Carexmalipoensis (Cyperaceae), a new species from southeast Yunnan, China

Carexmalipoensis, a new species from southeast Yunnan, China, is here described and illustrated. It is morphologically similar to C.trichophylla in sect. Euprepes, but differs from it by its longer inflorescences and peduncles, pendulous spikes, hispidulous female glumes, densely hispidulous utricles, and longer nutlets.

Rare mutation in MKRN3 in two twin sisters with central precocious puberty: Two case reports

BACKGROUND

Caused by premature activation of the hypothalamic-pituitary-gonadal axis, there is increasing incidence of central precocious puberty (CPP), especially in girls. Makorin ring finger protein 3 (MKRN3), a maternal imprinted gene with a highly conserved sequence, is the most common genetic etiology associated with CPP. Approximately 50 different mutations in MKRN3 have been found in CPP.

CASE SUMMARY

This case report involves identical twin sisters presenting with premature thelarche at the age of 6 years. The left hand bone age of both patients revealed advanced age (9 years). Pelvic B ultrasound indicated enlargement of the ovaries. Luteinizing hormone (LH) releasing hormone testing confirmed CPP. Whole-exome sequencing detected the c.841C>T mutation in MKRN3, leading to a single base substitution, in the twins. This mutation was inherited from the father and paternal grandmother. After 3 mo of treatment with a gonadotropin-releasing hormone analog, levels of LH, follicle-stimulating hormone, and estradiol in the proband’s sister returned to normal levels.

CONCLUSION

Here, we report a rare mutation (c.841C>T) in MKRN3 in identical twin sisters with CPP.

[Characteristics of gastric mucosa microbiota in children with chronic gastritis and duodenal ulcer]

Objective: To investigate the differences of gastric mucosa microbiota between children with chronic gastritis and duodenal ulcer under the condition of Helicobacter pylori (Hp) infection. Methods: This prospective cohort study involved 57 children with Hp infection diagnosed by gastric endoscopy who were admitted to the Children's Hospital of Zhejiang University School of Medicine due to "abdominal pain, abdominal distension and vomiting" between January 2018 to August 2018. According to gastroscopy and pathological examination, the children were divided into chronic gastritis group and duodenal ulcer group. Gastric mucosa from Hp infected patients were sampled, and the flora DNA was analyzed by high-throughput sequencing. The statistical difference of α diversity, β diversity between two groups were analyzed. The relative abundance of the two groups in each taxonomic level was analyzed statistically. T test, Rank sum test or χ² test was used for comparison between the two groups. Results: A total of 57 children diagnosed with Hp infection were enrolled in this study, including 42 cases of chronic gastritis (the age was (9.3±2.8) years, 22 males and 20 females) and 15 cases of duodenal ulcer (the age was (11.1±3.3) years, 9 males and 6 females). Alpha diversity index Chao and ACE in Hp infected chronic gastritis group were significantly higher than those in Hp infected duodenal ulcer group (217±50 vs. 183±64, t=2.088, P=0.009;218±47 vs. 192±76, t=1.566, P=0.016, respectively). The Beta-diversity index such as nonmetric multidimensional scaling (NMDS) analysis were significantly different in the two groups (analysis of similarity R=0.304, P=0.028). Among the main bacteria genera, there were 6 genera with significant differences between the two groups, which were Prevotella (0.190% (0.008%-1.983%) vs. 0.021% (0.005%-2.398%), Z=-2.537, P=0.011), Alloprevotella (0.097% (0.010%-0.813%) vs. 0.015% (0.003%-0.576%), Z=-2.492, P=0.013), Haemophilus (0.109% (0.004%-0.985%) vs. 0.014% (0.004%-0.356%), Z=-2.900, P=0.004), Neisseria (0.074% (0.004%-0.999%) vs. 0.024% (0.003%-0.255%), Z=-2.718, P=0.007), Streptococcus (0.166% (0.008%-1.869%) vs. 0.045% (0.006%-0.879%), Z=-2.537, P=0.010), and an unclassified-Microbacteriaceae (0.214% (0.060%-1.762%) vs. 0.117% (0.010%-0.954%), Z=-2.120, P=0.034). Linear discriminant analysis (LDA) effect sized analysis showed that at the genus level, only Prevotella was significantly enriched in the duodenal ulcer group (LDA=2.90, P=0.010), while Streptococcus, Neisseria and Haemophilus were significantly enriched in the chronic gastritis group (LDA=2.83, 2.82, 2.69, P=0.011, 0.007, 0.004, respectively). Conclusions: The gastric mucosal microbiota in duodenal ulcer associated with Hp is significantly different from that in chronic gastritis. Hp may promote the occurrence of peptic ulcer together with gastric microbiota.

Change in Quality of Life of OSAHS Patients with Minimally Invasive Surgery or CPAP Therapy: A 2-year Retrospective, Single-center Parallel-group Study

BACKGROUND

By including untreated obstructive sleep apnea-hypopnea syndrome (OSAHS) patients as the control group, this study explores the influence of minimally invasive surgical treatment and continuous positive airway pressure (CPAP) therapy on OSAHS patients, with the subjective and objective performance. The study also discusses their relationship, determines the effect factor, and provides a simple and practical method for evaluation of clinical efficacy.

METHODS

A total of 90 OSAHS patients, who were diagnosed in the Sleep Disorders Diagnosis and Treatment Center of Sichuan Province from May 2014 to May 2016, were selected for the present study. These patients were divided into three groups: surgery group, CPAP group, and untreated group. These patients were followed up at six months, one year, and two years, respectively. The physiological indicators, clinical symptoms, degree of daytime sleepiness and quality of life were compared among these three groups. The daytime sleepiness and the quality of life before and after minimally invasive surgery and CPAP treatment were evaluated, and the subjective and objective efficacy of surgery and CPAP treatment was explored.

RESULTS

Among these 90 patients, 11 (12.2%) patients had hypertension, while two (2.2%) patients had diabetes. The average AHI score was 50.53±23.39 per hour, and the mean minimum oxygen saturation and mean oxygen saturation was 71.25±14.16% and 90.13±5.90%, respectively. There were statistically significant differences in mouth breathing, morning sore throat and daytime sleepiness in the group having received surgery at 0.5 year and one year. In the CPAP group, there were statistically significant differences in mouth breathing, morning sore throat and daytime sleepiness at 0.5 year, one year and two years. Moreover, there were statistically significant differences in memory loss at one year and two years, and there were statistically significant differences in frequent nocturia at one year. The ESS value in the surgery group decreased at 0.5 year and one year, but increased at two years. The situation was the same in terms of the total points and in each dimension of the SF-36 paramter. The delta values of ESS among the three groups had statistical significance at 0.5 year, one year and two years, in which the CPAP group experienced the most changes, followed by the surgery group and the group received health education.

CONCLUSION

For minimally invasive surgery, CPAP therapy and health education can improve daytime sleepiness and quality of life. CPAP therapy was found to be the most effective, followed by minimally invasive surgery and provision of health education. However, the treatment of OSAHS should be comprehensive.

The profibrotic effects of MK-8617 on tubulointerstitial fibrosis mediated by the KLF5 regulating pathway

The discovery of hypoxia-inducible factor (HIF)-prolyl hydroxylase inhibitor (PHI) has revolutionized the treatment strategy for renal anemia. However, the presence of multiple transcription targets of HIF raises safety concerns regarding HIF-PHI. Here, we explored the dose-dependent effect of MK-8617 (MK), a kind of HIF-PHI, on renal fibrosis. MK was administered by oral gavage to mice for 12 wk at doses of 1.5, 5, and 12.5 mg/kg. In vitro, the human proximal tubule epithelial cell line HK-2 was treated with increasing doses of MK administration. Transcriptome profiling was performed, and fibrogenesis was evaluated. The dose-dependent biphasic effects of MK on tubulointerstitial fibrosis (TIF) were observed in chronic kidney disease mice. Accordingly, high-dose MK treatment could significantly enhance TIF. Using RNA-sequencing, combined with in vivo and in vitro experiments, we found that Krüppel-like factor 5 (KLF5) expression level was significantly increased in the proximal tubular cells, which could be transcriptionally regulated by HIF-1α with high-dose MK treatment but not low-dose MK. Furthermore, our study clarified that HIF-1α-KLF5-TGF-β1 signaling activation is the potential mechanism of high-dose MK-induced TIF, as knockdown of KLF5 reduced TIF in vivo. Collectively, our study demonstrates that high-dose MK treatment initiates TIF by activating HIF-1α-KLF5-TGF-β1 signaling. These findings provide novel insights into TIF induction by high-dose MK (HIF-PHI), suggesting that the safety dosage window needs to be emphasized in future clinical applications.-Li, Z.-L., Lv, L.-L., Wang, B., Tang, T.-T., Feng, Y., Cao, J.-Y., Jiang, L.-Q., Sun, Y.-B., Liu, H., Zhang, X.-L., Ma, K.-L., Tang, R.-N., Liu, B.-C. The profibrotic effects of MK-8617 on tubulointerstitial fibrosis mediated by the KLF5 regulating pathway.

[Effect of enteral nutrition on accidental upper gastrointestinal injury in children]

Objective: To evaluate the effectiveness of enteral nutrition in children with accidental upper gastrointestinal injury. Methods: The medical records of 128 patients with mechanical or chemical gastrointestinal mucosal injury, who were hospitalized in Department of Gastroenterology, Children's Hospital of Zhejiang University School of Medicine from January 1, 2011 to December 30, 2017, were collected. All cases were treated with enteral nutrition. The clinical features and etiologies were retrospectively analyzed. Weight-for-age Z score and lab findings including white blood cells, C-reactive protein, neutrophils, albumin, prealbumin, urea nitrogen and hemoglobin before and after treatment were extracted. The clinical characteristics, the duration of enteral nutrition and gastrointestinal mucosal healing between different etiologies were further analyzed. Normal distribution variables and categorized variables were compared with t test and χ(2) test respectively, and abnormal distribution data was compared with Wilcoxon test. Results: Among all the cases, 77 were males and 51 were females. The average age was (29±22) months. The mean duration of hospitalization and enteral nutrition were (11±7)d and (27±20)d respectively. Vomiting was the most common clinical presentation (72 cases, 56.3%). In 79 cases the problems were caused by mechanical injury, among which coins were most commonly seen. The rest 49 cases were caused by chemical injury. However, the duration of hospitalization ((13±8) d vs. (10±6)d, t=-3.089, P=0.002) and enteral nutrition ((39±22) vs. (19±14) d, t=-5.365, P=0.000) were longer in children with chemical injury than those with mechanical injury. A total of 112 cases got complete blood count and C-reactive protein both before and after enteral nutrition. Inflammatory markers, including leukocytes ((7.7±2.7) ×10(9)/L vs. (13.7±5.0) ×10(9)/L, t=12.244, P <0.05), neutrophils ((3.4±1.9)×10(9)/L vs. (9.4±4.6) ×10(9)/L, t=13.655, P<0.05), and C-reactive proteins (5.0(3.0,7.8) vs. 13.5(6.0,40.5) mg/L, Z=7.776, P <0.05) were significantly decreased. The nutritional markers, including the weight-for-age z score (-0.1 ± 1.0 vs. 0.0 ± 1.0, t=-2.622, P=0.010) and the prealbumin (0.1 ± 0.1 vs. 0.2 ± 0.0 g/L, t=-3.671, P=0.001) were significantly increased. Fifty-five (82.1%) children in mechanical injury group recovered in 4 weeks, while 27 (79.4%) children in chemical injury group recovered in 7 weeks. Conclusion: Enteral nutrition can provide adequate nutritional requirements for children with upper gastrointestinal injury, and may help to decrease imflammation and improve mucosal healing.

[A bibliometric analysis of literature on hand-transmitted vibration in China, 1990-2016]

Objective: To investigate the features of literature on hand-transmitted vibration in China, 1990-2016. Methods: In September 2017, the studies on hand-transmitted vibration in China, which were published in Chinese or English during 1990-2016, with "China" and "Taiwan" as the places where author affiliations were located, were retrieved. A bibliometric analysis was performed to investigate the type of articles, publication time, the journals in which articles were published, author affiliations, author regions, and funding. Results: A total of 205 articles on hand-transmitted vibration were retrieved. There were 7.59 articles on average published annually from 1990 to 2016. In the 205 articles, 114 (55.61%) were published in the journals indexed in one or two core journal databases. In the 64 journals, 22 (34.38%) were indexed in one or two core journal databases. The first authors were from 22 provincial regions (provinces, autonomous regions, or centrally administered municipalities) in China, with 152 articles (74.15%) by the authors in the top five regions. There were a total of 876 authors, and the co-authorship degree was 4.27 (876/205). Most of the first authors (136 articles, 66.34%) were affiliated with universities or institutes for prevention and control of occupational diseases. Among the 205 articles, 103 (50.24%) were original articles or investigations, and 72 (35.12%) were funded. Conclusion: The studies on hand-transmitted vibration fluctuated and increased from 1990 to 2016, with a relatively concentrated distribution in terms of sources, regions, and institutions. Interregional and international academic exchange should be strengthened.

Removing a metal foreign object successfully from a patient's retroperitoneal space using laparoscopy and a novel navigation system

Trauma with foreign objects retained within the human body has become a common surgical emergency condition. Traditional surgical methods often involve creating large incisions in soft tissue and may lead to additional complications during wound healing. We have developed a new method of removing foreign bodies from patients' abdomens by using laparoscopy with the help of a novel navigation system that provides accurate positioning. This approach is minimally invasive and simple. This is the first combination of both technologies in this field.

[Eosinophilic esophagitis in children: analysis of 22 cases]

Objective: Eosinophilic esophagitis (EoE) is a chronic immune-mediated esophageal disease.The current domestic reports of EoE in children is rare.The aim of this study was to analyze the clinical features, the diagnosis and treatment advance of EoE in children by case analysis and literature review. Method: Clinical data of 22 children with EoE from January, 2011 to December, 2015 in Children's Hospital, Zhejiang University School of Medicine were recorded, retrospective analysis was performed on clinical presentation, gastroendoscopy and histopathological examination features and the treatment. Result: (1) Clinical data: EoE can occur at any age in children (5 months to 13 years). The most common clinical manifestations of EoE are vomiting and abdominal pain, 45% (10/22) and 41%(9/22) respectively. (2) Endoscopy and pathological features of esophageal mucosa: 11 cases with coarse mucous membrane (50%), 6 cases with congestion or erosion of esophageal membrane (27%), 5 cases with longitudinal crack (23%), 3 cases with ring uplift (14%), 3 cases with granular uplift (14%), 3 cases with normal mucosa(14%). Histopathologic manifestation is eosinophil infiltration and the eosinophil counts were all more than or equal to 15/HP. (3) Laboratory results: 13 cases had increasing eosinophil counts and eosinophils proportion (62%). (4)Allergy history: among 22 cases, 7 patients had allergy history (32%). (5) Situation of treatment and remission: 16 cases had clinical remission by oral omeprazole; 2 cases had clinical remission by oral Omeprazole and Montelukast sodium; 1 case acquired remission by elimination diet; 1 case acquired remission by elimination diet and oral prednisone. 2 cases dropped out; Only 2 patients received gastroendoscopy re-examination after 3 months and revealed esophageal mucosal histologic complete recovery. Conclusion: The clinical symptoms of EoE in children varies.Esophageal mucosal features of gastroendoscopy examination in children with EoE were longitudinal crack, white exudates or plaques, paper mucosa, ring uplift and granular uplift.Most patients could achieve remission by using proton-pump inhibitors, only few children needed elimination diet and change formula, or even oral glucocorticoids.

GCK mutations in Chinese MODY2 patients: a family pedigree report and review of Chinese literature

BACKGROUND

Maturity-onset diabetes of the young type 2 (MODY2) is caused by mutations in the glucokinase (GCK) gene and is rare in the Chinese population. We report three Chinese families with MODY2 and the sequencing of the GCK gene.

METHODS

Three unrelated Chinese families with MODY2 and their pedigrees were investigated. In Family 1, the proband was a 7-year-old girl with impaired fasting glucose (IFG) and impaired glucose tolerance (IGT). Her mother and maternal grandfather had IFG. In Family 2, the proband was a boy who had diabetes mellitus at 11 years. His sister had IFG. His father and grandmother had diabetes mellitus at 22 and 25 years, respectively. In Family 3, the proband was a boy who had IFG and IGT at 12 years. His sister had diabetes mellitus at 8 years. His father and grandfather had IFG and/or IGT. The GCK gene was directly sequenced.

RESULTS

Diabetes mellitus or IFG/IGT was found among three consecutive generations in three families. One novel nonsense heterozygous mutation in exon 5 (c.556 C>T, p.Arg 186 stop) was detected in Family 1. Another novel frameshift mutation in exon 4 (c.367-374dupTTCGACTA, p.Ile 126 fs) was found in Family 2. A previously reported, a missense heterozygous mutation in exon 5 (c.571 C>T, p.Arg 191Trp) was detected in Family 3.

CONCLUSIONS

The thorough investigation of three Chinese families with MODY2 revealed two novel mutations and one known mutation. GCK gene sequencing helps in MODY2, especially when there is uncertain IFG or IGT.

A novel mutation of PAX6 identified in a Chinese twin family with congenital aniridia complicated with nystagmus

Genetic variations within the paired box gene 6 (PAX6) gene are associated with congenital aniridia. To detect the genetic defects in a Chinese twin family with congenital aniridia and nystagmus, exons of PAX6 were amplified by polymerase chain reaction (PCR), sequenced and compared with a reference database. Six members from the family of three generations were included in the study. The twins' father presented with congenital aniridia, nystagmus and cataract at birth, while the twins presented with congenital aniridia and nystagmus. A novel mutation c.888 insA in exon 10 of PAX6 was identified in all affected individuals. This study suggests that the novel mutation c.888 insA is likely responsible for the pathogenesis of the congenital aniridia and nystagmus in this pedigree. To the best of our knowledge, this is the first report of this mutation in PAX6 gene in pedigree with aniridia. Furthermore, no PAX6 gene defect was reported in twins with congenital aniridia.

Risk factors for arterial ischemic and hemorrhagic stroke in childhood

This study assessed potential etiologies of arterial ischemic stroke and hemorrhagic stroke among children of Mainland China. From January 1996-June 2006, 251 patients with consecutive childhood stroke (aged 1 month through 16 years) were admitted to Beijing Children's Hospital. Arterial ischemic stroke accounted for the majority of cases (62.5%). Idiopathic stroke (32.5%) was more common than cardiac stroke (8.9%), vascular or arteriopathic stroke (21.0%), hematologic disorder-associated stroke (10.8%), and other etiologies (26.8%). Vitamin K deficiency was a major etiology in 72 of 94 hemorrhagic strokes (76.6%), most of which occurred in breastfeeding infants (80.6%) and those who received no vitamin K after birth (73.6%). Arteriovenous malformation (6.4%) was a frequent etiology in the remaining hemorrhagic stroke cases. We found that ischemic stroke in children is more common than hemorrhagic stroke, and many cases of ischemic stroke are idiopathic. Vitamin K deficiency was a major etiology in these young infants who experienced hemorrhagic stroke.

Arterial ischemic stroke: experience in Chinese children

The aim of this study was to review cases of pediatric arterial ischemic stroke among Chinese subjects and thereby evaluate risk factors, clinical and neuroimaging features, and treatment, to establish a reasonable guideline for assessment and management of the disease. Between 1996 and 2006, 157 children (male:female ratio, 1.4:1) with arterial ischemic stroke were identified at Beijing Children's Hospital. The median age at stroke was 32 months (range, 4-192). Among patients with determined etiology, infections (12.1%), moyamoya disease (12.1%), and trauma (10.8%) were the most common. In 51 patients, there were no obvious risk factors (32.5%). Hemiplegia was the most common presenting feature (81.5%). The region of left middle cerebral artery was most frequently affected (36.3%), followed by the right middle cerebral artery (29.9%). Of the 157 patients, 56 were treated by intravenous thrombolytic agents (35.7%), all but one of them successfully (the one exception involving hemorrhagic complication). Randomized controlled trials are needed to establish primary prevention, acute treatment, and secondary prevention of pediatric ischemic stroke.

Csk-binding protein (Cbp) negatively regulates epidermal growth factor-induced cell transformation by controlling Src activation

Epidermal growth factor receptor (EGFR) and Src tyrosine kinase cooperate in regulating EGFR-mediated cell signaling and promoting cell transformation and tumorigenesis in pathological conditions. Activation of Src is tightly regulated by the C-terminal Src kinase (Csk). The Csk-binding protein (Cbp) is a ubiquitously expressed transmembrane protein. Its functions include suppression of T-cell receptor activation through recruiting Csk and inhibiting Src family kinase (SFK). However, a potential role of Cbp in EGF-induced cell activities has not been investigated. Here, we report that EGF-stimulation-induced Cbp tyrosine phosphorylation followed by Cbp-Csk association, in a SFK-dependent manner. Expression of wild-type (wt) Cbp remarkably suppressed EGF-induced activation of Src, ERK1/2, and Akt-1 enzymes, and NIH3T3 cell transformation, as well as colony formation of a breast cancer cell line (MDA-MB-468) in soft agar. In contrast, expression of CbpY317F or knockdown endogenous Cbp in NIH3T3 cells by RNA interference significantly enhanced EGF-induced activation of these enzymes and cell transformation. In addition, overexpression of multiple receptor tyrosine kinases (RTKs)-induced Cbp tyrosine phosphorylation. These results demonstrate that Cbp functions as a negative regulator of cell transformation and tumor cell growth through downregulation of Src activation, suggesting that Cbp might be broadly involved in RTKs-activated signaling pathways and tumorigenesis.

Effect of cyclosporine on anterior chamber-associated immune deviation with retinal transplantation

PURPOSE

To determine whether immunosuppression using cyclosporine interferes with anterior chamber associated immune deviation (ACAID) and can promote survival of retinal allografts in the anterior chamber.

METHODS

Neonatal neural retinas of C57BL/6 mice or ovalbumin were injected into the anterior chamber of BALB/c adult mice. In the test group recipients were injected with cyclosporine (10 mg/kg per day) from day 0 to 11 or from day 11 to 34 after implantation. At 12 and 35 days after transplantation, lymphocytes from the test group were injected into naive BALB/c mice to assay for the presence of suppressor T cells (adoptive transfer). The fate of the retinal grafts was determined by histologic examination at day 12 and 35. To evaluate the potential neurotoxic effects of cyclosporine in the absence of immune rejection mechanisms, cyclosporine was given to SCID mice during days 11 to 34 after syngeneic neonatal neural retinal grafts were placed in the anterior chamber.

RESULTS

At 12 days after transplantation, spleens of both cyclosporine-treated and control mice contained suppressor cells against donor alloantigens. The retinal grafts in the anterior chamber of both groups of mice were fully developed and well differentiated. The same duration of administration of cyclosporine did not interfere with the production of efferent suppressor cells after inoculation of ovalbumin into the anterior chamber. At 35 days after transplantation, only spleen cells from the cyclosporine-treated group showed the capacity to suppress donor-specific delayed hypersensitivity. However, allografts in the cyclosporine group had deteriorated by 35 days in a fashion similar to the control group. Syngeneic grafts in SCID mice showed differentiated retinal layers 35 days after transplantation.

CONCLUSIONS

Cyclosporine treatment does not interfere with the ability of allogeneic neonatal retinal grafts to induce anterior chamber associated immune deviation when placed in the anterior chamber, nor does prolonged treatment with this drug interfere with the persistence of allospecific suppressor cells for 35 days after the graft. Because 35-day grafts of cyclosporine-treated mice display histologic evidence of graft failure similar to grafts placed in the anterior chamber of untreated mice, graft destruction is either the result of immune effector mechanisms not inhibited by cyclosporine, or the consequence of nonimmunologic factors.

Immunity and immune privilege elicited by cultured retinal pigment epithelial cell transplants

PURPOSE

To determine whether cultured retinal pigment epithelial (RPE) cells implanted in the subconjunctival space induce an immune response against autoantigens and whether an active downregulation is achieved by RPE grafts placed in the anterior chamber and within the subretinal space.

METHODS

Cultured RPE cells from eyes of newborn C57BL/6 mice were implanted in the subconjunctival space, the anterior chamber, or the subretinal space of eyes of adult C57BL/6 mice. At postimplantation day 12, the recipients were evaluated for RPE-specific delayed hypersensitivity and examined clinically and histologically for evidence of rejection. To facilitate their identification, RPE cells were labeled with 5-bromodeoxyuridine, before intraocular transplantation.

RESULTS

Cultured RPE cells implanted in the subconjunctival space of syngeneic mice elicited an intense RPE-specific delayed hypersensitivity associated with a vehement cellular infiltration of the graft when examined at postimplantation day 12. By contrast, grafts in the anterior chamber and subretinal space displayed no evidence of rejection, and their recipients failed to display RPE-specific delayed hypersensitivity. Additionally, the spleens of these mice contained regulatory T cells that suppressed RPE-specific delayed hypersensitivity in naive syngeneic recipients.

CONCLUSIONS

Cultured RPE cells can induce an immune response against autoantigens. Implantation of RPE cells in immune-privileged sites of the eye induces a deviant immune response that is associated with spleen cells that suppress RPE-specific delayed hypersensitivity and autoimmune rejection.

Unconventional rejection of neural retinal allografts implanted into the immunologically privileged site of the eye

The unique feature of neural transplantation in the central nervous system is that the graft is derived from and implanted into an immunologically privileged site. The eye, as a part of the central nervous system, normally maintains an immunosuppressive microenvironment in which alloantigens induce an active down-regulation of specific delayed hypersensitivity. To determine whether neural retinal allografts are eventually rejected and, if so, what type of immunity is associated with rejection, we implanted allogeneic and syngeneic newborn neural retinal grafts into the anterior chamber of the eyes of immune-competent mice. In addition, similar allografts were implanted into severe combined immune-deficient (SCID) mice. The fate of these grafts was determined by clinical and histological examination. At post-implantation day 12, all allogeneic and syngeneic grafts survived comparably well with no evidence of inflammation. At post-implantation day 35, the syngeneic grafts in the immune-competent mice and the allogeneic grafts in the SCID mice continued to thrive, whereas the allografts in the immune-competent mice were remarkably reduced in size and had lost the organization of their retinal cell layers. Interestingly, these grafts' deterioration occurred with no obvious cellular infiltration. When systemic graft-specific immunity was examined, it was found that delayed hypersensitivity was impaired at post-implantation day 12 in allograft recipients. However, by post-implantation 35 day when deterioration was detected in these grafts, suppression of immunity was replaced by vigorous delayed hypersensitivity. These results suggest that intraocular retinal allografts eventually succumb to rejection and that rejection is correlated with the emergence of donor-specific delayed hypersensitivity. The possible relationships of atypical, chronic rejection of intraocular neural retinal allografts to emergent delayed hypersensitivity are discussed.

Corneal electroretinographic function rescued by normal retinal pigment epithelial grafts in retinal degenerative Royal College of Surgeons rats

PURPOSE

This study was designed to examine whether retinal function can be rescued by allogeneic normal retinal pigment epithelial (RPE) grafts in Royal College of Surgeons (RCS) with retinal degeneration and, if so, whether this rescued function can be measured and followed by recording the corneal electroretinogram (ERG).

METHODS

RPE donors were RCS-Long Evans crossbred F1 rats with phenotypically normal retinas. Half an RPE sheet was implanted in the subretinal space of RCS rats at postnatal day 20. The fundi of the recipients' eyes were examined, and the corneal ERGs were recorded. The eyes were also examined histologically.

RESULTS

The RPE grafts were identified by fundus examination in all 21 recipients. No clinical or histologic evidence of inflammation was detected in the media or the retina of the host eye. Eighteen of 21 (86%) recipients showed rescued corneal ERG function. In nine recipients, the PIII response in the grafted eye was significantly greater than in the nongrafted eye. In the other nine recipients, the ERG in the grafted eye showed a b-wave and an a-wave, whereas no b-wave was detected in the nongrafted eye. Recipients of the sham operation (n = 13) revealed no ERG function rescue. To determine long-term corneal ERG function in RPE recipients, 8 of 18 animals in which ERG function was rescued were randomly selected for continued observation. These recipients sustained rescued ERG function for 16 to 17 weeks, at which time the experiment ended.

CONCLUSION

Results indicate that retinal function of degenerative RCS rats, as measured by corneal ERG, can be rescued by implantation of allogeneic normal RPE into the subretinal space of the eye. Furthermore, this rescued function can be followed up over a relatively long period of time, thus providing a useful model for studying the functional changes of RPE allografts resulting from either immunologic or neurobiologic influences.

Immune privilege in the eye: an evolutionary adaptation

The purpose of this study was to determine whether immune privilege exists in the eye of goldfish and to explore from an evolutionary point of view the relationship between the immunological and neurobiological microenvironments in the eye. Neural retinal or scale allografts and autografts were implanted into the vitreous cavity or the anterior chamber of goldfish eyes. Histological examinations were conducted to determine the fate of these grafts. In order to detect donor-specific immune suppression induced by intraocular retinal allografts, scale allografts obtained from the same donors were subsequently implanted orthotopically and evaluated. Neural retinal allografts implanted intraocularly were rapidly rejected by postimplantation day 8. In contrast, neural retinal autografts survived well within the eye with no inflammation. Prior intraocular allografts, either scale or retinal grafts, did not prevent rejection of subsequent scale allografts nor did they induce down-regulation of systemic immunity. Thus, immune privilege does not exist in the goldfish eye, implying that immune privilege in the eye (or central nervous system) may be an evolutionary adaptation acquired by higher vertebrates. Considering that the capacity for neural regeneration in the central nervous system diminishes during evolution, the hypothesis that immune privilege and neural regeneration may be mutually exclusive properties is addressed.

Immunologic consequences of intraocular implantation of retinal pigment epithelial allografts

Immune rejection is a major concern for potential therapeutic RPE transplantation. The purpose of this study is to determine the pattern and consequences of immune responses to intraocular retinal pigment epithelial (RPE) allografts. RPE allografts which derive from C57BL/6 newborn mice were implanted into the subretinal space (SR), anterior chamber (AC) and subconjunctival space (SCon) of the eyes of adult BALB/c mice. After implantation, clinical, histological and immunological examinations were conducted. Results revealed that RPE allografts implanted into SR and AC had a prolonged survival which is associated with a suppression of donor-specific delayed hypersensitivity (DH) for at least 12 days. In contrast, similar RPE grafts implanted into the SCon induced conventional DH and grafts were rejected. Moreover, previously healthy intraocular RPE grafts were rejected 2 weeks after a donor-specific challenge and rejection was accomplished with extensive cell infiltration which subsequently damaged intraocular tissue of the host eye. These results suggested that intraocular RPE allografts enjoyed immune privilege and induced a down-regulation of immune responses. However, this privilege is not absolute and static--DH was able to emerge and grafts were rejected in a cell-mediated fashion.

Subretinal space and vitreous cavity as immunologically privileged sites for retinal allografts

PURPOSE

Because immune rejection is likely to be a major barrier to successful retinal transplantation, it is important to determine whether immune privilege for allogeneic retinal grafts is a feature of the subretinal space and vitreous cavity.

METHODS

Newborn neural retinas of C57BL/6 mice were implanted into the subretinal space, vitreous cavity, or subconjunctival space of eyes of adult BALB/c (disparate from C57BL/6 at major and minor histocompatibility loci). At postimplantation day 12, the recipients were evaluated for donor-specific delayed hypersensitivity and examined clinically and histologically for evidence of rejection.

RESULTS

Newborn neural retinal allografts in the subconjunctival space were destroyed by postimplantation day 12 and these recipients displayed intense donor-specific delayed hypersensitivity. By contrast, grafts in the subretinal space and vitreous cavity at postimplantation day 12 were found to be well differentiated and with no evidence of inflammation; these recipients failed to display donor-specific delayed hypersensitivity. Moreover, their spleens contained regulatory T cells that suppressed donor-specific delayed hypersensitivity in naive syngeneic recipients.

CONCLUSIONS

Allogeneic newborn neural retinal grafts implanted in the subretinal space and vitreous cavity experience immune privilege and induce deviant immune responses resembling anterior chamber associated immune deviation.

Immunity and immune privilege elicited by autoantigens expressed on syngeneic neonatal neural retina grafts

Achieving the long-term goal of successful engraftment of retinal tissues into eyes blinded by endogenous retinal failure will depend, at least in part, on controlling the immune response to antigens expressed on retinal grafts. Since histoincompatible tissues will have to be used for such transplants, methods to control immune rejection directed at transplantation alloantigens must be devised. In addition, it has recently been observed in mice that developing neural retinal tissues express retina-specific antigens that have the potential to contribute to graft failure. To examine the potential risk of this contribution, syngeneic neonatal neural retinas were implanted into the anterior chamber, vitreous cavity, and subconjunctival space of adult BALB/c mice. During two weeks post-implantation, the fate of these grafts was observed clinically and histologically, and the retina-specific immune responses of the recipients were evaluated. Whereas grafts placed intraocularly thrived, carried out their inherent developmental potential, and were healthy and intact at the end of the observation interval. Grafts placed extraocularly expressed their differentiation program poorly. These grafts underwent rapid decline and attrition, although the process was not accompanied by significant inflammation. Recipients of subconjunctival, but not AC or VC, implants developed retina-specific delayed hypersensitivity. Alternatively, mice bearing AC and VC implants of neonatal neural retina developed retina-specific anterior chamber associated immune deviation. It is concluded that retinal autoantigens are expressed on developing neural retinal tissues and these antigens are highly immunogenic when retinal grafts are placed at conventional body sites. When similar grafts are placed in immune privileged compartments of the normal eye, they enjoy significant survival. Circumstantial evidence indicates that intraocular retinal grafts are protected and maintained in part by the emergence of systemic retinal auto-antigen-specific immune suppression.

Reciprocal retinal transplantation: a tool for the study of an inherited retinal degeneration

The pathogenesis of retinal degeneration in rd mutant mice has been extensively studied, the gene responsible for the defect has been cloned, and the neural retina has been identified as the primary site for the degeneration. However, the possible contributory role of the ocular environment in this form of retinal degeneration remains undetermined. Retinal transplantation, which provides the opportunity to implant the neural retinal into a genetically defined intraocular environment, was used to examine this possibility. A reciprocal retinal transplantation paradigm was designed based on three experimental groups: (1) normal immature retina transplanted into rd/rd mutant eyes, (2) rd/rd immature retina transplanted into normal eye, and (3) normal immature retina transplanted into normal eyes. The rates of survival and histological characteristics of the grafts were compared between the three groups. At post-transplantation Day 3 (PTD 3), there were no differences between the three groups. Between PTD 10 and 15, the retinal grafts in group 1 showed degeneration. In contrast, the retinal grafts in groups 2 and 3 survived and developed well. At PTD 30, the retinal grafts in both groups 1 and 2 showed degeneration, but the retinal grafts in group 3 survived and remained differentiated well. These results suggest that the retinal degeneration of rd mice may be caused by both a deficit of the neural retina and intraocular environmental changes which are elicited either as a result of mutation or as a sequel to retinal degeneration.

Immune responses elicited by transplantation and tissue-restricted antigens expressed on retinal tissues implanted subconjunctivally

In recent years there has been renewed interest in experimental retinal transplantation. Immunological rejections represent a major barrier to the success of retinal transplants. We recently reported that strongly histoincompatible neuroretinal grafts placed in the subconjunctival space of adult recipient mice were rejected, whereas similar grafts placed in the anterior chamber of the eye were accepted. Since retinal tissues are known to express retina-restricted autoantigens that can induce specific systemic immune responses and can serve as targets of destructive autoimmune attack, it is important to determine whether retinal transplants can evoke immune responses directed at retina-restricted antigens, and whether such responses might be deleterious to the graft. In this study, neonatal neural retinal grafts were placed into the subconjunctival space of eyes of normal allogeneic and syngeneic mice. Delayed hypersensitivity to the relevant alloantigens and to putative retina-restricted autoantigens was assayed. The results reveal that neural retina grafts sensitized their recipients to both alloantigens and retina-specific autoantigens. Moreover, in some recipients, a delayed, destructive uveitis developed, implying that graft-elicited immune responses directed at retina-restricted antigens may provoke autoimmune reactions in previously normal eyes of recipients. These findings indicate that grafts of developing neural retina tissue express both transplantation antigens and retina-restricted antigens in immunogenic form, and that grafting leads to systemic immunization against both sets of antigens.

Immune privilege extended to allogeneic tumor cells in the vitreous cavity

Inoculation of alloantigenic P815 tumor cells into the vitreous cavity of eyes of BALB/c mice resulted in the intraocular development of progressively growing tumors. We observed by clinical and histologic examination that the tumors acquired a blood supply, lacked significant necrosis or degeneration, and gradually penetrated the globe into the orbit. Mice bearing these intraocular tumors did not develop tumor-specific delayed hypersensitivity (DH), and their spleens contained lymphocytes capable of suppressing tumor-specific DH when transferred adoptively into naive, syngeneic recipients. The authors conclude that the vitreous cavity (VC) is an immunologically privileged site for histoincompatible tumor cells and that the privilege is mediated by active suppression of DH, similar to anterior chamber (AC)-associated, immune deviation.

In vivo staining of the mammalian retina by means of a simple fluorescent method

Intraocular injections of microliter volumes of a solution containing the fluorescent stain Fluoro-Gold produces an intense and long-lasting in vivo stain of the cells forming the neural retina of rats and mice. The label is incorporated by the neuro-retinal cells, while other intraocular structures such as the lens, iris, ciliary processes and even the optic nerve head exclude it. The fluorophore can be easily demonstrated under epi-illumination by means of commonly used fluorescence filter combinations. The stain has proven to be compatible with cryostat sectioning and with plastic embedding. Furthermore, electron dense lysosomal and lamellar bodies in retinal neurons which have incorporated the stain may provide a means for identification of Fluoro-Gold labeled cells at the electron microscopic level which is consistent with previous results. Intraocular injection of Fluoro-Gold fills the need for a reliable, simple, and robust in vivo and in toto stain of the neural retina.

Intraretinal transplantation of fluorescently labeled retinal cell suspensions

Dissociated cell suspensions of neonatal neural retina, labeled with the fluorescent dyes Fast blue or Fluoro-gold, were transplanted into the retina of normal adult rats or of rats affected by late stage phototoxic retinopathy. Light microscopy showed good survival, differentiation, and integration of the transplants, as well as permanence of the label up to 100 days. The results indicate that the transplantation of dissociated, fluorescently labeled retinal cells has a number of advantages over the transplantation of solid fragments of retinal tissue, previously performed by ourselves and others. The following are some of the most immediate procedural advantages: the number of transplanted cells can be assessed, the transplanted cells are in a more intimate contact with the host tissue and therefore integrate better with the host, and the fluorescent tags permit precise determination of the survival and distribution of the transplanted cells.