Differences between scar and dermal cultured fibroblasts derived from a patient with recurrent abdominal incision wound herniation

Genetic and biologic risk factors associated with hernia formation: A review

BACKGROUND

This systematic review aims to identify genetic and biologic markers associated with abdominal hernia formation.

METHODS

Following PRIMSA-guidelines, we searched PubMed, MEDLINE, Embase, Scopus, and COCHRANE databases.

RESULTS

Of 5946 studies, 65 were selected, excluding parastomal hernias due to insufficient data. For inguinal hernias, five studies unveiled 92 susceptible loci across 66 genes, predominantly linked to immune responses. Eleven studies observed elevated MMP-2 levels, with seven highlighting greater MMP-2 in direct compared to indirect inguinal hernias. One incisional hernia study identified unique gene-expression profiles in 174 genes associated with inflammation and cell-adhesion. In hiatal hernias, several genetic risk loci were identified. For all hernia categories, type I/III collagen ratios diminished.

CONCLUSIONS

Biological markers in inguinal hernias appears consistent. Yet, the genetic predisposition in incisional hernias remains elusive. Further research to elucidate these genetic and biological intricacies can pave the way for more individualized patient care.

Adherent Abdominal Scar Revision Does Not Require Total Scar Removal

Abdominal surgery can cause notable scars that adhere to the abdominal tissues below. Full scar removal is generally not recommended due to the risk of intestinal damage and delayed wound healing. Here, we describe a surgical scar-revision procedure for adherent abdominal scars that does not involve either opening the abdominal cavity or total scar removal. A 58-year-old woman exhibited an aesthetically displeasing hypertrophic adherent abdominal scar that extended from the umbilical fold to the pubic area and distorted the umbilicus. It arose from multiple laparotomies for hernia repair and subsequent complications. Pain/discomfort and functional impairment were absent. Scar-revision surgery was conducted under general anesthesia. The skin around the adherent scar was excised down to the subcutaneous layer with a minimal margin. However, only the epidermis and superficial dermal layer of the adherent scar were removed; the deep scar dermis remained. The skin flaps on either side of the midline were then advanced and sutured over the remnant dermis. One year after surgery, the aesthetic and functional outcomes were excellent. Furthermore, no hypertrophic scars or epidermal cysts were found. This technique is effective, efficient, does not involve intraabdominal procedures, provides a vascularized tissue layer, and results in an aesthetically pleasing scar.

Vocal fold myofibroblast profile of scarring

OBJECTIVES/HYPOTHESIS

Vocal fold fibroblasts (VFF) are responsible for extracellular matrix synthesis supporting lamina propria in normal and diseased conditions. When tissue is injured, VFF become activated and differentiate into myofibroblasts to facilitate wound healing response. We investigated if vocal fold myofibroblasts can be utilized as surrogate cells for scarred VFF.

STUDY DESIGN

In vitro.

METHODS

Normal VFF cell lines from a 21-year-old male (N21), 59-year-old female (N59), and a scar VFF cell line from a 56-year-old female (S56) were used in this study. 10 ng/mL of transforming growth factor (TGFβ1) was applied for 5 days to normal VFF. Myofibroblast differentiation was determined with immunocytochemistry and western blot, measuring alpha smooth muscle actin (α-SMA). Cell growth, proliferation, contractile properties, and gene expression profiles were evaluated.

RESULTS

N21, N59, and S56 VFF presented elongated configuration. N21+ and N21- VFF demonstrated significantly greater proliferation compared to N59+, N59-, and S56 VFF at 6 days. α-SMA was expressed in all cells. Fibronectin, alpha smooth actin, connective tissue growth factor, and metallopeptidase inhibitor were the highest genes expression in VFF treated with transforming growth factor β1 (TGFβ1). At 24 hours, S56 VFF showed lower contraction compared to N21+ and N59+ VFF, but at 60 hours S56 VFF had lower collagen contraction compared to all cell groups. Highest collagen contraction matrices were measured with VFF treated with TGFβ1 at 24 hours and N59- VFF at 60 hours.

CONCLUSION

VFF treated with TGFβ1 (myofibroblasts) appear to have similar phenotypic characteristics but different genotypic behavior compared to scar VFF.

LEVEL OF EVIDENCE

N/A. Laryngoscope, 126:E110-E117, 2016.

Characterization of human vocal fold fibroblasts derived from chronic scar

OBJECTIVES/HYPOTHESIS

In vitro modeling of cell-matrix interactions that occur during human vocal fold scarring is uncommon, as primary human vocal fold scar fibroblast cell lines are difficult to acquire. The purpose of this study was to characterize morphologic features, growth kinetics, contractile properties, α-smooth muscle actin (α-SMA) protein expression and gene expression profile of human vocal fold fibroblasts derived from scar (sVFF) relative to normal vocal fold fibroblasts (nVFF).

STUDY DESIGN

In vitro.

METHODS

We successfully cultured human vocal fold fibroblasts from tissue explants of scarred vocal folds from a 56-year-old female and compared these to normal fibroblasts from a 59-year-old female. Growth and proliferation were assessed by daily cell counts, and morphology was compared at 60% confluence for 5 days. Gel contraction assays were evaluated after seeding cells within a collagen matrix. α-SMA was measured using western blotting and immunocytochemistry (ICC). Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) was used to assess differential extracellular matrix gene expression between the two cell types.

RESULTS

sVFF were morphologically indistinguishable from nVFF. sVFF maintained significantly lower proliferation rates relative to nVFF on days 3 to 6 (day 3: P = .0138; days 4, 5, and 6: P < .0001). There were no significant differences in contractile properties between the two cell types at any time point (0 hours: P = .70, 24 hours: P = .79, 48 hours: P = .58). ICC and western blot analyses revealed increased expression of α-SMA in sVFF as compared with nVFF at passages 4 and 5, but not at passage 6 (passage 4: P = .006, passage 5: P = .0015, passage 6: P = .8860). Analysis of 84 extracellular matrix genes using qRT-PCR revealed differential expression of 15 genes (P < .01).

CONCLUSIONS

nVFF and sVFF displayed differences in proliferation rates, α-SMA expression, and gene expression, whereas no differences were observed in contractile properties or morphology. Further investigation with a larger sample size is necessary to confirm these findings.

Fibroblast expression of α-smooth muscle actin, α2β1 integrin and αvβ3 integrin: influence of surface rigidity

Open wound contraction necessitates cell and connective tissue interactions, that produce tension. Investigating fibroblast responses to tension utilizes collagen coated polyacrylamide gels with differences in stiffness. Human foreskin fibroblasts were plated on native type I collagen-coated polyacrylamide gel cover slips with different rigidities, which were controlled by bis-acrylamide concentrations. Changes in alpha smooth muscle actin (αSMA), α2β1 integrin (CD49B) and αvβ3 integrin (CD-51) were documented by immuno-histology and Western blot analysis. Cells plated on rigid gels were longer, and expressed αvβ3 integrin and αSMA within cytoplasmic stress fibers. In contrast, cells on flexible gels were shorter, expressed α2β1 integrin and had fine cytoskeletal microfilaments without αSMA. Increased tension changed the actin makeup of the cytoskeleton and the integrin expressed on the cell's surface. These in vitro findings are in agreement with the tension buildup as an open wound closes by wound contraction. It supports the notion that cells under minimal tension in early granulation tissue express α2β1 integrin, required for organizing fine collagen fibrils into thick collagen fibers. Thicker fibers create a rigid matrix, generating more tension. With increased tension cytoskeletal stress fibers develop that contain αSMA and αvβ3 integrin that replaces α2β1 integrin, consistent with cell switching from collagen to non-collagen proteins interactions.

Are collagens the culprits in the development of incisional and inguinal hernia disease?

Incidence curves for the development of inguinal hernia disease and recurrences thereof exhibit a linear rise over the years and therefore suggest multi-factorial underlying causes. Several studies have revealed marked changes in the abundance and composition of interstitial collagens in patients with (recurrent) hernia diseases, adult groin hernia and incisional hernia. These observations led to the hypothesis that hernia formation and the recurrence of incisional hernia may be explained by disordered tissue renewal and by abnormal wound healing, respectively. Interstitial collagens, owing to their long half-lives and biomechanical strength, are most likely critical components of the biological system of tissue remodelling. An overview of the literature is provided, and the consequences for surgical practice are discussed.

Profiling of differentially expressed genes in wound margin biopsies of horses using suppression subtractive hybridization

Disturbed gene expression may disrupt the normal process of repair and lead to pathological situations resulting in excessive scarring. To prevent and treat impaired healing, it is necessary to first define baseline gene expression during normal repair. The objective of this study was to compare gene expression in normal intact skin (IS) and wound margin (WM) biopsies using suppression subtractive hybridization (SSH) to identify genes differentially expressed during wound repair in horses. Tissue samples included both normal IS and biopsies from 7-day-old wounds. IS cDNAs were subtracted from WM cDNAs to establish a subtracted (WM-IS) cDNA library; 226 nonredundant cDNAs were identified. Detection of genes previously shown to be expressed 7 days after trauma, including the pro-α2-chain of type 1 pro-collagen (COL1A2), annexin A2, the pro-α3-chain of type 6 pro-collagen, β-actin, fibroblast growth factor 7, laminin receptor 1, matrix metalloproteinase 1 (MMP1), secreted protein acidic cystein rich, and tissue inhibitor of metalloproteinase 2, supported the validity of the experimental design. A RT-PCR assay confirmed an increase or induction of the cDNAs of specific genes (COL1A2, MMP1, dermatan sulfate proteoglycan 2, cluster differentiation 68, cluster differentiation 163, and disintegrin and metalloproteinase domain 9) within wound biopsies. Among these, COL1A2 and MMP1 had previously been documented in horses; 68.8% of the cDNAs had not previously been attributed a role during wound repair, of which spermidine/spermine- N-acetyltransferase, serin proteinase inhibitor B10, and sorting nexin 9 were highly expressed and whose known functions in other processes made them potential candidates in regulating the proliferative response to wounding. In conclusion, we identified novel genes that are differentially expressed in equine wound biopsies and that may modulate repair. Future experiments must correlate changes in mRNA levels for precise molecules with spatiotemporal protein expression within tissues.

Alpha V integrin prolongs collagenase production through Jun activation binding protein 1

Robust expression of alphav integrin and matrix metalloproteinase 1 (MMP1) plays an important role in cancer metastasis and wound healing. A patient with an abnormal scar that appeared stretched and thinned out was found to have fibroblasts that overexpressed alphav integrin; therefore, a relationship between alphav integrin expression and MMP1 production was sought. A yeast 2 hybrid screen revealed alphav integrin interacts with jun activation binding domain-1 (JAB1). Mesenchymal-derived cells were transfected with the alphav integrin gene and incorporated into collagen lattices. Transfected cells maximally contracted collagen lattices beginning on day 5, whereas control transfected cells did not contract lattices. Late-phase collagen lattice contraction was inhibited by a pan-MMP inhibitor, BB4. Overexpression of alphav correlated with enhanced MMP1 transcription, as determined by a luciferase assay (P < or = 0.05). Diminution of JAB1 with JAB1 antisense abolished alphav integrin up-regulation of MMP1. We conclude alphav integrin signals through JAB1 to prolong MMP1 production and that this signaling pathway in fibroblasts may lead to abnormal scarring.

Autoantibody-associated congenital heart block: TGFβ and the road to scar

Few diseases exemplify the integration of research from bench to bedside as well as neonatal lupus (NL), often referred to as a model of passively acquired autoimmunity. The signature histologic lesion of autoimmune congenital heart block (CHB) is fibrosis of the conducting tissue and, in some cases, the surrounding myocardium. It is astounding how rapid, and in most cases, irreversible, the fibrotic response to injury is. The mechanism by which maternal anti-SSA/Ro-SSB/La antibodies initiate and finally eventuate in atrioventricular (AV) nodal scarring is not yet defined. In vitro and in vivo studies suggest that one pathologic cascade leading to scarring may be initiated via apoptosis, resulting in the translocation of SSA/Ro-SSB/La antigens and surface binding by maternal autoantibodies. Subsequently, the Fc portion of the bound immunoglobulin engages Fcgamma receptors on tissue macrophages, resulting in the release of TGFbeta at a threshold that favors a pro-fibrotic milieu and irreversible scarring. This cascade also involves a tissue-specific activation of TGFbeta, which promotes the transdifferentiation of fibroblasts into myofibroblasts, a scarring phenotype. Phagocytosis of opsonized apoptotic cardiocytes is distinct from macrophage pathways engaged in physiologic clearance of dying tissue, which also results in the release of TGFbeta but in the latter case appropriately serves to dampen inflammation. Downregulation of TGFbeta (activation/secretion pathway) may provide the basis of a novel approach to treatment of CHB in the future.

Overexpression of integrin alphav promotes human osteosarcoma cell populated collagen lattice contraction and cell migration

Cells attach and interact with the extracellular matrix (ECM) through heterodimeric alphabeta integrin receptors. Specifically, the promiscuous alphavbeta3 integrin and the alpha2beta1 integrin receptors engage numerous matrix components to influence cell adhesion, cell motility, and matrix organization. However, the role of alphav integrin mediating cell-collagen interactions is not clear. In the in vitro cell populated collagen lattice (PCL), a model of cell-matrix interaction, integrin receptors play a role in lattice contraction. To elucidate alphav integrins' effects on cell-collagen interactions, human osteosarcoma (HOS) cells were transfected with alphav integrin (alphav-pcDNA 3.1+). Control HOS cells were transfected with pcDNA 3.1+ vector alone. HOS-alphav cell PCLs contracted to a greater degree than control HOS cell PCLs (P < or = 0.0001). RT-PCR revealed that HOS-alphav cells express both beta1 and beta3 integrins, indicating that alphav has the potential to form a partnership with either beta1 or beta3 integrin. The alphavbeta3 specific inhibitory antibody LM609 significantly retarded HOS-alphav cell PCL contraction (P < or = 0.001), suggesting that alphavbeta3 promotes enhanced HOS-alphav cell PCL contraction. When plated on plastic, control HOS cells show greater elongation compared to HOS-alphav cells. In addition, HOS-alphav cells migrated faster and to a greater degree than control HOS cells (P < or = 0.0001). The possibility that enhanced HOS-alphav cell migration and HOS-alphav cell PCL contraction was caused by increased myosin ATPase activity was examined. HOS-alphav cells showed less myosin ATPase activity than control HOS cells, by an ATP cell contraction bioassay. The enhancement of HOS-alphav cell migration and lattice contraction appears unrelated to increased myosin ATPase activity.

Transdifferentiation of cardiac fibroblasts, a fetal factor in anti-SSA/Ro-SSB/La antibody-mediated congenital heart block

The signature lesion of autoantibody-associated congenital heart block (CHB) is fibrosis of the conducting tissue. To date, participation of myofibroblasts in the cascade to injury has been unexplored. The importance of myofibroblast/macrophage cross-talk is demonstrated by the novel finding of these cell types in the heart of a neonate dying of CHB. This clue to pathogenesis prompted consideration of the mechanism by which maternal anti-SSA/Ro-SSB/La Abs initiate an inflammatory response and promote fibrosis. Isolated cardiocytes from 16-24 wk abortuses were rendered apoptotic by exposure to poly (2-) hydroxyethylmethacrylate; flow cytometry confirmed surface expression of Ro/La. Apoptotic cardiocytes were incubated with affinity-purified Abs to 52 and 60 kDa Ro from CHB mothers (opsonized) or IgG fractions from healthy donors (nonopsonized). Macrophages cultured with opsonized apoptotic cardiocytes expressed proinflammatory markers, supported by a three-fold increase in active alpha(V)beta(3) integrin. Fetal cardiac fibroblasts exposed to supernatants obtained from macrophages incubated with opsonized apoptotic cardiocytes (but not nonopsonized) dramatically increased expression of the myofibroblast marker alpha-smooth muscle actin (SMAc). The "opsonized" supernatant reversed an inhibitory effect of the "nonopsonized" supernatant on proliferation of fibroblasts (120 vs 69%, p < 0.05). Parallel experiments examined the effects of two cytokines and their neutralizing Abs on fibroblasts. TGFbeta1 increased SMAc staining but decreased proliferation. TNF-alpha did not affect either readout. Addition of anti-TGFbeta1 Abs to the "opsonized" supernatant blocked SMAc expression but increased proliferation, while anti-TNF-alpha blocking Abs had no effects. These data suggest that transdifferentiation of cardiac fibroblasts to a scarring phenotype is a pathologic process initiated by maternal Abs.

Differential expression of integrin alpha v and beta 3 in serosal tissue of human intraperitoneal organs and adhesion

OBJECTIVE

To assess the expression of integrin alpha v and beta 3 in the serosal tissue of intraperitoneal organs and adhesions in persons with and without adhesions.

DESIGN

Prospective study.

SETTING

Academic research centers.

PATIENT(S)

Fifty-seven patients undergoing abdominal or pelvic surgery.

MAIN OUTCOME MEASURE(S)

Integrin alpha v and beta 3 messenger RNA (mRNA) expression was evaluated by quantitative reverse transcription polymerase chain reaction.

RESULT(S)

The serosal tissue of the parietal peritoneum, uterus, fallopian tubes, ovary, and the large and small bowel, as well as peritoneal adhesions, skin, fascia, subcutaneous tissue, and omentum, expresses integrin alpha v and beta 3 mRNA. The level of alpha v and beta 3 mRNA expression varied among these tissues; expression of the former substance was highest in uterine serosa and lowest in the skin and small bowel, and expression of the latter substance was highest in the fallopian tubes and skin and lowest in the uterine serosa. Parietal peritoneum and adhesions express equal levels of integrin alpha v; however, integrin beta 3 expression was >100-fold lower in adhesions than in peritoneum. The level of integrin beta 3 expression in omentum, small and large bowels, and subcutaneous tissue was 100-fold to 10,000-fold lower than in other tissues.

CONCLUSION(S)

Serosal tissue of peritoneal organs and adhesions express variable levels of integrin alpha v and beta 3 mRNA. On the basis of such variation and the knowledge that tissue injury alters local integrin expression, integrins may play a key role in adhesion development, particularly in tissue with higher integrin expression.