ProBDNF contributed to patrolling monocyte infiltration and renal damage in systemic lupus erythematosus

Monocyte aberrations have been increasingly recognized as contributors to renal damage in systemic lupus erythematosus (SLE), however, recognition of the underlying mechanisms and modulating strategies is at an early stage. Our studies have demonstrated that brain-derived neurotrophic factor precursor (proBDNF) drives the progress of SLE by perturbing antibody-secreting B cells, and proBDNF facilitates pro-inflammatory responses in monocytes. By utilizing peripheral blood from patients with SLE, GEO database and spontaneous MRL/lpr lupus mice, we demonstrated in the present study that CX3CR1+ patrolling monocytes (PMo) numbers were decreased in SLE. ProBDNF was specifically expressed in CX3CR1+ PMo and was closely correlated with disease activity and the degree of renal injury in SLE patients. In MRL/lpr mice, elevated proBDNF was found in circulating PMo and the kidney, and blockade of proBDNF restored the balance of circulating and kidney-infiltrating PMo. This blockade also led to the reversal of pro-inflammatory responses in monocytes and a noticeable improvement in renal damage in lupus mice. Overall, the results indicate that the upregulation of proBDNF in PMo plays a crucial role in their infiltration into the kidney, thereby contributing to nephritis in SLE. Targeting of proBDNF offers a potential therapeutic role in modulating monocyte-driven renal damage in SLE.

New insights on the association of weight loss with the reduction in carotid intima-media thickness among patients with obesity: an updated systematic review and meta-analysis

OBJECTIVES

Carotid intima-media thickness (CIMT) is a noninvasive marker of atherosclerosis, a typical pathologic process underlying cardiovascular diseases (CVDs). It is essential to explore the relationships between weight loss and the reduction of CIMT.

STUDY DESIGN

This was an updated systematic review and meta-analysis.

METHODS

A systematic literature search was conducted to collect relevant clinical trials. The pooled results of meta-analyses were assessed by weighted mean difference (WMD) and the corresponding 95 % confidence interval (95% CI).

RESULTS

Thirty-three articles involving 2273 participants were collected in this meta-analysis. Among all participants with obesity, the pooled mean of weight loss was -23.26 kg (95% CI: -27.71 to -18.81), and the pooled mean change of CIMT was -0.06 mm (95% CI: -0.08 to -0.04). Compared with Non-surgical interventions, Surgical ones could lead to much higher weight loss (Pbetween groups < 0.001). A more significant CIMT reduction was identified among Surgical intervention patients than among Non-surgical intervention participants (Pbetween groups < 0.001).

CONCLUSIONS

Effective interventions, especially Surgical interventions, could reduce the weight of patients with obesity, followed by the decline of CIMT, which might further disturb atherosclerosis progression and lower CVD risk.

Platelets reprogram monocyte functions by secreting MMP-9 to benefit postoperative outcomes following acute aortic dissection

Platelets have a great ability to modulate immune responses. Monocyte-platelet aggregates (MPAs) are associated with the pathogenesis of cardiac disease. Notably, a low preoperative platelet count often indicates poor postoperative recovery following acute aortic dissection (AAD). The functions of platelets and MPAs in AAD, however, remain poorly understood. We found that, despite decreased platelet counts, platelets were also activated in AAD patients, with significant alterations in immune-modulating mediators. Of interest, monocytes in AAD patients had a suppressed immune status, which was correlated with poor outcomes following surgery. Interestingly, platelets preferentially aggregated with monocytes, and the levels of MPAs were related to recovery after surgical repair in AAD patients. Platelets restored suppressed monocyte functions in AAD patients by forming aggregates and partly by secreting matrix metalloproteinase-9 (MMP-9). Thus, the results point to a previously unknown mechanism for platelets involving monocyte reprogramming, which may improve postoperative outcomes following complex cardiovascular surgery.

Brain-Derived Neurotrophic Factor Precursor Contributes to a Proinflammatory Program in Monocytes/Macrophages After Acute Myocardial Infarction

Background The imbalance of monocyte/macrophage polarization toward the preferential proinflammatory phenotype and a lack of normal inflammation resolution are present in acute myocardial infarction (AMI). Our previous study showed that upregulation of brain-derived neurotrophic factor precursor (proBDNF) in M2-like monocytes may contribute to the proinflammatory response in the Stanford type-A acute aortic dissection. The present study aimed to investigate the role of proBDNF signaling in monocytes/macrophages in the progress of AMI. Methods and Results We observed the upregulation of proBDNF in the proinflammatory monocytes of patients with AMI. The upregulation of proBDNF was also observed in the circulating proinflammatory Ly6C^high monocytes and cardiac F4/80⁺CD86⁺ macrophages 3 days after AMI in a mice model. To neutralize proBDNF, the mice subjected to AMI were injected intraperitoneally with a monoclonal anti-proBDNF antibody. Echocardiography, 2,3,5-triphenyltetrazolium chloride staining, and positron emission tomography/computed tomography results demonstrate that monoclonal anti-proBDNF antibody treatment further impaired cardiac functions, increased infarct size, and exacerbated the proinflammatory state. Moreover, the level of proinflammatory Ly6C^high in the blood and F4/80⁺CD86⁺ in the heart was further increased in monoclonal anti-proBDNF antibody mice. RNA sequencing revealed that matrix metalloprotease-9 protein level was dramatically increased, along with the activated proinflammatory-related cytokines. Matrix metalloprotease-9 inhibitor treatment attenuated the deteriorated effect of monoclonal anti-proBDNF antibody on cardiac function and infarct areas. Conclusions Our study shows that endogenous proBDNF in monocytes/macrophages may exert protective roles in cardiac remodeling after AMI by regulating matrix metalloprotease-9 activity.

[Clinical study of induction chemotherapy followed by allogeneic hematopoietic stem cell transplantation in the treatment of FLT3-ITD(+) acute myeloid leukemia with normal karyotype]

Objective: To assess the efficacy of induction chemotherapy followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT) in the treatment of FLT3-ITD(+) acute myeloid leukemia (AML) with normal karyotype. Methods: The clinical data of FLT3-ITD(+) AML patients with normal karyotype in the First Affiliated Hospital of Nanjing Medical University from Jan 2018 to March 2021 were retrospectively analyzed. Results: The study included 49 patients with FLT3-ITD(+)AML, 31 males, and 18 females, with a median age of 46 (16-59) years old. All patients received induction chemotherapy, and 24 patients received sequential allo-HSCT (transplantation group) . The median follow-up time was 465 days, the one-year overall survival (OS) from diagnosis was (70.0 ± 7.4) %, and one-year disease-free survival (DFS) was (70.3±7.4) %. The one-year OS was significantly different between the transplantation group and the non-transplantation group [ (85.2 ± 7.9) % vs (52.6 ± 12.3) %, P=0.049]. but one-year DFS [ (84.7 ± 8.1) % vs (55.2 ± 11.9) %, P=0.061] was not. No significance was found in one-year OS between patients with low-frequency and high-frequency FLT3-ITD(+) (P>0.05) . There were 12 patients with high-frequency FLT3-ITD(+) in the transplantation and the non-transplantation groups, respectively. The one-year OS [ (68.8 ± 15.7) % in the transplantation group vs (26.2 ± 15.3) % in the non-transplantation group, P=0.027] and one-year DFS [ (45.5 ± 21.3) % in the transplantation group vs (27.8±15.8) % in the non-transplantation group, P=0.032] were significantly different between the two groups. Conclusion: Induction chemotherapy followed by allo-HSCT can enhance the prognosis of FLT3-ITD(+) patients, particularly those with FLT3-ITD high-frequency mutation.

Systemic blockade of proBDNF inhibited the expansion and altered the transcriptomic expression in CD3+B220+ cells in MRL/lpr lupus mice

OBJECTIVES

The overexpansion of CD3⁺B220⁺ cells is the hallmark and main pathological mechanism of clinical manifestations of spontaneously developed MRL/lpr mice, which are primarily used as a mouse model of SLE. Our recent report demonstrated that blocking brain-derived neurotrophic factor precursor (proBDNF) suppressed the antibody-secreting cell differentiation and proliferation and inhibited the progression of SLE; however, the effect of proBDNF blockade on these CD3⁺B220⁺ cells in MRL/lpr mice is unclear.

METHODS

To explore the effect of proBDNF on CD3⁺B220⁺ cells, MRL/lpr mice at 12 weeks old were intraperitoneally injected with monoclonal anti-proBDNF antibody (McAb-proB) or control IgG continuously for 8 weeks. The manifestations in mice were observed, and peripheral blood and splenocytes were collected and analysed via flow cytometry at 20 weeks old. In addition, splenic CD3⁺B220⁺ cells were subjected to RNA sequencing (RNA-seq) analysis to identify transcriptomic alterations.

RESULTS

CD3⁺B220⁺ cells in peripheral blood (p=0.0101) and spleen (p<0.0001) were expanded in MRL/lpr mice. Meanwhile, inhibition of proBDNF signalling reduced the percentage of CD3⁺B220⁺ cells in peripheral blood (p=0.0036) and spleen (p=0.0280), alleviated lymphadenopathy, reduced urine protein level (p<0.0001) and increased the body weight (p=0.0493). RNA-seq revealed 501 upregulated and 206 downregulated genes in splenic CD3⁺B220⁺ cells in McAb-proB-treated MRL/lpr mice compared with IgG-treated mice. The differentially expressed genes were found to be involved in apoptosis, tumour necrosis factor signalling, and T cell differentiation and proliferation.

CONCLUSION

Systemic blockade of proBDNF inhibited the overexpansion of CD3⁺B220⁺ cells and altered their signals related to cell cycle, cell apoptosis and the immune response, which may contribute to the attenuation of disease symptoms in murine lupus.

[Status of HVPG clinical application in China in 2021]

Objective: The investigation and research on the application status of Hepatic Venous Pressure Gradient (HVPG) is very important to understand the real situation and future development of this technology in China. Methods: This study comprehensively investigated the basic situation of HVPG technology in China, including hospital distribution, hospital level, annual number of cases, catheters used, average cost, indications and existing problems. Results: According to the survey, there were 70 hospitals in China carrying out HVPG technology in 2021, distributed in 28 provinces (autonomous regions and municipalities directly under the central Government). A total of 4 398 cases of HVPG were performed in all the surveyed hospitals in 2021, of which 2 291 cases (52.1%) were tested by HVPG alone. The average cost of HVPG detection was (5 617.2±2 079.4) yuan. 96.3% of the teams completed HVPG detection with balloon method, and most of the teams used thrombectomy balloon catheter (80.3%). Conclusion: Through this investigation, the status of domestic clinical application of HVPG has been clarified, and it has been confirmed that many domestic medical institutions have mastered this technology, but it still needs to continue to promote and popularize HVPG technology in the future.

[The efficacy of eltrombopag plus cyclosporine A in patients with transfusion-dependent non-severe aplastic anemia: a retrospective study from single center]

The main purpose of our study was to evaluate the efficacy and safety of eltrombopag plus cyclosporine A (CsA) in transfusion-dependent non-severe aplastic anemia(TD-NSAA). The clinical characteristics of 13 TD-NSAA patients who received initial treatment of eltrombopag plus CsA from 2019 to 2021 were retrospectively analyzed. The 3-month overall hematological response (OR) rate was 12/13. Until the end of follow-up, 12 patients responded, among whom 2 patients reached complete response (CR) and 9 patients reached partial response (PR) and 1 with HR. Paroxysmal nocturnal hemoglobinuria (PNH) developed in one patient at 6 months after treatment. Five of thirteen patients reported mild adverse reactions, which were all manageable. Compared with historical data, the combination of eltrombopag with CsA is an effective regimen in patients with TD-NSAA.

Up-regulation of proBDNF/p75NTR signaling in antibody-secreting cells drives systemic lupus erythematosus

Inappropriate expansion of antibody-secreting cells (ASCs) is typical of systemic lupus erythematosus (SLE), but the regulatory signaling of pathogenic ASCs is unclear. The present study shows that brain-derived neurotrophic factor precursor (proBDNF) and its high-affinity pan-75 neurotrophin receptor (p75^NTR) are highly expressed in CD19⁺CD27^hiCD38^hi ASCs in patients with SLE and in CD19⁺CD44^hiCD138⁺ ASCs in lupus-like mice. The increased proBDNF⁺ ASCs were positively correlated with clinical symptoms and higher titers of autoantibodies in SLE. Administration of monoclonal antibodies against proBDNF or specific knockout of p75^NTR in CD19⁺ B cells exerted a therapeutic effect on lupus mice by limiting the proportion of ASCs, reducing the production of autoantibodies and attenuating kidney injury. Blocking the biological function of proBDNF or p75^NTR also inhibits ASC differentiation and antibody production in vitro. Together, these findings suggest that proBDNF-p75^NTR signaling plays a critical pathogenic role in SLE through promoting ASC dysfunction.

Early-Life Multiple Sevoflurane Exposures Alleviate Long-term Anxiety-Like Behaviors in Mice via the proBDNF/ERK Pathway

Early-life multiple anesthetics exposure causes neurotoxicity and hence cognitive dysfunction on developing brain. However, the effects of early-life multiple sevoflurane exposures on emotional changes, especially upon stress, are far beyond understood. In young male C57BL6/J mice, the present study showed that 3% sevoflurane inhalation for 2 h in three consecutive days did not influence anxiety-like behaviors as measured by open field test, light dark transition, and elevated plus maze test. In addition, foot shocks stress induced both the short- and long-term anxiety-like behaviors. However, triple sevoflurane exposures ameliorated the long-term anxiety-like behaviors induced by the foot shocks. In parallel, foot shocks stress upregulated the expression of phosphorylated extracellular signal-regulated kinase (p-ERK) and brain-derived neurotrophic factor precursor (proBDNF) in the anterior cingulate cortex (ACC), which were significantly inhibited by triple sevoflurane exposures. Immunofluorescence further indicated that the increased p-ERK was mainly expressed in the proBDNF-positive staining cells. Intra-ACC injection of recombinant proBDNF protein upregulated the p-ERK expression and blocked the anxiolytic effect of sevoflurane exposure on long-term anxiety-like behaviors. Therefore, our study demonstrated that multiple sevoflurane exposures alleviate long-term anxiety-like behaviors upon acute stress in young mice by inhibiting proBDNF-ERK signaling in the ACC.

Diagnostic value of the combined detection of CEA, NSE and IL-18 for lung cancer and their relationship with apoptosis gene Bcl-2

This study aims to investigate the value of the combined detection of carcinoembryonic antigen (CEA), Neuron-specific enolase (NSE) and the level of Interleukin-18 (IL-18) in the serum in the diagnosis of lung cancer. The correlation between these parameters and the expression levels of B-cell lymphoma-2 (Bcl-2) protein were also studied. Eighty patients with lung cancer were included in the lung cancer group. These patients underwent surgery in the Department of Oncology of Huai'an Second People's Hospital between February 2016 and February 2018. During the same period, another 80 patients with benign lung lesions were registered in the benign lesion group and 80 healthy people were enrolled in the control group. Enzyme-linked immunosorbent assay (ELISA) was used to detect the expression levels of CEA, NSE and IL-18. The diagnostic critical value of these factors was used as positive indicator. When CEA, NSE and IL-18 levels were positive at the same time, the combined detection was considered to be positive. WB was used to detect Bcl-2 expression level. We also analyzed the possible correlation between CEA, NSE, IL-18 levels and the Bcl-2 expression levels. The CEA, NSE and IL-18 expression levels in the serum of the lung cancer group were significantly higher than those in the benign lesion and the control groups (p<0.05). The area under ROC curve for CEA, NSE and IL-18 respectively was 0.770 (0.697-0.843), 0.829 (0.767-0.890), 0.721 (0.642-0.800) (p<0.001). IL-18 level was negatively correlated with the level of Bcl-2 mRNA in the tissue (r=-0.380, p<0.001). In conclusion, CEA, NSE and IL-18 have a good auxiliary diagnostic value in patients with lung cancer. The combined detection could improve the sensitivity and specificity of lung can¬cer diagnosis. There was a negative correlation between IL-18 and Bcl-2 levels which suggested a potential inhibitory role of IL-18 on the lung cancer cells apoptosis pathway.

[Application of thoracoscopy-guided thoracic paravertebral block for analgesia after single-port video-assisted pulmonary lobectomy]

Objective: To investigate the effects of thoracoscopy-guided thoracic paravertebral block for analgesia after single-port video-assisted pulmonary lobectomy. Methods: From December 2019 to April 2020, 60 patients receiving single-port video-assisted pulmonary lobectomy at Ningbo Medical Center Lihuili Hospital were selected. The patients were randomly and equally divided into control group and paravertebral block group using a random number table. Patients of paravertebral block group were injected into the thoracic 4-5 intercostal, paravertebral 1 cm using 0.375% ropivacaine (20 ml) with thoracoscopy-guided at the end of surgery, while patients of control group were given patient controlled intravenous analgesia (PCIA). Postoperative visual analogue scale (VAS) and Ramsay sedation scale were recorded at 6, 12, 24, 36, 48 h after the surgery. The incidence of postoperative adverse reactions, additional dose and times of pethidine, the time to resume eating, the rate of postoperative active cough, the first time to get out of bed after surgery and postoperative hospital stay of two groups' patients were recorded. t test and chisquare test were used for statistical analysis. Results: The VAS score of paravertebral block group were lower than those of control group at all time points (all P<0.05). The Ramsay sedation scale of paravertebral block group were higher than those of control group at all time points (all P<0.05). The additional dose and times of pethidine of paravertebral block group were (8.2±2.3) mg and (0.2±0.1) time, which were lower than (87.8±15.3) mg and (1.8±0.3) time of control group, the differences were statistically significant (t=28.91, 34.37, all P<0.05). Incidence of nausea, vomiting and pruritus of paravertebral block group were 10.0%, 6.7% and 0, which were lower than 40.0%, 30.0% and 13.3% of control group, the differences were statistically significant (χ(2)=7.20, 5.45, 4.29, all P<0.05). The rate of postoperative active cough of paravertebral block group was 33.3%, which was higher than 10.0% of control group, the difference was statistically significant (χ(2)=4.81, P<0.05). The time to resume eating, the first time to get out of bed after surgery and postoperative hospital stay were (6.5±0.4) h, (20.9±3.1) h and (4.6±1.0) d, which were lower than (8.5±0.7) h, (28.6±4.8) h and (6.1±1.3) d of control group, the differences were statistically significant (t=13.47, 7.39, 4.19, all P<0.05). Conclusion: Thoracic paravertebral block under thoracoscopy-guided can effectively reduce the postoperative pain of single-port thoracoscopic lobectomy, with fewer adverse reactions, and is beneficial to postoperative recovery.

ProBDNF promotes sepsis-associated encephalopathy in mice by dampening the immune activity of meningeal CD4+ T cells

BACKGROUND

Sepsis-associated encephalopathy (SAE) increases the mortality of septic patients, but its mechanism remains unclear. The present study aimed to investigate the roles of T lymphocytes, proBDNF, and their interaction in the pathogenesis of SAE.

METHODS

Fear conditioning tests were conducted for cognitive assessment in the lipopolysaccharide (LPS, 5 mg kg^-1)-induced septic mice. Meninges and peripheral blood were harvested for flow cytometry or qPCR. FTY720 and monoclonal anti-proBDNF antibody (McAb-proB) were used to investigate the effect of lymphocyte depletion and blocking proBDNF on the impaired cognitive functions in the septic mice.

RESULTS

In the septic mice, cognitive function was impaired, the percentage of CD4⁺ T cells were decreased in the meninges (P = 0.0021) and circulation (P = 0.0222), and pro-inflammatory cytokines were upregulated, but the anti-inflammatory cytokines interleukin (IL)-4 (P < 0.0001) and IL-13 (P = 0.0350) were downregulated in the meninges. Lymphocyte depletion by intragastrically treated FTY720 (1 mg kg^-1) for 1 week ameliorated LPS-induced learning deficit. In addition, proBDNF was increased in the meningeal (P = 0.0042) and peripheral (P = 0.0090) CD4⁺ T cells. Intraperitoneal injection of McAb-proB (100 μg) before LPS treatment significantly alleviated cognitive dysfunction, inhibited the downregulation of meningeal (P = 0.0264) and peripheral (P = 0.0080) CD4⁺ T cells, and normalized the gene expression of cytokines in the meninges. However, intra-cerebroventricular McAb-proB injection (1 μg) did not have such effect. Finally, exogenous proBDNF downregulated the percentage of CD4⁺ T cells in cultured splenocytes from septic mice (P = 0.0021).

CONCLUSION

Upregulated proBDNF in immune system promoted the pathogenesis of SAE through downregulating the circulating CD4⁺ T cells, limiting its infiltration into the meninges and perturbing the meningeal pro-/anti-inflammatory homeostasis.

The regulatory role of ProBDNF in monocyte function: Implications in Stanford type-A aortic dissection disease

Brain-derived neurotrophic factor precursor (proBDNF) has been reported to strengthen the dysfunction of monocytes/macrophages in animal studies. However, it is still unknown the roles of proBDNF in the dysfunction of monocytes in the inflammatory diseases in humans. In the present study, we showed that proBDNF and pan neurotrophic receptor p75 were significantly upregulated in monocytes from healthy donors (HD) after lipopolysaccharide treatment. Exogenous proBDNF treatment upregulated CD40 and proinflammatory cytokines expression in monocytes including interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α. In Stanford type-A acute aortic dissection (AAD) patients, proBDNF was upregulated in CD14⁺ CD163⁺ CX3CR1⁺ M2- but not CD14⁺ CD68⁺ CCR2⁺ M1-like monocytes. In addition, sera from AAD patients activated gene expression of proinflammatory cytokines in cultured PBMCs from HD, which was attenuated by proBDNF monoclonal antibody (Ab-proB) treatment. These findings suggested that upregulation of proBDNF in M2-like monocytes may contribute to the proinflammatory response in the AAD.

Diabetes impairs mobilization of mouse bone marrow-derived Lin(-)/VEGF-R2(+) progenitor cells

Endothelial progenitor cells circulating in the peripheral blood (PB) contribute to vascular repair. This study aimed to evaluate the potential of a 'cocktail' consisting of erythropoietin, granulocyte colony-stimulating factor and tetrahydrobiopterin to mobilize hematopoietic lineage negative/vascular endothelial growth factor receptor 2 positive (Lin(-)/VEGF-R2(+)) cells from the bone marrow (BM) to PB in non-diabetic and diabetic mice. Diabetes was induced in mice by intraperitoneal injection of streptozotocin. Diabetic mice were studied after 16weeks of hyperglycemia. Half the mice in each group (non-diabetic and diabetic) received daily intraperitoneal injections of the cocktail for 6 consecutive days while the other half received vehicle buffer. Mobilization of Lin(-)/VEGF-R2(+) cells, which were expanded in MCP301 medium, was evaluated after isolating them from BM and PB and their phenotypic and morphological properties were studied. We found that 16weeks of diabetes affected neither the total number of BM mononucleated cells nor the number of Lin(-)/VEGF-R2(+) cells in BM compared with non-diabetic controls. In non-diabetic mice, cocktail treatment resulted in a significant decrease in BM Lin(-)/VEGF-R2(+) cells, paralleled by a significant increase of these cells in PB. Such changes in the number of Lin(-)/VEGF-R2(+) cells in BM and PB after the cocktail treatment were less marked in diabetic mice. In vitro studies of BM Lin(-)/VEGF-R2(+) cells from diabetic and non-diabetic mice did not reveal any differences in either phenotypes or colony forming potential. These findings indicate that diabetes impairs the mobilization of Lin(-)/VEGF-R2(+) cells from BM to PB. Impaired mobilization of BM Lin(-)/VEGF-R2(+) cells soon after the onset of diabetes may contribute to complications such as diabetic retinopathy.

Intramedullary nailing for adult hypophosphatasia: a case report

Hypophosphatasia is a rare genetic metabolic disorder characterised by defective bone mineralisation secondary to serum and bone alkaline phosphatase deficiency. We report a 46-year-old woman who underwent multiple intramedullary nailings for fractures and deformities of 6 long bones over 13 years.

The use of a reverse flow sural fasciocutaneous flap in a patient with multiple trauma: a case report

Provision of soft-tissue coverage for defects in the distal leg and foot is a challenge, especially in patients with multiple injuries and major soft-tissue defects. Major flap reconstruction requires expertise and the results are variable, with high morbidity. We report a case in which a reverse flow sural fasciocutaneous flap was used for treatment of an open fracture-dislocation of the right ankle after repeated debridement in a 64-year-old man with a history of chronic smoking, diabetes mellitus, and hypertension.

Potential long-term inhibition of ocular neovascularisation by recombinant adeno-associated virus-mediated secretion gene therapy

Neovascularisation (NV) within the eye often results in visual loss. Vascular endothelial growth factor (VEGF) has been implicated in the development of ocular NV. Previous studies have shown that VEGF antagonists successfully suppressed retinal and choroidal NV in animal models. However, the systemic approach and transient nature of the delivery systems used in these studies hinder therapeutic application. To achieve stable and localised ocular anti-angiogenic therapy, we explored the use of recombinant adeno-associated virus (rAAV)-mediated secretion gene therapy (SGT). In this study, we generated a rAAV vector encoding soluble VEGF receptor 1, sFlt-1 (AAV-CMV.sflt) and determined its ability to inhibit cautery-induced corneal NV and laser-induced choroidal NV. Delivery of AAV-CMV.sflt into the anterior chamber resulted in transgene expression in the iris pigment epithelium and corneal endothelium, which reduced the development of corneal NV in the stroma of cauterised rats by 36% compared with cauterised control groups (P = 0.009). Subretinal delivery of AAV-CMV.sflt near the equator of the eye also suppressed choroidal NV at the laser lesions around the optic nerve by 19% (P = 0.002), indicating that there was diffusion of the secreted anti-angiogenic protein across the retina. Both results suggest that the long-term suppression of ocular NV is possible through the use of stable rAAV-mediated SGT.

Uptake dynamics and retinal tolerance of phosphorothioate oligonucleotide and its direct delivery into the site of choroidal neovascularization through subretinal administration in the rat

This study aimed to investigate uptake dynamics and retinal tolerance of phosphorothioate oligonucleotides (PS-oligos) following subretinal injection. A fluorescent-labeled PS-oligo (FL-oligo) with random sequence was administered into the subretinal space of rat by transsclera-choroid-retinal pigment epithelium (RPE) injection at doses of 0.129, 1.29, and 12.9 microg in 2.0 microl solution. The uptake dynamics were evaluated by fundus fluorescent photography in real time and by fluorescence microscopy using flat mounts and cryosections. Immunophenotyping for CD4+, CD8+ cytotoxic lymphocytes, and CD68+ macrophages was performed to assess cellular infiltration in the retina. In addition, the FL-oligo was injected subretinally in a rat model of choroidal neovascularization (CNV) for direct delivery into the site of CNV. Subretinal administration of FL-oligo resulted in both dose-dependent and time-dependent distribution in the retina, where it accessed the RPE and all layers of the neuroretina. CD4+, CD8+ cytotoxic lymphocytes, and CD68+ macrophages were observed at the site of needle penetration. However, in areas far from the injection site where the FL-oligo appeared strongly, cellular infiltration was absent, and the retinal morphology was preserved very well. The FL-oligo was successfully delivered into the site of intense laser photocoagulation. It was predominantly localized to the RPE, macrophages, and some choroid cells and remained detectable for at least 56 days after injection. Our results demonstrate for the first time that subretinal injection efficiently introduced PS-oligo into the RPE and neuroretina with an acceptable level of safety. Subretinal administration of antiangiogenic oligonucleotides may hold great potential for the treatment of CNV.

Inhibition of angiogenesis by adenovirus-mediated sFlt-1 expression in a rat model of corneal neovascularization

Pathological angiogenesis, or the production of new capillary vessels from preexisting vasculature, within the eye is a serious event that often leads to blindness. Upregulation of vascular endothelial growth factor (VEGF) has been linked to neovascularization in the eye, suggesting that it could be a suitable target to inhibit angiogenic changes. This work investigated whether the presence of a proven antiangiogenic factor, the soluble variant of the VEGF receptor, sFlt-1, in the anterior chamber is sufficient to inhibit new vessel formation in the cornea in an animal model of corneal neovascularization. A recombinant adenovirus vector that can mediate efficient in vivo gene transfer and expression in ocular cells was selected as a delivery agent. We have shown that after the injection of Ad.betagal into the anterior chamber of normal and cauterized rat eyes, corneal endothelial cells and cells of the trabecular meshwork were efficiently transduced and that beta-galactosidase (beta-Gal) expression was maintained up to 10 days postinjection. Cauterization significantly increased the amount of immunoreactive VEGF in vehicle- or Ad.null-injected animals (t test, p < 0.001 and p < 0.001, respectively). However, when cauterization was combined with Ad.sflt injection there was no statistically significant increase in the amount of immunoreactive VEGF (p = 0.12). The injection of Ad.sflt into the anterior chamber slowed or inhibited VEGF-induced angiogenic changes. After cauterization, 100% of uninjected and vehicle-injected and 82% of Ad.null-injected animals developed moderate to severe corneal angiogenesis in contrast to 18% of Ad.sflt-injected animals. These in vivo results suggest that the transient presence of antiangiogenic agents in the anterior chamber can be successfully used to inhibit the development of corneal angiogenesis.

In vivo use of oligonucleotides to inhibit choroidal neovascularisation in the eye

BACKGROUND

We have previously demonstrated the in vivo uptake of oligonucleotides in the rat eye and have continued with experiments to look at the effectiveness of targeted oligonucleotide sequences. Vascular endothelial growth factor (VEGF) is correlated with new blood vessel formation and has been implicated in numerous eye diseases characterised by abnormal blood vessel proliferation. An oligonucleotide targeted to the VEGF sequence was examined for its effect on VEGF production in vitro and the development of choroidal neovascularisation in vivo in the eye.

METHODS

A series of sequences were assessed in an in vitro screening system using retinal pigment epithelial (RPE) cells to demonstrate a reduction in VEGF. A targeted sequence was further investigated using an animal model of choroidal neovascularisation where a krypton laser was used to produce a wound healing response in the choroid and retina. The oligonucleotide was injected into the vitreous and the development of choroidal neovascularisation assessed using fluorescein angiography.

RESULTS

The targeted sequence was shown in vitro to downregulate the VEGF produced by RPE cells grown under hypoxic conditions and when injected into laser treated eyes was shown to be preferentially taken up in the laser lesion. Fluorescein angiography demonstrated that the test oligonucleotide was successful in reducing laser-mediated choroidal neovascularisation.

CONCLUSIONS

A sequence corresponding to the 5'UTR of the VEGF gene has provided encouraging results for the treatment of neovascularisation.

Combined effect of cyclosporine and sirolimus on improving the longevity of recombinant adenovirus-mediated transgene expression in the retina

OBJECTIVES

To reevaluate the longevity and intraocular safety of recombinant adenovirus (rAd)-mediated gene delivery after subretinal injection, and to prolong transgene expression through the combination of 2 synergistic immunosuppressants.

METHODS

An rAd vector carrying green fluorescent protein (GFP) gene was delivered subretinally in the rat eye. The GFP expression was monitored in real time by fundus fluorescent photography. Intraocular safety was examined by observation of changes of retinal pigmentation, cell infiltration in virus-contacted area, immunophenotyping for CD4(+) and CD8(+) cytotoxic T lymphocytes, and CD68(+) macrophages, histologic findings, and dark-adapted electroretinography. Two synergistic immunosuppressants, cyclosporine and sirolimus, were used alone or in combination to prolong transgene expression by temporary immunosuppression.

RESULTS

The GFP expression peaked on day 4, dramatically decreased on day 10, and was not detectable on day 14. The decreased GFP expression was coincident with cell infiltration in virus-contacted area. Immunostaining showed that the infiltrating cells were CD4(+) and CD8(+) cytotoxic T lymphocytes and CD68(+) macrophages. Clumped retinal pigmentation and decreased b wave of dark-adapted electroretinogram were observed at 3 to 4 weeks after injection. Histologic examination confirmed rAd-induced retinal degeneration. Transient immunosuppression by cyclosporine and sirolimus, either alone or in combination, improved transgene expression, with the combination being the most efficient. The combined immunosuppression attenuated but did not retard the rAd-induced retinal damage.

CONCLUSIONS

Transgene expression mediated by rAd after subretinal delivery is short-term and toxic to the retina. Combination of cyclosporine and sirolimus may act as an immunosuppressive adjunct to prolong rAd-mediated gene transfer.

CLINICAL RELEVANCE

The intraocular safety of rAd should be carefully considered before clinical trials are performed.

Controlled production of active cathepsin D in retinal pigment epithelial cells following adenovirus-mediated gene delivery

The transduction of a low cathepsin D-producing retinal pigment epithelial cell line with a recombinant adenovirus, Ad.proCatD, carrying a viral promoter and the precursor form of the lysosomal enzyme cathepsin D, procathepsin D, led to the upregulation of proCatD expression. However, the resultant aspartic protease activity did not exceed that observed in normal primary human retinal pigment epithelial cells. Following the injection of Ad. proCatD into rat eyes, immunohistochemistry and Western blot analysis localized the expression of procathepsin D to the retinal pigment epithelial cell layer and to the sclera/choroid/retinal epithelial cell layers, respectively. This upregulation of procathepsin D expression was accompanied by a limited increase in aspartic protease activity. The injected eyes did not demonstrate any of the retinal changes that have been associated with the overproduction and secretion of active cathepsin D. Immunoelectronmicroscopy of Ad.proCatD-transduced retinal pigment epithelial cells demonstrated the presence of cathepsin D not only in cytoplasmic vesicles and lysosomes but also in the nucleoli and, less strongly, elsewhere in euchromatic regions of some 10% of cells. In spite of the upregulated expression of procathepsin D, the production of active cathepsin D in Ad.proCatD-transduced retinal pigment epithelial cells was strictly controlled. It is proposed that active cathepsin D production is controlled at the point of posttranslational modification by an intranuclear feedback mechanism initiated by the relative excess of procathepsin D in Ad. proCatD-transduced retinal pigment epithelial cells.

Long-term real-time monitoring of adeno-associated virus-mediated gene expression in the rat retina

PURPOSE

Previous studies have demonstrated that adeno-associated virus (AAV) efficiently transduced retinal pigmented epithelial (RPE) cells. The goal of this study was to further evaluate and characterize transgene expression within the RPE cells over time in vivo.

METHODS

Adeno-associated virus-mediated gene transfer was monitored and quantified by retinal photography following subretinal injection of a recombinant AAV encoding the green fluorescent protein gene (rAAVCMV-gfp) into rat eyes. Retinal function of transduced rat eyes was measured by electroretinography.

RESULTS

The maximum level of transgene expression was reached at 8 weeks postinjection followed by a gradual decrease throughout the experimental period. Interestingly, it was observed that while gfp expression was stable in some RPE cells, gfp fluorescence completely disappeared in other cells over the duration of the experiment. The expression of AAV-mediated gfp in RPE cells did not alter the retinal function for over 1 year

CONCLUSIONS

These results confirm the importance of this direct visualization system to study vector transgene expression in vivo and support the use of AAV for diseases treatable by targeting RPE cells.

Matrix metalloproteinase (MMP) expression in experimental choroidal neovascularization

PURPOSE

Matrix metalloproteinases (MMP) are a family of proteolytic enzymes that degrade basement membrane and extracellular matrix proteins. To gain information on the possible role of MMPs in choroidal neovascularization (CNV), we have analyzed the mRNA expression of MMP-2 and MMP-9, two forms of MMPs implicated in ocular neovascularization, in a rat model.

METHODS

Choroidal neovascularization was induced in pigmented rats by krypton laser photocoagulation of the fundus whereafter eyes were enucleated at 1, 3, 5, 7, 10 and 60 days. Antisense and sense riboprobes were generated using DNA complementary to MMP-2 and MMP-9, and mRNA expression was analyzed using in situ hybridization.

RESULTS

In the untreated eyes MMP-2 mRNA expression was weakly detected in cells within the choroid. In laser-treated eyes MMP-2 mRNA expression was markedly increased and mainly localized to macrophage-like and retinal pigment epithelial (RPE)-like cells invading the choroid, subretinal space and inner retina. This increase in MMP-2 mRNA expression peaked at day 10 whereafter a decline was detected. MMP-9 mRNA expression was low in untreated eyes and did not increase following laser treatment.

CONCLUSION

The results show that MMP-2 mRNA expression is increased in experimental CNV, and support of a role for MMP-2 in the development of CNV in age-related macular degeneration.

Overexpression of vascular endothelial growth factor (VEGF) in the retinal pigment epithelium leads to the development of choroidal neovascularization

Vascular endothelial growth factor (VEGF) has been strongly implicated in the development of choroidal neovascularization found in age-related macular degeneration. Normally expressed in low levels, this study investigates whether the overexpression of VEGF in the retinal pigment epithelium is sufficient to cause choroidal neovascularization in the rat retina. A recombinant adenovirus vector expressing the rat VEGF(164) cDNA (AdCMV.VEGF) was constructed and injected into the subretinal space. The development of neovascularization was followed by fluorescein angiography, which indicates microvascular hyperpermeability of existing and/or newly forming blood vessels, and histology. VEGF mRNA was found to be overexpressed by retinal pigment epithelial cells and resulted in leaky blood vessels at 10 days postinjection, which was maintained for up to 31 days postinjection. By 80 days postinjection, new blood vessels had originated from the choriocapillaris, grown through the Bruch's membrane to the subretinal space, and disrupted the retinal pigment epithelium. This ultimately led to the formation of choroidal neovascular membranes and the death of overlying photoreceptor cells. By controlling the amount of virus delivered to the subretinal space, we were able to influence the severity and extent of the resulting choroidal neovascularization. These results show that even temporary overexpression of VEGF in retinal pigment epithelial cells is sufficient to induce choroidal neovascularization in the rat eye.

Inhibition of diclofenac formulated in hyaluronan on angiogenesis in vitro and its intraocular tolerance in the rabbit eye

PURPOSE

To investigate the effect of diclofenac, a potent nonsteroidal anti-inflammatory drug, formulated in hyaluronan (diclofenac/HA) on angiogenesis in vitro and its intraocular toxicity in vivo.

METHODS

The effect of diclofenac/HA on angiogenesis was determined by choriocapillary endothelial cells on Matrigel stimulated by vascular endothelial growth factor (VEGF). The tube areas were quantified by image digital analysis. For toxicity study, diclofenac/HA was injected intravitreally with a dose range from 100 to 1080 microg in 26 rabbits following gas compression vitrectomy. Potential toxicity was assessed by indirect ophthalmoscopy and by histological studies (light and electron microscopy). Retinal function was monitored by electroretinography (ERG) in six rabbits that received 400 microg of diclofenac/HA.

RESULTS

Diclofenac/HA, 180, 90 microg/ml, inhibited tube formation to 24% and 55% of the standard group (Media Ham's F12 plus 5% fetal calf serum and 50 ng/ml VEGF) respectively (P<0.01). Intravitreal injection of 540 microg or higher doses of diclofenac/HA resulted in ocular toxicity in the rabbit, demonstrated as cataract, vitreous haze and retinal damage observed by indirect ophthalmoscopy and light- and electron-microscopic examinations. No toxicity was observed in the eyes that received 400 microg or less diclofenac/HA, which was further supported by the normal ERG examined at 4 and 25 days post injection.

CONCLUSIONS

Diclofenac/HA inhibits tube formation in vitro and is non-toxic to the rabbit retina at concentrations that are inhibitory to tube formation. Our results suggest diclofenac/HA may be an effective candidate to inhibit ocular neovascularisation related to granulomatous reaction in the eye.

The use of adenovirus-mediated gene transfer to develop a rat model for photoreceptor degeneration

PURPOSE

To investigate the effects of recombinant adenovirus-mediated downregulation of cathepsin S (CatS) on the retinal pigment epithelium and/or neural retina in vivo.

METHODS

The expression of green fluorescent protein (gfp) after subretinal injection of a recombinant adenovirus, Ad.gfp, into rat eyes was first established by in vivo fundus fluorescence photography and fluorescence microscopy. The autofluorescent debris accumulation in Ad.CatSAS (recombinant adenovirus carrying the antisense CatS gene)injected rat eyes was monitored by fluorescence microscopy, and the antisense CatS RNA expression was demonstrated by in situ hybridization. Changes in the retinal morphology were assessed by light microscopy. ResuLTS. The gfp expression was present in 30% to 90% of the injection area at 3 days and was absent 9 days after Ad.gfp injection. In Ad.CatSAS-injected eyes, the expression of antisense CatS RNA was demonstrated by in situ hybridization. Autofluorescent debris accumulation was significantly higher in Ad.CatSAS-injected eyes than in control eyes. The shortening of photoreceptor outer segments in Ad.CatSAS-injected eyes coincided with intense autofluorescent debris accumulation. The number of layers of photoreceptor cells decreased with time and were 11, 9, and 8 at 7, 14, and 28 days after Ad.CatSAS injection, respectively. In control eyes, the number of layers of photoreceptor cells (14) remained unchanged.

CONCLUSIONS

These results demonstrate that recombinant adenovirus-mediated transient modulation of gene expression in retinal pigment epithelial (RPE) cells could induce changes in the retina, and, in spite of the low expression of endogenous CatS in RPE cells, this enzyme plays an important role in maintenance of normal retinal function.

The role of vascular endothelial growth factor (VEGF) in abnormal vascular changes in the adult rat eye

The aim of this project was to determine if the subretinal delivery of a recombinant adenovirus encoding vascular endothelial growth factor (VEGF) was sufficient to induce changes resembling choroidal neovascularisation (CNV) in a rat model. A recombinant adenovirus was produced encoding vegf164 cDNA (Ad.RSV.VEGF). Transduction of cultured RPE cells confirmed VEGF expression and ensured the absence of Ad.RSV.VEGF-related toxicity. Following subretinal injection into rat eyes, fluorescein angiography indicated that the in vivo delivery of Ad.RSV.VEGF was associated with vascular leakage. Histological analysis demonstrated that changes resembling the early signs of CNV development were also present in the Ad.RSV.VEGF injected eyes. These results suggest that while a transient VEGF expression in the RPE layer is able to induce CNV-related changes, it may be insufficient for the development of a full neovascular membrane. This study demonstrates that virus-mediated gene delivery, in addition to its clinical applications, is a potentially efficient research tool for investigating gene expression-related physiological changes in vitro and in vivo.

Preferential adenovirus-mediated transduction of cells at the sites of laser photocoagulation in the rat eye

PURPOSE

This study aimed to investigate the feasibility of recombinant adenovirus-mediated gene transfer into cells implicated in the development of choroidal neovascularization (CNV).

METHODS

A rat model of CNV which used laser photocoagulation was developed. Gene delivery into the laser spots was investigated following subretinal injection of recombinant adenoviruses, AdRSVlacZ, AdCMVlacZ or AdCMVgfp. Immunohistochemical analysis was performed using a proliferating cell nuclear antigen antibody and a cytokeratin-specific antibody to identify the cell types transduced by the recombinant adenoviruses.

RESULTS

At 7 days post-injection, lacZ expression was detected in 51.6 +/- 13.2% and 71.2 +/- 19.3% of laser spots in AdRSVlacZ- and AdCMVlacZ-injected eyes, respectively. By 28 days post-injection, lacZ expression was only present in AdCMVlacZ-injected eyes. In vivo fundus fluorescent photography of AdCMVgfp-injected eyes detected gfp expression in 79.9 +/- 12.7% and 35.6% +/- 19.7% of laser spots at 4 and 7 days post-injection, respectively. Although fundus fluorescent photography did not detect the gfp signal at 10 days post-injection, fluorescent microscopy revealed a gfp signal in 81.3 +/- 6.0% of laser spots. Immunohistochemical analysis detected retinal pigment epithelial (RPE) cells as the most predominant proliferating cell type in the laser spots, although several other proliferating cell types were also identified. X-gal staining showed that the majority of transduced cells were those present in the laser spots.

CONCLUSIONS

It is proposed that following laser photocoagulation, proliferating RPE cells are susceptible to adenovirus-mediated gene delivery and that they may be suitable targets for the delivery of antiangiogenic factors by recombinant adenoviruses in order to inhibit developing CNV membranes.

Dynamics of phosphorothioate oligonucleotides in normal and laser photocoagulated retina

AIMS

To investigate the distribution, persistence, and stability of fluorescently labelled phosphorothioate oligonucleotides (PS-ODNs) in normal and laser photocoagulated retina following intravitreal injection in the rat.

METHODS

Fluorescently labelled PS-ODNs were injected intravitreally into pigmented eyes at doses of 0.5-10.0 nmol in 2.0 microl solution. The dynamics of PS-ODNs was evaluated by fluorescent microscopy of cryosections and flat mounted retinal pigment epithelium (RPE)-choroid-sclera. Genescan analysis was used to assess the integrity of PS-ODNs in the retina after injection. The dynamics of PS-ODNs was also evaluated in the retina following krypton laser photocoagulation with a protocol producing choroidal neovascularisation (CNV).

RESULTS

Following intravitreal injection the PS-ODNs demonstrated dose and time dependent distribution and persistence in the retina, where they accessed all neural layers. However, they preferentially accumulated in the RPE layer, demonstrated as bright granules in the cytoplasm of the cells. Injections of 5.0 and 7.5 nmol of PS-ODNs exhibited strong fluorescence in the retina for 6 weeks after injection. Genescan analysis demonstrated that the PS-ODNs remained almost completely intact for at least 12 weeks. Following laser treatment, the PS-ODNs were concentrated in the regions of laser photocoagulation and retained high intensity for at least 8 weeks after injection, particularly localised to macrophages, RPE, and the local choroidal tissue.

CONCLUSIONS

These results indicate that PS-ODNs are stable and accessible to most neural layers of the retina, and they preferentially accumulate in the RPE layer following intravitreal injection. The successful delivery of PS-ODNs into normal and laser photocoagulated retina suggests that PS-ODNs may have potential in the development of therapy for attenuating retinal degenerations and CNV.

Generation and characterization of a recombinant adenovirus expressing vascular endothelial growth factor for studies of neovascularization in the eye

There is accumulating evidence that an increased expression of vascular endothelial growth factor from retinal pigment epithelial cells may be important in choroidal neovascularization. In vivo studies have demonstrated that subretinal injection of recombinant adenovirus vectors produces long-term transgene expression specifically within retinal pigment epithelial cells. A recombinant adenovirus encoding of vascular endothelial growth factor (Ad.RSV.VEGF) was therefore produced and characterized in order to determine whether an upregulation of vascular endothelial growth factor expression is sufficient to induce choroidal neovascularization. Ad.RSV.VEGF was produced by homologous recombination and its identity confirmed by restriction enzyme analysis. Ad.RSV.VEGF was characterized in vitro by the transduction of cultured retinal pigment epithelial cells. The in vitro characterization confirmed vascular endothelial growth factor mRNA and protein expression from Ad.RSV.VEGF and demonstrated the biological activity of the vascular endothelial growth factor protein. A preliminary in vivo study suggested that the subretinal injection of Ad.RSV.VEGF induced vascular leakage.

[Biosynthesis of a single peptide chain containing human chorionic gonadotropin beta and C3D of complement]

In view of the strong immunity-enhancing function of HEL-C3d3 designed by Dr. Paul W. Dempsey, we made our efforts to produce a similar recombinant protein of hCG beta. With polymerase chain reaction, we introduced a Bam HI restriction site into the 3' terminal of hCG beta cDNA. The new cDNA and its terminal's correctness has been confirmed by sequencing. Then we have it covalently attached to the C3d3 cDNA at the pre-designed Bam HI/Bgl II site. Having the chimeric DNA correctly cloned into the protein nuclear polyhedrosis virus (AcNPV) expression vector pVL1393, we constructed the expression vector pVL1393-(hCG beta-C3d3). The insect cells were co-transfected with the expression vector and linearized nuclear polyhedrosis virus DNA, and recombinant viruses AcNPV-(hCG beta-C3d3) were screened out. Through anti-hCG beta immunoaffnity chromatography, the recombinant hCG beta-C3d3 chimera polypeptide was purified from culture supernatant of insect cells infected by the recombinant viruses. In RIA test, the expressed product competitively inhibits the binding of 125I-hCG beta to hCG beta-antibody. On SDS-PAGE and Western blot, the recombinant peptide hCG beta-C3d3 obviously appears to be with a molecular weight of 116KD. Therefore, we arrive at a conclusion that it has a normal immunogenic ability.

Evaluation of adeno-associated virus-mediated gene transfer into the rat retina by clinical fluorescence photography

The purpose of this study was to evaluate recombinant adeno-associated virus (AAV) as an in vivo gene transfer vector for the retina and to explore the possibility of monitoring the expression of green fluorescent protein (GFP) using a noninvasive method. Rats were injected subretinally with rAAV-gfp or rAAV-lacZ. Strong expression of the reporter gene in a circular area surrounding the injection site was observed in retinal whole mounts and tissue sections. Higher magnification revealed that cells demonstrating high levels of green fluorescence were hexagonal in shape, indicating they were retinal pigment epithelium (RPE) cells. Histological observation of retinal sections demonstrated that recombinant AAV specifically transduced RPE cells. Ten animals were injected with rAAV-gfp for longitudinal studies and the fluorescence was monitored by retinal fluorescence photography. The GFP signal was detected in 100% of the animals as early as 2 weeks postinjection and remained present throughout the experimental period of 4 months. After 2 weeks, a gradual increase in the number of transduced cells occurred before reaching maximal levels of GFP expression at 8 weeks. This was followed by a small decrease over 4 weeks before reaching stable expression at 16 weeks. Our results demonstrated that rAAV efficiently transduces rat RPE cells and that retinal fluorescence photography is suitable for monitoring GFP expression. By using this noninvasive technique, we demonstrated that repetitive measurements of GFP expression in vivo in the rAAV-gfp-transduced retina are possible. This study demonstrated that retinal fluorescence photography is a potent tool for studying AAV-mediated gene delivery in the retina.

Expression of cell adhesion molecules and vascular endothelial growth factor in experimental choroidal neovascularisation in the rat

AIMS

To investigate the longevity and reproducibility of choroidal neovascularisation (CNV) induced by krypton laser photocoagulation in the rat. The presence of cell adhesion molecules (CAMs) and vascular endothelial growth factor (VEGF) during the development of CNV was also studied.

METHODS

67 pigmented rats underwent retinal photocoagulation by krypton laser. The eyes were examined by either single or serial fluorescein angiography at 3 days, 1, 2-3, 4-5, 7-8, and 12 weeks post photocoagulation. The expression of CAMs (ICAM-1, E-selectin, and CD44) and VEGF post photocoagulation was studied by immunohistochemistry.

RESULTS

CNV related fluorescein leakage appeared in 46.4% of 766 laser spots delivered to the 58 eyes that were tested at 2-3 weeks post treatment. The ratio of hyperfluorescent laser sites did not change significantly at 8 weeks post laser. The number of leaky spots was independent of the total number of lesions delivered to each eye (at 2-3 weeks post laser 10-15 spots/eye: 44% and 25-30 spots/eye: 49%; t = 0.7673; p = 0.3903). Nine eyes were followed by serial angiography between 2 and 12 weeks. The laser spots with fluorescein leakage at 2 weeks (51.5%) remained leaky at 12 weeks (51.5%). Histopathologically, macrophage accumulation peaked at 5 days and CNV was firstly observed at 1 week post photocoagulation. ICAM-1, E-selectin, CD44, and VEGF were maximally induced at 3-5 days post laser photocoagulation, and were localised to RPE, choroidal vascular endothelial, and inflammatory cells. VEGF was also detected in intravascular leucocytes at the sites of laser lesions.

CONCLUSIONS

These studies demonstrated that krypton laser photocoagulation can be successfully used to produce lesions similar to those of human CNV. The response induced remained present for an extended period of time (12 weeks), thus offering a potential model to screen candidate CNV inhibitory agents. In addition, it is proposed that the expression of ICAM-1, E-selectin, CD44, and VEGF before new vessel formation might be linked to the initiation of CNV.

Recombinant adenovirus-mediated gene delivery into the rat retinal pigment epithelium in vivo

PURPOSE

The present paper describes changes following the subretinal injection of a recombinant replication-deficient adenovirus carrying the beta-galactosidase reporter gene construct into the rat retina.

METHODS

Ad.RSV.betagal-mediated transduction of rat retinal pigment epithelium (RPE) cells in vitro and in vivo was examined following X-gal staining.

RESULTS

There was a low level of beta-galactosidase expression in the RPE cells at 4 days postinjection. At 7 days postinjection, a strong transgene expression was present in RPE cells and the expression was maintained at 14 days postinjection. Except for the accumulation of cells at the site of the injection, the morphology of the rest of the retina remained normal.

CONCLUSION

These results demonstrate that the RPE layer can be successfully targeted for gene delivery in the rat.

A new look at the sequential development of elbow-ossification centers in children

The pattern and sequence of ossification of the six secondary ossification centers around the elbow in the child were mainly derived from studies done >30 years ago. This series reexamined the sequence and pattern based on a cross-sectional study of the elbow radiographs of 1,577 Chinese children with elbow injuries; age range, from newborn to 17 years. The ratio of girls to boys was 1:2. Each child had a radiograph of the normal and the injured elbow giving a total of 3,154 radiographs. A percentile chart of ossification was constructed for each of the ossification centers in both sexes for easy reference. No differences in the timing and ossification pattern were found between the right and left elbow or between the normal and injured elbow in this study. The sequence of ossification in both boys and girls was found to be the same (i.e., the capitulum first, followed by the radial head, medial epicondyle, olecranon, trochlea, and last, the lateral epicondyle). The ages at which 50% of the girls were found to have positive radiologic ossification for each of these centers were ages 1, 5, 5, 9, 9, and 10 years, respectively. In boys, with the exception of the capitulum, an average delay of 2 years was found in each of the ossification centers, although the sequence remained similar.

Osteonecrosis of the femoral head treated with cementless total hip arthroplasty. A comparison with other diagnoses

Primary cementless Porous Coated Anatomic total hip arthroplasty was carried out in 36 hips in 29 patients with osteonecrosis (ON) patients and in 36 hips in 33 patients without ON. The ON was alcohol related in 11. steroid induced in 5, post-traumatic in 4, and idiopathic in 16 patients. The average follow-up period was 6 years. Clinical evaluation demonstrated 77.8% excellent or good results in the patients with ON, with the average Harris hip scores improved from 36.8 to 83.5. No revision of a prosthesis has yet been performed in the patients with ON. The patients with alcohol-related and steroid-induced ON had inferior clinical results when compared with the patients without ON. There were no statistically significant differences in the clinical results between the patients with post-traumatic or idiopathic ON and the patients without ON.

Experience with primary exeter total hip arthroplasty in patients with small femurs. Review at average follow-up period of 6 years

One hundred twelve hips in 101 Chinese patients received a primary cemented Exeter total hip arthroplasty (Howmedica, Hong Kong). Average age was 65 years. The most common diagnosis was avascular necrosis. Average follow-up period was 6 years (range, 3 years to 9 years, 6 months). The Harris hip score improved from a preoperative average of 41.2 to 82.2 at the last follow-up visit. Stem subsidence within the cement mantle occurred in 9% of the cases, and none of these stems had other evidence of loosening. Three hips in two patients were revised because of loosening at 5 to 8 years after surgery. Because of the small size of the femurs, stem oversizing was common. Oversizing of the stem and an incomplete cement mantle might account for the early loosening. Stems of a smaller size should be made available to this population.

Geschlossene Reposition und perkutane Drahtfixation kindlicher suprakondylärer Extensionsfrakturen vom Typ III

GOAL OF SURGERY

Closed reduction of acute type III (according to Gartland) supracondylar extension fractures of the distal humerus and unicondylar pin fixation.

INDICATIONS

Type III and unstable type II supracondylar fractures.

CONTRAINDICATIONS

Swelling of the elbow. Compartment syndrome.

PREOPERATIVE WORK UP

Radiographs of both elbows in the anterior-posterior and lateral projections.

POSITIONING AND ANAESTHESIA

Supine with arm on arm board. General anaesthesia.

SURGICAL TECHNIQUE

Closed reduction through manipulation under fluoroscopic control. Fixation with 2 Kirschner wires introduced percutaneously through the lateral condyle. Long arm cast for 4 to 5 weeks.

POSTOPERATIVE MANAGEMENT

Radiographs on the first postoperative day, 1 week later and at time of cast and pin removal 4 to 5 weeks postoperatively. At that time active mobilisation of the elbow is started. Follow-up for 1 to 2 years is recommended.

POSSIBLE COMPLICATIONS

Damage of ossific nucleus of physis. Damage to neurovascular structures. Wire migration. Pin tract infection.

RESULTS

Out of 82 children (mean age 6.5 years) 73 had a follow-up of more than 6 months. 80.8% had good or excellent results. 15.1% had a decrease of the carrying angle of more than 10 degrees (4.1% more than 20 degrees ). There were 2 pin tract infections and 1 iatrogenic transient ulnar palsy.

Uncemented porous-coated anatomic total hip replacement in Chinese patients

Primary uncemented Porous-Coated Anatomic total hip replacement was carried out in 72 hips in 62 Chinese patients. Their average age was 50 years and the average follow up was 3 1/2 years. The most common diagnosis was avascular necrosis. The average preoperative Harris score of 36.3 points improved to 83.2 at the last follow up. The pain score improved from 13.7 out of 44 to an average of 42. Seven of 8 hips with thigh pain had an inadequately fitting stem which had subsided. Only one cup was revised because of a technical error and one femoral component for loosening. Uncemented Porous-Coated Anatomic total hip replacement gave good early results in Chinese patients.

A quality study of a computerized medical birth registry

Processed by a computerized medical birth registry system, the birth records of 20,103 deliveries, from February 1992 to February 1993, were digitized with medium registry. From January 1, to February 28, 1993, the original records (n = 2,840 cases) of all 10 collaborative hospitals were requested for assessment of the data quality. Thirty-six items were scored, data of poor quality was found in 8 items; acceptable quality in 4 items; and good quality in 28 items. The feasibility of data transfer by floppy disc and per modem was evaluated. This registry system had shortened data processing time effectively and improved mutual feedback between data center and delivery units. Errors resulting from technical faults originating in preparation of the data for computerizing at hospital level could be effectively reduced. The validity of diagnosis remained as the major source of errors.

Closed reduction and percutaneous pinning for type III displaced supracondylar fractures of the humerus in children

From 1985 to 1991, 623 cases of supracondylar fracture of the humerus in children were admitted to one center, of which 403 were analyzed in detail. Of these, 180 cases were classified as Gartland type III extension fractures, and 111 were treated via primary closed reduction and percutaneous smooth Kirschner wire pinning, of which 82 were followed up for an average of 3.5 years and were studied in detail clinically and radiologically. There were two cases of superficial pin tract infection and one of ulnar nerve palsy associated with the pinning. Nineteen fractures (10.5%) had an initial nerve palsy related to the injury. All recovered completely from 4 weeks to 40 weeks postinjury. Only one of nine cases (5%) with absent radial pulse required exploration. Eighty percent of all cases had excellent or good function according to the Flynn criteria of elbow assessment. The most important factor correlating with the final varus deformity was found to be the difference in Baumann's angle between the injured and the normal side after closed reduction and pin fixation. The results of cross pinning in eight cases were not found to be different from those of the lateral pinning group (74 cases). Ipsilateral fracture of the same limb occurred in 4.4% of the cases, the majority being a fracture of the distal radius. The average anesthetic time for the procedure was 54 min, and the average hospital stay was 2.9 days. Our study shows that cross or lateral percutaneous pinning was found to be effective in the treatment of Gartland type III extension fractures with a high success rate and minimal complications.

Data quality of a computerized medical birth registry

Processed by a computerized medical birth registry system, the birth records of 20,103 deliveries, from February 1992 to February 1993, were digitized with medium registry. From 1 January to 28 February 1993, the original records (n = 2840 cases) of all 10 collaborative hospitals were requested for assessment of data quality. Thirty-six items were scored, data of poor quality was found in eight; acceptable quality in four; and good quality in 28. The feasibility of data transfer by floppy disc and per modem was evaluated. This registry system had effectively shortened data processing time and improved mutual feedback between the data centre and the delivery units. Errors resulting from technical faults originating in the preparation of data for computerization at hospital level could be effectively reduced. The validity of diagnosis remained as the major source of errors.

Measurement of cervical canal sagittal diameter in Chinese males with cervical spondylotic myelopathy

BACKGROUND

Cervical canal encroachment can be properly assessed from lateral cervical radiographs either by defining its magnification rate or by a ratio-method. Data of the latter obtained from Chinese males with cervical myelopathy were compared with the data of general population in different age groups.

METHODS

A total of 200 Chinese males were included in this study. Half of them had undergone decompressive procedures for cervical myelopathy, while the remaining 100 cases were volunteers. Sagittal diameters of cervical canal and vertebra were measured from C3 to C6 on lateral cervical radiographs, while ratios (Torg-Pavlov's ratios) of the two reflected the extent of sagittal canal encroachment. Cut-off values and discriminant rates of these parameters in different age groups were obtained by discriminant analysis. The tube-to-film distance was set as 40 inches.

RESULTS

In myelopathic group (age < 55 y/o), Torg-Pavlov's ratios, as expressed by mean +/- standard deviation, were 0.77 +/- 0.12 for C3, 0.75 +/- 0.14 for C4, 0.80 +/- 0.14 for C5, and 0.81 +/- 0.15 for C6. In control group (age < 55 y/o) the ratios were 0.94 +/- 0.12, 0.95 +/- 0.13, 0.97 +/- 0.13, and 0.97 +/- 0.13 respectively. In myelopathic group (age > or = 55 y/o), the ratios were 0.76 +/- 0.09, 0.71 +/- 0.10, 0.73 +/- 0.11, and 0.76 +/- 0.11; while in control group (age > or = 55 y/o), the ratios were 0.93 +/- 0.10, 0.89 +/- 0.09, 0.88 +/- 0.11, and 0.91 +/- 0.12 respectively. The cutoff values and their discriminant rates are also presented.

CONCLUSIONS

The differences of canal sagittal diameter as well as Torg-Pavlov ratio between myelopathic and control group of Chinese males in individual age group were statistically significant. It is concluded that congenitally narrow cervical canal is a major predisposing factor to cervical spondylotic myelopathy.

Reconstruction of extensor mechanism after trauma and infection by transposition of the Achilles tendon: report of technique and four cases

High-energy injuries to the knee often involve extensive soft tissue loss as well as fractures. In certain situations, the patellar tendon may be lost due to initial injury or post-injury complications such as infection. Use of the gastrocnemius flap is a popular method of covering the defect as well as controlling infection and promoting healing by increasing local vascularity. We present a method of reconstructing the patellar tendon by extending the use of the gastrocnemius flaps using its Achilles tendon and calcaneal insertion. The distal insertion of the Achilles tendon is fixed to the tibial tuberosity with a cancellous screw, and the proximal end is sutured to the quadriceps muscles. The knee is immobilized for 1 week, after which the knee is mobilized in a hinged brace. Three of the four cases had good results, one a moderate result (the initial injury was extensive, with dislocation of the knee).

Ultrasonographic hip morphometry in infants

Ultrasonographic study of 463 normal children (926 hips) from birth to 6 months of age with equal sex distribution was performed. Hip morphometry, including Graf's alpha and beta angles. Morin's head coverage percentage, and head size were measured. Using the same technique, a group of 52 babies was measured longitudinally from birth to 6 months of age, with three measurements taken for each hip for a total of 312 measurements. Results showed that the boys had a consistently higher alpha angle, a lower beta angle, better head coverage, and larger head size through the 6 months. Differences between the right and left hips were only noted in the beta angle. The containment of the hip was found to increase rapidly in the first 4 months. Comparing data from the longitudinal versus the cross-sectional group, no statistically significant differences were detectable in all the parameters measured. Intraobserver variations were found to be best with alpha angle measurements, with a standard deviation of 3.22 degrees.

Limb fracture pattern in different pediatric age groups: a study of 3,350 children

The fracture patterns of 3,350 children with 3,413 limb fractures admitted to one center from 1986 to 1990 were analyzed retrospectively. The overall boy-to-girl ratio was 2.7:1, rising to 5.5:1 in the adolescent group. Distal radius fracture was the most common fracture (19.87%), followed by supracondylar fracture of the humerus (16.64%) and forearm shaft fracture (13.36%). Specific age group breakdown showed that supracondylar fracture of the humerus was the most common fracture occurring in the age groups 0 to 3 years and 4 to 7 years, accounting for 28.94 and 31.18% of all limb fractures, respectively. Fracture of the distal radius occurred in 27.06% of the 8 to 11 year age group and 23.31% of the 12 to 16 year group. Open fractures were uncommon (2.17%), and greenstick fractures were found only in 5.27% of this hospital series. The nondominant arm was found to have more fractures although the number was not statistically significant. Seasonal variation in incidence occurred, with more cases in the summer and autumn months. The open reduction rate in the treatment varied from 10.15% in the 0 to 3 year age group to 33.95% in the 12 to 16 year group. Forty-five percent of the 0 to 3 year age group were discharged from hospital within 24 h, contrasting with 30% in the other age groups. Overall incidence of fractures requiring hospital treatment was estimated to range from 35 per 10,000 in the 0 to 3 year age group to 62, 60, and 57 per 10,000 in the 4 to 7, 8 to 11, and 12 to 16 year groups, respectively.