Stepwise combined cell transplantation using mesenchymal stem cells and induced pluripotent stem cell-derived motor neuron progenitor cells in spinal cord injury

BACKGROUND

Spinal cord injury (SCI) is an intractable neurological disease in which functions cannot be permanently restored due to nerve damage. Stem cell therapy is a promising strategy for neuroregeneration after SCI. However, experimental evidence of its therapeutic effect in SCI is lacking. This study aimed to investigate the efficacy of transplanted cells using stepwise combined cell therapy with human mesenchymal stem cells (hMSC) and induced pluripotent stem cell (iPSC)-derived motor neuron progenitor cells (iMNP) in a rat model of SCI.

METHODS

A contusive SCI model was developed in Sprague-Dawley rats using multicenter animal spinal cord injury study (MASCIS) impactor. Three protocols were designed and conducted as follows: (Subtopic 1) chronic SCI + iMNP, (Subtopic 2) acute SCI + multiple hMSC injections, and (Main topic) chronic SCI + stepwise combined cell therapy using multiple preemptive hMSC and iMNP. Neurite outgrowth was induced by coculturing hMSC and iPSC-derived motor neuron (iMN) on both two-dimensional (2D) and three-dimensional (3D) spheroid platforms during mature iMN differentiation in vitro.

RESULTS

Stepwise combined cell therapy promoted mature motor neuron differentiation and axonal regeneration at the lesional site. In addition, stepwise combined cell therapy improved behavioral recovery and was more effective than single cell therapy alone. In vitro results showed that hMSC and iMN act synergistically and play a critical role in the induction of neurite outgrowth during iMN differentiation and maturation.

CONCLUSIONS

Our findings show that stepwise combined cell therapy can induce alterations in the microenvironment for effective cell therapy in SCI. The in vitro results suggest that co-culturing hMSC and iMN can synergistically promote induction of MN neurite outgrowth.

Replacing Animal Testing with Stem Cell-Organoids : Advantages and Limitations

Various groups including animal protection organizations, medical organizations, research centers, and even federal agencies such as the U.S. Food and Drug Administration, are working to minimize animal use in scientific experiments. This movement primarily stems from animal welfare and ethical concerns. However, recent advances in technology and new studies in medicine have contributed to an increase in animal experiments throughout the years. With the rapid increase in animal testing, concerns arise including ethical issues, high cost, complex procedures, and potential inaccuracies.Alternative solutions have recently been investigated to address the problems of animal testing. Some of these technologies are related to stem cell technologies, such as organ-on-a-chip, organoids, and induced pluripotent stem cell models. The aim of the review is to focus on stem cell related methodologies, such as organoids, that can serve as an alternative to animal testing and discuss its advantages and limitations, alongside regulatory considerations.Although stem cell related methodologies has shortcomings, it has potential to replace animal testing. Achieving this requires further research on stem cells, with potential societal and technological benefits.

Impaired Osteogenesis in Human Induced Pluripotent Stem Cells with Acetaldehyde Dehydrogenase 2 Mutations

Acetaldehyde dehydrogenase 2 (ALDH2) is the second enzyme involved in the breakdown of acetaldehyde into acetic acid during the process of alcohol metabolism. Roughly 40% of East Asians carry one or two ALDH2*2 alleles, and the presence of ALDH2 genetic mutations in individuals may affect the bone remodeling cycle owing to accumulation of acetaldehyde in the body. In this study, we investigated the effects of ALDH2 mutations on bone remodeling. In this study, we examined the effects of ALDH2 polymorphisms on in vitro osteogensis using human induced pluripotent stem cells (hiPSCs). We differentiated wild-type (ALDH2*1/*1-) and ALDH2*1/*2-genotyped hiPSCs into osteoblasts (OBs) and confirmed their OB characteristics. Acetaldehyde was administered to confirm the impact caused by the mutation during OB differentiation. Calcium deposits formed during osteogenesis were significantly decreased in ALDH2*1/*2 OBs. The expression of osteogenic markers were also decreased in acetaldehyde-treated OBs differentiated from the ALDH2*1/*2 hiPSCs. Furthermore, the impact of ALDH2 polymorphism and acetaldehyde-induced stress on inflammatory factors such as 4-hydroxynonenal and tumor necrosis factor α was confirmed. Our findings suggest that individuals with ALDH2 deficiency may face challenges in acetaldehyde breakdown, rendering them susceptible to disturbances in normal bone remodeling therefore, caution should be exercised regarding alcohol consumption. In this proof-of-concept study, we were able to suggest these findings as a result of a disease-in-a-dish concept using hiPSCs derived from individuals bearing a certain mutation. This study also shows the potential of patient-derived hiPSCs for disease modeling with a specific condition.

A single-centre retrospective study of factors affecting steroid-free remission of immunoglobulin G4-related disease conducted in South Korea: A notable outcome after complete resection

OBJECTIVES

Few studies have examined factors affecting steroid-free remission (SFR) in patients with immunoglobulin G4-related disease (IgG4-RD). The aim of this study was to investigate clinical factors affecting SFR in IgG4-RD.

METHODS

The medical records of 68 patients who met the 2020 revised comprehensive diagnostic criteria for IgG4-RD were reviewed retrospectively. SFR was defined as remission maintained for at least 6 months without corticosteroids. Cox regression analysis was performed to examine the associations between SFR and various clinical factors. The relapse rate after SFR was examined using the log-rank test.

RESULTS

After a median follow-up of 36 months, 30.9% (21/68) of patients with IgG4-RD achieved SFR. Multivariate Cox regression analysis revealed that IgG4-RD diagnosed by complete resection rather than by common diagnostic procedures was the only factor positively associated with SFR (hazard ratio, 7.41; 95% confidence interval, 2.23-24.60; P = .001). Furthermore, relapse after attainment of SFR was significantly less common in the group that underwent complete resection than in the group that did not undergo complete resection (log-rank P = .006).

CONCLUSIONS

Patients with IgG4-RD diagnosed by complete resection had a higher likelihood of achieving SFR and a lower rate of relapse after attaining SFR.

Etanercept-synthesizing adipose-derived stem cell secretome: A promising therapeutic option for inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract, with tumor necrosis factor (TNF)-α playing a key role in its pathogenesis. Etanercept, a decoy receptor for TNF, is used to treat inflammatory conditions. The secretome derived from adipose-derived stem cells (ASCs) has anti-inflammatory effects, making it a promising therapeutic option for IBD.

AIM

To investigate the anti-inflammatory effects of the secretome obtained from ASCs synthesizing etanercept on colon cells and in a dextran sulfate sodium (DSS)-induced IBD mouse model.

METHODS

ASCs were transfected with etanercept-encoding mini-circle plasmids to create etanercept-producing cells. The secretory material from these cells was then tested for anti-inflammatory effects both in vitro and in a DSS-induced IBD mouse model.

RESULTS

This study revealed promising results indicating that the group treated with the secretome derived from etanercept-synthesizing ASCs [Etanercept-Secretome (Et-Sec) group] had significantly lower expression levels of inflammatory mediators, such as interleukin-6, Monocyte Chemoattractant Protein-1, and TNF-α, when compared to the control secretome (Ct-Sec). Moreover, the Et-Sec group exhibited a marked therapeutic effect in terms of preserving the architecture of intestinal tissue compared to the Ct-Sec.

CONCLUSION

These results suggest that the secretome derived from ASCs that synthesize etanercept has potential as a therapeutic agent for the treatment of IBD, potentially enhancing treatment efficacy by merging the anti-inflammatory qualities of the ASC secretome with etanercept's targeted approach to better address the multifaceted pathophysiology of IBD.

Predictors of renal relapse in Koreans with lupus nephritis after achieving complete response: a 35-years of experience at a single center

BACKGROUND/AIMS

Renal relapse has known to be a poor prognostic factor in patients with lupus nephritis (LN), but there were few studies that identified the risk factors of renal relapse in real world. We conducted this study based on 35-years of experience at a single center to find out predictors of renal relapse in Korean patients with LN after achieving complete response (CR).

METHODS

We retrospectively analyzed the clinical, laboratory, pathologic and therapeutic parameters in 296 patients of LN who reached CR. The cumulative risk and the independent risk factors for renal relapse were examined by Kaplan-Meier methods and Cox proportional hazards regression analyses, respectively.

RESULTS

The median follow-up period from CR was 123 months. Renal relapse had occurred in 157 patients. Renal relapse occurred in 38.2%, 57.6% and 67.9% of patients within 5-, 10-, and 20-year, respectively. The age at diagnosis of SLE and LN were significantly younger, and the proportions of severe proteinuria and serum hypoalbuminemia were higher in patients with renal relapse. Interestingly, the proportion of receiving cytotoxic maintenance treatment was higher in patients with renal relapse. In Cox proportional hazards regression analyses, only young-age onset of LN (by 10 years, HR = 0.779, p = 0.007) was identified to independent predictor of renal relapse.

CONCLUSION

Young-age onset of LN was only independent predictor and the patients with severe proteinuria and serum hypoalbuminemia also tended to relapse more, despite of sufficient maintenance treatment. Studies on more effective maintenance treatment regimens and duration are needed to reduce renal relapse.

Effects of stepwise administration of osteoprotegerin and parathyroid hormone-related peptide DNA vectors on bone formation in ovariectomized rat model

Osteoporosis is a metabolic bone disease that impairs bone mineral density, microarchitecture, and strength. It requires continuous management, and further research into new treatment options is necessary. Osteoprotegerin (OPG) inhibits bone resorption and osteoclast activity. The objective of this study was to investigate the effects of stepwise administration of OPG-encoded minicircles (mcOPG) and a bone formation regulator, parathyroid hormone-related peptide (PTHrP)-encoded minicircles (mcPTHrP) in osteoporosis. The combined treatment with mcOPG and mcPTHrP significantly increased osteogenic marker expression in osteoblast differentiation compared with the single treatment groups. A model of postmenopausal osteoporosis was established in 12-week-old female rats through ovariectomy (OVX). After 8 weeks of OVX, mcOPG (80 µg/kg) was administered via intravenous injection. After 16 weeks of OVX, mcPTHrP (80 µg/kg) was injected once a week for 3 weeks. The bone microstructure in the femur was evaluated 24 weeks after OVX using micro-CT. In a proof-of-concept study, stepwise treatment with mcOPG and mcPTHrP on an OVX rat model significantly improved bone microstructure compared to treatment with mcOPG or mcPTHrP alone. These results suggest that stepwise treatment with mcOPG and mcPTHrP may be a potential treatment for osteoporosis.

Characteristics of patients with psoriatic arthritis in Korea: focusing on axial involvement

BACKGROUND/AIMS

We aimed to clarify the clinical characteristics of psoriatic arthritis (PsA) in Korean patients focusing on PsA with axial involvement.

METHODS

A retrospective medical chart review was performed to identify PsA patients at a single tertiary center. Cases of AS patients with psoriasis were recruited from a prospective AS registry of the same center. Demographics, laboratory findings, and radiologic characteristics were assessed.

RESULTS

A total of 69 PsA patients were identified. In PsA patients, spondylitis (46.4%) was the most common form. Compared to AS patients with psoriasis, PsA patients with radiographic axial involvement were older (50.9 vs. 32.4 years; p < 0.001) and showed greater peripheral disease activity (peripheral arthritis 78.1 vs. 12.5%, p < 0.001; enthesitis 50.0 vs. 6.3%, p = 0.003). AS patients with psoriasis presented a higher rate of HLA-B*27 positivity (81.3 vs. 17.2%; p < 0.001) and a more frequent history of inflammatory back pain (100.0 vs. 75.0%; p = 0.039) than PsA patients with radiographic axial involvement. Significant proportions of PsA patients with radiographic axial involvement had cervical spine involvement (10/18, 55.6%) and spondylitis without sacroiliitis (10/23, 43.5%).

CONCLUSION

We demonstrate that axial involvement is common in Korean PsA patients, and its characteristics can be distinct from those of AS.

Intranasal administration of induced pluripotent stem cell-derived cortical neural stem cell-secretome as a treatment option for Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is the most common neurodegenerative disorder in the elderly, resulting in gradual destruction of cognitive abilities. Research on the development of various AD treatments is underway; however, no definitive treatment has been developed yet. Herein, we present induced pluripotent stem cell (iPSC)-derived cortical neural stem cell secretome (CNSC-SE) as a new treatment candidate for AD and explore its efficacy.

METHODS

We first assessed the effects of CNSC-SE treatment on neural maturation and electromagnetic signal during cortical nerve cell differentiation. Then to confirm the efficacy in vivo, CNSC-SE was administered to the 5×FAD mouse model through the nasal cavity (5 μg/g, once a week, 4 weeks). The cell-mediated effects on nerve recovery, amyloid beta (Aβ) plaque aggregation, microglial and astrocyte detection in the brain, and neuroinflammatory responses were investigated. Metabolomics analysis of iPSC-derived CNSC-SE revealed that it contained components that could exert neuro-protective effects or amplify cognitive restorative effects.

RESULTS

Human iPSC-derived CNSC-SE increased neuronal proliferation and dendritic structure formation in vitro. Furthermore, CNSC-SE-treated iPSC-derived cortical neurons acquired electrical network activity and action potential bursts. The 5×FAD mice treated with CNSC-SE showed memory restoration and reduced Aβ plaque accumulation.

CONCLUSIONS

Our findings suggest that the iPSC-derived CNSC-SE may serve as a potential, non-invasive therapeutic option for AD in reducing amyloid infiltration and restoring memory.

Safety and effectiveness of tofacitinib in Korean adult patients with rheumatoid arthritis: A post-marketing surveillance study

OBJECTIVES

The aim of this article is to assess the safety and effectiveness of tofacitinib in patients with rheumatoid arthritis in routine clinical settings in Korea.

METHODS

This is a prospective, multi-centre post-marketing surveillance study. Data were prospectively collected within 6 months after the start of tofacitinib therapy. Safety was evaluated based on the presence of adverse events (AEs) observed in patients who received at least one dose of tofacitinib. Effectiveness was assessed according to the proportion of patients who achieved low disease activity and remission, American College of Rheumatology 20 criteria (ACR20), European League Against Rheumatism (EULAR) response, and change of Disease Activity Score in 28 Joints (DAS28).

RESULTS

The incidence rates [patients with events per 100 patient-years (PY)] of AEs and serious AEs were 56.92 and 10.69, respectively. Regarding AEs of special interest, the incidence rates were 4.33 per 100 PY for serious infections and infestations, 5.78 per 100 PY for herpes zoster, no event of tuberculosis, 0.29 per 100 PY for malignancy, 0.29 per 100 PY for venous thromboembolism (one event of deep vein thrombosis and no event of pulmonary embolism), 0.87 per 100 PY for major adverse cardiovascular event, and 0.58 per 100 PY for mortality. Moreover, ∼40.48% and 21.60% of patients achieved low disease activity and remission of DAS28-erythrocyte sedimentation rate. The EULAR response was classified as good responders with 39.12% in the DAS28-erythrocyte sedimentation rate.

CONCLUSIONS

The benefit/risk profile of tofacitinib in adult patients with rheumatoid arthritis in routine clinical settings in Korea was similar to long-term clinical trial data.

Predictors for future development of systemic lupus erythematosus in Korean Sjögren's syndrome patients

OBJECTIVE

This study determined the impact of demographic factors, clinical manifestations, disease activity, and serological tests at baseline on future SLE development in Sjögren's syndrome (SS) patients.

METHODS

This retrospective study assessed 1,082 SS patients without other autoimmune diseases at baseline who visited our hospital between January 2012 and March 2021. We analyzed demographic features, extra-glandular manifestations (EGMs), clinical indices, and laboratory values at baseline between the two groups divided per future SLE development (SS/SLE group vs SS group). The probability and predictors of SLE development in SS patients were estimated using the Kaplan-Meier method and Cox proportional hazards models.

RESULTS

The median follow-up duration was 1083.5 days. Forty-nine patients (4.5%) developed SLE that met the 2012 Systemic Lupus International Collaborating Clinics or 2019 EULAR/ACR classification criteria. The baseline EULAR SS disease activity index (ESSDAI) score was significantly higher in the SS/SLE group (p < .001). The SS/SLE group had more lymphadenopathy and renal involvement (p = .015 and p = .017, respectively). Shorter SS disease duration (<3 years) (hazard ratio [HR] = 2.12, p = .0328), high ESSDAI (HR = 8.24, p < .0001), leukopenia (HR = 4.17, p = .0005), thrombocytopenia (HR = 3.38, p = .0059), hypocomplementemia (HR = 29.06, p<.0001), and positive for anti-dsDNA (HR = 13.70, p < .0001), anti-ribonucleoprotein (RNP) (HR = 3.82, p = .0027), and anti-ribosomal P (HR = 6.70, p = .0002) at baseline were SLE development predictors in SS patients.

CONCLUSION

Shorter disease duration and higher disease activity of SS at baseline may be risk factors for future SLE development. Serologic predictors of SLE development are hypocomplementemia, leukopenia, thrombocytopenia, and positivity for anti-dsDNA, anti-RNP, and anti-ribosomal P antibodies. If the above factors are observed, close monitoring will be necessary during the follow-up period, considering the possibility of future SLE development.

[Clinical effects of anterolateral thigh flap with blood supply source of medial femoral perforator in repairing the wounds on extremities]

Objective: To investigate clinical effects of anterolateral thigh flap with blood supply source of medial femoral perforator in repairing the wounds on extremities. Methods: A retrospective observational study was conducted. From October 2018 to June 2021, Suzhou Ruihua Orthopedic Hospital admitted 12 patients (11 males and 1 female, aged 24-64 years) who met the inclusion criteria, and did not have the lateral circumflex femoral artery during anterolateral thigh flap resection, or changed to medial femoral perforator as a source of blood supply due to small perforator to repair the wound with flap transplantation. The wounds were on the upper limbs in 7 cases and on the lower limbs in 5 cases. The wound area after debridement was 8.0 cm×5.0 cm-24.0 cm×6.5 cm, and the applied flap area was 9 cm×6 cm-25 cm×7 cm. During transplantation, the perforating branch or source artery of the flap was anastomosed end to end with the vascular pedicle of the recipient area. Subcutaneous beauty suture was performed on all the donor wounds. After operation, the survival of the flap and vascular crisis were observed; and the wound healing at the donor site was observed. During follow-up, the texture of the flap and complications at the donor site were observed. At the last follow-up, the effect of flap repair was evaluated by using the modified self-made comprehensive efficacy rating table. Results: After operation, all the flaps of patients survived without vascular crisis; the wounds in the donor site healed smoothly. During follow-up of 6 to 26 months, the flaps had good texture; only linear scars remained in the donor area without scar contracture, pain or other discomfort. At the last follow-up, the total score of flap repair effect of 12 patients was 75-95, with an average of 87, of which 5 cases were rated as excellent, 6 cases as good, and 1 case as fair, and the proportion of excellent and good patients was 11/12. Conclusions: The application of anterolateral thigh flap with blood supply from the medial femoral perforator to repair wounds on extremities is an alternative method for the vascular variations such as no descending branch, oblique branch, or small perforator of the lateral circumflex femoral artery during the resection of the anterolateral thigh flap. This operation has the advantages of simple operation, small trauma, and others, which effectively ensures the smooth operation.

[Effects of tibial second toe free flap bridged with blood flow and nerve in the treatment of severe flexion contracture of the proximal interphalangeal joint]

Objective: To investigate the effects of tibial second toe free flap bridged with blood flow and nerve in the treatment of severe flexion contracture of the proximal interphalangeal joint. Methods: A retrospective observational study was conducted. From March 2013 to October 2019, 9 patients with severe flexion contracture (type Ⅲ) of the proximal interphalangeal joint after trauma operation, conforming to the inclusion criteria, were hospitalized in Suzhou Ruihua Orthopaedic Hospital, including 5 males and 4 females, aged from 17 to 62 years. After the contracture tissue affecting the extension of the proximal interphalangeal joint was cut off, and the scar tissue was resected, the size of the volar wound near the proximal interphalangeal joint in extended position was 2.0 cm×1.0 cm-2.5 cm×1.5 cm, with the length of proper digital artery and nerve defect being 1.0-1.5 cm. A free flap of the same size as the wound was cut from the tibial side of the second toe and transplanted to repair the wound, and the defective proper digital artery and nerve was repaired by bridging with the tibial proper plantar digital artery and nerve of about 1.5 cm in length. The full-thickness skin graft was taken from the proximal tibial side of the lower leg to repair the wound at flap donor site. The wound at skin graft donor site was sutured directly. The survival of flap and skin graft was observed after operation. The patients were followed up, and at the last follow-up, the recovery of the affected finger and the second toe, including the donor and recipient areas were observed, the two-point discrimination distances of the flap repaired site and the pulp of the affected finger were observed and measured at the same time, the blood flow patency of bridged vessel of the affected finger was examined by Allen test, and the function of the proximal interphalangeal joint of the affected finger was evaluated according to Chinese Medical Association's standard for the range of motion of proximal interphalangeal joint. Results: The flaps and skin grafts survived smoothly after operation. The follow-up after operation lasted for 5 to 22 months, with a mean of 10 months. At the last follow-up, the flap repaired site had good shape, good color and texture, with the two-point discrimination distance being 9-12 mm, and the two-point discrimination distance of the pulp of the affected finger was 6-10 mm; the Allen test results of the affected fingers were all negative (i.e., the bridged vessels had good blood flow patency), with no recurrence of flexion contracture, and the function of the proximal interphalangeal joint was evaluated as excellent; the skin graft area of the second toe was not ruptured but was a little pigmented, and the flexion and extension activities of toe were good. Conclusions: The tibial second toe free flap bridged with blood flow and nerve has reliable therapeutic effect in the treatment of severe flexion contracture of the proximal interphalangeal joint, and the color and texture of the flap repaired area are good. Bridging to repair the severely contracted proper digital artery and nerve is beneficial to improve the blood supply of the finger body and rebuild the sensation.

[Effects of bilobated superficial peroneal artery perforator flap in repairing two adjacent wounds of the fingers]

Objective: To investigate the therapeutic efficacy of bilobated superficial peroneal artery perforator flap in repairing two adjacent wounds of the fingers. Methods: A retrospective observational study was conducted. From January 2021 to January 2022, 15 patients with two adjacent wounds of the fingers who met the inclusion criteria were hospitalized in Suzhou Ruihua Orthopaedic Hospital, including 10 males and 5 females, aged 25 to 51 years. The area of single wound after debridement was from 2.5 cm×2.0 cm to 7.5 cm×2.5 cm. All the wounds were repaired by the bilobated superficial peroneal artery perforator flap from the lower leg. The single lobe area of bilobated flap was from 3.0 cm×2.0 cm to 8.0 cm×3.0 cm. The wounds in all the donor sites were sutured directly. During the operation, the number of resected flaps, the number and type of carried perforators were recorded, and the calibers of perforator and superficial peroneal artery and the length of vascular pedicle were measured. The survival of flap and the wound healing in the donor and recipient sites were recorded after operation. The recovery of donor and recipient sites were recorded during follow-up. At the last follow-up, the repair effect of flap was evaluated by the comprehensive evaluation scale, and the sensory function of flap was evaluated by the sensory function evaluation standard of British Medical Research Association. Results: During the operation, 15 bilobated flaps were successfully resected, carrying 36 superficial peroneal artery perforators, all of which were septocutaneous perforators with the caliber of 0.2-0.8 mm. The caliber of superficial peroneal artery was 0.4-1.1 mm and the length of vascular pedicle was 3-8 cm. After operation, all the flaps survived with no vascular crisis occurred, and the wounds in donor and recipient sites healed well. During the follow-up of 6 to 12 months, the color and texture of flaps were similar to those of normal tissue in the hand and the appearance of flap was good in 10 cases; the other 5 cases underwent the stage Ⅱ flap thinning and plastic surgery 6 months after operation due to the bloated appearance of flaps. There was only linear scar in the donor site of lower leg, with no obvious scar hyperplasia or pigmentation, and there was no obvious adverse effect on the sensation or motor function of the distal limbs in the donor area. At the last follow-up, the repair effect of flap of 15 patients was excellent in 11 cases and good in 4 cases, and the sensory function of the flap was evaluated as grade S2 in all cases. Conclusions: The bilobated superficial peroneal artery perforator flap has high proportion of septocutaneous perforator, and the blood supply is sufficient and reliable. Using this flap to repair two adjacent wounds of the fingers causes minimal damage to the donor area, only one group of blood vessels is needed to be anastomosed to repair two wounds, the difficulty of microoperation is reduced, and good flap repair effect and sensory function can be obtained.

[Effects of free superficial peroneal artery perforator flap in repairing small and medium-sized thermal crush injury wounds in the hand]

Objective: To investigate the surgical methods and clinical effects of free superficial peroneal artery perforator flap in repairing small and medium-sized thermal crush injury wounds in the hand. Methods: A retrospective observational study was conducted. From August 2018 to December 2021, 12 patients (19 wounds) with small and medium-sized thermal crush injury in the hand who met the inclusion criteria were hospitalized in Suzhou Ruihua Orthopaedic Hospital, including 5 males and 7 females, aged from 30 to 54 years. The area of the wound was from 2.5 cm×2.0 cm to 14.0 cm×3.5 cm, and all the wounds were repaired by using free superficial peroneal artery perforator flaps from lower leg on one side (including single flap, multiple flaps, and multiple flaps with one pedicle resected from the same donor site). The area of the flap was from 3.5 cm×3.0 cm to 16.0 cm×4.0 cm. The wound in the donor site was sutured directly. The vascular crisis and survival of the flap were observed after operation. The texture, appearance, color, hyperpigmentation, sensation, and two-point discrimination of the flap repaired area were followed up, as well as the hyperplasia of scar and pain condition in the donor and recipient sites. At the last follow-up, the curative effect of flap repair was evaluated by the comprehensive evaluation scale, and the extension and flexion functions of the reserved digital joint were evaluated by the total active movement systematic evaluation method recommended by American Academy for Surgery of Hand. Results: One flap developed arterial crisis on the first day after operation but survived after timely exploration. The other 18 flaps survived successfully after operation. Follow-up of 4 to 24 months after operation showed good texture and appearance in the flap repaired area; the color of the flap repaired area was similar to that of the normal skin around the recipient site, without pigmentation; the protective sensation was restored in all cases, but there was no two-point discrimination; there was no obvious hypertrophic scarring or pain in the donor or recipient site. At the last follow-up, the curative effect of flap repair was evaluated with 3 flaps being excellent and 16 flaps being good; the extension and flexion functions of the reserved digital joint were also assessed, being excellent in 8 fingers, good in 9 fingers, and fair in 2 fingers. Conclusions: The blood supply of superficial peroneal artery perforator flap is sufficient and reliable, and multiple flaps of this type or multiple flaps with one pedicle can be resected from one donor site. The use of this flap to repair small and medium-sized thermal crush injury wounds in the hand results in minimal damage to the donor area, and good postoperative appearance and texture of the flap.

[Effects of tensile force on the vascular lumen formation in three-dimensional printed tissue]

Objective: To explore the effects of tensile force on vascular lumen formation in three-dimensional printed tissue. Methods: The experimental research method was used. Human umbilical vein endothelial cells (HUVECs) were extracted from discarded umbilical cord tissue of 3 healthy women (aged 22 to 35 years) who gave birth in the Department of Gynaecology and Obstetrics of Suzhou Ruihua Orthopaedic Hospital from September 2020 to May 2021. Human skin fibroblasts (HSFs) were extracted from discarded normal skin tissue of 10 male patients (aged 20 to 45 years) who underwent wound repair in the Department of Hand Surgery of Suzhou Ruihua Orthopaedic Hospital from September 2020 to September 2022. After identification of the two kinds of cells, the 4th to 6th passage of cells were taken for the follow-up experiments. HUVECs and HSFs were used as seed cells, and polycaprolactone, gelatin, hyaluronic acid, and fibrin were used as scaffold materials, and the three-dimensional printed vascularized tissue was created by three-dimensional bioprinting technology. The printed tissue with polycaprolactone scaffold of 6 and 10 mm spacing, and without polycaprolactone scaffold were set as 6 mm spacing polycaprolactone group, 10 mm spacing polycaprolactone group, and non-polycaprolactone group, respectively. After 4 days of culture, the printed tissue in 10 mm spacing polycaprolactone group was selected to detect the cell survival by cell viability detection kit, and the cell survival rate was calculated. After 14 days of culture, the printed tissue in three groups were taken, and the shape change of tissue was observed by naked eyes; immunofluorescence staining was performed to observe the arrangement of filamentous actin, and lumen diameter, total length, and number of branches of vessel in the tissue. The tissue with micro-spring structure in the above-mentioned three groups was designed, printed, and cultured for 9 days, and the tensile force applied in the printed tissue was measured according to the force-displacement curve. The number of samples was all 3 in the above experiments. Data were statistically analyzed with one-way analysis of variance and Tukey test. Results: After 4 days of culture, the cell survival rate in printed tissue in 10 mm spacing polycaprolactone group was (91.3±2.2)%. After 14 days of culture, the shape change of printed tissue in non-polycaprolactone group was not obvious, while the shape changes of printed tissue in 6 mm spacing polycaprolactone group and 10 mm spacing polycaprolactone group were obvious. After 14 days of culture, the arrangement of filamentous actin in the printed tissue in non-polycaprolactone group had no specific direction, while the arrangement of filamentous actin in the printed tissue in 6 mm spacing polycaprolactone group and 10 mm spacing polycaprolactone group had a specific direction. After 14 days of culture, The vascular lumen diameters of the printed tissue in 6 mm spacing polycaprolactone group and 10 mm spacing polycaprolactone group were (6.0±1.3) and (10.8±1.3) μm, respectively, which were significantly larger than 0 μm in non-polycaprolactone group (P<0.05), and the vascular lumen diameter of printed tissue in 10 mm spacing polycaprolactone group was significantly larger than that in 6 mm spacing polycaprolactone group (P<0.05); the total length and number of branches of blood vessel in the printed tissue in 6 mm spacing polycaprolactone group and 10 mm spacing polycaprolactone group were significantly shorter or less than those in non-polycaprolactone group (P<0.05), and the total length and number of branches of blood vessel in the printed tissue in 10 mm spacing polycaprolactone group were significantly shorter or less than those in 6 mm spacing polycaprolactone group. After 9 days of culture, the tensile forces applied in the printed tissue in 6 mm spacing polycaprolactone group and 10 mm spacing polycaprolactone group were (2 340±59) and (4 284±538) μN, respectively, which were significantly higher than 0 μN in non-polycaprolactone group (P<0.05), and the tensile force applied in the printed tissue in 10 mm spacing polycaprolactone group was significantly higher than that in 6 mm spacing polycaprolactone group (P<0.05). Conclusions: The three-dimensional printed scaffold structure can exert different tensile force in the printed tissue, and the vascular lumen diameter of the printed tissue can be regulated by adjusting the tensile force.

Prochondrogenic effect of decellularized extracellular matrix secreted from human induced pluripotent stem cell-derived chondrocytes

Cartilage is mainly composed of chondrocytes and the extracellular matrix (ECM), which exchange important biochemical and biomechanical signals necessary for differentiation and homeostasis. Human articular cartilage has a low ability for regeneration because it lacks blood vessels, nerves, and lymphatic vessels. Currently, cell therapeutics, including stem cells, provide a promising strategy for cartilage regeneration and treatment; however, there are various hurdles to overcome, such as immune rejection and teratoma formation. In this study, we assessed the applicability of the stem cell-derived chondrocyte ECM for cartilage regeneration. Human induced pluripotent stem cell (hiPSC)-derived chondrocytes (iChondrocytes) were differentiated, and decellularized ECM (dECM) was successfully isolated from cultured chondrocytes. Isolated dECM enhanced in vitro chondrogenesis of iPSCs when recellularized. Implanted dECM also restored osteochondral defects in a rat osteoarthritis model. A possible association with the glycogen synthase kinase-3 beta (GSK3β) pathway demonstrated the fate-determining importance of dECM in regulating cell differentiation. Collectively, we suggested the prochondrogenic effect of hiPSC-derived cartilage-like dECM and offered a promising approach as a non-cellular therapeutic for articular cartilage reconstruction without cell transplantation. STATEMENT OF SIGNIFICANCE: Human articular cartilage has low ability for regeneration and cell culture-based therapeutics could aid cartilage regeneration. Yet, the applicability of human induced pluripotent stem cell-derived chondrocyte (iChondrocyte) extracellular matrix (ECM) has not been elucidated. Therefore, we first differentiated iChondrocytes and isolated the secreted ECM by decellularization. Recellularization was performed to confirm the pro-chondrogenic effect of the decellularized ECM (dECM). In addition, we confirmed the possibility of cartilage repair by transplanting the dECM into the cartilage defect in osteochondral defect rat knee joint. We believe that our proof-of-concept study will serve as a basis for investigating the potential of dECM obtained from iPSC-derived differentiated cells as a non-cellular resource for tissue regeneration and other future applications.

[Clinical effects of free anterolateral thigh perforator flap pedicled with descending genicular artery in repairing wounds after lower leg limb-sparing surgery]

Objective: To explore the clinical effects of free anterolateral thigh perforator flap pedicled with descending genicular artery in repairing wounds after lower leg limb-sparing surgery. Methods: A retrospective observational study was conducted. From January 2019 to June 2021, 12 patients with wounds after lower leg limb-sparing surgery who met the inclusion criteria were admitted to Suzhou Ruihua Orthopedic Hospital, including 6 males and 6 females, aged 17 to 74 years, with original wound area ranging from 17 cm×9 cm to 40 cm×15 cm. Five patients had infection in wounds. The wounds were all repaired by free anterolateral thigh perforator flap from contralateral thigh, with area of 18 cm×10 cm to 37 cm×9 cm. The artery of flap was anastomosed with the descending genicular artery, and the wounds in donor areas were sutured directly. Seven patients were transplanted with split-thickness skin grafts from the contralateral thigh to cover the remaining wounds that can not be covered by flap and the wounds in donor areas were covered with gauze. During the operation, the types of perforating branch carried by flap and the types of arteries and veins in recipient areas were recorded. The survival and occurrence of vascular crisis of flap, the survival of skin graft, the wound healing in donor and recipient areas, and the length of hospital stay after flap transplant surgery were recorded. During follow-up, the color and texture of flap, reinfection in lower leg, and fracture healing were recorded. At the last follow-up, the limb salvage function of patients was evaluated according to the functional evaluation criteria of Chen Zhongwei's amputated limb replantation. Results: The types of perforating branches carried by flaps were as follows: 6 cases of only carrying the descending branch of the lateral circumflex femoral artery, 3 cases of only carrying the oblique branch of the lateral circumflex femoral artery, and 3 cases of carrying the descending branch of the lateral circumflex femoral artery and oblique branch of the lateral circumflex femoral artery after internal pressurization anastomosis. The types of arteries in the recipient area of flap were as follows: one case of main trunk of the descending genicular artery, 8 cases of the saphenous branch of the descending genicular artery, and 3 cases of the articular branch of the descending genicular artery. The types of veins in the recipient area of flap were as follows: 8 cases of one accompanying vein of the descending genicular artery and one branch of the great saphenous vein, and 4 cases of two branches of the great saphenous vein. All the flaps survived without vascular crisis, and all the skin grafts also survived. The wounds in the donor and recipient areas were all healed. The length of hospital stay of patient after flap transplant surgery ranged from 13 to 79 days. During the follow-up of 6 to 23 months, the color and texture of flap were both good, with no infection in lower leg wound. Internal or external fixation were removed after fracture healing in 5 patients, and bone graft internal fixation was performed in 7 patients whose fractures were not healed after surgery and all the incisions healed without infection. At the last follow-up, the limb salvage effect of patients was evaluated as followings: excellent in 7 patients, good in 4 patients, and fair in one patient. Conclusions: Free anterolateral thigh flap pedicled with descending genicular artery can effectively repair the wounds after lower leg limb-sparing surgery and control infection with short length of hospital stay, while not increasing the risk of secondary injury of distal limb vessels. Thus, it can obtain satisfactory limb salvage effect which is worthy of clinical promotion.

[Morphological study on the transverse branch of lateral femoral circumflex artery based on digital subtraction angiography]

Objective: To summarize the morphological characteristics of the transverse branch of lateral femoral circumflex artery (LFCA) using digital subtraction angiography (DSA) and explore its clinical significance. Methods: A retrospective observational study was conducted. From October 2020 to May 2021, 62 patients with soft tissue injuries in the extremities were hospitalized in Suzhou Ruihua Orthopedic Hospital, including 40 males and 22 females, aged from 20 to 72 years. DSA was performed in the lateral femoral region of patients before the anterolateral thigh flap transplantation, and in combination with imaging scale to observe and measure the general condition of the blood vessels and the occurrence (with the occurrence rate being calculated), source artery, location of the origin point, direction of course, and the location of the perforating point of the cutaneous perforator of the transverse branch of LFCA, and in addition to classify the morphological characteristics of the transverse branch. Results: DSA detection showed that the femoral artery, the deep femoral artery, and the branches of LFCA were clearly distinguishable in 62 patients. Transverse branches of LFCA were observed in 59 patients, including 52 cases with a single transverse branch, and 7 cases with double transverse branches. The occurrence rate of transverse branches was 95.2% (59/62). A total of 66 transverse branches of LFCA were observed, of which 3 originated from the deep femoral artery, and 63 originated from the LFCA. The origin point of the transverse branch was 6.5-12.7 cm away from the anterior superior iliac spine. The transverse branch which was approximately perpendicular to the long axis of the body, originated outwards, ran between the ascending branch of LFCA and the oblique branch of LFCA, and branched along the way, with the trunk running under the greater trochanter. The perforating point of the cutaneous perforator of the transverse branch was 8.0-18.0 cm away from the anterior superior iliac spine. In the classification of morphological characteristics of the transverse branch of LFCA, the most common type was the one that originated from the same trunk with other branches of LFCA, accounting for 50.0% (31/62), followed by the one that originated from the singular trunk of LFCA (12 cases) or deep femoral artery (3 cases), accounting for 24.2% (15/62); the special type accounted for 21.0% (13/62), including 7 cases of double transverse branches and 6 cases of the transverse branch originated from the same trunk with multiple other branches of LFCA; those with small/absent transverse branch only accounted for 4.8% (3/62). Among the above-mentioned common trunk relationship of two branches, those with shared trunk of ascending and transverse branches were most frequently observed, accounting for 77.4% (24/31); those with shared trunks of the transverse and oblique branches (5 cases) and the transverse and descending branches (2 cases) accounted for 22.6% (7/31) altogether. Conclusions: A high incidence rate of the transverse branch of LFCA is observed through DSA. The transverse branch originates from the lateral femoral artery approximately perpendicular to the long axis of the body, mainly from the same trunk with another main branch of LFCA, especially the ascending branch. This positioning analysis can provide an important reference for the design and resection of anterolateral femoral flaps.

[Curative effects of the superficial peroneal artery perforator flap carrying multiple perforators in repairing hand and foot wounds]

Objective: To investigate the curative effects of the superficial peroneal artery perforator flap carrying two and more homologous perforators in repairing hand and foot wounds. Methods: A retrospective observational study was conducted. From January to September 2021, 23 patients with hand and foot wounds combined with bone or tendon exposure who met the inclusion criteria were admitted to Suzhou Ruihua Orthopaedic Hospital, including 16 males and 7 females, aged 23 to 68 years. After expansion of the wound, the wound area was 3.0 cm×2.0 cm to 11.0 cm×4.0 cm. All the wounds were repaired with the superficial peroneal artery perforator flap carrying two and more homologous perforators. The area of the resected flap was 4.0 cm×2.0 cm to 12.0 cm×5.0 cm. All the wounds in donor areas were sutured directly. During the operation, the resection of the flap, the number and caliber of carried perforators, the caliber of superficial peroneal artery, the length of vascular pedicle, and the number of accompanying veins of the superficial peroneal artery were recorded. The survival of the flap, the occurrence of complications, and the wound healing in the donor area were observed after operation. The recovery of the donor and recipient areas was followed up. At the last follow-up, the comprehensive evaluation scale was used to evaluate the curative effect of flap repair, and the sensory grading scale was used to evaluate the sensory function of the recipient area. Results: Totally 24 flaps were successfully resected in surgical operations, carrying 56 superficial peroneal artery perforators in total, with the caliber of perforators of 0.20-0.70 mm. The calibers of all perforators carried by 7 flaps were smaller than 0.40 mm. Nineteen flaps carried 2 perforators each, 3 flaps carried 3 perforators each, 1 flap carried 4 perforators, and 1 flap carried 5 perforators. During the operation, the superficial peroneal artery was resected with a caliber of 0.40-1.50 mm, the vascular pedicle was 2-6 cm in length, and each superficial peroneal artery had two accompanying veins. After operation, all the flaps survived smoothly, no vascular crisis or distal necrosis occurred, and the wounds healed well in the donor area. During the follow-up of 6 to 10 months after operation, the color, texture, and elasticity of the recipient area were good. Among them, 6 recipient areas were thinned and reshaped because of bloating. There was only linear scar and no obvious scar hyperplasia or pigmentation in the donor area, without significant change in sensory or motor function. At the last follow-up, the curative effect evaluation of flap repair was excellent in 22 flaps and good in 2 flaps, and the sensory function evaluation of the recipient area was grade S3 in 1 area and grade S2 in 23 areas. Conclusions: The superficial peroneal artery perforator flap with two and more homologous perforators has sufficient and reliable blood supply and is effective in repairing hand and foot wounds. It provides an ideal solution for the clinical problem in which the original operation scheme is abandoned due to the existence of only multiple slender perforators of caliber smaller than 0.40 mm, and only a single perforator in the operative field that cannot satisfy the needs of the flap blood supply and recipient area.

Recent updates of stem cell-based erythropoiesis

Blood transfusions are now an essential part of modern medicine. Transfusable red blood cells (RBCs) are employed in various therapeutic strategies; however, the processes of blood donation, collection, and administration still involve many limitations. Notably, a lack of donors, the risk of transfusion-transmitted disease, and recent pandemics such as COVID-19 have prompted us to search for alternative therapeutics to replace this resource. Originally, RBC production was attempted via the ex vivo differentiation of stem cells. However, a more approachable and effective cell source is now required for broader applications. As a viable alternative, pluripotent stem cells have been actively used in recent research. In this review, we discuss the basic concepts related to erythropoiesis, as well as early research using hematopoietic stem cells ex vivo, and discuss the current trend of in vitro erythropoiesis using human-induced pluripotent stem cells.

Development of Spondyloarthritis After COVID-19 in HLA-B27-Positive Monozygotic Twins: Case Reports With Single Cell Transcriptome Profiling

A subset of spondyloarthritis (SpA) called 'reactive arthritis' is triggered by causal pathogens, usually bacteria related to venereal disease or gastrointestinal infection. During the outbreak of coronavirus disease 2019 (COVID-19), there have been case reports about SpA after COVID-19, but the causality is still elusive. We described cases of 23-year-old monozygotic twins both diagnosed with SpA after COVID-19. The probable linkage between SpA and COVID-19 was elaborated with our cases as well as literature reviews. Of note, shared genetic traits by monozygotic twins, particularly HLA-B27 positivity, might have contributed to their susceptibility to COVID-19-induced SpA. Moreover, single-cell transcriptome analysis revealed that the transcriptomic profile of peripheral compartment of SpA after COVID-19 was distinctive from that of typical radiographic axial SpA as shown by differential expression of ribosomal protein S26 (RPS26) and small nucleolar RNA host gene 5 (SNHG5) in nearly all subsets of peripheral blood mononuclear cells.

[Anatomical characteristics and clinical application of anterolateral thigh perforator flap pedicled with oblique branch trunk of lateral circumflex femoral artery in the muscular septum]

Objective: To explore the anatomical characteristics of the anterolateral thigh perforator flap pedicled with oblique branch trunk of lateral circumflex femoral artery in the muscular septum and the clinical effect of this flap in repairing skin and soft tissue defects in the extremities. Methods: A retrospective observational study was conducted. From December 2020 to April 2021, 59 patients with skin and soft tissue defects in the extremities admitted to the Department of Hand Surgery of Suzhou Ruihua Orthopaedic Hospital met the inclusion criteria, including 46 males and 13 females, aged 20 to 81 years. The wound area after debridement ranged from 8 cm×5 cm to 38 cm×20 cm. According to the condition of the wound, the perforators in the anterolateral femoral region on the unaffected side were located by color Doppler ultrasound. The anterolateral thigh perforator flap with the oblique branch of lateral circumflex femoral artery as the source artery was designed, and the wound was repaired by unilateral flap or series combination of bilateral flaps (with the area of unilateral flap ranging from 7 cm×5 cm to 37 cm×11 cm). The wound of the donor site was sutured directly. The following items were recorded, including the number of perforators in the anterolateral femoral region marked before operation, the course characteristics of oblique branch trunk of lateral circumflex femoral artery and its perforators, and the number, origin, and type of perforators observed during operation, the flap repair mode and the flap harvest time. After operation, the survival condition of the flap, the wound healing time in the recipient site, and the suture healing in the donor area were observed, and the recovery of the donor and recipient areas was followed up. At the last follow-up, the sensation function evaluated by sensory rating scale of British Medical Research Association and two-point discrimination of the area transplanted with flap were recorded, and the improved comprehensive curative effect evaluation scale of flap was used to evaluate the repair effect of the flap. Results: A total of 156 perforators were marked in the anterolateral femoral region before operation, and 144 perforators were observed during the operation, of which 98 came from the oblique branch of the lateral circumflex femoral artery, and the first perforator of the oblique branch was the intermuscular septal perforator. Once formed, most oblique branch trunk of lateral circumflex femoral artery in the muscular septum could be divided into the deep branch and the superficial branch at the middle and upper 1/3 junction of the line between the anterior superior iliac spine and the lateral edge of the patella, the deep branch mainly ran in the muscle of vastus intermedius and vastus lateralis, and rarely developed the skin perforators, while the superficial branch mainly ran in the muscular septum between the rectus femoris and the vastus lateralis, and grew out the perforators to the proximal skin of the anterolateral femoral region. Fifty-six patients were repaired with unilateral flap and 3 patients with bilateral flap in series combination, with the harvesting time of the unilateral flap ranged from 9 to 99 min. Three patients developed arterial crisis within 48 hours after operation and survived after timely exploration; the flap of 1 patient developed necrosis 11 days after operation and was repaired by abdominal split-thickness skin graft; the other flaps survived smoothly. The wound healing time in the recipient area was 10 to 42 days after operation, and the sutures in the donor area healed well. During the follow-up of 6 to 10 months, 8 patients underwent thinning and plastic surgery 6 months after operation because of bloating in the flap transplantation area, while the other patients had a good shape of the flap transplantation area, with no deep tissue infection such as osteomyelitis, with soft texture, good elasticity, no pain, and good blood circulation; all the donor areas were left with linear scars, normal blood circulation in the distal extremities, no limitation of knee joint motion or quadriceps muscle strength. At the last follow-up, the sensation function was restored in the flap transplantation area of the affected limb, including 14 cases of S1 grade and 45 cases of S2 grade; there was only one point of two-point discrimination; the curative effect evaluation of flap repair included excellent in 24 cases, good in 35 cases, and general in 3 cases. Conclusions: The anterolateral thigh perforator flap pedicled with oblique branch trunk of lateral circumflex femoral artery in the muscular septum has the advantages of relatively concealed donor area, large cutting width, and simple operation during surgery. It protects the donor area to the greatest extent while repairing skin and soft tissue defects in the extremities, and is a useful supplement to the classic anterolateral thigh perforator flap.

[The regularity of sensory recovery after wound repair on the wrist and back of hand with anterolateral femoral flap without nerve anastomosis]

Objective: To investigate the regularity of sensory recovery after repairing the wounds on the wrist and back of hand with anterolateral femoral flap without nerve anastomosis. Methods: A cross-sectional study was conducted. From January 2018 to December 2020, patients who underwent free anterolateral femoral flaps without nerve anastomosis to repair wounds on the wrist and back of hand and met the inclusion criteria in Changshu Hai Yu Health Centre and Suzhou Ruihua Orthopedic Hospital were included in this study. Depending on the time interval between the day of the patient's surgery and the day of the cross-sectional survey, 80 patients were divided into 6-month group (15 males and 5 females, aged 22-63 years), 12-month group (16 males and 4 females, aged 21-65 years), 18-month group (15 males and 5 females, aged 25-61 years), and 24-month group (14 males and 6 females, aged 20-65 years), with 20 patients in each group. The area of skin and soft tissue defects after debridement ranged from 6.0 cm×4.5 cm to 18.0 cm×9.0 cm. Anterolateral femoral flaps were cut with areas of 7 cm×5 cm to 20 cm×10 cm and a thickness of 1.0 to 2.5 cm. Each transplanted flap was divided into A (proximal), B/D (bilateral), C (distal), and E (central) regions. The pain sensation, touch sensation, cold sensation, warmth sensation, and two-point discrimination (2-PD) in the aforementioned five regions and the differences in the five senses of the whole flap were tested and compared. Data were statistically analyzed with one-way analysis of variance, Fisher's exact probability test, chi-square test, or McNemar test. Results: In A region of anterolateral femoral flap without nerve anastomosis, compared with those in 6-month group, the pain sensation, touch sensation, cold sensation, and warmth sensation of flap of patients in 12-month group were significantly recovered (with χ2 values of 10.10, 14.55, 12.13, and 4.29, respectively, P<0.05 or P<0.01); compared with that in 12-month group, the warmth sensation of flap of patients in 18-month group recovered significantly (χ2=5.23, P<0.05). In B region, compared with those in 6-month group, the pain sensation, touch sensation, and cold sensation of flap of patients in 12-month group recovered significantly (with χ2 values of 5.58, 3.96, and 4.29, respectively, P<0.05); compared with those in 12-month group, the pain sensation, touch sensation, cold sensation, and warmth sensation of flap of patients in 18-month group recovered significantly (with χ2 values of 5.58, 3.96, 7.03, and 12.38, respectively, P<0.05 or P<0.01). In C region, compared with that in 6-month group, the pain sensation of flap of patients in 12-month group recovered significantly (χ2=4.80, P<0.05); Compared with that in 12-month group, the warmth sensation of flap of patients in 18-month group recovered significantly (χ2=10.16, P<0.01). In D region, compared with those in 6-month group, the pain sensation, touch sensation, and cold sensation of flap of patients in 12-month group recovered significantly (with χ2 values of 5.58, 4.29, and 3.96, respectively, P<0.05); compared with those in 12-month group, the pain sensation, touch sensation, cold sensation, and warmth sensation of flap of patients in 18-month group recovered significantly (with χ2 values of 5.58, 4.29, 3.96, and 10.10, respectively, P<0.05 or P<0.01). In E region, compared with that in 6-month group, the cold sensation of flap of patients in 12-month group recovered significantly (χ2=4.80, P<0.05); compared with those in 12-month group, the pain sensation, touch sensation, and warmth sensation of flap of patients in 18-month group recovered significantly (with χ2 values of 6.47, 4.91, and 9.23, respectively, P<0.05 or P<0.01). The five senses in the 5 regions of flap of patients in 24-month group were similar to those in 18-month group (P>0.05). The recovery of 2-PD in the 5 regions of flap of patients was similar between the two adjacent groups (P>0.05). In 12-month group, the recoveries of pain sensation, touch sensation, and cold sensation of flap of patients in A region were better than those in the other 4 regions (P<0.05 or P<0.01), the recovery of warmth sensation was better than that of B region, C region, and E region (P<0.05 or P<0.01); in 18-month group, the recovery of pain sensation, touch sensation, cold sensation, and warmth sensation of flap of patients in A region of was better than those in area C region (P<0.05). Compared with those in 6-month group, the pain sensation, touch sensation, and cold sensation of the whole flap of patients in 12-month group recovered significantly (with χ2 values of 7.62, 7.03, and 5.58, respectively, P<0.05 or P<0.01). Compared with the 12-month group in which 10, 11, 10, and 4 patients had a recovery of pain, touch sensation, cold sensation, and warmth sensation in the whole flap, the 18-month group had significantly more patients with sensations recovered, which were 17, 17, 16, and 14, respectively (with χ2 values of 5.58, 4.29, 3.96, and 10.10, respectively, P<0.05 or P<0.01). The five senses of the whole flap of patients in 24-month group were similar to those in 18-month group (P>0.05). Conclusions: In the anterolateral femoral flap without nerve anastomosis for repairing wounds on the wrist and back of hand, the sensation gradually recovered from the proximal end to the distal end. The sensation of touch, pain, and cold began to recover from 6 months after operation, and entered the stable recover period at 18 months after operation. Warmth sensation began to recover from 12 months after operation, and entered the stable recovery period at 18 months after operation. The 2-PD of most flaps was still not recovered 2-year after operation.

Differential effects of periodontal microbiome on the rheumatoid factor induction during rheumatoid arthritis pathogenesis

Association between exposure to periodontal bacteria and development of autoantibodies related to rheumatoid arthritis (RA) has been widely accepted; however, direct causal relationship between periodontal bacteria and rheumatoid factor (RF) is currently not fully understood. We investigated whether periodontal bacteria could affect RF status. Patients with preclinical, new-onset, or chronic RA underwent periodontal examination, and investigation of subgingival microbiome via 16S rRNA sequencing. Degree of arthritis and RF induction was examined in collagen-induced arthritis (CIA) mice that were orally inoculated with different periodontal bacteria species. Subsequently, single-cell RNA sequencing analysis of the mouse spleen cells was performed. Patients with preclinical RA showed an increased abundance of the Porphyromonadacae family in the subgingival microbiome compared to those with new-onset or chronic RA, despite comparable periodontitis severity among them. Notably, a distinct subgingival microbial community was found between patients with high-positive RF and those with negative or low-positive RF (p=0.022). Oral infections with the periodontal pathogens P. gingivalis and Treponema denticola in CIA mice similarly enhanced arthritis score, but resulted in different levels of RF induction. Genes related to B cell receptor signaling, B cell proliferation, activation, and differentiation, and CD4⁺ T cell costimulation and cytokine production were involved in the differential induction of RF in mice exposed to different bacteria. In summary, periodontal microbiome might shape RF status by affecting the humoral immune response during RA pathogenesis.

[Comparative study of the effects between second toe tibial dorsal artery flap and second toe tibial plantar proper artery flap in repairing finger skin and soft tissue defects]

Objective: To compare the effects between second toe tibial dorsal artery flap (2-TDAF) and second toe tibial plantar proper artery flap (2-TPPAF) in repairing finger skin and soft tissue defects. Methods: A retrospective cohort study was conducted. From January 2019 to June 2020, 27 patients with skin and soft tissue defects at the fingertips with area of 1.5 cm×1.2 cm-2.6 cm×1.8 cm after debridement who met the inclusion criteria were admitted to Suzhou Ruihua Orthopaedic Hospital, including 21 males and 6 females, aged 19-59 (37±10) years. According to flap repair methods used in the defective fingers, the patients were divided into 2-TDAF group (12 cases) and 2-TPPAF group (15 cases). The area of 2-TDAF ranged from 1.5 cm×1.2 cm to 2.5 cm×1.6 cm, and the area of 2-TPPAF ranged from 1.7 cm×1.3 cm to 2.6 cm×1.8 cm. Full-thickness skin grafts from the medial side of the ipsilateral leg were grafted to the wounds in donor sites, and the wounds in donor sites of skin grafts were directly sutured. Flap arterial diameter, flap excision time, flap survival situation of patients in 2 weeks after operation, and follow-up time were recorded. At the last follow-up, the two-point discrimination distance of flap graft site, total action motion (TAM) of the finger joints, and wound healing of the flap donor site were recorded; the Vancouver scar scale (VSS) was used to score the scar in donor area of the second toe and the recipient area of fingers; the appearance and self-satisfaction subscales of the Michigan hand outcomes questionnaire (MHQ) were used to evaluate the affected finger. Data were statistically analyzed with independent sample t test or Fisher's exact probability test. Results: The flap artery diameter of patients in 2-TDAF group was 0.35-0.80 (0.56±0.14) mm and the flap cutting time was (14.0±2.7) min, which were significantly shorter than 0.80-1.35 (1.02±0.16) mm and (19.7±3.4) min in 2-TPPAF group (with t values of 7.81 and 4.79, respectively, P<0.01). The flaps of patients in the 2 groups in recipient areas survived well in 2 weeks after operation, and the wounds in donor areas of flaps of patients in the 2 groups healed well at the last follow-up. There was no statistically significant difference in the postoperative follow-up time, and two-point discrimination distance of flap graft site, TAM of the finger joints, VSS score of scar in the second toe donor site and the finger recipient site, and the appearance and self-satisfaction of MHQ scores of the affected finger at the last follow-up (P>0.05). Conclusions: Compared with 2-TPPAF, 2-TDAF has a shallower anatomical layer and shorter time for surgical flap removal, which can preserve the proper arteries and nerves at the base of the toes and reduce the damage to the donor site.

[Clinical effects of proximal ulnar artery perforator flap combined with iliac bone graft in the reconstruction of subtotal thumb or finger defects]

Objective: To explore the clinical effects of proximal ulnar artery perforator flap combined with iliac bone graft in the reconstruction of subtotal thumb or finger defects. Methods: A retrospective observational study was conducted. From August 2016 to August 2019, 7 patients with thumb or finger defects caused by mechanical damage who met the inclusion criteria were admitted to Ruihua Affiliated Hospital of Soochow University, including 6 males and 1 female, aged 46 to 58 years. Their length of fingers was repaired with iliac bone, with length of 2.0 to 3.0 cm. After the bone graft, the skin defect area of the affected finger ranged from 2.8 cm×2.2 cm to 6.0 cm×3.2 cm. Then the free proximal ulnar artery perforator flap with area of 3.0 cm×2.4 cm to 6.5 cm×3.5 cm was used to cover the wounds. The wounds in donor sites of iliac crest and flap were directly sutured. The survival of flap in one week post surgery and the donor site wound healing in 2 weeks post surgery were observed, respectively. During the follow-up, the appearance and sensory function of the affected finger, bone healing, and scar hypertrophy of wound in the donor site were observed and evaluated. At the last follow-up, the functional recovery of the affected finger was evaluated with trial standard for the evaluation of functions of the upper limbs of the Hand Surgery Society of Chinese Medical Association. Results: In one week post surgery, all the flaps survived. In 2 weeks post surgery, the iliac bone and the wounds in forearm donor site healed. During the follow-up of 5 to 13 months, the flap was good in appearance, without obvious pigmentation; the sensory recovery reached level S2 in 5 patients and S0 in 2 patients; all the grafted iliac bones were bony union without obvious resorption; the wounds in donor site healed well, with only mild scar formation. At the last follow-up, the shape of the reconstructed finger was close to the healthy finger, and the functional evaluation results were excellent in 3 cases and good in 4 cases. Conclusions: The use of proximal ulnar artery perforator flap combined with iliac bone graft to reconstruct subtotal thumb or finger can partially restore part of the appearance and function, with less damage to the donor site. It is a good choice for patients who have low expectations of appearance and function for the reconstructed finger.

Isolated Tuberculous Myositis: A Systematic Review and Multicenter Cases

Objective

To investigate the clinical features and associated underlying conditions of isolated tuberculous myositis (ITBM), a rare extrapulmonary tuberculosis (TB).

Methods

A systematic literature search and a multicenter survey were performed using a triangulation strategy. Data from the identified ITBM cases were extracted and analyzed to determine the underlying conditions, clinical presentations, treatments, and outcomes.

Results

Based on the systematic review, we identified 58 ITBM, including 9 pediatric, cases in the literature published from 1981 to 2021 25 (43.1%) immunocompromised and 33 (56.9%) non-immunocompromised patients. Immunocompromised cases had a significant shorter symptom duration (median 30.0 vs. 75.0 days) and a higher prevalence of multilocular involvement (20.8% vs. 0%). Among 24 immunocompromised adult patients, dermatomyositis/polymyositis (DM/PM; n=10, 41.7%) were the most common underlying diseases in adults with ITBM identified in the systematic review. Over the past 20 years, 11 Korean adults with ITBM were identified in the multicenter survey. Of 7 immunocompromised cases, two (28.6%) were DM/PM patients. TB death rate of immunocompromised patients was 0.0% and 5/23 (21.7%) in the pediatric and adult ITBM cases identified in the systematic review, respectively, and 3/7 (42.9%) in survey-identified ITBM cases.

Conclusion

ITBM has a unique clinical presentation including fever, tenderness, local swelling, overlying erythema, abscess formation and was associated with a grave outcome, especially in immunocompromised hosts. DM/PM was a highly prevalent underlying disease in both systematic review-identified and survey-identified immunocompromised ITBM patients.

[Clinical effects of free superficial peroneal artery perforator flaps in repairing skin and soft tissue defects of the hallux]

Objective: To explore the clinical effects of free superficial peroneal artery perforator flaps in repairing skin and soft tissue defects of the hallux. Methods: A retrospective observational study was conducted. From January 2020 to January 2021, 13 patients with skin and soft tissue defects of the hallux who met the inclusion criteria were admitted to Department of Foot and Ankle Surgery of Ruihua Affiliated Hospital of Soochow University, including 12 males and 1 female, aged 26 to 53 years. Before operation, the perforating point of the superficial peroneal artery perforator was located by color Doppler ultrasound on the calf on the same side of the affected hallux and marked on the body surface. The operation was performed under spinal anesthesia combined with continuous epidural anesthesia. The area of skin and soft tissue defect after debridement was 4.5 cm×2.5 cm to 12.0 cm×3.0 cm. According to the size and shape of the wound, the superficial peroneal artery perforator flap was designed with the line between the fibular head and the lateral malleolus tip parallel shifting 2 cm to the tibial side as the flap axis line, and the perforating point of the perforator near the midpoint of the axis line as the center. The cut area of the flap was 5.0 cm×3.0 cm to 13.0 cm×4.0 cm, and part of the deep fascia was cut when the pedicle was freed. The donor site wound was sutured directly. During the operation, the number and type of the perforator and the cutting time of the flap were recorded, and the length of the perforator pedicle and diameter of the perforator were measured. The survival of the flap, the healing time and the healing condition of the donor and recipient areas were recorded after operation. The color, texture, elasticity of the flap, standing and walking functions of patients, the recovery of the donor area, and the patients' satisfaction with the recovery of the donor and recipient areas were recorded during the follow-up. At the last follow-up, the sensation of the flap was evaluated by the British Medical Association sensory function evaluation standard, the function of the affected limb was evaluated by the American Society of Foot and Ankle Surgery scoring system, and the excellent and good rate of the function of the affected limb was calculated. Results: A total of 13 perforators of the superficial peroneal artery were detected during the operation, all of which were septocutaneous perforators, and the perforator diameter was 0.3 to 0.5 mm. The vascular pedicle length was 2 to 5 cm. Flap cutting time was 11 to 26 minutes. The flaps of 13 patients all survived completely. The wounds at the donor and recipient sites healed well 9 to 18 days after operation. During follow-up of 6 to 14 months, the flaps had good color, texture, and elasticity; 11 patients had no obvious bloated appearance, and the other 2 patients underwent flap thinning and plastic surgery in the second stage because of their bloated appearance; all the patients returned to normal walking and standing functions. There was only one linear scar left in the donor site, with no obvious scar hyperplasia or hyperpigmentation. All the patients were satisfied with the recovery of the donor and recipient areas. At the last follow-up, the sensation of the flap was evaluated as grade S3 in 2 cases, grade S2 in 9 cases, and grade S1 in 2 cases; the function of the affected limb was evaluated as excellent in 7 cases and good in 6 cases, with an excellent and good rate of 100%. Conclusions: The free superficial peroneal artery perforator flap has relatively constant vascular anatomy, which is thin and wear-resistant, with less damage to the donor site after flap excision, and can preserve the shape and function of the hallux to the greatest extent. It is an effective method for repairing skin and soft tissue defect of the hallux.

Anti-fibrotic effect of a selective estrogen receptor modulator in systemic sclerosis

Background

The rarity of systemic sclerosis (SSc) has hampered the development of therapies for this intractable autoimmune disease. Induced pluripotent stem cell (iPSC) can be differentiated into the key disease-affected cells in vitro. The generation of patient-derived iPSCs has opened up possibilities for rare disease modeling. Since these cells can recapitulate the disease phenotypes of the cell in question, they are useful high-throughput platforms for screening for drugs that can reverse these abnormal phenotypes.

Methods

SSc iPSC was generated from PBMC by Sendai virus. Human iPSC lines from SSc patients were differentiated into dermal fibroblasts and keratinocytes. The iPSC-derived differentiated cells from the SSc patients were used on high-throughput platforms to screen for FDA-approved drugs that could be effective treatments for SSc.

Results

Skin organoids were generated from these cells exhibited fibrosis that resembled SSc skin. Screening of the 770-FDA-approved drug library showed that the anti-osteoporotic drug raloxifene reduced SSc iPSC-derived fibroblast proliferation and extracellular matrix production and skin fibrosis in organoids and bleomycin-induced SSc-model mice.

Conclusions

This study reveals that a disease model of systemic sclerosis generated using iPSCs-derived skin organoid is a novel tool for in vitro and in vivo dermatologic research. Since raloxifene and bazedoxifene are well-tolerated anti-osteoporotic drugs, our findings suggest that selective estrogen receptor modulator (SERM)-class drugs could treat SSc fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02987-w.

The Role of Transforming Growth Factor Beta in Joint Homeostasis and Cartilage Regeneration

Transforming growth factor-beta (TGF-β) is an important regulator of joint homeostasis, of which dysregulation is closely associated with the development of osteoarthritis (OA). In normal conditions, its biological functions in a joint environment are joint protective, but it can be dramatically altered in different contexts, making its therapeutic application a challenge. However, with the deeper insights into the TGF-β functions, it has been proven that TGF-β augments cartilage regeneration by chondrocytes, and differentiates both the precursor cells of chondrocytes and stem cells into cartilage-generating chondrocytes. Following documentation of the therapeutic efficacy of chondrocytes augmented by TGF-β in the last decade, there is an ongoing phase III clinical trial examining the therapeutic efficacy of a mixture of allogeneic chondrocytes and TGF-β-overexpressing cells. To prepare cartilage-restoring chondrocytes from induced pluripotent stem cells (iPSCs), the stem cells are differentiated mainly using TGF-β with some other growth factors. Of note, clinical trials evaluating the therapeutic efficacy of iPSCs for OA are scheduled this year. Mesenchymal stromal stem cells (MSCs) have inherent limitations in that they differentiate into the osteochondral pathway, resulting in the production of poor-quality cartilage. Despite the established essential role of TGF-β in chondrogenic differentiation of MSCs, whether the coordinated use of TGF-β in MSC-based therapy for degenerated cartilage is effective is unknown. We herein reviewed the general characteristics and mechanism of action of TGF-β in a joint environment. Furthermore, we discussed the core interaction of TGF-β with principal cells of OA cell-based therapies, the chondrocytes, MSCs, and iPSCs. Impact Statement Transforming growth factor-beta (TGF-β) has been widely used as a core regulator to improve or formulate therapeutic regenerative cells for degenerative joints. It differentiates stem cells into chondrocytes and improves the chondrogenic potential of differentiated chondrocytes. Herein, we discussed the overall characteristics of TGF-β and reviewed the comprehension and utilization of TGF-β in cell-based therapy for degenerative joint disease.

Mitigating Effect of Estrogen in Alzheimer’s Disease-Mimicking Cerebral Organoid

Alzheimer’s disease (AD) is the most common condition in patients with dementia and affects a large population worldwide. The incidence of AD is expected to increase in future owing to the rapid expansion of the aged population globally. Researchers have shown that women are twice more likely to be affected by AD than men. This phenomenon has been attributed to the postmenopausal state, during which the level of estrogen declines significantly. Estrogen is known to alleviate neurotoxicity in the brain and protect neurons. While the effects of estrogen have been investigated in AD models, to our knowledge, they have not been investigated in a stem cell-based three-dimensional in vitro system. Here, we designed a new model for AD using induced pluripotent stem cells (iPSCs) in a three-dimensional, in vitro culture system. We used 5xFAD mice to confirm the potential of estrogen in alleviating the effects of AD pathogenesis. Next, we confirmed a similar trend in an AD model developed using iPSC-derived cerebral organoids, in which the key characteristics of AD were recapitulated. The findings emphasized the potential of estrogen as a treatment agent for AD and also showed the suitability of AD-recapitulating cerebral organoids as a reliable platform for disease modeling and drug screening.

Chronic kidney disease in Korean patients with lupus nephritis: over a 35-year period at a single center

INTRODUCTION

Chronic kidney disease (CKD) is a major risk factor for overall morbidity and mortality even in lupus nephritis (LN) patients. However, less attention has been paid to the development of CKD in patients with LN. The objective of this study was to identify predictors for CKD with 35-year experience depending on newly revised guidelines for patients with LN.

METHODS

We conducted a retrospective cohort study for 401 patients who visited Seoul St. Mary's Hospital between January 1985 and December 2019. We analyzed clinical and laboratory indices, treatment response, the final renal function, and biopsy findings. The timing and cumulative risk of developing CKD were identified by Kaplan-Meier methods. Independent risk factors for developing CKD were examined by Cox proportional hazard regression analyses.

RESULTS

The median follow-up time after the diagnosis of LN was 131 months. CKD occurred in 15.5% of patients within 10 years after the diagnosis of LN. The development of CKD was associated with delayed-onset LN, acute renal dysfunction at onset of LN, and failure to reach complete response (CR) at 6 or 12 months rather than histopathological findings or the severity of proteinuria at onset of LN. Cumulative incidence of progression to CKD was significantly higher in patients with the three predictors mentioned above.

CONCLUSION

Ten-year cumulative incidence of CKD was about 15%. Our results showed that delayed-onset LN, acute renal dysfunction at the onset of LN, and inadequate treatment response assessed at 6 or 12 months after treatment were predictors for the development of CKD in LN. Key Points • CKD is a major risk factor for overall morbidity and mortality in LN patients. • Ten-year cumulative incidence of CKD was about 15% • Delayed-onset LN, acute renal dysfunction at the onset of LN, and inadequate treatment response assessed at 6 or 12 months after treatment were predictors for the development of CKD in LN.

Lupus Heart Disease Modeling with Combination of Induced Pluripotent Stem Cell-Derived Cardiomyocytes and Lupus Patient Serum

Background and Objectives

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease mainly affecting young women of childbearing age. SLE affects the skin, joints, muscles, kidneys, lungs, and heart. Cardiovascular complications are common causes of death in patients with SLE. However, the complexity of the cardiovascular system and the rarity of SLE make it difficult to investigate these morbidities. Patient-derived induced pluripotent stem cells (iPSCs) serve as a novel tool for drug screening and pathophysiological studies in the absence of patient samples.

Methods and Results

We differentiated CMs from HC- and SLE-iPSCs using 2D culture platforms. SLE-CMs showed decreased proliferation and increased levels of fibrosis and hypertrophy marker expression; however, HC-and SLE-monolayer CMs reacted differently to SLE serum treatment. HC-iPSCs were also differentiated into CMs using 3D spheroid culture and anti-Ro autoantibody was treated along with SLE serum. 3D-HC-CMs generated more mature CMs compared to the CMs generated using 2D culture. The treatment of anti-Ro autoantibody rapidly increased the gene expression of fibrosis, hypertrophy, and apoptosis markers, and altered the calcium signaling in the CMs.

Conclusions

iPSC derived cardiomyocytes with patient-derived serum, and anti-Ro antibody treatment could serve in effective autoimmune disease modeling including SLE. We believe that the present study might briefly provide possibilities on the application of a combination of patient-derived materials and iPSCs in disease modeling of autoimmune diseases.

A clinical comparison of an endothelin receptor antagonist and phosphodiesterase type 5 inhibitors for treating digital ulcers of systemic sclerosis

OBJECTIVES

To assess the efficacy of an endothelin receptor antagonist (ERA) and phosphodiesterase type5 inhibitors (PDE5is) for treating SSc-related digital ulcers (DUs).

METHODS

This prospective, multicentre, observational cohort study recruited patients with active SSc-related DUs from 13 medical centres in South Korea. The primary outcome was time to cardinal ulcer (CU) healing. A secondary outcome was time to new DU occurrence. Patients were followed up 4, 8, 12 and 24 weeks after treatment initiation.

RESULTS

Sixty-three patients were analysed. Their mean age was 49.9 years (s.d. 11.4) and 49 were female. Twenty-eight had limited SSc. Forty-nine patients received ERA, 11 received a PDE5i (9 sildenafil, 1 udenafil and 1 tadalafil) and 3 received other medication. The hazard ratio (HR) for time to CU healing in the ERA group vs the PDE5i group was 0.75 (95% CI 0.35, 1.64; P = 0.47) in an unadjusted model and 0.80 (95% CI 0.36, 1.78; P = 0.59) in a model adjusted for age, sex, use of calcium channel blockers (CCBs), total DU number and initial CU area. The HR for new DU development in the ERA group vs the PDE5i group was 0.39 (95% CI 0.16, 0.93; P = 0.03) in an unadjusted model and 0.32 (95% CI 0.13, 0.81; P = 0.02) in an adjusted model. No patients receiving CCBs developed new DUs at 24 weeks.

CONCLUSION

Time to CU healing is comparable for ERA and PDE5i. ERAs are more effective in reducing new DU occurrence than PDE5is. CCBs may be effective as a background medication.

Renal function deterioration is an independent mortality determinant in Koreans diagnosed with lupus nephritis

OBJECTIVE

To evaluate the predictors of mortality, mortality rate, and causes of death in patients with lupus nephritis (LN) depending on final renal function.

METHODS

The cohort included 401 Korean patients diagnosed with LN between 1985 and 2019. We retrospectively analyzed the clinical and laboratory indices, treatment response, and the final renal function. The final renal function was defined by the last stable level of eGFR measured in an out-patient department more than 3 times before death occurred and was categorized into five groups depending on CKD stage.

RESULTS

The median follow-up time after the diagnosis of LN was 131 months. No difference in baseline demographic characteristics and laboratory findings was found except for the proportion of Hb less than 10 mg/dl and baseline eGFR (p = 0.011 and 0.037). We found no significant differences in therapeutic parameters, but all the response parameters including treatment response at 6 months (p = 0.004) and 12 months (p = 0.004), time to remission (p < 0.001), final renal response (p < 0.001), and the final renal function (p < 0.001) differed significantly between the two groups. In multivariate Cox proportional hazards analysis, the final renal function was an independent risk factor predicting mortality. The main causes of death were infection and SLE flare. Contrary to existing knowledge, SLE flare also triggered mortality in a few patients with LN progressed to end-stage renal disease (ESRD). Only two cases of mortality occurred in the kidney transplantation (KT) group (n = 25) with a median follow-up period of 224 months. The overall mortality rates calculated using the Kaplan-Meier method were 6.8%, 10.3%, 19.7%, and 28.0% at 5, 10, 20, and 30 years, respectively.

CONCLUSION

Renal function deterioration was an independent determinant of mortality in Korean patients with LN. SLE flare also caused mortality in patients with LN who required maintenance dialysis, suggesting the benefit of KT on lupus activity and survival.

Application of Induced Pluripotent Stem Cells for Disease Modeling and 3D Model Construction: Focus on Osteoarthritis

Since their discovery in 2006, induced pluripotent stem cells (iPSCs) have shown promising potential, specifically because of their accessibility and plasticity. Hence, the clinical applicability of iPSCs was investigated in various fields of research. However, only a few iPSC studies pertaining to osteoarthritis (OA) have been performed so far, despite the high prevalence rate of degenerative joint disease. In this review, we discuss some of the most recent applications of iPSCs in disease modeling and the construction of 3D models in various fields, specifically focusing on osteoarthritis and OA-related conditions. Notably, we comprehensively reviewed the successful results of iPSC-derived disease models in recapitulating OA phenotypes for both OA and early-onset OA to encompass their broad etiology. Moreover, the latest publications with protocols that have used iPSCs to construct 3D models in recapitulating various conditions, particularly the OA environment, were further discussed. With the overall optimistic results seen in both fields, iPSCs are expected to be more widely used for OA disease modeling and 3D model construction, which could further expand OA drug screening, risk assessment, and therapeutic capabilities.

Human kidney organoids model the tacrolimus nephrotoxicity and elucidate the role of autophagy

BACKGROUND/AIMS

Tacrolimus has been used as an immunosuppressive agent in organ transplantation. Despite the therapeutic benefits, tacrolimus's use is limited due to its nephrotoxicity. To reduce tacrolimus nephrotoxicity, effective humanized experimental models may be helpful. Here, we modeled tacrolimus nephrotoxicity using kidney organoids derived from human inducible pluripotent stem cells (iPSCs) in vitro.

METHODS

Kidney organoids were differentiated from the CMC11 iPSC cell line, re-seeded in 96-well plates, and treated with tacrolimus at doses of 0, 30, or 60 μM for 24 hours. This in vitro model was compared to a mouse model of tacrolimus nephrotoxicity and the associated mechanisms were investigated.

RESULTS

The size of the kidney organoids and cell viability decreased in dose-dependent manners after treatment with tacrolimus. The number of tubular cells decreased with a loss of polarity, similar to the effects seen in mouse tacrolimus nephrotoxicity. Ultrastructural analysis showed numerous vacuoles in the proximal tubular cells of the kidney organoids treated with tacrolimus. Tacrolimus treatment induced oxidative stress and mitochondrial dysfunction, and autophagic activity was enhanced in the kidney organoids. Rapamycin, an autophagy inducer, accelerated cell death in the kidney organoid model of tacrolimus nephrotoxicity, which was attenuated by treatment with 3-methyladenine, an autophagy inhibitor. These findings indicate that the augmentation of autophagy by rapamycin treatment accelerated tacrolimus nephrotoxicity.

CONCLUSION

Our data suggest that human kidney organoids are an effective in vitro model of tacrolimus nephrotoxicity and that autophagy plays a critical role in tacrolimus nephrotoxicity.

Review of the Current Trends in Clinical Trials Involving Induced Pluripotent Stem Cells

In 2006, the induced pluripotent stem cell (iPSC) was presented to the world, paving the way for the development of a magnitude of novel therapeutic alternatives, addressing a diverse range of diseases. However, despite the immense cell therapy potential, relatively few clinical trials evaluating iPSC-technology have actually translated into interventional, clinically applied treatment regimens. Herein, our aim was to determine trends in globally conducted clinical trials involving iPSCs. Data were derived both from well-known registries recording clinical trials from across the globe, and databases from individual countries. Comparisons were firstly drawn between observational and interventional studies before the latter was further analyzed in terms of therapeutic and nontherapeutic trials. Our main observations included global distribution, purpose, target size, and types of disorder relevant to evaluated trials. In terms of nontherapeutic trials, the USA conducted the majority, a large average number of participants-187-was included in the trials, and studies on circulatory system disorders comprised a slightly higher proportion of total studies. Conversely, Japan was the frontrunner in terms of conducting therapeutic trials, and the average number of participants was much lower, at roughly 29. Disorders of the circulatory, as well as nervous and visual systems, were all studied in equal measure. This review highlights the impact that iPSC-based cell therapies can have, should development thereof gain more traction. We lastly considered a few companies that are actively utilizing iPSCs in the development of therapies for various diseases, for whom the global trends in clinical trials could become increasingly important.

Promoting Long-Term Cultivation of Motor Neurons for 3D Neuromuscular Junction Formation of 3D In Vitro Using Central-Nervous-Tissue-Derived Bioink

3D cell printing technology is in the spotlight for producing 3D tissue or organ constructs useful for various medical applications. In printing of neuromuscular tissue, a bioink satisfying all the requirements is a challenging issue. Gel integrity and motor neuron activity are two major characters because a harmonious combination of extracellular materials essential to motor neuron activity consists of disadvantages in mechanical properties. Here, a method for fabrication of 3D neuromuscular tissue is presented using a porcine central nervous system tissue decellularized extracellular matrix (CNSdECM) bioink. CNSdECM retains CNS tissue-specific extracellular molecules, provides rheological properties crucial for extrusion-based 3D cell printing, and reveals positive effects on the growth and maturity of axons of motor neurons compared with Matrigel. It also allows long-term cultivation of human-induced-pluripotent-stem-cell-derived lower motor neurons and sufficiently supports their cellular behavior to carry motor signals to muscle fibers. CNSdECM bioink holds great promise for producing a tissue-engineered motor system using 3D cell printing.

Re-evaluation of the prognostic significance of oropharyngeal dysphagia in idiopathic inflammatory myopathies

OBJECTIVE

To investigate the prognostic significance of videofluorographic swallowing study (VFSS)-confirmed oropharyngeal dysphagia in idiopathic inflammatory myopathies (IIMs).

METHOD

We reviewed the medical records of patients who were diagnosed with IIM between 2009 and 2020 at Seoul St Mary's Hospital. All oropharyngeal dysphagia cases were limited to VFSS-confirmed dysphagia found during the initial diagnostic work-up for IIM. We described the findings on VFSS and the course of the dysphagic symptoms. Logistic regression and survival analyses were performed to evaluate the risk of pneumonia and mortality, respectively.

RESULTS

We found 88 patients with IIM who met the criteria. Among them, 17 patients (19%) had oropharyngeal dysphagia. Except for two cases lost to follow-up and one deceased case, all of the patients with dysphagia (14 of 14) had swallowing function restored within 6 months. The risk of pneumonia within 3 months from the diagnosis of IIM was significant [odds ratio = 4.49, 95% confidence interval (CI) 1.07-18.88]. The median follow-up duration was 34 and 27 months for the groups without and with dysphagia, respectively. The survival analysis failed to demonstrate that the presence of oropharyngeal dysphagia increased the risk of death (hazard ratio = 0.77, 95% CI: 0.085-7.00).

CONCLUSIONS

Oropharyngeal dysphagia found at the initial diagnosis of IIM improved within 3-6 months in nearly all cases. Furthermore, IIM patients who had oropharyngeal dysphagia at the initial diagnosis of IIM were not likely to have shorter survival, even if the risk of pneumonia was increased in the short term.

Perichondrium-inspired permeable nanofibrous tube well promoting differentiation of hiPSC-derived pellet toward hyaline-like cartilage pellet

The pellet formation has been regarded as a golden standard forin vitrochondrogenic differentiation. However, a spatially inhomogeneous chondrogenic microenvironment around a pellet resulted from the use of a traditional impermeable narrow tube, such as the conical tube, undermines the differentiation performance and therapeutic potential of differentiated cartilage pellet in defective articular cartilage treatment. To address this drawback, a perichondrium-inspired permeable nanofibrous tube (PINaT) well with a nanofibrous wall permeable to gas and soluble molecules is proposed. The PINaT well was fabricated with a micro deep drawing process where a flat thin nanofibrous membrane was transformed to a 3.5 mm deep tube well with a ∼50µm thick nanofibrous wall. Similar toin vivoperichondrium, the PINaT well was found to allow oxygen and growth factor diffusion required for chondrogenic differentiation across the entire nanofibrous wall. Analyses of gene expressions (COL2A1, COL10A1, ACAN, and SOX9), proteins (type II and X collagen), and glycosaminoglycans contents were conducted to assess the differentiation performance and clinical efficacy of differentiated cartilage pellet. The regulated spatially homogeneous chondrogenic microenvironment around the human induced pluripotent stem cell-derived pellet (3 × 10⁵cells per pellet) in the PINaT well remarkably improved the quality of the differentiated pellet toward a more hyaline-like cartilage pellet. Furthermore, an accelerated chondrogenic differentiation process of the pellet produced by the PINaT well was achieved for 14 days, demonstrating a hyaline cartilage-specific marker similar to the control pellet differentiated for 20 days. Finally, the enhanced clinical efficacy of the hyaline-like cartilage pellet was confirmed using an osteochondral defect rat model, with the repaired tissue resembling hyaline cartilage rather than fibrous cartilage after 8 weeks of regeneration.

Restoration of Osteogenesis by CRISPR/Cas9 Genome Editing of the Mutated COL1A1 Gene in Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) is a genetic disease characterized by bone fragility and repeated fractures. The bone fragility associated with OI is caused by a defect in collagen formation due to mutation of COL1A1 or COL1A2. Current strategies for treating OI are not curative. In this study, we generated induced pluripotent stem cells (iPSCs) from OI patient-derived blood cells harboring a mutation in the COL1A1 gene. Osteoblast (OB) differentiated from OI-iPSCs showed abnormally decreased levels of type I collagen and osteogenic differentiation ability. Gene correction of the COL1A1 gene using CRISPR/Cas9 recovered the decreased type I collagen expression in OBs differentiated from OI-iPSCs. The osteogenic potential of OI-iPSCs was also recovered by the gene correction. This study suggests a new possibility of treatment and in vitro disease modeling using patient-derived iPSCs and gene editing with CRISPR/Cas9.

Pathogenic Role of Circulating Citrullinated Antigens and Anti-Cyclic Monoclonal Citrullinated Peptide Antibodies in Rheumatoid Arthritis

We examined whether it is possible to directly detect citrullinated antigens in the serum of rheumatoid arthritis (RA) patients using a monoclonal antibody (mAb) designed to be specific for citrullinated peptides. In order to confirm the potential of the mAb as a direct arthritis-inducing substance through experimental model of RA, a monoclonal antibody (mAb) 12G1 was generated using by immunization of mice with a challenging cyclic citrullinated peptide. Immunohistochemical analysis of RA-affected synovial tissue showed that our mAb 12G1 could indeed detect citrullinated proteins in target tissues. Subsequently, serum levels of citrullinated type II collagen and filaggrin were measured in healthy volunteers, patients with RA, ankylosing spondylitis (AS), and systemic lupus erythematosus (SLE) using a 12G1-based sandwich ELISA. This showed that citrullinated filaggrin showed 78.9% sensitivity and 85.9% specificity for RA diagnosis with a cutoff optical density (OD) value of 1.013, comparable with the results from a second-generation anti-citrullinated protein antibody (ACPA) test. Circulating citrullinated collagen and filaggrin were detected even in sera of RA patients who were negative for both rheumatoid factor (RF) and ACPA. ELISA results also showed that RF and ACPA titers showed significantly positive correlation with both citrullinated collagen and filaggrin OD values in sera of RA patients. 12G1 challenging aggravated the severity of murine arthritis. In summary, mAb 12G1 can directly detect citrullinated proteins in RA target tissue and in sera of RA patients and 12G1 showed direct arthritogenic potential in vivo. This, 12G1 might be useful for diagnosis of RA including seronegative RA and may help to elucidate the pathophysiological role of citrullination in RA.

[Clinical effects of anterolateral thigh perforator flap with sensory nerves in repairing the plantar skin and soft tissue defects]

Objective: To explore the clinical effects of anterolateral thigh perforator flap with sensory nerves in repairing the plantar skin and soft tissue defects. Methods: From January 2016 to March 2019, 13 male patients with plantar skin and soft tissue defects were admitted to the Department of Foot and Ankle Surgery of Ruihua Affiliated Hospital of Soochow University, aged 27 to 73 years. The retrospective cohort study was conducted. The wounds of 4 patients underwent 2 times of debridement. The wounds of 9 patients underwent 1 time of debridement and 1 or 2 time(s) of vacuum sealing drainage. Then all the wounds of patients were repaired with flaps when the wounds were clean and dry with no purulent exudation and were negative in secretion culture. The wound areas of this group of patients after wound debridement were 13.0 cm×5.5 cm to 36.0 cm×10.5 cm, and the wounds were repaired with anterolateral thigh perforator flaps with sensory nerves with area of 14 cm×6 cm to 37 cm×11 cm. The wound of 1 patient was repaired with a bilobed flap. The oblique or descending branch of the lateral circumflex femoral artery and its accompanying vein in the flap were anastomosed with the posterior tibial artery and its accompanying vein or the medial plantar artery and its accompanying vein in recipient sites. The lateral femoral cutaneous nerve in the flap was anastomosed with the recipient saphenous nerve or medial plantar cutaneous nerve. The donor sites were directly sutured. The survival of flaps and the healing of wounds in the donor and recipient areas were recorded, and the ulcers of the plantar repaired flap were followed up for 3 months after operation. The sensory function of the flap was evaluated by the sensory evaluation standard of British Medical Research Council (BMRC), and the ankle and foot function score system of American Orthopedic Foot and Ankle Society (AOFAS) was used for comprehensive functional evaluation at the last follow-up. Results: All the 14 flaps in 13 cases survived, and venous crisis occurred in two cases and the flaps survived smoothly after the venous re-anastomosis. One patient developed deep tissue infection after being discharged and was healed after secondary debridement. The donor and recipient areas of the remaining patients healed well. The patients were followed up for 6 to 18 months, the shape of flaps was slightly bloated in 5 patients, and the shape and texture of flaps in the other 8 patients were good. Six patients had ulcers in flaps at 3 months of follow-up after operation, which were healed after stopping weight-bearing activities. At the last follow-up, little linear scar hyperplasia could be seen in the donor site of patients; the BMRC sensory function evaluation results were S₁ grade in 4 cases, S₂ grade in 7 cases, and S₃ grade in 2 cases; the AOFAS scores were excellent in 3 cases, good in 7 cases, fair in 2 cases, and poor in 1 case. Conclusions: The anterolateral thigh perforator flaps with sensory nerves can repair the plantar skin and soft tissue defects with the donor sites directly sutured and good shape of flaps, which provide a good treatment method for the recovery of plantar proprioceptive sensation and weight-bearing function.

Influence of proton pump inhibitor or rebamipide use on gut microbiota of rheumatoid arthritis patients

OBJECTIVE

Patients with RA commonly use gastrointestinal (GI) protective drugs for treatment and prevention of drug-associated GI injuries. However, how these drugs affect the gut microbiota in RA patients remains unknown. The objective of this study was to examine the gut microbiota of RA patients according to use of GI protective drugs such as proton pump inhibitors (PPIs), histamine 2-receptor antagonists and rebamipide.

METHODS

Faecal samples were obtained from 15 healthy controls and 32 RA patients who were receiving PPI, histamine 2-receptor antagonist or rebamipide. Bacterial DNA was extracted from the faecal samples and 16S rRNA sequencing was performed. Microbial composition and function were analysed using Quantitative Insights Into Microbial Ecology and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States.

RESULTS

RA patients exhibited reduced diversity and altered composition of the gut microbiota compared with healthy controls. The gut microbiota of RA patients receiving acid-suppressing drugs, particularly PPIs, was distinct from that of RA patients receiving rebamipide (PPI vs rebamipide, P = 0.005). Streptococcus was enriched in RA patients receiving PPI, while Clostridium bolteae was enriched in RA patients receiving rebamipide. The gut microbiota of PPI users was abundant with microbial functional pathway involved in the production of virulence factors. This featured microbial function was positively correlated with relative abundance of Streptococcus, the differentially abundant taxa of PPI users.

CONCLUSION

The gut microbiota of RA patients receiving PPIs was distinguishable from that of those receiving rebamipide. The enriched virulent function in the gut microbiota of PPI users suggests that inappropriate PPI use may be harmful in RA patients.