytokines and reduces injury-related collagen accumulation. The aim of the present study was to investigate the effect of PTX on the vascular response to injury. We treated rabbits with PTX (100 mg/kg/day) or placebo (saline) subcutaneously from 2 days before angioplasty of an iliac artery until euthanasia 7 or 28 days later. At 7 days after injury, PTX treatment was associated with a more differentiated (less proliferation, more smoothelin-positive) intimal smooth muscle cell phenotype. Furthermore, PTX reduced myofibroblast accumulation in adventitia. At 28 days after injury, PTX-treated rabbits had a 48.5% larger lumen area (P = 0.03) and a 28.1% larger area within the external elastic lamina (P = 0.04). There were no significant differences between PTX-treated rabbits and the placebo group with regard to neointima and media area. Angioplasty induced marked neoadventitial hyperplasia, which was reduced by 20.5% (P = 0.01) in the PTX-treated group. Finally, PTX reduced collagen density in all three arterial layers. We conclude that PTX treatment induces less proliferation within the vessel wall early after angioplasty and increases late lumen size after angioplasty by a positive effect on vascular remodeling. Martin Busk and Michael Maeng contributed equally to this paper. Returned for 1. Revision: 6 September 2007 1. Revision received: 4 October 2007 Returned for 2. Revision: 24 October 2007 2. Revision received: 31 October 2007     

Comparison of peri‐implant clinical and radiographic status around short (6 mm in length) dental implants placed in cigarette‐smokers and never‐smokers: Six‐year follow‐up results

Background

It is hypothesized that peri‐implant clinical and radiographic inflammatory parameters (probing depth [PD], bleeding on probing [BOP] and plaque index [PI]; and radiographic (crestal bone loss [CBL]) are worse among cigarette‐smokers (CS) compared with never‐smokers (NS) with short implants.

Purpose

The present 6‐year follow‐up retrospective study compared the peri‐implant clinical and radiographic parameters in CS and NS with short dental implants (6 mm in length).

Materials and methods

Fifty‐six male individuals were included. These individuals divided into 2 groups as follows: (a) Group‐1: 29 self‐reported systemically healthy CS with 48 short‐implants; and (b) Group‐2: 27 self‐reported systemically healthy NS with 43 short implants. Peri‐implant PD, PI, BOP, and CBL were measured. Group comparisons were done using the Kruskal‐Wallis test and sample size was estimated. Level of significance was set at P values < .05.

Results

In groups 1 and 2, the follow‐up durations were 6.2 ± 0.1 years and 6.1 ± 0.3 years, respectively. A cigarette smoking history of 8.9 ± 3.6 pack years was reported by individuals in Group‐1. At follow‐up, scores of peri‐implant PD, BOP, PI, and mesial and distal CBL were comparable around short implants in both groups.

Conclusion

Under strict oral hygiene maintenance protocols, short dental implants can remain functionally stable in CS in a manner similar to NS.     

Metformin‐associated risk of acute dialysis in patients with type 2 diabetes: A nationwide cohort study

Recent guidelines governing anti‐diabetic medications increasingly advocate metformin as first‐line therapy in all patients with type 2 diabetes. However, metformin could be associated with increased risk of acute kidney injury (AKI), acute dialysis and lactate acidosis in marginal patients. In a retrospective nationwide cohort study, a total of 168 443 drug‐naïve patients with type 2 diabetes ≥50 years, initiating treatment with either metformin or sulphonyl in Denmark between 2000 and 2012 were included in this study (70.7% initiated treatment with metformin); calculation of 1‐year risk of acute dialysis was based on g‐standardization of cause‐specific Cox regression models for acute dialysis, end‐stage renal disease and death. One‐year risks of acute dialysis were 92.4 per 100 000 (95% CI, 67.1‐121.3) and 142.7 per 100 000 (95% CI, 118.3‐168.0) for sulphonylurea and metformin, respectively. The metformin‐associated 1‐year risk of acute dialysis was increased by 50.3 per 100 000 (95% CI, 7.9‐88.6), corresponding to a risk ratio of 1.53 (95% CI, 1.06‐2.23), and a number needed to harm of 1988, thus providing evidence of potential concerns pertaining to the increasing use of metformin.     

Several Conventional Risk Markers Suggesting Presence of Albuminuria Are Weak Among Rural Africans With Hypertension

The objective of this cross‐sectional study was to investigate risk markers indicating the presence of albuminuria in patients with hypertension in rural sub‐Saharan Africa (SSA). Urine albumin‐creatinine ratio, glycated hemoglobin (HbA_1c), blood pressure, anthropometry, and other patient characteristics including medications were assessed. We identified 160 patients with hypertension, of whom 68 (42.5%) were co‐diagnosed with diabetes mellitus (DM). Among the included participants, 57 (35.6%) had albuminuria (microalbuminuria [n=43] and macroalbuminuria [n=14]). A backward multivariate logistic regression model identified age (per 10‐year increment) (odds ratio [OR], 1.42; 95% confidence interval [CI], 1.03–1.95), HbA_1c >53 compared with <48 mmol/mol (OR, 3.81; 95% CI, 1.74–8.35), and treatment with dihydropyridine calcium channel blockers (OR, 2.59; 95% CI, 1.09–6.16) as the variables significantly associated with albuminuria. Only dysregulated DM and age were the conventional risk markers that seemed to suggest albuminuria among patients with hypertension in rural SSA.