Autophagy in an extruded disc compared to the remaining disc after lumbar disc herniation in the same patient

Three-Dimensional Bioprinting for Intervertebral Disc Regeneration

The rising demand for organ transplants and the need for precise tissue models have positioned the in vitro biomanufacturing of tissues and organs as a pivotal area in regenerative treatment. Considerable development has been achieved in growing tissue-engineered intervertebral disc (IVD) scaffolds, designed to meet stringent mechanical and biological compatibility criteria. Among the cutting-edge approaches, 3D bioprinting stands out due to its unparalleled capacity to organize biomaterials, bioactive molecules, and living cells with high precision. Despite these advancements, polymer-based scaffolds still encounter limitations in replicating the extracellular matrix (ECM)-like environment, which is fundamental for optimal cellular activities. To overcome these challenges, integrating polymers with hydrogels has been recommended as a promising solution. This combination enables the advancement of porous scaffolds that nurture cell adhesion, proliferation, as well as differentiation. Additionally, bioinks derived from the decellularized extracellular matrix (dECM) have exhibited potential in replicating biologically relevant microenvironments, enhancing cell viability, differentiation, and motility. Hydrogels, whether derived from natural sources involving collagen and alginate or synthesized chemically, are highly valued for their ECM-like properties and superior biocompatibility. This review will explore recent advancements in techniques and technologies for IVD regeneration. Emphasis will be placed on identifying research gaps and proposing strategies to bridge them, with the goal of accelerating the translation of IVDs into clinical applications.

FOXG1 interaction with SATB2 promotes autophagy to alleviate neuroinflammation and mechanical abnormal pain in rats with lumbar disc herniation

BACKGROUND

Most patients with lumbar disc herniation can be relieved or cured by surgical or non-surgical treatment; however, postoperative persistent radiculopathy is common. This study demonstrates the regulation of autophagy by the FOXG1/SATB2 axis in lumbar disc herniation (LDH).

METHODS

Rat dorsal root neurons were induced with TNF-α in vitro. Sprague Dawley (SD) rats were used to construct the LDH rat model, which was treated with L. paracasei S16 or oe-FOXG1. Paw withdrawal threshold or latency assay (PWT/L) was performed. Peripheral blood samples were collected and analysed using ELISA and miRNAseq. RT-qPCR was used to analyse the expression of FOXG1, LC3B, Beclin1, p62, and SATB2. TUNEL staining and flow cytometry were used to analyse apoptosis. The expression of Cyclin D1, PCNA, Ki67, FOXG1, SATB2, and autophagy proteins was measured using western blotting.

RESULTS

TNF-α induced low expression of FOXG1 and SATB2 in dorsal root ganglion (DRG) neurons of rats. TNF-α induced an increase in p62 protein and a decrease in LC3II/I and Beclin-1 proteins in neurons, which were blocked by oe-FOXG1. oe-FOXG1 suppressed inflammation and apoptosis in TNF-α-induced DRG neurons and LDH rats and promoted the expression of Cyclin D1, PCNA, and Ki67. Many miRNAs were increased in the peripheral blood of LDH rats, but decreased after L. paracasei S16 intervention. L. paracasei S16 affects miR-31a-5p and SATB2 expression. Dual luciferase reporter gene assay confirmed that miR-31a-5p bound to SATB2. Co-IP analysis confirmed the interaction between FOXG1 and SATB2. Silencing of SATB2 inhibited the beneficial effects of oe-FOXG1 in TNF-α-induced dorsal root ganglion neurons. Animal experiments further demonstrated that oe-FOXG1 improved LDH disease characteristics by downregulating PWT, PWL, inflammation, and apoptosis levels and upregulating SATB2-autophagy levels.

CONCLUSIONS

MiR-31a-5p/SATB2 is involved in the treatment of L. paracasei S16 in LDH rats. Overexpression of FOXG1 promotes autophagy through SATB2 to improve LDH levels This provides a new approach for the treatment of LDH.

Significance of Necroptosis in Cartilage Degeneration

Cartilage, a critical tissue for joint function, often degenerates due to osteoarthritis (OA), rheumatoid arthritis (RA), and trauma. Recent research underscores necroptosis, a regulated form of necrosis, as a key player in cartilage degradation. Unlike apoptosis, necroptosis triggers robust inflammatory responses, exacerbating tissue damage. Key mediators such as receptor-interacting serine/threonine-protein kinase-1 (RIPK1), receptor-interacting serine/threonine-protein kinase-3(RIPK3), and mixed lineage kinase domain-like (MLKL) are pivotal in this process. Studies reveal necroptosis contributes significantly to OA and RA pathophysiology, where elevated RIPK3 and associated proteins drive cartilage degradation. Targeting necroptotic pathways shows promise; inhibitors like Necrostatin-1 (Nec-1), GSK'872, and Necrosulfonamide (NSA) reduce necroptotic cell death, offering potential therapeutic avenues. Additionally, autophagy's role in mitigating necroptosis-induced damage highlights the need for comprehensive strategies addressing multiple pathways. Despite these insights, further research is essential to fully understand necroptosis' mechanisms and develop effective treatments. This review synthesizes current knowledge on necroptosis in cartilage degeneration, aiming to inform novel therapeutic approaches for OA, RA, and trauma.

Case report: Spontaneous regression of extruded lumbar disc herniation with acupuncture therapy

Most patients with lumbar disc herniation (LDH) derive benefit from conservative treatment, prompting growing global interest in non-surgical approaches. Despite being recognized as one of the effective conservative therapies, there is currently limited evidence to support the sole efficacy of acupuncture in treating patients with acute extruded LDH. Here we report the case of a 52-year-old male who presented with low back pain and persistent radiating lower limb pain and numbness. Physical examination and magnetic resonance imaging (MRI) revealed an extruded LDH at the L5/S1 level, compressing the nerve root and causing severe radiculopathy symptoms. After 23 days of continuous inpatient acupuncture treatment, followed by 5 intermittent outpatient acupuncture treatment over 2 months, patient's pain and numbness was significantly alleviated and a followed-up MRI showed a remarkable regression of the extruded disc fragment. In this case, acupuncture as a monotherapy is safe and effective, but more conclusive evidence is needed.

Comparative Analysis of Autophagy and Apoptosis in Disc Degeneration: Understanding the Dynamics of Temporary-Compression-Induced Early Autophagy and Sustained-Compression-Triggered Apoptosis

The purpose of this study was to investigate the initiation of autophagy activation and apoptosis in nucleus pulposus cells under temporary compression (TC) and sustained compression (SC) to identify ideal research approaches in intervertebral disc degeneration. Various techniques were used: radiography (X-ray), magnetic resonance imaging (MRI), transmission electron microscope (TEM), H&E staining, Masson's trichrome staining, immunohistochemistry (IHC) (LC3, beclin-1, and cleaved caspase-3), and real-time polymerase chain reaction (RT-qPCR) for autophagy-related (beclin-1, LC3, and P62) and apoptosis-related (caspase-3 and PARP) gene expression analysis. X-ray and MRI revealed varying degrees of disc degeneration, ranging from moderate to severe in both groups. The severity was directly linked to compression duration, with SC resulting in notably severe central NP cell degeneration. Surprisingly, TC also caused similar, though less severe, degeneration. Elevated expression of LC3 and beclin-1 was identified after 6 weeks, but it notably declined after 12 weeks. Central NP cells in both groups exhibited increased expression of cleaved caspase-3 that was positively correlated with the duration of SC. TC showed fewer apoptotic markers compared to SC. LC3, beclin-1, and P62 mRNA expression peaked after 6 weeks and declined after 12 weeks in both groups. Cleaved caspase-3 and PARP expression peaked in SC, positively correlating with longer compression duration, while TC showed lower levels of apoptosis gene expression. Furthermore, TEM results revealed different events of the autophagic degradation process after 2 weeks of compression. TCmay be ideal for studying early triggered autophagy-mediated degeneration, while SC may be ideal for studying late or slower-triggered apoptosis-mediated degeneration.

Non-surgical Restoration of L3/L4 Disc Herniation

We report the case of a 52-year-old Asian man presenting with severe lower back pain and bilateral radiculopathy due to acute L3/L4 disc extrusion, causing severe spinal canal stenosis and bilateral L4 nerve root compression. Following a ten-week conservative management plan consisting of high-velocity, low-amplitude spinal manipulation, adjunctive therapies, and home exercise, the patient experienced significant pain relief, functional improvement, and near resolution of deficits. A six-month follow-up MRI revealed the resolution of the L3/L4 disc extrusion, and the patient remained asymptomatic at nine months. This case highlights the potential for spontaneous resorption of a lumbar disc herniation and symptomatic improvement with conservative management, including chiropractic treatment. A favorable natural course of a disc herniation should be considered when deciding between early surgical intervention and conservative management, warranting further prospective studies to evaluate the effectiveness of chiropractic treatment and the role of spontaneous regression in symptomatic lumbar disc herniation.