Thiamine as a Possible Neuroprotective Strategy in Neonatal Hypoxic-Ischemic Encephalopathy

A Systematic Review of Human Paenibacillus Infections and Comparison of Adult and Pediatric Cases

BACKGROUND

Neonatal infections due to Paenibacillus species have increasingly been reported over the last few years.

METHODS

We performed a structured literature review of human Paenibacillus infections in pediatric and adult patients to compare the epidemiology of infections between these distinct patient populations.

RESULTS

Forty reports describing 177 infections were included. Two additional cases were brought to our attention by colleagues. There were 38 Paenibacillus infections occurring in adults caused by 23 species. The clinical presentations of infections were quite variable. In contrast, infections in infants were caused primarily by Paenibacillus thiaminolyticus (112/141, 79%). All the infants with Paenibacillus infection presented with sepsis syndrome or meningitis, often complicated by extensive cerebral destruction and hydrocephalus. Outcomes were commonly poor with 17% (24/141) mortality. Cystic encephalomalacia due to brain destruction was common in both Ugandan and American infant cases and 92/141 (65%) required surgical management of hydrocephalus following their infection.

CONCLUSIONS

Paenibacillus species seem to cause a clinical syndrome in infants characterized by brain abscesses, hydrocephalus and death. This contrasts with infection in adults, which is sporadic with only rare involvement of the central nervous system and very few deaths.

Thiamine: An indispensable regulator of paediatric neuro-cardiovascular health and diseases

The sustainable developmental goals emphasize good health, reduction in preventable neonatal and under-five mortalities, and attaining zero hunger. However, South Asian countries report a higher incidence of neonatal and under-five mortalities when compared to the Western world, many of which are attributed to maternal and perinatal micronutrient deficiencies. Isolated nutrient deficiency in the absence of calorie deficit poses a diagnostic challenge since such deficiencies present with acute multisystemic and enigmatic manifestations. Thiamine (vitamin B1) is a micronutrient of prime importance which exerts indispensable roles in energy metabolism. Deficiency of thiamine can lead to catastrophic consequences. This review provides insight into the biochemical actions of thiamine in energy metabolism, the compromised aerobic metabolism resulting from thiamine deficiency, and the crucial role of thiamine in the proper functioning of the nervous, cardiovascular, and immune systems. The review also explores the acute life-threatening consequences of thiamine deficiencies in neonates and infants and the speculative role of thiamine in other pathologies like encephalopathy, sepsis, and autism spectrum disorders. However, routine assessment of thiamine in pregnant women and neonates is yet to be implemented, due to the lack of affordable and automated diagnostic techniques, and the cost-intensive nature of mass spectrometry-based quantification.

CONCLUSION

Physicians are recommended to have a low threshold for suspecting thiamine deficiency especially in vulnerable populations. Laboratory diagnosis of thiamine deficiency needs to be implemented as a standard of care, especially in endemic regions. Further, public health policies on food fortification, mandatory supplementation, and surveillance are imperative to eliminate thiamine deficiency-induced health hazards.

WHAT IS KNOWN

• South Asian countries report a higher incidence of neonatal and under-five mortalities, many of which are attributed to maternal and perinatal micronutrient deficiencies. • Preventable causes of neonatal/ infantile deaths include birth factors (low birth weight, birth asphyxia), infectious diseases (pneumonia, diarrhoea, tetanus, tuberculosis, measles, diphtheria, malaria, acute infections), deficiency diseases and genetic diseases (vitamin & mineral deficiencies, IEMs, congenital heart disease, unexplained PPHN, SIDS etc).

WHAT IS NEW

• Acute thiamine deficiency presenting as multisystemic syndromes, has unfortunately been a long standing unresolved public health concern. However, accessible surveillance and diagnostic strategies remain elusive in most clinical settings. • Despite decades of reports and emerging guidelines, diagnosis of thiamine deficiency is often missed and policy mandates at national level are yet to be implemented even in endemic countries. • This review provides a comprehensive summary of the biochemical role of thiamine, its key functions and effects on major organ systems, the diagnostic gap, the enigmatic presentation of acute thiamine deficiency, the plausible role of thiamine in other pathologies and the preventive measures at individual and community level.

Small Molecules, α-Synuclein Pathology, and the Search for Effective Treatments in Parkinson's Disease

Parkinson's disease (PD) is a progressive age-related neurodegenerative disorder affecting millions of people worldwide. Essentially, it is characterised by selective degeneration of dopamine neurons of the nigro-striatal pathway and intraneuronal aggregation of misfolded α-synuclein with formation of Lewy bodies and Lewy neurites. Moreover, specific small molecules of intermediary metabolism may have a definite pathophysiological role in PD. These include dopamine, levodopa, reduced glutathione, glutathione disulfide/oxidised glutathione, and the micronutrients thiamine and ß-Hydroxybutyrate. Recent research indicates that these small molecules can interact with α-synuclein and regulate its folding and potential aggregation. In this review, we discuss the current knowledge on interactions between α-synuclein and both the small molecules of intermediary metabolism in the brain relevant to PD, and many other natural and synthetic small molecules that regulate α-synuclein aggregation. Additionally, we analyse some of the relevant molecular mechanisms potentially involved. A better understanding of these interactions may have relevance for the development of rational future therapies. In particular, our observations suggest that the micronutrients ß-Hydroxybutyrate and thiamine might have a synergistic therapeutic role in halting or reversing the progression of PD and other neuronal α-synuclein disorders.

Histone modifications in hypoxic ischemic encephalopathy: Implications for therapeutic interventions

Hypoxic-ischemic encephalopathy (HIE) is a brain injury induced by many causes of cerebral tissue ischemia and hypoxia. Although HIE may occur at many ages, its impact on the neonatal brain is greater because it occurs during the formative stage. Recent research suggests that histone modifications may occur in the human brain in response to acute stress events, resulting in transcriptional changes and HIE development. Because there are no safe and effective therapies for HIE, researchers have focused on HIE treatments that target histone modifications. In this review, four main histone modifications are explored, histone methylation, acetylation, phosphorylation, and crotonylation, as well as their relevance to HIE. The efficacy of histone deacetylase inhibitors in the treatment of HIE is also explored. In conclusion, targeting histone modifications may be a novel strategy for elucidating the mechanism of HIE, as well as a novel approach to HIE treatment.

Role of mitochondria in neonatal hypoxic-ischemic encephalopathy

Neonatal hypoxic-ischemic encephalopathy, an important cause of death as well as long-term disability in survivors, is caused by oxygen and glucose deprivation, and limited blood flow. Following hypoxic-ischemic injury in the neonatal brain, three main biochemical damages (excitotoxicity, oxidative stress, and exacerbated inflammation) are triggered. Mitochondria are involved in all three cascades. Mitochondria are the nexus of metabolic pathways to offer most of the energy that our body needs. Hypoxic-ischemic injury affects the characteristics of mitochondria, including dynamics, permeability, and ATP production, which also feed back into the process of neonatal hypoxic-ischemic encephalopathy. Mitochondria can be a cellular hub in inflammation, which is another main response of the injured neonatal brain. Some treatments for neonatal hypoxic-ischemic encephalopathy affect the function of mitochondria or target mitochondria, including therapeutic hypothermia and erythropoietin. This review presents the main roles of mitochondria in neonatal hypoxic-ischemic encephalopathy and discusses some potential treatments directed at mitochondria, which may foster the development of new therapeutic strategies for this encephalopathy.

Pharmacological Doses of Thiamine Benefit Patients with the Charcot-Marie-Tooth Neuropathy by Changing Thiamine Diphosphate Levels and Affecting Regulation of Thiamine-Dependent Enzymes

Charcot-Marie-Tooth (CMT) neuropathy is a polygenic disorder of peripheral nerves with no effective cure. Thiamine (vitamin B1) is a neurotropic compound that improves neuropathies. Our pilot study characterizes therapeutic potential of daily oral administration of thiamine (100 mg) in CMT neuropathy and its molecular mechanisms. The patient hand grip strength was determined before and after thiamine administration along with the blood levels of the thiamine coenzyme form (thiamine diphosphate, ThDP), activities of endogenous holo-transketolase (without ThDP in the assay medium) and total transketolase (with ThDP in the assay medium), and transketolase activation by ThDP [1 - (holo-transketolase/total transketolase),%], corresponding to the fraction of ThDP-free apo-transketolase. Single cases of administration of sulbutiamine (200 mg) or benfotiamine (150 mg) reveal their effects on the assayed parameters within those of thiamine. Administration of thiamine or its pharmacological forms increased the hand grip strength in the CMT patients. Comparison of the thiamin status in patients with different forms of CMT disease to that of control subjects without diagnosed pathologies revealed no significant differences in the average levels of ThDP, holo-transketolase, or relative content of holo and apo forms of transketolase. However, the regulation of transketolase by thiamine/ThDP differed in the control and CMT groups: in the assay, ThDP activated transketolase from the control individuals, but not from CMT patients. Thiamine administration paradoxically decreased endogenous holo-transketolase in CMT patients; this effect was not observed in the control group. Correlation analysis revealed sex-specific differences in the relationship between the parameters of thiamine status in both the control subjects and patients with the CMT disease. Thus, our findings link physiological benefits of thiamine administration in CMT patients to changes in their thiamine status, in particular, the blood levels of ThDP and transketolase regulation.

Ameliorative effects of thiamin on learning behavior and memory dysfunction in a rat model of hypothyroidism: implication of oxidative stress and acetylcholinesterase

Hypothyroidism causes learning and memory impairment. Considering the neuroprotective properties of thiamine (Vitamin B1), this study was conducted to investigate the effects of thiamine on acetylcholinesterase (AChE) activity, oxidative damage, and memory deficits in hypothyroid rats.In this study, 50 rats (21 days old) were randomly divided into 5 groups and treated with propylthiouracil (0.05% in drinking water) and thiamine (50, 100, and 200 mg/kg, oral) for 7 weeks. Following that, Morris water maze (MWM) and passive avoidance (PA) tests were performed. Finally, oxidative stress indicators and AChE activity were measured in brain tissue.Treatment of hypothyroid rats with thiamine, especially at 100 and 200 mg/kg, alleviated the ability to remember the location of the platform as reflected by less time spent and distance to reach the platform, during the MWM test (P < 0.05 to P < 0.001). In the PA test, the latency to enter the dark chamber and light stay time were increased in rats who received thiamine compared to the hypothyroid group (P < 0.05 to P < 0.001). In addition, thiamine increased the levels of total thiol groups and superoxide dismutase while decreasing the levels of malondialdehyde and AChE.Our results suggest that thiamine supplementation could effectively improve memory loss in a rat model of hypothyroidism. The positive effects of thiamin on the learning and memory of hypothyroid rats may be due to amelioration of redox hemostasis and cholinergic disturbance.

Human Paenibacillus Infections: A Systematic Review with Comparison of Adult and Infant Cases

Neonatal infections due to Paenibacillus species have increasingly been reported over the last few years. We performed a structured literature review of human Paenibacillus infections in infants and adults to compare the epidemiology of infections between these distinct patient populations. Thirty-nine reports describing 176 infections met our inclusion criteria and were included. There were 37 Paenibacillus infections occurring in adults caused by 23 species. The clinical presentations of infections were quite variable. In contrast, infections in infants were caused by only 3 species: P. thiaminolyticus (112/139, 80%), P. alvei (2/139, 1%) and P. dendritiformis (2/139, 1%). All of the infants with Paenibacillus infection presented with a sepsis syndrome or meningitis, often complicated by extensive cerebral destruction and hydrocephalus. Outcomes were commonly poor with 17% (24/139) mortality. Cystic encephalomalacia due to brain destruction was common in both Ugandan and American cases and 92/139 (66%) required surgical management of hydrocephalus following their infection. Paenibacillus infections are likely underappreciated in infants and effective treatments are urgently needed.

A narrative review on treatment strategies for neonatal hypoxic ischemic encephalopathy

Background and Objective

Hypoxic-ischemic encephalopathy (HIE) is a leading cause of death and disability worldwide. Therapeutic hypothermia (TH) represents a significant achievement in the translation of scientific research to clinical application, but it is currently the only neuroprotective treatment for HIE. This review aims to revisit the use of TH for HIE and its longitudinal impact on patient outcomes to readers new to the field of HIE. We discuss how emerging therapies address the broader pathophysiology of injury progression in the neonatal brain days to years after HIE.

Methods

We included full articles and book chapters published in English on PubMed with references to "hypoxic ischemic encephalopathy", "birth asphyxia", "therapeutic hypothermia", or "neonatal encephalopathy". We limited our review to outcomes on term infants and to new therapeutics that are in the second phase of clinical trials.

Key Content and Findings

Despite the use of TH for HIE, mortality remains high. Analysis of longitudinal studies reveals a high incidence of ongoing disability even with the implementation of TH. New therapeutics addressing the secondary phase and the less understood tertiary phase of brain injury are in clinical trials as adjunctive treatments to TH to support additional neurological repair and regeneration.

Conclusions

TH successfully improves outcomes after HIE, and it continues to be optimized. Larger studies are needed to understand its use in mild cases of HIE and if certain factors, such as sex, affect long term outcomes. TH primarily acts in the initial phases of injury, while new pharmaceutical therapies target additional injury pathways into the tertiary phases of injury. This may allow for more effective approaches to treatment and improvement of long-term functional outcomes after HIE.

Thiamine pyrophosphokinase deficiency: report of two Chinese cases and a literature review

Thiamine pyrophosphokinase (TPK) deficiency, is a rare autosomal recessive disorder of congenital metabolic dysfunction caused by variants in the TPK1 gene. TPK1 variants can lead to thiamine metabolic pathway obstacles, and its clinical manifestations are highly variable. We describe two cases of TPK deficiency with completely different phenotypes and different therapeutic effects, and 26 cases of previously reported were retrospectively reviewed to improve our understanding of the clinical and genetic features of the disease. Patients with TPK deficiency present with ataxia, dysarthria, dystonia, disturbance of consciousness, seizures, and other nervous system dysfunction. Different gene variant sites may lead to different clinical features and therapeutic effects. Gene analysis is important for the diagnosis of TPK deficiency caused by TPK1 variants, and thiamine supplementation has been the mainstay of treatment for TPK deficiency to date.

Analysis of Inequalities and Inequities in Maternal Mortality in Chocó, Colombia

We used a mixed design study to analyze the inequalities and inequities in Maternal Mortality (MM) for Chocó (Colombia) between 2010-2018. The quantitative component consisted of an analytical ecological design, where proportions, ratios, measures of central tendency and rates ratios, rate difference, Gini and concentration indices were calculated to measure inequalities. The qualitative component had a phenomenological and interpretive approach. One hundred thirty-one women died in Choco between 2010-2018. The Maternal Mortality Ratio was 224/100.000 live births. The Gini coefficient was 0.35, indicating inequality in the distribution of the number of MM with respect to live births. The health service offers have been concentrated in the private sector in urban areas (77%). The exercise of midwifery has played an important role in maternal and perinatal care processes, especially in territories where the State has been absent. Nevertheless, it occurs in complex circumstances such as the armed conflict, lack of transportation routes, and income deficits, affecting the timelines and care quality for these vulnerable groups. MM in Chocó has been a consequence of deficiencies in the health system and weaknesses in its infrastructure (absence of a high level of maternal-perinatal care). This is in addition to the territory's geographical characteristics, which increase vulnerability and health risks for women and their newborns. In Colombia, as well as in other countries, many maternal and newborn deaths are preventable because their causes are due to social injustices.

Acute Encephalopathy Caused by Inherited Metabolic Diseases

Acute encephalopathy is a critical medical condition that typically affects previously healthy children and young adults and often results in death or severe neurological sequelae. Inherited metabolic diseases that can cause acute encephalopathy include urea cycle disorders, amino acid metabolism disorders, organic acid metabolism disorders, fatty acid metabolism disorders, mutations in the thiamine-transporter gene, and mitochondrial diseases. Although each inherited metabolic disease is rare, its overall incidence is reported as 1 in 800-2500 patients. This narrative review presents the common inherited metabolic diseases that cause acute encephalopathy. Since diagnosing inherited metabolic diseases requires specific testing, early metabolic/metanolic screening tests are required when an inherited metabolic disease is suspected. We also describe the symptoms and history associated with suspected inherited metabolic diseases, the various tests that should be conducted in case of suspicion, and treatment according to the disease group. Recent advancements made in the understanding of some of the inherited metabolic diseases that cause acute encephalopathy are also highlighted. Acute encephalopathy due to inherited metabolic diseases can have numerous different causes, and recognition of the possibility of an inherited metabolic disease as early as possible, obtaining appropriate specimens, and proceeding with testing and treatment in parallel are crucial in the management of these diseases.

Effect of thiamine pyrophosphate on the characteristics of farrowing and piglet vitality

Asphyxia is considered the main non-infectious cause of prepartum mortality in swine, as well as an important factor that negatively affects neonatal vitality and can trigger physiological and metabolic disorders. Hence, the search for pharmacological protocols to reduce the harmful effects of asphyxia is a key area of research. Recent observations show that administering thiamine pyrophosphate (TPP) prior to a hypoxic event in certain species (rabbits, rats) has a neuroprotector effect that preserves energy metabolism under hypoxic conditions. Given this, the objective of this study was to evaluate a prophylactic protocol in high- and low-vitality neonate piglets based on TPP's effect on physiological and metabolic responses, body temperature, and weight. A total of 149 piglets born from 15 multiparous sows were used. The dams were randomly divided into two groups: control (NaCl 0.9%) and TPP (25 ml of TTP) administered 24 and 12 h before the expected farrowing date. The following reproductive variables of the sows were recorded: duration of farrowing, total number of piglets born per litter, number of liveborn piglets per litter, number of stillbirths and mummified fetuses at birth, and number of live piglets at weaning. In addition, the expulsion interval and vitality of all neonates were evaluated, body temperatures were recorded at ten intervals, and physiological profiles (blood gases, electrolytes, glucose) were registered for each neonate. Results show that the TPP-treated sows had shorter farrowing duration (P = 0.0060) and higher percentage of high-vitality neonates (60%). Moreover, their offspring exhibited greater vitality, fewer imbalances in their physiological and metabolic profiles, and greater weight gain at weaning (P < 0.0001). Findings suggest that administering TPP exerts a protective effect when hypoxic events occur, though this differs from results obtained with rat pups, where applying TPP after such events did not provide protection from asphyxia-induced damage. These differences may be due to the moment at which TPP was applied. The application time we selected was distinct from the procedure followed with rats because it was based on a dataset that describes the influence of administering TPP as a prophylactic treatment before a hypoxic event. Prophylactic administration of TPP to sows at the end of gestation exerted a neuroprotective effect on neonatal vitality and gas exchanges and energy metabolism in the offspring that were reflected in the greater weekly weight gain in those piglets.

New Therapeutic Paradigms in Neonatal Hypoxic-Ischemic Encephalopathy

In neonates with hypoxic-ischemic encephalopathy (HIE), neuroprotection mediated by therapeutic hypothermia (TH) is the standard of care in developed nations; however TH may be not beneficial or contraindicated in developing world. Moreover, in most of the clinical trials, hypothermic neuroprotection was incomplete because many infants still die or suffer significant neurological sequelae. Therefore, finding innovative, neuroprotective compounds for this encephalopathy represents an important and urgent need. In reference to the recent review by Zhou , ACS Chem. Neurosci. 2023 14, 1-9, in this viewpoint, we discuss the therapeutic role of ketone bodies and thiamine in neonatal HIE, their possible synergistic effect, and how these micronutrients may provide additive neuroprotection to TH and improve safer and effective treatment strategies also helpful in low-middle-income countries.

Ifosfamide-induced Encephalopathy With Rapid Response to Thiamine: A Pediatric Case

Ifosfamide is an important chemotherapeutic agent used in the therapeutic protocols of many malignant tumors. Central nervous system toxicity of ifosfamide manifests with encephalopathy in 10% to 30% of patients treated with ifosfamide. Thiamine and methylene blue have been reported beneficial in the treatment and prevention of ifosfamide-induced encephalopathy (IIE). We describe an episode of encephalopathy developed at the third cycle of ifosfamide treatment in a child with Ewing sarcoma. With the administration of thiamin, the encephalopathy resolved and no episode was noted during subsequent courses of ifosfamide. Previous use of cisplatin, concomitant use of opioids, low levels of serum albumin and hemoglobin, and elevated levels of serum creatinine are potential risk factors for IIE. The current case illustrates the possibility of IIE even in the absence of such additional risk factors, treated successfully with thiamin and draws attention to the need for close neurological monitorization of patients treated with ifosfamide.