Effect of PENN-DIABEX, a novel polyherbal formulation, in high fat diet streptozotocin-induced diabetic rats

Diabetes, a chronic metabolic disorder affecting millions worldwide, presents a significant health challenge characterized by impaired glucose regulation and potential complications. This study examines the antidiabetic effects of a polyherbal formulation (PENN-DIABEX) prepared from five different medicinal plant extracts. The objective is to ascertain its efficacy in managing streptozotocin (STZ) induced diabetes in rats. To accomplish this, six distinct groups of rats were involved five with induced diabetes and one serving as a normal control. Among the diabetic groups, one received no treatment, functioning as the diabetic control group. The remaining three groups were administered PHF in three different doses while the 6th group was given metformin. On the last day of the experiment, all rats were sacrificed, and blood samples were taken in collecting tubes to analyze blood biochemical parameters. Additionally, tissue samples from the liver, kidney, and pancreas were preserved in formalin solution for subsequent histopathological activity. The results of the study revealed that treatment with PHF in diabetic rats led to a significant (P < 0.01) improvement in fasting blood glucose levels (FBG), glycated hemoglobin (HbA1c), and various biochemical markers including LFTs, RFTs, and lipid profiling. Furthermore, the histology of the liver, kidney, and pancreas indicated that the formulation did not induce any metabolic toxicity. Comparative analysis of the antidiabetic effects of PHF with those of metformin, revealed that the PHF showed better results than the standard drug. This suggests its potential utilization as a safer and alternative approach in the treatment of diabetes.

Proximal humerus fractures: deltopectoral open reduction and internal fixation vs deltosplit minimally invasive plate osteosynthesis: which surgical approach provides superior results?

Purpose

To compare the two main surgical approaches to address proximal humerus fractures (PHFs) stratified for Neer fracture types, to demonstrate which approach gives the best result for each fracture type.

Methods

A literature search was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines in PubMed, Web of Science, and Cochrane databases up to 4 January 2022. Inclusion criteria were studies comparing open reduction and internal fixation (ORIF) with deltopectoral (DP) approach and minimally invasive plate osteosynthesis (MIPO) with deltosplit (DS) approach of PHFs. Patient's demographic data, fracture type, Constant-Murley Score (CMS), operation time, blood loss, length of hospital stay, complications, fluoroscopy time, and radiological outcomes were extracted. Results were stratified for each type of Neer fracture.

Results

Eleven studies (798 patients) were included in the meta-analysis. No functional difference was found in the CMS between the two groups for each type of Neer (P = n.s.): for PHFs Neer II, the mean CMS was 72.5 (s.e. 5.9) points in the ORIF group and 79.6 (s.e. 2.5) points in the MIPO group; for Neer III, 77.8 (s.e. 2.0) in the ORIF and 76.4 (se 3.0) in the MIPO; and for Neer IV, 70.6 (s.e. 2.7) in the ORIF and 60.9 (s.e. 6.3) in the MIPO. The operation time in the MIPO group was significantly lower than in the ORIF group for both Neer II (P = 0.0461) and Neer III (P = 0.0037) fractures.

Conclusion

The MIPO with DS approach demonstrated no significant differences in the results to the ORIF with DP approach for the different Neer fractures in terms of functional results, with a similar outcome, especially for the Neer II and III fracture types. The MIPO technique proved to be as safe and effective as the ORIF approach.

Short-term clinical and radiographic outcomes in patients treated with a modern intramedullary nailing system for 2-part proximal humerus fractures

OBJECTIVES

The optimal surgical treatment of displaced proximal humerus fractures (PHFs) remains controversial. There are advocates for both open reduction and internal fixation with plate and screws (ORIF) and intramedullary nailing (IMN). The purpose this study was to evaluate the early-term clinical and radiographic outcomes of IMN for isolated, displaced 2-part surgical neck PHFs using a modern, straight nail system and to determine the effect of preoperative patient and fracture characteristics on outcome.

METHODS

This was a case series of 23 patients with displaced 2-part surgical neck PHFs who were treated with ORIF using a straight IMN with minimum follow-up of 1 year (mean 2.5 years [range, 1.1-4.6]). Patients were identified retrospectively and contacted for measurement of active range of motion (AROM) and patient reported outcome measures (PROMs) including the American Shoulder and Elbow Surgeons (ASES) score, Oxford Shoulder Score (OSS), and Single Assessment Numeric Evaluation (SANE), EuroQol-5D (EQ-5D), and Visual Analog Scale Pain score (VAS Pain). Plain radiographs were evaluated to assess the quality of the reduction and failure of fixation. Complications and reoperations were identified.

RESULTS

Reduction was anatomic in 12 (52%) patients, acceptable in 9 (39%), and 2 (9%) were malreduced. There were no differences in reduction quality based on sex (p = 0.37), age at surgery (p = 0.68), calcar comminution (p = 0.68), number of screws in the head (p = 0.99), or medial hinge disruption (p = 0.06). At final follow-up, the mean ASES score was 92 ± 10, OSS was 45 ± 4, SANE was 93 ± 7, EQ-5D of 0.85 ± 0.17, and VAS Pain was 0 ± 1. The mean active forward flexion was 143° ± 16°, active external rotation was 68° ± 20°, and internal rotation was T11 ± 4 vertebrae. Two (9%) patients underwent reoperation and 2 (9%) patients experienced clinical failure not requiring reoperation.

CONCLUSIONS

Straight IMN is a reliable treatment for displaced 2-part surgical neck PHFs with excellent radiographic and clinical outcomes in early follow-up. The implant facilitated anatomic or acceptable alignment of the fracture in the vast majority of patients.

A Comparison of Complications and Survivorship after Reverse Total Shoulder Arthroplasty for Proximal Humerus Fracture compared with Cuff Tear Arthropathy

Objectives

Traditionally used to treat rotator cuff tear arthropathy (CTA), reverse total shoulder arthroplasty (RTSA) is becoming increasingly utilized for the treatment of proximal humeral fractures (PHF). The purpose of this study was to use a matched cohort analysis to assess differences in 90-day complications as well as 2-year and 5-year implant survival between patients undergoing RTSA for CTA and patients undergoing RTSA for PHF.

Methods

Patients with at least a 5-year follow-up who underwent primary RTSA for either PHF or CTA were identified in a national database (PearlDiver Technologies) using current procedural terminology (CPT) and international classification of diseases (ICD) 9 and 10 codes. Patients with a surgical indication of PHF were matched with patients with a surgical indication of CTA based on age, sex, Charlson Comorbidity Index, smoking status, and obesity (body mass index (BMI)>30). All-cause revision at the 2-year and 5-year postoperative time intervals were assessed. Reimbursements for the surgical care episode up to the 30-day, 90-day, and 1-year postoperative intervals were also assessed. Bivariate analysis was performed with a significance set at P<0.05.

Results

In total, 802 PHF patients were matched with 802 CTA patients. Compared to CTA patients, PHF patients undergoing RTSA were significantly at increased risk of atrial fibrillation, anemia, and heart failure within 90 days of surgery. Notably, there was no significant difference in all-cause revision surgery at 2-year and 5-year postoperative intervals or hospital reimbursements at the 30-day, 90-day, and 1-year postoperative intervals.

Conclusion

Preoperative indication appears to be an important driver of healthcare utilization for RTSA, as PHF patients undergoing RTSA have a higher risk of short-term postoperative complications compared to CTA patients. However, there is no difference in hospital reimbursement for the two indications of RTSA, suggesting that current payment modalities may not appropriately adjust for risk based on the surgical indication.

Single domain antibodies targeting pathological tau protein: Influence of four IgG subclasses on efficacy and toxicity

BACKGROUND

Eleven tau immunoglobulin G (IgG) antibodies have entered clinical trials to treat tauopathies, including Alzheimer's disease, but it is unclear which IgG subclass/subtype has the ideal efficacy and safety profile. Only two subtypes, with or without effector function, have been examined in the clinic and not for the same tau antibody. The few preclinical studies on this topic have only compared two subtypes of one antibody each and have yielded conflicting results.

METHODS

We selected two single domain antibodies (sdAbs) derived from a llama immunized with tau proteins and utilized them to generate an array of Fc-(sdAb)2 subclasses containing identical tau binding domains but differing Fc region. Unmodified sdAbs and their IgG subclasses were tested for efficacy in primary cultures and in vivo microdialysis using JNPL3 tauopathy mice.

FINDINGS

Unmodified sdAbs were non-toxic, blocked tau toxicity and promoted tau clearance. However, the efficacy/safety profile of their Fc-(sdAb)2 subclasses varied greatly within and between sdAbs. For one of them, all its subtypes were non-toxic, only those with effector function cleared tau, and were more effective in vivo than unmodified sdAb. For the other sdAb, all its subtypes were toxic in tauopathy cultures but not in wild-type cells, suggesting that bivalent binding of its tau epitope stabilizes a toxic conformation of tau, with major implications for tau pathogenesis. Likewise, its subclasses were less effective than the unmodified sdAb in clearing tau in vivo.

INTERPRETATION

These findings indicate that tau antibodies with effector function are safe and better at clearing pathological tau than effectorless antibodies, Furthermore, tau antibodies can provide a valuable insight into tau pathogenesis, and some may aggravate it.

FUNDING

Funding for these studies was provided by the National Institute of Health (R01 AG032611, R01 NS077239, RF1 NS120488, R21 AG 069475, R21 AG 058282, T32AG052909), and the NYU Alzheimer's Disease Center Pilot Grant Program (via P30 AG008051).

Tau Ubiquitination in Alzheimer's Disease

Paired helical filaments (PHFs) from the Alzheimer's disease (AD) brain are highly ubiquitinated and ubiquitination likely plays a vital role in tau filament formation. Whether tau ubiquitination is the causality or consequence of the disease in AD remains elusive. The following questions are worth considering: What does the extent of tau ubiquitination contribute to tau pathology in AD? Does tau ubiquitination influence aggregation or spreading during disease progression? In addition, tau is polyubiquitinated in nerve growth factor-induced PC12 cells and participates in mitogen-activated protein kinase signaling, in addition to its microtubule stabilization function. Therefore, ubiquitination possibly mediates tau signaling under physiological conditions, but tau aggregation in the pathobiology of AD. Here, we review the advancements in tau ubiquitination and the potential therapeutic effects of targeting tau ubiquitination to alleviate tau pathology in AD.

To target Tau pathologies, we must embrace and reconstruct their complexities

The accumulation of hyperphosphorylated fibrillar Tau aggregates in the brain is one of the defining hallmarks of Tauopathy diseases, including Alzheimer's disease. However, the primary events or molecules responsible for initiation of the pathological Tau aggregation and spreading remain unknown. The discovery of heparin as an effective inducer of Tau aggregation in vitro was instrumental to enabling different lines of research into the role of Tau aggregation in the pathogenesis of Tauopathies. However, recent proteomics and cryogenic electron microscopy (cryo-EM) studies have revealed that heparin-induced Tau fibrils generated in vitro do not reproduce the biochemical and ultrastructural properties of disease-associated brain-derived Tau fibrils. These observations demand that we reassess our current approaches for investigating the mechanisms underpinning Tau aggregation and pathology formation. Our review article presents an up-to-date survey and analyses of 1) the evolution of our understanding of the interactions between Tau and heparin, 2) the various structural and mechanistic models of the heparin-induced Tau aggregation, 3) the similarities and differences between brain-derived and heparin-induced Tau fibrils; and 4) emerging concepts on the biochemical and structural determinants underpinning Tau pathological heterogeneity in Tauopathies. Our analyses identify specific knowledge gaps and call for 1) embracing the complexities of Tau pathologies; 2) reassessment of current approaches to investigate, model and reproduce pathological Tau aggregation as it occurs in the brain; 3) more research towards a better understanding of the naturally-occurring cofactor molecules that are associated with Tau brain pathology initiation and propagation; and 4) developing improved approaches for in vitro production of the Tau aggregates and fibrils that recapitulate and/or amplify the biochemical and structural complexity and diversity of pathological Tau in Tauopathies. This will result in better and more relevant tools, assays, and mechanistic models, which could significantly improve translational research and the development of drugs and antibodies that have higher chances for success in the clinic.

Dynamics of Internalization and Intracellular Interaction of Tau Antibodies and Human Pathological Tau Protein in a Human Neuron-Like Model

We and others have shown in various in vivo, ex vivo and cell culture models that several tau antibodies interact with pathological tau within neurons. To further clarify this interaction in a dynamic human model, we differentiated SH-SY5Y cells with retinoic acid and BDNF to create a neuron-like model. Therein, tau antibodies were primarily taken up by receptor-mediated endocytosis, and prevented toxicity of human brain-derived paired helical filament-enriched tau (PHF). Subsequently, we monitored in real-time the interaction of antibodies and PHF within endocytic cellular compartments. Cells were pre-treated with fluorescently-tagged PHF and then incubated with tau antibodies, 4E6, 6B2, or non-specific isotype control IgG1 labeled with a pH sensitive dye. The uptake and binding of the efficacious antibody, 4E6, to PHF occurred mainly within the soma, whereas the ineffective antibody, 6B2, and ineffective control IgG1, were visualized via the processes and showed limited colocalization with PHF within this period. In summary, we have developed a neuron-like model that clarifies the early intracellular dynamics of the interaction of tau antibodies with pathological tau, and identifies features associated with efficacy. Since the model is entirely human, it is suitable to verify the therapeutic potential of humanized antibodies prior to extensive clinical trials.

Comparison of regional flortaucipir PET with quantitative tau immunohistochemistry in three subjects with Alzheimer's disease pathology: a clinicopathological study

Background

The objective of this study was to make a quantitative comparison of flortaucipir PET retention with pathological tau and β-amyloid across a range of brain regions at autopsy.

Methods

Patients with dementia (two with clinical diagnosis of AD, one undetermined), nearing the end of life, underwent 20-min PET, beginning 80 min after an injection of ~370 mBq flortaucipir [¹⁸F]. Neocortical, basal ganglia, and limbic tissue samples were obtained bilaterally from 19 regions at autopsy and subject-specific PET regions of interest corresponding to the 19 sampled target tissue regions in each hemisphere were hand drawn on the PET images. SUVr values were calculated for each region using a cerebellar reference region. Abnormally phosphorylated tau (Ptau) and amyloid-β (Aβ) tissue concentrations were measured for each tissue region with an antibody capture assay (Histelide) using AT8 and H31L21 antibodies respectively.

Results

The imaging-to-autopsy interval ranged from 4–29 days. All three subjects had intermediate to high levels of AD neuropathologic change at autopsy. Mean cortical SUVr averaged across all three subjects correlated significantly with the Ptau immunoassay (Pearson r = 0.81; p < 0.0001). When Ptau and Aβ_1-42 were both included in the model, the Ptau correlation with flortaucipir SUVr was preserved but there was no correlation of Aβ_1-42 with flortaucipir. There was also a modest correlation between limbic (hippocampal/entorhinal and amygdala) flortaucipir SUVr and Ptau (Pearson r = 0.52; p < 0.080). There was no significant correlation between SUVr and Ptau in basal ganglia.

Conclusions

The results of this pilot study support a quantitative relationship between cortical flortaucipir SUVr values and quantitative measures of Ptau at autopsy. Additional research including more cases is needed to confirm the generalizability of these results.

Trial registration, NIH Clinicaltrials.gov NCT # 02516046. Registered August 27, 2015. https://clinicaltrials.gov/ct2/show/NCT02516046?term=02516046&draw=2&rank=1

Reconsideration of Amyloid Hypothesis and Tau Hypothesis in Alzheimer's Disease

The so-called amyloid hypothesis, that the accumulation and deposition of oligomeric or fibrillar amyloid β (Aβ) peptide is the primary cause of Alzheimer's disease (AD), has been the mainstream concept underlying AD research for over 20 years. However, all attempts to develop Aβ-targeting drugs to treat AD have ended in failure. Here, we review recent findings indicating that the main factor underlying the development and progression of AD is tau, not Aβ, and we describe the deficiencies of the amyloid hypothesis that have supported the emergence of this idea.

Beta-amyloid 1-42 monomers, but not oligomers, produce PHF-like conformation of Tau protein

The mechanistic relationship between amyloid β1-42 (Aβ1-42) and the alteration of Tau protein are debated. We investigated the effect of Aβ1-42 monomers and oligomers on Tau, using mice expressing wild-type human Tau that do not spontaneously develop Tau pathology. After intraventricular injection of Aβ1-42, mice were sacrificed after 3 h or 4 days. The short-lasting treatment with Aβ monomers, but not oligomers, showed a conformational PHF-like change of Tau, together with hyperphosphorylation. The same treatment induced increase in concentration of GSK3 and MAP kinases. The inhibition of the kinases rescued the Tau changes. Aβ monomers increased the levels of total Tau, through the inhibition of proteasomal degradation. Aβ oligomers reproduced all the aforementioned alterations only after 4 days of treatment. It is known that Aβ1-42 monomers foster synaptic activity. Our results suggest that Aβ monomers physiologically favor Tau activity and dendritic sprouting, whereas their excess causes Tau pathology. Moreover, our study indicates that anti-Aβ therapies should be targeted to Aβ1-42 monomers too.

STED imaging of tau filaments in Alzheimer's disease cortical grey matter

Alzheimer's disease (AD) involves the propagation of filaments of tau protein throughout the cerebral cortex. Imaging tau filaments and oligomers in human brain at high resolution would help contribute insight into the mechanism and progression of tauopathic diseases. STED microscopy is a nano-scale imaging technique and we aimed to test the abilities of this method for resolving tau structures within human brain. Using autopsied 50μm AD brain sections, we demonstrate that STED microscopy can resolve immunolabelled tau filaments at 77nm resolution. Ribbon-like tau filaments imaged by STED appeared smooth along their axis with limited axial undulations. STED also resolved 70-80nm wide tau puncta. Of the fluorophores tested, STAR635p was optimal for STED imaging in this tissue. This was in part due to brain tissue autofluorescence within the lower wavelength ranges (488-590nm). Further, the stability and minimal photobleaching of STAR635p allowed STED z-stacks of neurons packed with tau filaments (neurofibrillary tangles) to be collated. There was no loss of x-y image resolution of individual tau filaments through the 20μm z-stack. This demonstrates that STED can contribute to nano-scale analysis and characterisation of pathologies within banked human autopsied brain tissue. Resolving tau structures at this level of resolution provides promising avenues for understanding mechanisms of pathology propagation in the different tauopathies as well as illuminating what contributes to disease heterogeneity.

Microtubule-associated protein tau in bovine retinal photoreceptor rod outer segments: comparison with brain tau

Recent studies have suggested a possible involvement of abnormal tau in some retinal degenerative diseases. The common view in these studies is that these retinal diseases share the mechanism of tau-mediated degenerative diseases in brain and that information about these brain diseases may be directly applied to explain these retinal diseases. Here we collectively examine this view by revealing three basic characteristics of tau in the rod outer segment (ROS) of bovine retinal photoreceptors, i.e., its isoforms, its phosphorylation mode and its interaction with microtubules, and by comparing them with those of brain tau. We find that ROS contains at least four isoforms: three are identical to those in brain and one is unique in ROS. All ROS isoforms, like brain isoforms, are modified with multiple phosphate molecules; however, ROS isoforms show their own specific phosphorylation pattern, and these phosphorylation patterns appear not to be identical to those of brain tau. Interestingly, some ROS isoforms, under the normal conditions, are phosphorylated at the sites identical to those in Alzheimer's patient isoforms. Surprisingly, a large portion of ROS isoforms tightly associates with a membranous component(s) other than microtubules, and this association is independent of their phosphorylation states. These observations strongly suggest that tau plays various roles in ROS and that some of these functions may not be comparable to those of brain tau. We believe that knowledge about tau in the entire retinal network and/or its individual cells are also essential for elucidation of tau-mediated retinal diseases, if any.